Llq Pain
Left lower quadrant pain is discomfort localized to the lower left abdomen, commonly associated with diverticulitis, ovarian pathology, or sigmoid colon disorders.
Left Lower Quadrant (LLQ) Pain
Left lower quadrant (LLQ) pain refers to pain localized to the area of the abdomen bounded superiorly by the transumbilical (horizontal) plane, medially by the midline (linea alba), and inferiorly/laterally by the left inguinal ligament and iliac crest. It encompasses a broad differential of gastrointestinal, urological, gynaecological, vascular, and musculoskeletal pathologies that either originate from or are referred to this region.
Understanding LLQ pain requires a systematic approach: identify the organ system responsible, determine whether the process is acute or chronic, and decide whether it constitutes a surgical emergency.
2. Epidemiology and Risk Factors
LLQ pain is one of the most common presentations to the Emergency Department. The relative frequency of causes varies by age, sex, and ethnicity:
| Factor | Key Epidemiological Points |
|---|---|
| Age | Young adults → ovarian pathology, ectopic pregnancy, testicular torsion; Middle-aged/elderly → diverticulitis, colorectal cancer, ischaemic colitis |
| Sex | Female patients have a wider differential (gynaecological causes); Male patients → consider sigmoid diverticulitis, hernias, testicular pathology |
| Ethnicity/Region | In Western populations, diverticulosis is predominantly left-sided (sigmoid). In Asian populations (including Hong Kong), left-sided diverticulosis is still the most common, but there is a significantly higher proportion of right-sided (caecal) diverticulosis [1][2]. This is critical because right-sided diverticulitis in Asia is often confused with acute appendicitis. |
| Prevalence of diverticulosis | Increases with age: ~5% at age 40, ~65% by age 85. Mean age of diagnosis of acute diverticulitis = 63 years [1]. |
| Colorectal cancer | Incidence 74.1/100k/y in HK (1st in all cancers + males, 2nd in females); rectosigmoid is the most common site (70% left-sided tumours) [3]. |
| Condition | Risk Factors |
|---|---|
| Sigmoid diverticulitis | Obesity, low-fibre diet, high fat/red meat, decreased physical activity, smoking, NSAIDs, steroids, opiates [1][2], age > 40, connective tissue disease (e.g. Marfan syndrome) |
| Colorectal cancer | Age > 50, family history (FAP, HNPCC), IBD-related colitis, prior polyps, red/processed meat, obesity, DM, smoking, alcohol [3] |
| Ischaemic colitis | Elderly female (90% > 60 years); cardiac disease, AF, atherosclerosis, vasopressors, hypovolaemia [4] |
| Sigmoid volvulus | Older adult males, mean age 70; long redundant sigmoid, chronic constipation, Hirschsprung disease, neuropsychiatric disease (institutionalized patients) [5] |
| Ectopic pregnancy | Previous ectopic, PID, tubal surgery, IUD use, assisted reproduction |
| Ovarian torsion | Ovarian cyst/mass, pregnancy, ovarian hyperstimulation |
| Ureteric colic | Male predominance, age 40-60; dehydration, high oxalate diet, low fluid intake, family history [6] |
| Inguinal/femoral hernia | Male sex, ageing, obesity, chronic cough, chronic constipation, smoking, prior hernia repair [7] |
High Yield: In Hong Kong, always think about sigmoid diverticulitis in an elderly patient with LLQ pain, fever, and leucocytosis — this is the "left-sided appendicitis" of the Western world [1][2].
3. Anatomy and Function
Understanding LLQ pain requires knowledge of what structures live in or refer pain to the left lower quadrant.
| Structure | Key Anatomical Points |
|---|---|
| Descending colon | Retroperitoneal (secondarily); transitions to the sigmoid colon at the pelvic brim |
| Sigmoid colon | Intraperitoneal, has its own mesentery (mesosigmoid); narrowest calibre of the colon → highest intraluminal pressure by Laplace's law → most common site for diverticulosis in Western populations [2][8] |
| Left ureter | Retroperitoneal; crosses the pelvic brim near the bifurcation of the left common iliac artery (a site of ureteric narrowing where stones lodge) [6] |
| Left ovary and fallopian tube (females) | Intraperitoneal; attached to broad ligament via mesovarium and mesosalpinx |
| Left spermatic cord (males) | Passes through the inguinal canal |
| Left iliac vessels | External iliac artery and vein |
| Sigmoid mesocolon | Contains superior rectal and sigmoid arteries (branches of IMA) |
| Psoas major and iliacus muscles | Retroperitoneal; relevant for psoas abscess and referred back/hip pain |
This is crucial for understanding ischaemic colitis and diverticular bleeding:
- The inferior mesenteric artery (IMA) supplies the descending colon, sigmoid colon, and upper rectum via:
- Left colic artery
- Sigmoid arteries (2-4 branches)
- Superior rectal artery
- The marginal artery of Drummond connects the SMA territory with the IMA territory at the splenic flexure
- Watershed areas (vulnerable to ischaemia):
These watershed zones explain why ischaemic colitis classically affects the splenic flexure and rectosigmoid junction — they sit at the boundary between two major arterial territories, so they get the least reliable perfusion.
- Diverticula develop at well-defined points of weakness where the vasa recta penetrate the circular muscle layer [2][8]
- The colon only has an incomplete outer longitudinal muscle layer (the three taeniae coli), so between the taeniae the wall is thinner
- The rectum is never affected because the outer smooth muscle encompasses the full circumference (there are no taeniae coli in the rectum) [2]
- Right-sided diverticula in Asia are true diverticula (contain all layers of the bowel wall — congenital), whereas left-sided diverticula are false diverticula (only mucosa and submucosa protrude through the muscularis propria — acquired) [8]
Understanding why pain starts vague and then localizes is fundamental:
- Visceral pain (from stretching, distension, or ischaemia of a hollow viscus): carried by autonomic (sympathetic) afferents → poorly localized, felt at the midline because the gut is a midline structure embryologically
- Foregut (stomach to D2) → T6-T9 → epigastric
- Midgut (D2 to 2/3 transverse colon) → T9-T10 → periumbilical
- Hindgut (distal 1/3 transverse colon to upper rectum) → T11-L2 → hypogastric / suprapubic
- Somatic (parietal) pain: when inflammation reaches the parietal peritoneum, which is innervated by somatic nerves → sharp, well-localized pain to the specific quadrant
- Referred pain: pain felt at a distant site sharing the same dermatome (e.g., diaphragmatic irritation → shoulder tip pain via C3-C5 phrenic nerve)
This is why diverticulitis starts as vague lower abdominal/suprapubic discomfort (visceral, hindgut) and then localizes to the LLQ when the inflamed sigmoid irritates the overlying parietal peritoneum.
4. Etiology (Focus on Hong Kong)
The causes of LLQ pain can be organized by organ system. The lecture slides list the following as the key causes of LLQ pain [9]:
- Sigmoid diverticulitis
- Cancer of the sigmoid colon
- Torsion of ovarian cyst* (asterisk = can cause pain on left OR right side)
- Ruptured ectopic pregnancy*
- Ureteric colic*
- Inguinal/femoral hernia*
- Testicular pathology*
The asterisked (*) conditions can present on either side.
4.1 Gastrointestinal Causes
Definition and Terminology:
- Diverticulum: sac-like outpouching from a hollow viscus [2]
- Diverticulosis (coli): presence of multiple false diverticula (mucosa + submucosa protrude through muscularis propria) [2]
- Diverticular disease: symptomatic diverticulosis [2]
- Diverticulitis: inflammation of a diverticulum [2]
Pathophysiology (from first principles):
- Bowel wall weakening with ageing + increased intraluminal pressure (e.g. chronic constipation, low-fibre diet) [2]
- The sigmoid has the narrowest lumen of the colon → by Laplace's law (Wall tension = Pressure × Radius / Wall thickness), for a given pressure the wall stress is highest in the narrowest segment, and a low-fibre diet produces small, hard stools requiring greater intraluminal pressure to propel → this promotes herniation of mucosa through weak points
- Outpouching occurs at the weakest points — where vasa recta penetrate the circular muscle [2][8]
- Obstruction of the diverticular neck by a faecolith → stasis of luminal contents → bacterial overgrowth → inflammation → microperforation → pericolic inflammation/abscess [2]
- If the perforation is contained by mesentery/omentum → localized abscess (Hinchey I-II)
- If free perforation → purulent or faecal peritonitis (Hinchey III-IV) [1]
Hinchey Classification (staging of complicated diverticulitis) [1]:
| Stage | Description | Treatment Approach |
|---|---|---|
| I | Pericolic or mesenteric abscess | Conservative: antibiotics, bowel rest, monitoring |
| II | Walled-off pelvic abscess | IV antibiotics + bowel rest + image-guided drainage |
| III | Generalized purulent peritonitis | IV antibiotics + bowel rest + surgery |
| IV | Generalized faecal peritonitis | IV antibiotics + bowel rest + surgery |
Pathophysiology:
- Adenoma-carcinoma sequence (APC → KRAS → TP53 mutations over ~10-15 years)
- Left-sided tumours tend to be annular/constricting (apple-core lesion) → present with obstructive symptoms (change in bowel habit, pencil-thin stools, colicky pain)
- Right-sided tumours tend to be polypoid/fungating → present with occult bleeding and iron deficiency anaemia
- In the LLQ context, sigmoid cancer is the key concern — it can present as LLQ pain, altered bowel habit, PR bleeding, or acute large bowel obstruction
Pathophysiology [4]:
- The colon is the most vulnerable segment of the GIT to ischaemia as it receives less blood than the rest of the GIT
- Non-occlusive causes (95%) dominate — transient systemic low-flow states (e.g. heart failure, post-cardiac surgery, hypovolaemia)
- Characteristically affects watershed areas — splenic flexure (Griffiths' point) and rectosigmoid junction (Sudeck's point)
- Reperfusion injury mediates most of the mucosal damage
- Majority is transient — transmural necrosis occurs in only 15% when ischaemia is prolonged [4]
Why the left colon? The IMA territory (left colon) has fewer collateral pathways than the SMA territory (right colon). The marginal artery of Drummond may be poorly developed at the splenic flexure, and Sudeck's point relies on narrow terminal branches.
Pathophysiology [5]:
- Volvulus = torsion of a segment of the alimentary tract around its mesentery → bowel obstruction
- More common in older adult males, mean age 70 [5]
- Risk factors: long redundant sigmoid colon with narrow mesenteric attachment, chronic constipation (fecal overloading causes elongation and dilatation), Hirschsprung disease, neuropsychiatric institutionalization
- Torsion compromises the mesenteric blood supply → ischaemia → gangrene → perforation if not decompressed
Pathophysiology:
- Ulcerative colitis (UC) involves continuous, superficial inflammation starting from the rectum and extending proximally
- Left-sided colitis (proctosigmoiditis, left-sided colitis) is a common pattern → LLQ pain
- Occurs between 30-70s, no gender predominance [10]
- Risk factors: NSAIDs, family history of IBD [10]
- Protective factors: prior appendicectomy, smoking (paradoxically) [10]
- Very common: ~15% in US, up to 25% in East Asia, 3.7% in HK (Rome II criteria) [11]
- More common in younger (< 50y) and female patients [11]
- Pathophysiology is multifactorial: altered motility, visceral hypersensitivity, intestinal inflammation, serotoninergic imbalance, gut microbiota alterations, psychosocial factors [11]
- Presents with recurrent abdominal pain associated with defecation ± bloating, altered bowel habits
- LLQ is a common location because the sigmoid colon is the most motile segment
4.2.1 Left Ureteric Colic
Pathophysiology [6]:
- Kidney stone passes from the renal pelvis into the ureter → becomes lodged at sites of anatomical narrowing:
- Pelvi-ureteric junction (PUJ)
- Pelvic brim (where the ureter crosses the bifurcation of the common iliac artery)
- Vesico-ureteric junction (VUJ) (where the ureter pierces the bladder wall)
- Obstruction → acute rise in intraluminal pressure → distension of the renal pelvis/ureter → prostaglandin release → ureteric smooth muscle spasm → severe colicky loin-to-groin pain
- A distal ureteric stone (near VUJ) can present with LLQ/suprapubic pain ± urinary frequency/urgency (due to bladder irritation)
Types of stones [6]:
- Calcium oxalate/phosphate (most common ~80%)
- Uric acid
- Struvite (infection stones — magnesium ammonium phosphate)
- Cystine (rare, autosomal recessive)
4.3 Gynaecological Causes
Pathophysiology:
- Implantation of the fertilized ovum outside the uterine cavity, most commonly in the fallopian tube (ampulla > isthmus)
- As the ectopic pregnancy grows, it outgrows the tubal blood supply → rupture → intraperitoneal haemorrhage
- Presents with sudden severe unilateral lower abdominal pain + vaginal bleeding + haemodynamic instability
- Always ask about last menstrual period (LMP) and do a urine/serum β-hCG in any woman of reproductive age with lower abdominal pain — this is a life-threatening emergency
Pathophysiology:
- The ovary (± fallopian tube) twists on its vascular pedicle (infundibulopelvic ligament containing the ovarian vessels)
- Torsion → venous congestion first (venous outflow is compromised at lower pressures than arterial inflow) → oedema → eventually arterial supply compromised → ischaemia → necrosis
- Presents with sudden onset severe unilateral lower abdominal/pelvic pain, often with nausea/vomiting
- Risk factors: ovarian cyst/mass (especially dermoid cysts or cystadenomas), pregnancy
Pathophysiology:
- Ascending infection from the lower genital tract (cervix) → endometrium → fallopian tubes → peritoneum
- Usually polymicrobial: Chlamydia trachomatis, Neisseria gonorrhoeae, anaerobes, Mycoplasma genitalium
- Can cause bilateral lower abdominal pain with cervical motion tenderness ("chandelier sign"), fever, vaginal discharge
- If predominantly left-sided adnexal involvement → LLQ pain
Pathophysiology [7]:
- Inguinal hernia: protrusion of abdominal contents through the inguinal canal
- Indirect: through the deep inguinal ring (congenital — patent processus vaginalis)
- Direct: through the posterior wall of the inguinal canal (Hesselbach's triangle) — acquired weakness
- Femoral hernia: protrusion through the femoral canal (medial to the femoral vein, below the inguinal ligament)
- More common in females (wider pelvis → larger femoral canal), but still less common than inguinal hernias even in females
- Higher risk of strangulation than inguinal hernias due to the rigid boundaries of the femoral ring
- An incarcerated hernia (contents cannot be reduced) can present as acute LLQ pain with signs of bowel obstruction
- A strangulated hernia (blood supply compromised) is a surgical emergency → ischaemia → necrosis → perforation
Relevant conditions:
- Testicular torsion: twisting of the spermatic cord → venous then arterial compromise → testicular ischaemia; peak bimodal age (neonates and adolescents); presents with sudden severe testicular pain ± LLQ pain (referred via the ilioinguinal nerve and genitofemoral nerve, which share L1-L2 dermatomes with the lower abdomen)
- Epididymo-orchitis: infection (STIs in young; UTI organisms in elderly) → scrotal pain/swelling + fever; Prehn's sign positive (pain relieved by elevation of testis — distinguishes from torsion, though unreliable)
4.6.1 Abdominal Aortic Aneurysm (AAA)
- Definition: abdominal aortic diameter > 50% larger than normal (normal = 2-2.5 cm, so aneurysm ≥ 3-3.5 cm) [12]
- 97% infrarenal, 95% associated with atherosclerosis [12]
- Ruptured AAA: classical triad of severe abdominal/back pain + hypotension + pulsatile abdominal mass [12]
- While typically presents with central/back pain, a leaking AAA can cause pain radiating to the left flank/LLQ or right flank depending on rupture site
- Can mimic a variety of diseases; 30% are misdiagnosed [12]
- Psoas abscess: retroperitoneal collection within the psoas muscle, often from vertebral osteomyelitis (TB in Hong Kong) or Crohn's disease → presents with hip flexion posture, LLQ/flank pain, fever
- Rectus sheath haematoma: bleeding into the rectus sheath, often from anticoagulation or coughing → localized abdominal wall tenderness that worsens with contraction (Carnett's sign positive)
- Lumbar spine pathology: radiculopathy from disc herniation or spinal stenosis can refer pain to the LLQ [13][14]
5. Classification
LLQ pain can be classified in several ways:
| Acute (hours-days) | Chronic/Recurrent (weeks-months) |
|---|---|
| Sigmoid diverticulitis | IBS |
| Ruptured ectopic pregnancy | Colorectal cancer |
| Ovarian torsion | IBD (UC flare) |
| Ureteric colic | Chronic diverticular disease |
| Sigmoid volvulus | Endometriosis |
| Strangulated hernia | Chronic constipation |
| Ischaemic colitis |
| System | Causes |
|---|---|
| GI | Diverticulitis, CRC, ischaemic colitis, sigmoid volvulus, IBD, IBS, constipation |
| Urological | Ureteric colic, UTI, pyelonephritis |
| Gynaecological | Ectopic pregnancy, ovarian torsion, PID, endometriosis, ruptured ovarian cyst |
| Vascular | AAA (leaking/ruptured), mesenteric ischaemia |
| Abdominal wall | Inguinal/femoral hernia, rectus sheath haematoma |
| Musculoskeletal | Psoas abscess, lumbar radiculopathy |
| Mechanism | Examples |
|---|---|
| Inflammation/Infection | Diverticulitis, PID, IBD, epididymo-orchitis |
| Obstruction | Ureteric colic, sigmoid volvulus, incarcerated hernia, CRC causing LBO |
| Ischaemia | Ischaemic colitis, ovarian torsion, testicular torsion, strangulated hernia |
| Haemorrhage | Ruptured ectopic, ruptured AAA, diverticular bleed |
| Perforation | Perforated diverticulitis |
6. Clinical Features — Symptoms and Signs (with Pathophysiological Basis)
This section integrates symptoms and signs for each major cause of LLQ pain, explaining why each feature occurs.
Pain characterization [15][16]:
| Feature | Clinical Relevance |
|---|---|
| Location | LLQ → sigmoid pathology, left ovary/tube, left ureter |
| Radiation | Loin to groin → renal/ureteric colic [15]; to back → AAA, pancreatitis; shoulder tip → haemoperitoneum [15] |
| Character | Colicky (waves) → obstruction (ureteric, intestinal); Constant → inflammation (diverticulitis, PID); Tearing → vascular (AAA dissection) |
| Severity | 10/10 → renal colic, ovarian torsion, ruptured ectopic |
| Time course | Progressive → diverticulitis [15]; Catastrophic onset → ruptured AAA [15]; Colicky ± pain-free remissions → intestinal, renal, biliary colic [15] |
| Exacerbating factors | Peritonitis: increased by movement, decreased by staying still [15]; Colic: often decreased by movement [15] |
| Associated symptoms | Fever → infection/inflammation; PR bleeding → CRC, ischaemic colitis, diverticular bleed; Vaginal bleeding → ectopic; Dysuria/haematuria → UTI/stone; Altered bowel habit → CRC, IBD, IBS |
| Feature | Type | Pathophysiological Basis |
|---|---|---|
| LLQ pain (constant, progressive) | Symptom | Inflammation of sigmoid diverticulum → pericolic inflammation irritates parietal peritoneum → localized somatic pain |
| Fever | Symptom | Bacterial translocation and cytokine release from infected/inflamed diverticulum |
| Leucocytosis | Sign (lab) | Bone marrow response to infection/inflammation (neutrophilia) |
| Clinical triad: lower abdominal pain + fever + leucocytosis [2] | — | The classic presentation of acute diverticulitis |
| Change in bowel habit (constipation or diarrhoea) | Symptom | Pericolic oedema narrows the sigmoid lumen → functional partial obstruction; inflammation stimulates colonic motility → diarrhoea |
| Nausea/vomiting | Symptom | Peritoneal irritation → vagal stimulation → nausea; partial obstruction → vomiting |
| LLQ tenderness ± guarding ± rebound | Sign | Inflamed sigmoid adheres to and irritates the anterior parietal peritoneum → somatic nerve activation |
| Palpable tender mass in LLQ | Sign | Phlegmon or walled-off abscess from contained perforation |
| Painless massive PR bleeding | Symptom | Rupture of vasa recta at the neck of the diverticulum → diverticular bleeding (distinct from diverticulitis, which usually has minimal bleeding) [2] |
| Recurrent dysuria, pneumaturia, faecaluria | Symptom | Colovesical fistula (most common fistula type) — direct communication between sigmoid and bladder from chronic diverticular inflammation [2] |
Clinical Pearl
Diverticular bleeding and diverticular inflammation (diverticulitis) rarely coexist. Bleeding comes from erosion of the vasa recta at the diverticular neck, whereas diverticulitis is from obstruction and infection of the diverticular sac. If a patient has massive PR bleeding, think diverticular bleed; if they have LLQ pain + fever + leucocytosis, think diverticulitis.
| Feature | Type | Pathophysiological Basis |
|---|---|---|
| Change in bowel habit | Symptom | Annular constricting tumour narrows the sigmoid lumen → alternating constipation and diarrhoea; overflow diarrhoea around an obstructing mass |
| PR bleeding (bright red or dark red) | Symptom | Tumour neovascularization is fragile → bleeds with passage of stool |
| LLQ pain (colicky or constant) | Symptom | Partial large bowel obstruction → colicky pain; tumour invasion of serosal/parietal peritoneum → constant pain |
| Weight loss, anorexia | Symptom | Cancer cachexia (TNF-α, IL-6 driven increased catabolism and anorexia) |
| Iron deficiency anaemia | Sign | Chronic occult blood loss (more typical of right-sided CRC, but can occur in left-sided too) |
| Palpable mass on DRE or abdominal exam | Sign | Large tumour bulk |
| Acute large bowel obstruction | Complication | Complete annular obstruction → distension proximal to tumour → colicky pain, absolute constipation, vomiting (late, faeculent) |
| Feature | Type | Pathophysiological Basis |
|---|---|---|
| Sudden onset cramping abdominal pain (milder and lateral compared to mesenteric ischaemia) [4] | Symptom | Mucosal ischaemia → visceral pain; the pain is less severe than SMA occlusion (acute mesenteric ischaemia) because ischaemic colitis is usually non-occlusive and transient |
| Urgency to defecate [4] | Symptom | Ischaemic inflammation stimulates rectal/sigmoid motility |
| Mild-to-moderate rectal bleeding within 24 hours of pain onset [4] | Symptom | Mucosal ischaemia → sloughing of mucosa → haemorrhage; more common with left colonic ischaemia [4] |
| Tenderness over involved intestines [4] | Sign | Inflamed ischaemic bowel irritates parietal peritoneum |
| Leucocytosis (but fever is unusual) [4] | Sign | Systemic inflammatory response; the absence of high fever distinguishes from infective colitis |
| Metabolic acidosis, raised lactate [4] | Sign (lab) | Tissue hypoperfusion → anaerobic glycolysis → lactic acidosis |
| Thumbprinting on AXR [4] | Sign (imaging) | Submucosal haemorrhage and oedema causes scalloped indentations along the colonic wall |
| Feature | Type | Pathophysiological Basis |
|---|---|---|
| Acute onset colicky abdominal pain | Symptom | Closed-loop obstruction → distension of twisted sigmoid segment |
| Massive abdominal distension | Sign | The twisted sigmoid becomes a closed loop — gas and secretions accumulate but cannot escape proximally or distally → dramatic distension |
| Absolute constipation (obstipation) | Symptom | Complete obstruction → no passage of stool or flatus |
| Vomiting (late) | Symptom | Large bowel obstruction → vomiting is a late feature (cf. SBO where vomiting is early) because the ileocaecal valve acts as a one-way valve |
| "Coffee bean" sign on AXR | Sign (imaging) | The massively distended sigmoid loop resembles a coffee bean pointing towards the RUQ from the pelvis |
| Empty rectum on DRE | Sign | Obstruction is at the sigmoid level → nothing passes distally |
| Feature | Type | Pathophysiological Basis |
|---|---|---|
| Severe colicky loin-to-groin pain [15] | Symptom | Ureteric obstruction → peristaltic waves against the obstruction → intermittent severe pain; pain follows the dermatome of the ureter (T11-L2) from loin → iliac fossa → groin → testis/labia |
| Restlessness, inability to lie still | Symptom | Colic is often relieved by movement [15] (in contrast to peritonitis where patients lie still) — patients writhe and roll trying to find a comfortable position |
| Haematuria (macro or micro) | Symptom/Sign | Stone traumatizes the urothelium → bleeding into the urinary tract |
| Nausea and vomiting | Symptom | Renal capsular distension → vagal stimulation → nausea/vomiting (afferents from the kidney travel with sympathetic nerves sharing the coeliac plexus) |
| Dysuria, frequency, urgency | Symptom | Distal ureteric stone near the VUJ irritates the bladder trigone → mimics UTI |
| Costovertebral angle tenderness | Sign | Distension of the renal pelvis → capsular stretch → tenderness on percussion over the 12th rib posteriorly |
| Feature | Type | Pathophysiological Basis |
|---|---|---|
| Sudden severe unilateral lower abdominal pain | Symptom | Tubal rupture → peritoneal irritation by blood |
| Amenorrhoea (4-8 weeks) | Symptom | The ectopic pregnancy produces β-hCG → suppresses menstruation |
| Vaginal bleeding (often scanty, dark) | Symptom | Declining progesterone from failing ectopic → endometrial shedding (decidual cast) |
| Shoulder tip pain [15] | Symptom | Haemoperitoneum → blood tracks to subdiaphragmatic space → irritates diaphragm → referred pain via phrenic nerve (C3-C5) |
| Haemodynamic instability (tachycardia, hypotension) | Sign | Intraperitoneal haemorrhage → hypovolaemic shock |
| Cervical motion tenderness | Sign | Blood in the pouch of Douglas irritates the peritoneum around the cervix |
| Adnexal tenderness ± mass | Sign | Haematosalpinx (blood-filled fallopian tube) or pelvic haematoma |
Must Know
NEVER forget to ask about LMP and perform a pregnancy test (urine/serum β-hCG) in ANY woman of reproductive age presenting with lower abdominal pain. A missed ectopic pregnancy is one of the most common causes of malpractice litigation in emergency medicine.
| Feature | Type | Pathophysiological Basis |
|---|---|---|
| Sudden severe unilateral lower abdominal/pelvic pain | Symptom | Twisting of the ovarian pedicle → venous congestion → ischaemic pain → peritoneal irritation |
| Nausea and vomiting (prominent) | Symptom | Peritoneal irritation → vagal response; ovarian afferents travel with sympathetic nerves → nausea |
| Intermittent, waxing/waning quality | Symptom | Ovary may partially de-tort and then re-tort → intermittent episodes |
| Adnexal tenderness, palpable mass | Sign | Congested, oedematous ovary ± pre-existing cyst |
| Low-grade fever (if necrosis) | Sign | Tissue necrosis → inflammatory cytokine release |
| Feature | Type | Pathophysiological Basis |
|---|---|---|
| Groin lump (may be reducible or irreducible) | Sign | Protrusion of peritoneal contents through the inguinal or femoral canal |
| LLQ/groin pain (constant if incarcerated) | Symptom | Incarceration → distension of herniated bowel loop → visceral pain; strangulation → ischaemic pain |
| Features of bowel obstruction (vomiting, distension, constipation) | Symptom | Incarcerated bowel loop → luminal obstruction |
| Tenderness, erythema over hernia site | Sign | Strangulation → inflammation and ischaemia of contents → overlying skin changes |
| Absent cough impulse | Sign | Contents are trapped (incarcerated) → no movement with cough |
| Feature | Type | Pathophysiological Basis |
|---|---|---|
| Bilateral lower abdominal pain (may be left-predominant) | Symptom | Ascending infection → salpingitis/oophoritis → peritoneal inflammation |
| Fever, malaise | Symptom | Systemic inflammatory response to pelvic infection |
| Vaginal discharge (purulent) | Symptom | Endocervical infection with Chlamydia or Neisseria → mucopurulent discharge |
| Cervical motion tenderness ("chandelier sign") | Sign | Movement of the cervix stretches the inflamed tubes/peritoneum → exquisite pain (patient "reaches for the chandelier") |
| Adnexal tenderness | Sign | Inflamed fallopian tube/ovary |
| Dyspareunia | Symptom | Pelvic peritoneal inflammation → pain on intercourse |
| Feature | Type | Pathophysiological Basis |
|---|---|---|
| Abdominal pain [10] | Symptom | Mucosal and submucosal inflammation → distension and spasm of the inflamed colon |
| Bloody diarrhoea with mucus | Symptom | Superficial mucosal ulceration → continuous bleeding; goblet cell depletion → reduced mucus production but mucus still present in stool |
| Tenesmus, urgency | Symptom | Rectal inflammation reduces compliance → sensation of incomplete evacuation |
| Passage of blood and mucus without stool | Symptom | Proctitis with little formed stool → only inflammatory exudate passes |
| Extraintestinal manifestations (joint pain, eye inflammation, skin lesions) | Symptom/Sign | Systemic immune dysregulation → erythema nodosum, pyoderma gangrenosum, uveitis, sacroiliitis |
| Feature | Type | Pathophysiological Basis |
|---|---|---|
| Recurrent abdominal pain associated with defecation [11] | Symptom | Visceral hypersensitivity → exaggerated perception of normal colonic distension; increased by emotional stress, meals, and throughout the day [11] |
| Cramping/colicky pain ± bloating, flatulence [11] | Symptom | Altered motility → uncoordinated contractions → sensation of cramping; fermentation of FODMAPs → gas |
| Altered bowel habits (diarrhoea and/or constipation) [11] | Symptom | IBS-D: increased transit time; IBS-C: decreased transit time |
| No alarm features (weight loss, nocturnal symptoms, PR bleeding, fever) | — | Functional disorder — no structural damage. Presence of alarm features should prompt investigation for organic pathology. |
7. Important Physical Examination Findings
| Finding | What It Suggests |
|---|---|
| LLQ tenderness with guarding/rebound | Peritonitis from diverticulitis, perforated viscus |
| Palpable LLQ mass | Diverticular phlegmon/abscess, sigmoid tumour |
| Generalised peritonism with board-like rigidity | Free perforation (Hinchey III-IV diverticulitis, perforated CRC) |
| Massively distended, tympanitic abdomen | Sigmoid volvulus, large bowel obstruction |
| Groin lump (irreducible, tender) | Incarcerated/strangulated hernia |
| Absent bowel sounds | Advanced peritonitis, paralytic ileus |
| High-pitched tinkling bowel sounds | Mechanical bowel obstruction |
- Always perform — can reveal:
- Rectal mass (low rectal tumour)
- Blood on glove (CRC, ischaemic colitis, diverticular bleed)
- Empty rectum (sigmoid volvulus, high obstruction)
- Tenderness in pouch of Douglas (pelvic abscess, ectopic pregnancy)
- Cervical motion tenderness → PID, ectopic pregnancy
- Adnexal mass → ovarian cyst, ectopic, tubo-ovarian abscess
- Cervical os open/closed → threatened/incomplete miscarriage
High Yield Summary
LLQ Pain — Key Takeaways:
- The most common cause of acute LLQ pain in elderly patients is sigmoid diverticulitis (clinical triad: LLQ pain + fever + leucocytosis)
- In Hong Kong/Asia, left-sided diverticulosis is still the most common, but right-sided disease is proportionally higher than in Western populations
- Diverticula form where vasa recta penetrate the circular muscle (weakest point); sigmoid has the narrowest lumen → highest intraluminal pressure (Laplace's law)
- The rectum is never affected by diverticulosis (complete circumferential outer muscle layer)
- Watershed areas (Griffiths' point at splenic flexure; Sudeck's point at rectosigmoid junction) are most vulnerable to ischaemic colitis
- Always rule out pregnancy (β-hCG) in women of reproductive age with LLQ pain — ruptured ectopic is life-threatening
- Sigmoid cancer presents with obstructive symptoms (change in bowel habit, colicky pain) due to annular constricting growth pattern
- Ureteric colic: severe colicky loin-to-groin pain, patient restless and writhing (cf. peritonitis where patient lies still)
- Sigmoid volvulus: elderly, constipated male → massive distension → "coffee bean" sign on AXR
- LLQ causes that can also cause RLQ pain (bilateral): ovarian torsion, ruptured ectopic, ureteric colic, inguinal/femoral hernia, testicular pathology
Active Recall - LLQ Pain
[1] Senior notes: felixlai.md (Diverticular disease — Epidemiology, Etiology, Hinchey Classification) [2] Senior notes: maxim.md (Diverticular disease — Definitions, Pathophysiology, Clinical features) [3] Senior notes: Ryan Ho GI.pdf (p163 — Colorectal Tumours, Epidemiology, Risk factors, Distribution) [4] Senior notes: Ryan Ho GI.pdf (p146 — Ischaemic Colitis, Vascular anatomy, Aetiology, Clinical features) [5] Senior notes: felixlai.md (Volvulus — Epidemiology, Etiology, Pathogenesis) [6] Senior notes: felixlai.md (Urinary Stones — Epidemiology, Etiology, Pathogenesis); Ryan Ho Urogenital.pdf (p140) [7] Senior notes: felixlai.md (Hernia — Risk factors, Pathophysiology) [8] Lecture slides: Diverticular diseases - Dr. J Tsang.pdf (p3 — Aetiology: low fibre diet, narrowest calibre sigmoid, true vs false diverticula) [9] Lecture slides: GC 195. Lower and diffuse abdominal pain RLQ problems; pelvic inflammatory disease; peritonitis and abdominal emergencies.pdf (p6 — LLQ causes) [10] Senior notes: felixlai.md (Ulcerative Colitis — Epidemiology, Etiology, Clinical manifestation) [11] Senior notes: Ryan Ho GI.pdf (p118 — IBS, Epidemiology, Pathophysiology, Clinical features) [12] Senior notes: Ryan Ho Cardiology.pdf (p222 — AAA, Definition, Epidemiology, Symptoms) [13] Lecture slides: GC 226. Lumbar Spine Pathology_Part B (2).pdf [14] Lecture slides: GC 226. Lumbar Spine Pathology_Part C (2).pdf [15] Senior notes: Ryan Ho GI.pdf (p102); Ryan Ho Fundamentals.pdf (p276 — Pain characterisation) [16] Lecture slides: GC 195 (p5 — RLQ causes, pain description)
Differential Diagnosis of LLQ Pain
The differential diagnosis of LLQ pain is best approached by thinking organ-system-by-organ-system, then refining based on the patient's age, sex, acuity, and associated features. The key clinical question at the bedside is always: "Is this a surgical emergency, or can I afford the luxury of time to investigate?"
The lecture slides explicitly list the following as the causes of LLQ pain [9]:
- Sigmoid diverticulitis
- Cancer of the sigmoid colon
- Torsion of ovarian cyst* (can be bilateral)
- Ruptured ectopic pregnancy* (can be bilateral)
- Ureteric colic* (can be bilateral)
- Inguinal/femoral hernia* (can be bilateral)
- Testicular pathology* (can be bilateral)
The asterisked conditions can cause pain on either side of the lower abdomen. This is a high-yield exam point — the lecture specifically flags these with an asterisk.
The lecture slide on formulating a differential diagnosis for lower abdominal pain [17] emphasizes constructing a systematic approach that considers both common and must-not-miss causes.
The table below organizes the differential by organ system, with the most important distinguishing features and a brief pathophysiological rationale for why each condition causes LLQ pain.
| System | Condition | Key Distinguishing Features | Why It Causes LLQ Pain |
|---|---|---|---|
| GI | Sigmoid diverticulitis | LLQ pain + fever + leucocytosis [1][2]; progressive constant pain; may have palpable LLQ mass; altered bowel habit | Obstruction of diverticular neck by faecolith → bacterial overgrowth → inflammation → pericolic/peritoneal irritation in LLQ |
| Cancer of sigmoid colon | Insidious change in bowel habit, PR bleeding, weight loss, iron deficiency anaemia; may present acutely with large bowel obstruction | Annular constricting tumour in sigmoid → partial/complete obstruction → colicky LLQ pain; direct serosal/peritoneal invasion → constant pain | |
| Ischaemic colitis | Sudden crampy abdominal pain + rectal bleeding within 24h [4]; elderly patient with cardiovascular risk factors; leucocytosis but fever unusual [4] | Hypoperfusion at watershed zones (Griffiths'/Sudeck's points) → mucosal ischaemia of the left colon → visceral then somatic pain | |
| Sigmoid volvulus | Elderly male, chronic constipation, massive distension, obstipation; "coffee bean" sign on AXR | Torsion of sigmoid around its mesentery → closed-loop obstruction → distension and ischaemia | |
| IBD — Ulcerative colitis (left-sided) | Bloody diarrhoea with mucus, tenesmus; young-to-middle-aged; diarrhoea rather than pain is predominant [1]; extraintestinal manifestations | Continuous mucosal inflammation from rectum extending proximally → LLQ pain when sigmoid/descending colon involved | |
| IBD — Crohn's disease | Fever, prolonged diarrhoea, weight loss, fatigue [18]; skip lesions, transmural; may have perianal disease, fistulae | Transmural inflammation of any GI segment — can involve sigmoid/descending colon | |
| IBS | Recurrent crampy pain associated with defecation, no alarm features [11]; increased by stress and meals [11] | Visceral hypersensitivity + altered motility in sigmoid → perceived pain in LLQ | |
| Infectious colitis | Acute diarrhoea (bloody or watery), fever, recent travel/antibiotic use; diarrhoea rather than pain is predominant [1] | Bacterial/protozoal invasion of colonic mucosa → inflammation; C. difficile if recent antibiotics | |
| Constipation / Faecal impaction | Elderly or immobile patients, palpable faecal mass in LLQ, history of infrequent bowel movements | Distension of sigmoid colon by retained stool → visceral pain | |
| Urological | Ureteric colic (left) | Severe colicky loin-to-groin pain, patient restless/writhing (cf. peritonitis where still); haematuria; pain decreased by movement [15] | Stone lodged at PUJ, pelvic brim, or VUJ → acute ureteric obstruction → peristaltic spasm against obstruction → referred pain along T11-L2 dermatomes to LLQ/groin |
| UTI / Cystitis | Dysuria, frequency, urgency, suprapubic pain, foul-smelling urine; NO fever or systemic upset [19] | Bladder mucosal inflammation → suprapubic/lower abdominal discomfort; can be perceived in LLQ | |
| Pyelonephritis (left) | Classical triad: loin pain + tenderness + fever [20]; systemic upset (rigors, malaise); costovertebral angle tenderness | Ascending infection → renal parenchymal inflammation → capsular distension → loin pain radiating to LLQ | |
| Gynaecological | Torsion of ovarian cyst | Sudden onset severe unilateral pelvic pain, nausea/vomiting; ovarian mass on USS; can be intermittent (partial torsion/detorsion) | Twisting of ovarian pedicle → venous then arterial compromise → ischaemia → peritoneal irritation |
| Ruptured ectopic pregnancy | Amenorrhoea 4-8 weeks, +β-hCG, vaginal bleeding, shoulder tip pain [15] if haemoperitoneum, haemodynamic instability | Tubal rupture → intraperitoneal haemorrhage → peritoneal irritation in the relevant iliac fossa | |
| PID | Bilateral lower abdominal pain, fever, purulent vaginal discharge, cervical motion tenderness, sexual history | Ascending infection from cervix → salpingitis → peritoneal inflammation in pelvis | |
| Tubo-ovarian abscess | Persistent fever despite antibiotics, pelvic mass, usually follows PID | Walled-off pelvic collection from spread of PID → pressure and inflammation in adnexa | |
| Endometriosis | Cyclical pelvic pain related to menses, dysmenorrhoea, dyspareunia, subfertility | Ectopic endometrial tissue in pelvis → cyclical bleeding and inflammation → adhesions and fibrosis | |
| Ruptured ovarian cyst (non-ectopic) | Pain often begins during strenuous physical activity or intercourse [18]; sudden then gradually improving | Cyst rupture → peritoneal irritation by cyst fluid ± blood | |
| Mittelschmerz | Mid-cycle pain (day 14), mild, self-limiting, in reproductive-age women | Physiological follicular rupture at ovulation → minor peritoneal irritation | |
| Abdominal Wall | Inguinal hernia | Groin lump ± cough impulse; if incarcerated → constant pain, features of IO; more common in males [7] | Bowel trapped in inguinal canal → distension → ischaemia if strangulated |
| Femoral hernia | More common in elderly females; lump below and lateral to pubic tubercle; 40% present with strangulation [21]; often irreducible | Bowel trapped in narrow femoral canal → high strangulation risk due to rigid boundaries | |
| Testicular | Testicular torsion | Sudden agonizing scrotal pain ± radiation to groin/lower abdomen [22]; adolescent male; high-riding testis, absent cremasteric reflex, -ve Prehn's sign | Torsion of spermatic cord → venous then arterial obstruction → testicular ischaemia; referred pain to LLQ via genitofemoral nerve (L1-L2) |
| Epididymo-orchitis | Storage LUTS + unilateral testicular pain + high fever/rigors [19]; +ve Prehn's sign (pain relieved by elevation) | Infection of epididymis → inflammation → referred pain to ipsilateral lower abdomen | |
| Vascular | Ruptured/leaking AAA | Classical triad: severe abdominal/back pain + hypotension + pulsatile abdominal mass [12]; 30% misdiagnosed [12] | Rupture of infrarenal aorta → retroperitoneal haemorrhage → pain radiating to flank/LLQ depending on rupture site |
| Musculoskeletal | Psoas abscess | Hip flexion posture, fever, LLQ/flank pain; TB contact or Crohn's disease history | Abscess within psoas muscle → inflammation irritates the retroperitoneum and iliopsoas fascia |
| Rectus sheath haematoma | Anticoagulation history, acute abdominal wall pain, +ve Carnett's sign | Inferior epigastric artery rupture → blood in rectus sheath → localized abdominal wall pain that worsens with muscle contraction | |
| Lumbar radiculopathy | Dermatomal distribution, back pain, neurological deficits; aggravated by Valsalva | Disc herniation/spinal stenosis → nerve root compression at L1-L2 → referred pain to LLQ [13][14] |
The following algorithm integrates the key decision points:
Key Differentiating Principles (Explaining "Why")
This is one of the most critical distinctions because both affect the sigmoid, both cause LLQ pain and both cause bowel wall thickening on CT [1]:
| Feature | Diverticulitis | CRC |
|---|---|---|
| Pericolonic/mesenteric inflammation (fat stranding) | Prominent | Minimal or absent |
| Length of involved segment | > 10 cm | Usually < 5 cm |
| Pericolonic lymph nodes | Absent (no enlarged nodes) | Present (enlarged) |
| Diverticula elsewhere | Present | May or may not be present |
| Luminal mass/shouldering | Absent | Present |
| Clinical resolution | Improves with antibiotics | Does not improve |
CRC can only be excluded with colonoscopy after resolution of acute inflammation [1]. This is because acute inflammation can make CT findings indistinguishable. Wait at least 6-8 weeks after an episode of diverticulitis before performing colonoscopy to rule out underlying malignancy, especially in patients > 50 years old or with alarm features.
Exam Trap
Never forget: diverticulitis and colorectal cancer can coexist. A patient presenting with "typical diverticulitis" still needs a follow-up colonoscopy after resolution, particularly if they are over 50 or have never been screened. Up to 1-2% of patients diagnosed with "diverticulitis" on CT are found to have CRC on subsequent colonoscopy.
In Hong Kong, right-sided diverticulitis is more common in the Asian population and is often confused with acute appendicitis [1][2]:
| Feature | Right-sided diverticulitis | Acute appendicitis |
|---|---|---|
| Age | Usually > 40 | Peak 20-30s |
| Pain pattern | RLQ from onset | Periumbilical → migrating to RLQ over 12-24h |
| Anorexia | Less prominent | Classical (part of MANTRELS score) |
| Imaging | CT: diverticula, fat stranding, no appendicolith | CT: dilated appendix, appendicolith, peri-appendiceal fat stranding |
While this distinction is more relevant to RLQ pain, it is worth knowing for LLQ pain in the reverse scenario: a long redundant sigmoid or pelvic appendix can present with LLQ pain mimicking left-sided diverticulitis.
| Feature | Diverticulitis | Ulcerative Colitis |
|---|---|---|
| Primary symptom | Abdominal pain is predominant | Diarrhoea is predominant [1] |
| Bleeding | Minimal (unless diverticular bleed, which is typically painless) | Bloody mucoid diarrhoea |
| Fever | Common | Less common unless severe/fulminant |
| Distribution | Segmental (sigmoid) | Continuous from rectum proximally |
| Age | Typically > 50 | Typically 20-40 |
| Extraintestinal features | Absent | Present (joints, eyes, skin) |
Diarrhoea rather than abdominal pain is the predominant symptom in both infectious colitis and IBD [1]. Key distinguishing features:
- Infectious colitis: travel history, recent antibiotics (C. difficile), food exposure, multiple household contacts
- C. difficile: classically associated with prior antibiotic use → produces toxins A (enterotoxin) and B (cytotoxin) → watery then bloody diarrhoea
- Stool cultures and C. difficile toxin assay are essential
| Feature | Ischaemic Colitis | Diverticulitis |
|---|---|---|
| Rectal bleeding | Develops within 24 hours of pain onset [4] — a hallmark | Uncommon (unless diverticular bleed) |
| Fever | Unusual [4] | Common |
| Cardiovascular risk factors | Prominent (AF, heart failure, vasopressors) | Not specifically associated |
| Location | Watershed areas (splenic flexure, rectosigmoid) | Sigmoid (at diverticular sites) |
| AXR | Thumbprinting [4] | Non-specific or localized ileus |
Why the distinction matters: ischaemic colitis is usually transient and self-limiting (managed conservatively with bowel rest and supportive care), whereas complicated diverticulitis may require drainage or surgery.
All three can present with massive colonic distension [5]:
| Feature | Sigmoid Volvulus | Ogilvie's Syndrome | Toxic Megacolon |
|---|---|---|---|
| Mechanism | Mechanical torsion of sigmoid | Functional (absent peristalsis without mechanical obstruction) | Inflammatory (colitis with systemic toxicity) |
| Typical patient | Elderly male, chronic constipation, neuropsychiatric disease | Hospitalized patient post-surgery or severe illness | IBD, C. difficile, infectious colitis |
| AXR | "Coffee bean" sign, massively dilated sigmoid | Diffuse colonic dilatation, often caecum most dilated | Transverse colon dilatation > 6 cm |
| Bloody diarrhoea | Absent (obstruction) | Absent | Most common presentation [5] |
| Systemic toxicity | Late (if ischaemia) | Minimal | Prominent (fever, tachycardia, leucocytosis) |
In any female of reproductive age, the differential must include [1][18]:
| Condition | Key Distinguishing Feature |
|---|---|
| Ruptured ectopic pregnancy | +β-hCG, amenorrhoea, vaginal bleeding, haemodynamic instability → life-threatening |
| Ovarian torsion | Sudden severe unilateral pain, nausea/vomiting, ovarian mass on USS, pain during exercise/intercourse [18] |
| PID | Bilateral lower abdominal pain, cervical motion tenderness, vaginal discharge, fever |
| Tubo-ovarian abscess | Persistent fever despite antibiotics [1], pelvic mass, usually a complication of PID [18] |
| Endometriosis | Cyclical pain related to menses, dysmenorrhoea, subfertility |
| Mittelschmerz | Mid-cycle, mild, self-limiting — diagnosis of exclusion |
| Feature | Inguinal Hernia | Femoral Hernia |
|---|---|---|
| Demographics | Male predominance [7] | 70% female, mostly elderly [21] |
| Neck location | Above and medial to pubic tubercle | Below and lateral to pubic tubercle |
| Reducibility | Usually reducible | Often irreducible (narrow neck) [21] |
| Strangulation risk | Lower | Up to 40% present with strangulation [21] |
| Cough impulse | Usually present | Often absent (incarcerated) |
Why does this matter? A femoral hernia must be considered in any elderly female with LLQ pain and signs of bowel obstruction, even without an obvious groin lump — the hernia may be small and easily missed under the inguinal ligament.
| Feature | Testicular Torsion | Epididymo-Orchitis |
|---|---|---|
| Age | Bimodal: neonatal + adolescent (12-18y) [22] | Young adults (STI) or elderly (UTI organisms) |
| Onset | Sudden, agonizing [22] | Gradual over hours-days |
| Prehn's sign | Negative (pain NOT relieved by elevation) [22] | Positive (pain relieved by elevation) |
| Cremasteric reflex | Absent [22] | Present |
| Testicular lie | High-riding, horizontal [22] | Normal |
| Systemic features | Nausea/vomiting, mild fever [22] | High fever, rigors [19] |
| Urgency | Surgical emergency — irreversible damage after 12h [22] | Antibiotics |
Why does testicular pathology cause LLQ pain? The testis is embryologically an intra-abdominal organ that descended into the scrotum. Its sensory innervation (via the genitofemoral nerve, L1-L2) shares dermatomes with the lower abdominal wall — so testicular pain is referred to the LLQ/RLQ. Always examine the scrotum in any male presenting with lower abdominal pain!
Clinical Pearl
"In a young man with lower abdominal pain and an empty scrotum on that side, think testicular torsion." Conversely, in an adolescent boy with "abdominal pain" who has not had his scrotum examined, you may miss a surgical emergency. The cremasteric reflex test has a sensitivity of ~99% in children for torsion (absent reflex = torsion until proven otherwise).
These are the conditions that will kill or cause irreversible harm if missed:
| Condition | Why It's an Emergency | Time-Sensitivity |
|---|---|---|
| Ruptured ectopic pregnancy | Intraperitoneal haemorrhage → hypovolaemic shock → death | Minutes to hours |
| Testicular torsion | Testicular ischaemia → irreversible infarction | < 6-12 hours |
| Strangulated hernia | Bowel ischaemia → necrosis → perforation → peritonitis | < 6 hours |
| Sigmoid volvulus with ischaemia | Closed-loop obstruction → gangrene → perforation | Hours |
| Ruptured AAA | Massive haemorrhage → death | Minutes |
| Perforated diverticulitis (Hinchey III-IV) | Faecal/purulent peritonitis → septic shock | Hours |
| Ovarian torsion | Ovarian infarction → loss of ovary | Hours |
A useful clinical shortcut — while not a substitute for systematic assessment, pattern recognition helps prioritize the differential:
| Patient Profile | Top Differentials |
|---|---|
| Adolescent male | Testicular torsion, acute appendicitis (pelvic appendix), Meckel's diverticulitis |
| Young woman (reproductive age) | Ectopic pregnancy, ovarian torsion, PID, endometriosis, mittelschmerz |
| Middle-aged adult | Ureteric colic, IBD flare, diverticulitis (if > 40), CRC (if > 50) |
| Elderly male | Sigmoid diverticulitis, CRC, sigmoid volvulus, ischaemic colitis, AAA |
| Elderly female | Sigmoid diverticulitis, CRC, ischaemic colitis, femoral hernia |
High Yield Summary
Differential Diagnosis of LLQ Pain — Key Exam Points:
- Lecture-listed causes: Sigmoid diverticulitis, sigmoid cancer, ovarian torsion*, ruptured ectopic*, ureteric colic*, inguinal/femoral hernia*, testicular pathology* (* = bilateral)
- Diverticulitis vs CRC on CT: diverticulitis has pericolonic fat stranding, > 10 cm involvement, absence of enlarged lymph nodes; CRC shows the opposite. CRC can only be excluded with colonoscopy after resolution of acute inflammation [1].
- Diverticulitis vs IBD/infectious colitis: diarrhoea is the predominant symptom in IBD and infectious colitis, while abdominal pain is predominant in diverticulitis [1].
- Ischaemic colitis hallmarks: sudden crampy pain + rectal bleeding within 24h; leucocytosis but fever unusual; thumbprinting on AXR [4].
- Right-sided diverticulitis in Asia is often confused with acute appendicitis [1][2].
- Femoral hernia: 70% female, 40% present with strangulation — most dangerous hernia [21].
- Testicular torsion: irreversible damage after 12h → surgical emergency; absent cremasteric reflex, high-riding testis [22].
- Always check β-hCG in women of reproductive age — ruptured ectopic is life-threatening.
- Sigmoid volvulus ddx: toxic megacolon (systemic toxicity + bloody diarrhoea) and Ogilvie's syndrome (hospitalized post-op patient, no mechanical obstruction) [5].
Active Recall - Differential Diagnosis of LLQ Pain
References
[1] Senior notes: felixlai.md (Diverticular disease — Differential diagnosis, Diagnosis) [2] Senior notes: maxim.md (Diverticular disease — Pathophysiology, Clinical features, Most common sites) [4] Senior notes: Ryan Ho GI.pdf (p146 — Ischaemic Colitis, Clinical features, Laboratory features) [5] Senior notes: felixlai.md (Volvulus — Differential diagnosis: Toxic megacolon, Ogilvie's syndrome) [7] Senior notes: felixlai.md (Hernia — Risk factors) [9] Lecture slides: GC 195. Lower and diffuse abdominal pain RLQ problems; pelvic inflammatory disease; peritonitis and abdominal emergencies.pdf (p6 — LLQ causes) [11] Senior notes: Ryan Ho GI.pdf (p118 — IBS, Clinical features) [12] Senior notes: Ryan Ho Cardiology.pdf (p222 — AAA, Classical triad, Misdiagnosis rate) [13] Lecture slides: GC 226. Lumbar Spine Pathology_Part B (2).pdf [14] Lecture slides: GC 226. Lumbar Spine Pathology_Part C (2).pdf [15] Senior notes: Ryan Ho GI.pdf (p102); Ryan Ho Fundamentals.pdf (p276 — Pain characterisation, Radiation) [17] Lecture slides: GC 195. Lower and diffuse abdominal pain RLQ problems; pelvic inflammatory disease; peritonitis and abdominal emergencies.pdf (p13 — Formulating differential diagnosis) [18] Senior notes: felixlai.md (Acute appendicitis — Differential diagnosis: gynaecological causes) [19] Senior notes: Ryan Ho Urogenital.pdf (p121 — Approach to Dysuria; p125 — Acute Cystitis) [20] Senior notes: Ryan Ho Urogenital.pdf (p127 — Acute Pyelonephritis) [21] Senior notes: Ryan Ho Urogenital.pdf (p225 — Femoral Hernia) [22] Senior notes: Ryan Ho Urogenital.pdf (p233 — Testicular Torsion)
Diagnostic Criteria, Algorithm and Investigations for LLQ Pain
LLQ pain is a symptom, not a diagnosis. There is no single "diagnostic criterion" for LLQ pain itself — instead, you apply a systematic investigative framework to identify the underlying cause. The approach follows a logical sequence:
- Resuscitate if haemodynamically unstable (ABCs first)
- History and physical examination to generate a working differential
- Bedside tests (urinalysis, pregnancy test) to immediately rule in/out life-threatening diagnoses
- Blood tests to assess severity and narrow the differential
- Imaging — the choice depends on the clinical scenario
- Endoscopy — only when appropriate and safe (never in the acute phase of suspected perforation)
The lecture slides lay out the investigation framework as [23]:
- Bedside tests: urinalysis, pregnancy test
- Blood tests: blood count, renal and liver function, amylase, clotting profile, arterial blood gas, type and screen
- Imaging: erect CXR, erect and supine AXR, USG, CT, contrast studies
- Endoscopy: colonoscopy, upper endoscopy
1. Diagnostic Criteria for Key Causes of LLQ Pain
Most causes of LLQ pain are diagnosed by a combination of clinical features, laboratory findings, and imaging rather than by a single set of formal criteria. However, several conditions have well-defined diagnostic frameworks:
There is no universally accepted formal "diagnostic criteria" set like the Tokyo criteria for cholecystitis. Instead, the diagnosis relies on a clinical-radiological approach:
| Component | Requirement |
|---|---|
| Clinical | LLQ pain (progressive, constant) + fever + leucocytosis → clinical triad [1][2] |
| Imaging confirmation | CT abdomen + pelvis with contrast is the gold standard [2][24] |
| CT findings of acute diverticulitis [1][24] | 1) Presence of colonic diverticula, 2) Localized bowel wall thickening ( > 4 mm), 3) Increased soft tissue density within pericolonic fat (fat stranding), 4) ± Complications (abscess, fistula, perforation) |
Why CT and not just clinical diagnosis? Because the clinical triad alone has a positive predictive value of only ~60-70%. CT both confirms the diagnosis and stages the severity (Hinchey classification), which directly guides management [24].
Distinguishing diverticulitis from CRC on CT [1]:
| Feature | Diverticulitis | CRC |
|---|---|---|
| Pericolonic fat stranding | Prominent | Minimal |
| Involved segment length | > 10 cm | Usually < 5 cm |
| Pericolonic lymph nodes | Absent (not enlarged) | Present (enlarged) |
| Diverticula elsewhere | Present | ± |
Colonoscopy: only after resolution of acute episode (risk of perforation during acute inflammation) [24]. Purpose: definitive diagnosis (localisation), rule out CRC and IBD, assess complications (stenosis), and therapeutic (endoscopic haemostasis) [24].
The diverticular disease lecture also mentions that initial workup for uncomplicated diverticulosis (asymptomatic) can include barium enema, colonoscopy, or CT colonography (CTC) [25].
Modified Alvarado (MANTREL) Score [26][27]:
| Component | Points |
|---|---|
| Migratory RLQ pain | 1 |
| Anorexia | 1 |
| Nausea or vomiting | 1 |
| Tenderness in RLQ | 2 |
| Rebound tenderness in RLQ | 1 |
| Elevated temperature > 37.5°C | 1 |
| Leucocytosis WBC > 10 × 10⁹/L | 1 |
| Total | 8 |
| Score | Interpretation |
|---|---|
| 0-3 | Unlikely → evaluate for other diagnoses [26] |
| 4-6 | Equivocal → consider USG or contrast CT [26][27] |
| ≥ 7 | Strongly suggestive → consider surgery or further imaging [26][27] |
Why include appendicitis here? In Hong Kong, right-sided diverticulitis is more common in Asians and is often confused with acute appendicitis [1]. The Alvarado score was designed for appendicitis, but awareness of this overlap is essential — if CT shows diverticula rather than an inflamed appendix, the diagnosis changes completely.
Revised Atlanta Criteria — requires ≥ 2 out of 3 [28][29]:
| Criterion | Detail |
|---|---|
| Clinical | Acute onset of persistent, severe epigastric pain often radiating to the back |
| Biochemical | Serum amylase or lipase ≥ 3× upper limit of normal |
| Imaging | Characteristic findings on USG, CT, or MRI |
Amylase peaks at 6-24 hours and normalizes in 3-5 days; lipase has a longer half-life (normalizes in 8-14 days) and is preferred for delayed presentations > 24 hours [29][30].
No formal diagnostic criteria — clinical + imaging + endoscopic diagnosis [4]:
| Component | Key Points |
|---|---|
| Clinical | Sudden crampy LLQ pain + rectal bleeding within 24h; elderly with CV risk factors; leucocytosis but fever unusual |
| Laboratory | ↑↑WBC, metabolic acidosis, ↑serum lactate, ↑LDH, ↑CPK, ↑amylase [4]; stool culture + C. difficile toxin to rule out infectious diarrhoea |
| Imaging | AXR: thumbprinting, pneumatosis (advanced) [4]; CT: bowel wall thickening, pericolonic fat stranding, mucosal hyperenhancement |
| Endoscopy | Colonoscopy (cautious, limited insufflation): oedematous/cyanotic mucosa, submucosal haemorrhage, ulceration in segmental distribution at watershed areas |
Diagnosis is primarily clinical + radiological [5]:
| Component | Key Finding |
|---|---|
| AXR | Coffee bean sign (massively dilated sigmoid loop from pelvis pointing toward RUQ); absence of rectal gas |
| CT | Whirl sign (twisted mesentery), dilated sigmoid, transition point at site of torsion |
| Contrast enema | Bird's beak / ace-of-spades sign at the site of torsion (rarely needed if CT available) |
Diagnosis confirmed by imaging [33][34]:
| Component | Key Points |
|---|---|
| Clinical | Severe colicky loin-to-groin pain, haematuria, restless patient |
| Urinalysis | Haematuria (present in ~85%, but absence does not exclude stones) |
| NCCT abdomen and pelvis | Gold standard — sensitivity ~97%, specificity ~96%; detects size, location, density of stone and degree of obstruction [33][34] |
| KUB X-ray | 90% of urinary stones are radio-opaque [30]; useful for follow-up but NCCT is standard for acute presentation |
The following mermaid diagram integrates the decision-making process from presentation to diagnosis:
3. Investigation Modalities: Detailed Breakdown
| Investigation | What It Tells You | Why You Do It | Key Findings |
|---|---|---|---|
| Urinalysis (dipstick + microscopy) [23][30] | Screen for urological causes | Haematuria → stone, tumour, UTI; Pyuria → UTI, pyelonephritis; Sterile pyuria → inflammation from adjacent diverticulitis [1] | RBCs, WBCs, nitrites, leucocyte esterase, casts, crystals |
| Urine pregnancy test [23][30] | Rule out ectopic pregnancy | Indicated in ALL women of childbearing age [26] — most critical bedside test | Positive β-hCG → must locate pregnancy (intrauterine vs ectopic) |
Sterile Pyuria Pitfall
Sterile pyuria (WBCs in urine but negative culture) can occur when an inflamed sigmoid diverticulum lies adjacent to the left ureter or bladder — the inflammation causes a reactive pyuria without actual urinary infection [1]. Do not automatically treat with antibiotics for UTI; correlate with clinical picture. Conversely, presence of colonic flora on urine culture indicates a colovesical fistula [1] — a complication of diverticulitis.
| Investigation | What It Tells You | Key Findings and Interpretation |
|---|---|---|
| CBC with differential [23][30] | Infection, inflammation, chronic bleeding | Leucocytosis with left shift (↑bands) → infection/inflammation (diverticulitis, appendicitis); Markedly ↑↑WBC ( > 16) → gangrenous/perforated appendix [26]; Anaemia (↓MCV) → chronic blood loss (CRC); Normal WBC does NOT rule out appendicitis or diverticulitis [26] |
| CRP [23] | Inflammatory marker | Elevated in diverticulitis, IBD, PID; CRP > 10 mg/L with WBC > 10 × 10⁹/L gives PPV 61.5% and NPV 88.1% for appendicitis [26]; very high CRP in complicated diverticulitis |
| LFT [23][30] | Hepatobiliary cause; baseline for surgery | Obstructive pattern (↑ALP, ↑GGT, ↑bilirubin) → biliary pathology; Mild ↑bilirubin → marker for appendiceal perforation [26] |
| RFT [23][30] | Hydration status; contrast suitability | HypoK, hypoCl → prolonged vomiting [30]; Cr → suitability for contrast CT [30]; ↑urea/Cr ratio → dehydration |
| Amylase / Lipase [23][30] | Rule out pancreatitis | Amylase peaks at 6-24h; lipase preferred if > 24h presentation [29][30]; ≥ 3× ULN diagnostic of pancreatitis [28][29]; mild elevations can occur in bowel obstruction, perforated ulcer, ischaemic bowel |
| Clotting profile + Type and Screen [23][30] | Baseline for surgery or procedure | Essential before any surgical intervention or invasive drainage |
| ABG + Lactate [23][30] | Ischaemia, acid-base status | Metabolic acidosis + ↑lactate → intestinal ischaemia [30]; Metabolic alkalosis → prolonged vomiting [30]; lactate is a sensitive marker for bowel ischaemia [5] |
| ± Cardiac enzymes + ECG [30] | Rule out basal MI | Inferior MI can present as epigastric/lower abdominal pain — always consider in elderly with risk factors |
| ± Glucose [30] | Rule out DKA | DKA can present with acute abdominal pain mimicking a surgical abdomen |
| Serum calcium + urate [33] | Underlying risk factors for stones | Hypercalcaemia → calcium stones; Hyperuricaemia → uric acid stones |
The lecture slides specifically list: blood count, renal and liver function, amylase, clotting profile, arterial blood gas, type and screen [23].
3.3 Imaging
The lecture slides list: erect CXR, erect and supine AXR, USG, CT, contrast studies [23].
The senior notes identify imaging of choice by site of pain [24]:
| Site of Pain | Imaging of Choice |
|---|---|
| RUQ | USG |
| LUQ | CT |
| RLQ | CT with IV contrast |
| LLQ | CT with IV contrast |
| Suprapubic | USG (TAS or TVS) |
| Finding | Significance | Why |
|---|---|---|
| Free gas under diaphragm (pneumoperitoneum) [1][30] | Perforated hollow viscus (e.g. perforated diverticulitis Hinchey III-IV, perforated peptic ulcer) | Free air escapes from the perforated bowel into the peritoneal cavity → rises to the highest point (subdiaphragmatic) when patient is erect |
| Pleural effusion | Pancreatitis (left-sided), basal pneumonia | Pancreatitis → diaphragmatic inflammation → reactive effusion; pneumonia can refer pain to abdomen |
| Finding | Diagnosis Suggested | Pathophysiological Basis |
|---|---|---|
| Proximal dilatation + distal collapse (SB > 3 cm, LB > 6 cm, caecum > 9 cm — "3-6-9 rule") [30][35] | Mechanical intestinal obstruction | Bowel dilates proximal to obstruction due to gas + fluid accumulation; distal bowel decompresses |
| > 5 air-fluid levels on erect AXR [30][35] | Diagnostic of intestinal obstruction | Fluid levels form at interfaces of gas and liquid within obstructed loops |
| Coffee bean sign (LLQ to RUQ) [30][35] | Sigmoid volvulus | Massively dilated sigmoid loop with its convexity pointing towards RUQ; the central crease represents the twisted mesentery |
| Thumbprinting [4][35] | Ischaemic colitis, UC | Submucosal haemorrhage and oedema cause scalloped indentations along the colonic wall |
| Pneumatosis intestinalis [35] | Advanced ischaemia/necrosis | Gas produced by necrotic bowel wall bacteria dissects into the submucosa |
| Radio-opaque stones along ureter [30] | Ureteric calculus | 90% of urinary stones are radio-opaque [30] (calcium-containing); trace ureter from kidney → tip of transverse process → SIJ → ischial spine → bladder [33] |
| Sentinel loop sign [29][30] | Localized ileus near inflammation (e.g. pancreatitis) | Focal inflammation causes reflex ileus of the adjacent bowel loop |
| Faecal loading in sigmoid/rectum | Faecal impaction/constipation | Accumulated faecal matter visible as mottled densities |
When AXR is NOT Enough
AXR is a screening tool, not a definitive investigation. It has low sensitivity for early diverticulitis, early ischaemia, and cannot stage disease. CT abdomen with contrast is the definitive imaging for most causes of acute LLQ pain [24]. AXR is most useful for: (1) confirming intestinal obstruction, (2) detecting pneumoperitoneum (if CXR equivocal), and (3) identifying volvulus.
| Modality | Indication | Key Findings |
|---|---|---|
| Transabdominal USS (TAS) | First-line for suprapubic pain, pelvic pathology; pregnant women; children [24][26] | Diverticulitis: bowel wall thickening > 4 mm at maximal tenderness, hypoechoic peridiverticular inflammatory reaction, mural/peridiverticular abscess with gas bubbles [1]; Appendicitis: non-compressible appendix > 6 mm, focal pain on compression, periappendiceal fat ↑echogenicity [26][27] |
| Transvaginal USS (TVS) | First-line for gynaecological causes (ectopic pregnancy, ovarian torsion, PID, ovarian cyst) [24] | Ectopic pregnancy: empty uterus with adnexal mass ± free fluid in pouch of Douglas; Ovarian torsion: enlarged ovary with absent/reduced Doppler flow, "whirlpool sign" of twisted pedicle |
| Doppler USS scrotum | Acute scrotal pain → testicular torsion vs epididymo-orchitis | Torsion: absent/reduced intratesticular blood flow, whirlpool sign, high-riding testis [22]; Epididymo-orchitis: increased flow (hyperaemia) |
| Renal USS | Screen for hydronephrosis in ureteric obstruction | Dilated renal pelvis/calyces; cannot reliably detect ureteric stones (only proximal and distal ends visualized) [33] |
USS advantages: no radiation, portable, real-time. Disadvantages: operator-dependent, limited by body habitus and bowel gas, lower sensitivity than CT for deep structures.
CT abdomen + pelvis with contrast is the imaging of choice for LLQ pain [24].
| Condition | CT Findings | Interpretation |
|---|---|---|
| Acute diverticulitis [1][24] | Colonic diverticula, localized bowel wall thickening > 4 mm, pericolonic fat stranding, ± abscess (fluid collection with surrounding inflammatory changes, containing air/air-fluid levels/necrotic debris), ± fistula (extraluminal air tracking to adjacent organ), ± free air (perforation) | Staging by Hinchey classification guides management; CT also distinguishes diverticulitis from CRC (see criteria in section 1.1) |
| Colorectal cancer | Short segment ( < 5 cm) irregular wall thickening, "apple-core" lesion, shouldering, enlarged pericolonic lymph nodes, ± liver metastases | Requires colonoscopy for tissue diagnosis; CT stages extent (T, N, M) |
| Ischaemic colitis [4] | Segmental bowel wall thickening at watershed areas, mucosal hyperenhancement ("target sign"), pericolonic fat stranding, thumbprinting, pneumatosis (advanced), portal venous gas (very advanced) [35] | Distribution (splenic flexure, rectosigmoid) is key to diagnosis; pneumatosis/portal gas = likely transmural necrosis → surgery |
| Sigmoid volvulus | Whirl sign (twisted mesentery and vessels), dilated sigmoid, transition point, "beak" sign at torsion point | If no signs of ischaemia → attempt endoscopic decompression first |
| Ureteric calculus | NCCT (no contrast needed): hyperdense focus in ureter, proximal hydroureter/hydronephrosis, perinephric stranding, tissue rim sign around stone | Size predicts passage: < 5 mm → 90% spontaneous passage; > 10 mm → rarely passes spontaneously; location (PUJ, pelvic brim, VUJ) determines symptoms [33] |
| Ruptured AAA | Loss of aortic wall calcification continuity, retroperitoneal haematoma (high-density collection around aorta), contrast extravasation (active bleeding) | Do NOT delay for CT if patient is haemodynamically unstable with suspected ruptured AAA → go straight to theatre |
| Psoas abscess | Hypodense collection within psoas muscle ± gas, ± adjacent vertebral body destruction (TB) | CT-guided drainage may be both diagnostic and therapeutic [36] |
Contrast Considerations
IV contrast is contraindicated in: (1) Renal insufficiency (check creatinine — eGFR < 30 is a relative contraindication; need pre-hydration if eGFR 30-45), (2) Contrast allergy (premedicate with steroids/antihistamines if history of reaction), (3) Pregnancy (relative — consider MRI instead). For ureteric colic, NCCT (non-contrast) is standard — contrast is not needed and may obscure small stones [33][34].
| Modality | Indication | Key Points |
|---|---|---|
| CT angiography (CTA) | Mesenteric ischaemia, AAA assessment | Gold standard for mesenteric ischaemia — shows arterial occlusion (absent enhancement) or venous thrombosis (filling defects) [35]; allows planning for endovascular intervention |
| MRI abdomen/pelvis | Pregnant patients, children (avoids radiation); characterization of pelvic masses | No ionizing radiation; higher non-diagnostic rate than CT [26]; useful for soft tissue characterization |
| Barium/water-soluble contrast enema | CT colonography (CTC) or contrast enema for uncomplicated diverticulosis [25]; colovesical fistula workup | AVOID in acute setting (risk of barium peritonitis if perforation); water-soluble contrast safer; shows "bird's beak" sign in volvulus |
| IV urogram (IVU) | Largely replaced by CTU; gives functional information | Risk of contrast nephrotoxicity and anaphylaxis; no longer standard for acute loin pain evaluation [33] |
| NCCT KUB | Standard investigation for acute loin pain / ureteric colic [34] | Allows assessment of level, size, density, and degree of obstruction of calculi [33] |
Why do we order both an erect CXR and supine AXR as "first-line" in any acute abdomen [23][30]?
- Erect CXR: Most sensitive for detecting free gas under the diaphragm (as little as 1 mL of free air can be detected under the right hemidiaphragm). It also rules out thoracic causes of abdominal pain (basal pneumonia, pleural effusion).
- Supine AXR: Shows bowel gas pattern (dilated loops → obstruction), faecal loading, radio-opaque stones, and specific signs (coffee bean, thumbprinting).
- Erect AXR: Air-fluid levels (multiple levels diagnostic of obstruction).
These are quick, cheap, readily available tests that can be done at the bedside or in the ED and may immediately confirm a surgical emergency (perforation, obstruction, volvulus) before waiting for CT.
The lecture mentions colonoscopy and upper endoscopy [23].
| Modality | Indication | Important Caveats |
|---|---|---|
| Colonoscopy | Only AFTER resolution of acute diverticulitis (6-8 weeks) to rule out CRC [24]; diagnosis of IBD; evaluation of lower GI bleeding; therapeutic decompression in sigmoid volvulus | AVOID in acute abdomen — gas insufflation during endoscopy may open a sealed-off perforation [24]; in sigmoid volvulus, flexible sigmoidoscopy can decompress and detort the bowel (use with rectal tube placement) |
| Upper endoscopy (OGD) | If upper GI cause suspected (e.g. perforated peptic ulcer with tracking to LLQ — Valentino's sign) | Rarely indicated for primary LLQ pain |
| Sigmoidoscopy | Ischaemic colitis (limited insufflation, cautious) | Shows oedematous, haemorrhagic, or ulcerated mucosa at watershed areas; biopsy confirms ischaemic changes |
| Cystoscopy | Haematuria evaluation; suspected colovesical fistula | Should be done in ALL patients with gross non-glomerular haematuria [33]; can visualize fistula opening in bladder |
- Indicated when diagnosis remains uncertain after all investigations, especially in young women (to differentiate gynaecological from GI causes) [24]
- Can be both diagnostic and therapeutic (e.g. appendicectomy, ovarian detorsion, washout of peritonitis)
4. Condition-Specific Investigation Pathways
| Step | Investigation | Purpose |
|---|---|---|
| 1 | CBC, CRP, LFT, RFT, amylase | Confirm inflammation, exclude pancreatitis, baseline |
| 2 | Urinalysis and culture | Sterile pyuria (adjacent inflammation) vs colonic flora (colovesical fistula) [1] |
| 3 | Urine pregnancy test (if applicable) | Exclude ectopic pregnancy |
| 4 | Erect CXR | Exclude perforation (pneumoperitoneum) |
| 5 | CT abdomen + pelvis with IV contrast | Gold standard: confirm diagnosis, Hinchey staging, exclude CRC, guide drainage [1][24] |
| 6 | Colonoscopy 6-8 weeks later | Rule out CRC (especially if age > 50, first episode, or alarm features) [24] |
| Step | Investigation | Purpose |
|---|---|---|
| 1 | CBC, RFT, lactate, ABG | Leucocytosis and lactate elevation suggest ischaemia |
| 2 | Supine AXR | Coffee bean sign — often diagnostic |
| 3 | CT abdomen (if AXR inconclusive) | Whirl sign, transition point, rule out ischaemia |
| 4 | Sigmoidoscopy | Therapeutic decompression (if no signs of ischaemia/peritonitis) + rectal tube placement |
| Step | Investigation | Purpose |
|---|---|---|
| 1 | CBC, CRP, lactate, ABG, LDH, CPK | ↑↑WBC, metabolic acidosis, ↑lactate, ↑LDH, ↑CPK [4] |
| 2 | Stool culture + C. difficile toxin | Rule out infectious diarrhoea [4] |
| 3 | AXR | Thumbprinting, pneumatosis |
| 4 | CT abdomen with contrast | Segmental wall thickening at watershed areas, target sign |
| 5 | Colonoscopy (cautious, limited insufflation) | Confirm mucosal ischaemic changes, biopsy; avoid in suspected transmural necrosis/perforation |
| Step | Investigation | Purpose |
|---|---|---|
| 1 | Urine β-hCG (bedside) | Rapid screen; if positive → proceed |
| 2 | Serum quantitative β-hCG | Levels guide USS interpretation (discriminatory zone: ~1500-2000 IU/L for TVS) |
| 3 | Transvaginal USS (TVS) | Locate pregnancy: if no intrauterine pregnancy with β-hCG above discriminatory zone → ectopic until proven otherwise |
| 4 | CBC, T/S, clotting | Baseline for possible emergency surgery |
| Step | Investigation | Purpose |
|---|---|---|
| 1 | Urinalysis (dipstick + microscopy) | Haematuria (present in ~85%); absence does not exclude stones |
| 2 | CBC, RFT, calcium, urate | Baseline; RFT for contrast suitability; calcium/urate for stone aetiology |
| 3 | NCCT KUB | Gold standard: stone location, size, density, degree of obstruction [33][34] |
| 4 | Renal USS (if NCCT unavailable or pregnant) | Hydronephrosis ± proximal/distal ureteric stone |
High Yield Summary
Diagnostic Approach to LLQ Pain — Key Exam Points:
- CT abdomen + pelvis with IV contrast is the imaging of choice for LLQ pain [24]. For ureteric colic specifically, use NCCT (no contrast needed).
- Bedside tests first: urinalysis + pregnancy test. Never skip the pregnancy test in a woman of reproductive age.
- Erect CXR for pneumoperitoneum; AXR for bowel gas pattern (coffee bean sign = volvulus, thumbprinting = ischaemia, air-fluid levels = obstruction).
- Diverticulitis diagnosis: clinical triad + CT showing wall thickening > 4 mm, fat stranding, diverticula. Colonoscopy only after acute resolution (6-8 weeks) to rule out CRC [24].
- Sterile pyuria in diverticulitis = adjacent inflammation; colonic flora in urine culture = colovesical fistula [1].
- Alvarado (MANTREL) score for appendicitis: ≥ 7 = strongly suggestive; 4-6 = consider imaging; 0-3 = unlikely [26].
- Revised Atlanta criteria for pancreatitis: ≥ 2/3 of epigastric pain + amylase/lipase ≥ 3× ULN + imaging findings [28].
- Blood tests panel: CBC, CRP, LFT, RFT, amylase, clotting, T/S, ± ABG/lactate, ± cardiac enzymes — all serve specific diagnostic purposes.
- Lactate + ABG are critical when you suspect ischaemic bowel — metabolic acidosis with raised lactate = tissue hypoperfusion.
- AVOID colonoscopy and barium enema in the acute phase of diverticulitis or any suspected perforation — risk of exacerbating the perforation [24].
Active Recall - Diagnostic Criteria, Algorithm and Investigations for LLQ Pain
References
[1] Senior notes: felixlai.md (Diverticular disease — Diagnosis, CT features, Urinalysis findings) [2] Senior notes: maxim.md (Diverticular disease — Clinical triad, CT findings) [4] Senior notes: Ryan Ho GI.pdf (p146 — Ischaemic Colitis, Laboratory features, AXR findings) [5] Senior notes: felixlai.md (Volvulus — Diagnosis, Biochemical tests, Lactate) [22] Senior notes: Ryan Ho Urogenital.pdf (p233 — Testicular Torsion, Doppler USS) [23] Lecture slides: GC 195. Lower and diffuse abdominal pain RLQ problems; pelvic inflammatory disease; peritonitis and abdominal emergencies.pdf (p12 — Investigations) [24] Senior notes: maxim.md (Acute abdomen — Imaging by site; Diverticular disease — CT, Colonoscopy, Hinchey) [25] Lecture slides: Diverticular diseases - Dr. J Tsang.pdf (p6 — Investigations for diverticulosis: Ba enema, colonoscopy, CTC) [26] Senior notes: Ryan Ho GI.pdf (p150 — Appendicitis workup, Alvarado score, Imaging) [27] Senior notes: felixlai.md (Acute appendicitis — Alvarado score, CT and USG findings) [28] Senior notes: felixlai.md (Acute pancreatitis — Diagnostic criteria) [29] Senior notes: maxim.md (Acute pancreatitis — Revised Atlanta criteria, Amylase vs Lipase) [30] Senior notes: Ryan Ho GI.pdf (p105); Ryan Ho Fundamentals.pdf (p279 — Investigations for acute abdomen) [31] Senior notes: felixlai.md (Acute cholecystitis — Tokyo criteria 2013) [32] Senior notes: Ryan Ho GI.pdf (p248 — TG13 diagnostic criteria for acute cholecystitis) [33] Senior notes: Ryan Ho Urogenital.pdf (p134 — KUB, NCCT, Cystoscopy, Upper tract imaging) [34] Senior notes: Ryan Ho Urogenital.pdf (p140 — NCCT for acute loin pain, IVU no longer standard) [35] Senior notes: Ryan Ho GI.pdf (p136 — AXR findings in IO, 3-6-9 rule, Coffee bean sign, Thumbprinting) [36] Senior notes: Ryan Ho Diagnostic Radiology.pdf (p81 — CT-guided drainage of pelvic abscess)
Management of LLQ Pain
The management of LLQ pain is cause-specific — there is no single treatment algorithm for "LLQ pain" itself. The overarching principles are:
- Resuscitate the patient (ABCs, haemodynamic stabilisation)
- Identify and treat surgical emergencies immediately (ruptured ectopic, testicular torsion, strangulated hernia, perforated diverticulitis, sigmoid volvulus with ischaemia)
- Determine the underlying cause (as per the diagnostic workup in the previous section)
- Institute cause-specific treatment — conservative, medical, interventional, or surgical
These are the initial resuscitative measures that apply regardless of the eventual diagnosis. Think of them as what you do while you are working up the cause [37][38].
| Measure | Rationale | Details |
|---|---|---|
| NPO (nil per os) [37][38] | Limits bowel distension; prepares for potential surgery; rests the bowel in inflammation | All patients with suspected surgical abdomen should be NPO until a plan is established |
| IV fluid resuscitation [37][38] | Compensates for: external losses (vomiting), internal losses (third-space sequestration), reduced oral intake | Crystalloids: normal saline (NS) or Ringer's lactate / Hartmann's solution; K⁺ replacement as needed but caution in AKI [37] |
| Nasogastric tube (NGT) decompression [37][38] | Decompresses dilated proximal bowel (reduces vomiting, aspiration risk); "drip and suck" principle | Placed on free drainage with 4-hourly aspiration; use non-vented (Ryle) or vented (Salem Sump) tube [37] |
| Analgesia | Pain control is essential and does NOT mask clinical signs when used appropriately | NSAIDs first-line for renal colic [34]; opioids for severe visceral pain; avoid opioids if bowel obstruction suspected (↓motility) |
| Broad-spectrum antibiotics [37][38] | Cover for bacterial translocation from obstructed/ischaemic/inflamed bowel | Indicated when infection suspected (diverticulitis, perforation, strangulation); prophylactic before any emergency surgery |
| Urinary catheter | Monitor urine output as a marker of end-organ perfusion | Especially important in haemodynamically unstable patients and those going to theatre |
| Blood tests + Type and Screen [37] | Baseline for surgery; cross-match blood if haemorrhage suspected | T/S mandatory before any operative intervention |
2. Condition-Specific Management
2.1 Acute Diverticulitis
This is the most common cause of LLQ pain requiring specific management in clinical practice. Management is stratified by the Hinchey classification [2][24][39].
A. Outpatient Management (mild, immunocompetent, tolerating oral intake, no significant comorbidities):
| Component | Details |
|---|---|
| Oral antibiotics for 7-10 days [39] | Amoxicillin-clavulanate (single agent) OR Metronidazole + Cotrimoxazole OR Ciprofloxacin OR Moxifloxacin [39] |
| Diet | Clear liquid diet initially → advance to low-residue diet as symptoms improve → long-term high-fibre diet |
| Follow-up | Review in 2-3 days to ensure clinical improvement |
Why antibiotics? The inflamed diverticulum contains trapped bacteria (faecal flora) that drive the infective process. Coverage must include Gram-negative aerobes (e.g. E. coli) and anaerobes (e.g. Bacteroides). Metronidazole ("metro" = measure, originally for Trichomonas) is the cornerstone anti-anaerobic agent.
Evolving Practice
According to WSES 2016 guidelines, antibiotics may not be strictly necessary for immunocompetent patients with uncomplicated diverticulitis and no systemic signs of infection [40]. However, this practice remains controversial and is not yet standard in Hong Kong — most local units still prescribe antibiotics routinely.
B. Inpatient Management (moderate symptoms, unable to tolerate oral, significant comorbidity, immunocompromised, failed outpatient therapy):
| Component | Details |
|---|---|
| NPO + IV fluids | Bowel rest; correct dehydration |
| IV antibiotics [39][40] | Piperacillin-tazobactam (tazocin) OR Metronidazole + Cephalosporin (e.g. cefuroxime) or Fluoroquinolone [39]; switch to PO after clinical resolution (typically 3-5 days) [40]; total course 10-14 days |
| Analgesia | Paracetamol ± opioids; avoid NSAIDs (may worsen diverticulitis/increase perforation risk) |
| Monitoring | Vital signs, abdominal examination, WBC/CRP trends |
CT abdomen staging using the Hinchey classification directly guides management [2][24]:
| Hinchey Stage | Description | Mortality | Management |
|---|---|---|---|
| I | Localised pericolic abscess | 0% | IV antibiotics ± percutaneous drainage if abscess > 4-5 cm [24][40] |
| II | Distant abscess (retroperitoneal/pelvic) | 5% | IV antibiotics + image-guided percutaneous drainage [24][40] |
| III | Generalised purulent peritonitis (abscess ruptured, bowel intact) | 25% | IV antibiotics + surgery: Hartmann's procedure or one-stage resection [24] |
| IV | Faecal peritonitis (bowel wall perforation) | 50% | IV antibiotics + surgery: Hartmann's procedure [24] |
Why the 4-5 cm cut-off for abscess drainage? [40]
- Abscesses < 4-5 cm tend to respond to antibiotics alone because the host's immune system can wall off and resorb small collections.
- Abscesses ≥ 4-5 cm have too large a bacterial load for antibiotics to sterilize — they need source control via percutaneous drainage (CT-guided insertion of a pigtail catheter into the abscess cavity to evacuate pus).
Microperforation (localized pericolic air or small fluid on CT) is NOT considered complicated disease — it is managed as uncomplicated diverticulitis [40].
Indications for emergency surgery [39]:
- Frank (free) perforation (Hinchey III-IV)
- Failure of medical treatment with IV antibiotics
- Colonic obstruction
- Abscess failing non-operative intervention
Surgical Options:
| Procedure | Description | When Used |
|---|---|---|
| Hartmann's procedure | Resection of diseased sigmoid → end colostomy + closure of rectal stump (Hartmann's pouch) | Emergency surgery for Hinchey III-IV [24]; safest option in septic, haemodynamically unstable patient — avoids anastomotic leak risk |
| One-stage resection with primary anastomosis | Resection of sigmoid + immediate colorectal anastomosis ± proximal diverting ileostomy | Selected Hinchey III patients who are haemodynamically stable, without severe contamination; lower morbidity than Hartmann's if patient is suitable |
| Laparoscopic lavage | Peritoneal washout without resection | Considered for Hinchey III (purulent peritonitis) in select centres; controversial — some evidence of higher re-intervention rate |
Why Hartmann's? In an emergency with faecal peritonitis, the bowel is oedematous, friable, and contaminated. Creating an anastomosis in this environment carries a very high leak rate (up to 30-50%). Hartmann's procedure avoids this risk by bringing the proximal end out as a colostomy and closing the rectal stump. Reversal of the colostomy can be attempted later (typically 3-6 months) when the patient has recovered.
Indications for elective surgery (interval sigmoid colectomy with primary anastomosis) [39][40]:
- Previous complicated diverticulitis (Hinchey III-IV that was managed non-operatively initially)
- Immunocompromised patients (higher risk of perforation and poorer healing)
- Inability to exclude malignancy on follow-up colonoscopy
- Persistent symptoms (smouldering diverticulitis)
- Fistula formation (e.g. colovesical — requires en-bloc resection of fistula tract + sigmoid colectomy + bladder repair)
- Stricture causing obstruction
Important Paradigm Shift
Recurrent episodes of uncomplicated diverticulitis are NO longer an indication for elective surgery [39][40]. This was previously thought to increase complication risk, but current evidence shows that prior uncomplicated attacks do NOT predict increased incidence or severity of future attacks. The old "two-strikes-and-you're-out" rule has been abandoned.
Diverticular bleeding is distinct from diverticulitis — they rarely coexist [2][24].
| Step | Management |
|---|---|
| 1 | Fluid resuscitation and blood transfusion [39] |
| 2 | 50% of diverticular bleeding stops spontaneously [24] |
| 3 | Colonoscopy to identify bleeding site and achieve haemostasis (adrenaline injection, metallic clips, thermal coagulation) [24][39] |
| 4 | If colonoscopy fails → mesenteric angiography with super-selective embolisation |
| 5 | If angiography fails → on-table lavage and colonoscopy |
| 6 | Indications for laparotomy and subtotal/total colectomy: haemodynamically unstable despite resuscitation; excessive blood transfusion > 6 units; frequent rebleeding or persistent bleeding [39] |
| Measure | Rationale |
|---|---|
| High-fibre diet [24] | Increases stool bulk → reduces intraluminal pressure → prevents new diverticula and symptoms |
| Bulk laxatives (e.g. methylcellulose) [24] | Same rationale as above |
| Weight reduction [24] | Obesity increases diverticular complications |
| Antispasmodics if colicky pain [24] | Reduce smooth muscle spasm in symptomatic uncomplicated diverticular disease (SUDD) |
| Avoid stimulant laxatives [24] | May increase intraluminal pressure → worsen disease |
| Avoid NSAIDs [24] | Increase risk of diverticular complications (bleeding and perforation) |
| Colonoscopy 6 weeks after acute episode [40] | Rule out CRC — 2.8% of CT-diagnosed "diverticulitis" cases turn out to be CRC [40] |
| Phase | Management | Details |
|---|---|---|
| Initial (no peritonitis/ischaemia) | Endoscopic decompression by flexible sigmoidoscopy [37][41] | Pass a sigmoidoscope to the site of torsion → gently advance past the twist → dramatic decompression with rush of gas/liquid stool → place a rectal flatus tube to maintain decompression |
| Post-decompression | Interval sigmoid colectomy | 50% recurrence rate with endoscopic decompression alone [41]; young patients should have sigmoid colectomy due to high recurrence [37]; elderly/frail patients may be managed with repeated decompression |
| Peritonitis / ischaemia / failed decompression | Emergency laparotomy | Resection of gangrenous sigmoid ± Hartmann's procedure if contamination/instability; primary anastomosis if bowel is viable and patient is stable |
Why does volvulus recur? The underlying predisposition — a long, redundant sigmoid with a narrow mesenteric attachment — is not corrected by decompression alone. Only resection removes the at-risk segment.
2.3 Ischaemic Colitis
| Component | Details | Rationale |
|---|---|---|
| NPO, NGT on suction if ileus [42] | Bowel rest | Reduce metabolic demand on ischaemic bowel |
| IV fluids | Optimise circulating volume | Improve splanchnic perfusion |
| Broad-spectrum antibiotics [42] | Cover for bacterial translocation | Ischaemic mucosa loses barrier function → risk of secondary infection |
| Rectal tube decompression [42] | Decompress distended colon | Reduce intraluminal pressure → improve mural perfusion |
| Withhold offending agents | Stop vasopressors, digoxin, diuretics if possible | These reduce splanchnic blood flow |
| ± Antithrombotics | If clinical indication of occlusive disease | Prevent clot propagation |
Features suggestive of severe ischaemia or infarction/necrosis [42]:
- Ongoing pain out of proportion to physical examination or with peritoneal signs
- Haemodynamic instability or sepsis, persistent fever
- Involvement of right colon (implies more extensive proximal disease)
- Pneumatosis coli or portalis, or perforation (free gas) on AXR
- Gangrene on colonoscopy
Surgical approach: Emergency laparotomy → resection of ischaemic segments ± primary anastomosis → second-look procedure at 24-48 hours to reassess viability [42]
Why is right colon involvement ominous? Right-sided ischaemic colitis implies SMA territory involvement (not just IMA watershed zones), suggesting a more proximal and severe vascular insult — often embolic or thrombotic rather than the typical non-occlusive cause.
Prognosis: Mortality < 5% in non-gangrenous disease but up to 50-75% if gangrene develops [42]
| Scenario | Management |
|---|---|
| Resectable, no perforation/ischaemia | Endoscopic self-expanding metallic stent (SEMS) as bridge to surgery [41] → elective definitive resection 1-2 weeks later; allows bowel preparation → better surgical outcome, lower stoma rate, more time to stage disease |
| Resectable, stable but stenting not feasible | Emergency resection: left-sided → Hartmann's procedure or one-stage resection with primary anastomosis ± diverting ileostomy; choice depends on degree of contamination and patient fitness |
| Unresectable/metastatic | Palliative SEMS → avoid surgery and stoma for terminal patients [41] |
| Perforation or ischaemia | Emergency laparotomy → resection |
SEMS contraindications [41]:
- Perforated or strangulated obstruction
- Persistent coagulopathy
- Distal rectal lesion ≤ 5 cm from anal verge (excruciating pain if stent migrates beyond dentate line)
SEMS outcomes [41]: 92% successful deployment; median patency 106 days; complications include 11% migration, 4.5% perforation, 12% re-obstruction
2.5 Ureteric Colic (Left)
| Component | Details | Rationale |
|---|---|---|
| Analgesia: NSAIDs first-line [34] | e.g. diclofenac, ketorolac | NSAIDs inhibit prostaglandin synthesis → reduce ureteric smooth muscle spasm and renal pelvic pressure; more effective than opioids for renal colic |
| Opioids (second-line) [34] | Hydromorphine, pentazocine, tramadol | For patients who cannot tolerate NSAIDs (renal impairment, peptic ulcer) |
| α-blockers [34] | Tamsulosin 0.4 mg daily | Reduce recurrent colic; relax ureteric smooth muscle (high density of α₁-receptors in distal ureter) |
| Antibiotics if infection [34] | Empirical broad-spectrum | Infected obstructed system = urological emergency → decompression needed |
Indications:
- Uncontrolled sepsis
- Progressively worsening renal function
- (Intractable pain)
| Method | Details | Pros/Cons |
|---|---|---|
| Percutaneous nephrostomy (PCN) [34] | External drainage of renal pelvis under imaging guidance | Quicker → preferred in septic shock; C/I: bleeding tendency, distorted anatomy, obesity |
| JJ ureteric stent [34] | Internal drainage from renal pelvis to bladder | More comfortable; C/I: BPH, non-compliant bladder, stone impaction |
Chance of spontaneous passage [43]:
| Stone Size | Spontaneous Passage Rate |
|---|---|
| ≤ 4 mm | 95% |
| 4-10 mm | Progressively decreasing |
| ≥ 10 mm | Unlikely → stone removal definitely indicated |
Medical expulsion therapy (MET) [43]:
- α-blocker tamsulosin 0.4 mg daily × 4 weeks (off-label)
- Best for distal ureteric stones > 5 mm (highest density of α₁-receptors in distal ureter)
- α-blockers make patients 1.45× more likely to pass ureteric stones
Definitive stone removal — modalities by site (EAU guidelines) [34]:
| Site | Scenario | Modality of Choice |
|---|---|---|
| Renal | Asymptomatic | Conservative; chemolysis (urine alkalinisation) for urate stones |
| < 10 mm | ESWL or RIRS > PCNL | |
| 10-20 mm (non-lower pole) | ESWL or RIRS or PCNL | |
| > 20 mm | PCNL > RIRS or ESWL | |
| Lower pole 10-20 mm | RIRS or PCNL > ESWL (if unfavourable factors for ESWL) | |
| Proximal ureter | — | ESWL or ureteroscopy |
| Distal ureter | — | Ureteroscopy (semi-rigid or flexible) > ESWL |
Breakdown of modalities:
-
ESWL = Extracorporeal Shock Wave Lithotripsy ("litho" = stone, "tripsy" = crushing): focused shock waves fragment the stone from outside the body. Non-invasive but C/I in bleeding tendency, active urosepsis, pregnancy [43]. Less effective for hard stones (cystine, brushite), lower pole stones (fragments trapped by gravity), and stones > 1000 HU on CT [43].
-
RIRS = Retrograde Intrarenal Surgery: flexible ureteroscope passed retrogradely through the urethra → bladder → ureter → renal pelvis; laser lithotripsy fragments the stone. More invasive than ESWL but higher single-procedure stone-free rate.
-
PCNL = Percutaneous Nephrolithotomy ("nephro" = kidney, "litho" = stone, "tomy" = cutting): percutaneous tract created from the flank into the renal collecting system; rigid nephroscope fragments and extracts stones. Best for large stones > 20 mm and staghorn calculi.
-
Ureteroscopy (URS): semi-rigid or flexible scope passed retrogradely into the ureter; best for distal ureteric stones.
2.6 Gynaecological Emergencies
| Scenario | Management |
|---|---|
| Haemodynamically unstable | Emergency laparotomy or laparoscopy → salpingectomy (removal of affected tube) |
| Haemodynamically stable, unruptured | Options: (1) Methotrexate (if β-hCG < 5000, mass < 3.5 cm, no fetal cardiac activity, compliant patient); (2) Laparoscopic salpingectomy (definitive); (3) Laparoscopic salpingotomy (if contralateral tube damaged — fertility-sparing) |
| Declining β-hCG, stable | Expectant management with serial β-hCG monitoring (selected cases) |
Why salpingectomy over salpingotomy? Salpingectomy removes the entire tube → lower risk of persistent trophoblastic tissue and recurrent ectopic in the same tube. Salpingotomy is reserved for women with contralateral tubal damage who want to preserve fertility.
| Management | Details |
|---|---|
| Emergency laparoscopic detorsion | Untwist the ovarian pedicle → assess viability → if viable, preserve ovary (oophoropexy); if necrotic, perform oophorectomy |
| Timing | Urgent — ovarian salvage rates are highest within 6-12 hours |
| Severity | Management |
|---|---|
| Outpatient (mild) | Empirical: IM ceftriaxone 500 mg single dose + oral doxycycline 100 mg BD × 14 days ± oral metronidazole 400 mg BD × 14 days (for anaerobic cover) |
| Inpatient (moderate-severe) | IV ceftriaxone + doxycycline + metronidazole; switch to oral when afebrile for 24-48h |
| Tubo-ovarian abscess | IV antibiotics + image-guided percutaneous or surgical drainage if > 5 cm or failing antibiotics |
| All cases | Contact tracing and treatment of sexual partners; test for STIs |
| Presentation | Management |
|---|---|
| Reducible hernia | Elective surgical repair — laparoscopic (TEP or TAPP) or open mesh repair [44] |
| Incarcerated hernia (not strangulated) | Attempt gentle manual reduction under sedation/analgesia → if successful, proceed to semi-urgent elective repair; if irreducible → urgent surgery |
| Strangulated hernia | Emergency surgery → assess bowel viability at operation → hernia repair if viable; bowel resection + stoma if non-viable [37][44] |
| Femoral hernia | Early elective repair recommended regardless of symptoms due to high strangulation risk (22% at 3 months, 45% at 21 months) [44] |
Why NOT attempt manual reduction of a strangulated hernia? If the bowel is already gangrenous, pushing it back into the abdomen risks (1) peritonitis from necrotic bowel contents, (2) reduction en masse (the hernia sac and contents are reduced together but the constriction persists), and (3) masking the clinical picture [44].
Surgical approaches for femoral hernia [44]:
- Lockwood's infrainguinal approach: hernia sac dissected from below the inguinal ligament
- Lotheissen's transinguinal approach: inguinal canal opened as for inguinal hernia repair
- McEvedy's high approach: preferred if strangulation — allows bowel resection from above
| Component | Management |
|---|---|
| Emergency scrotal exploration [22] | Indicated regardless of duration of torsion — even late exploration can salvage some testes |
| Bilateral orchidopexy | Both testes fixed to the scrotal wall to prevent recurrence (the contralateral testis is at risk — Bell-clapper deformity is usually bilateral [22]) |
| Manual detorsion (if emergency OT not immediately available) [22] | Performed under sedation/analgesia; technique: "open the book" — rotate the affected testis outward (medial to lateral, like opening a book) because most torsions twist inward; confirm success by relief of pain and descent of testis |
| Time-sensitivity | Irreversible damage after ~12 hours of ischaemia [22]; salvage rate ~100% at < 6h, ~50% at 12h, < 10% at > 24h |
Management follows a step-up approach based on disease severity:
| Severity | Treatment |
|---|---|
| Mild-Moderate (outpatient) | Oral and/or topical (rectal) 5-ASA (mesalazine) — first-line for induction and maintenance of remission in UC |
| Moderate (not responding to 5-ASA) | Add oral corticosteroids (prednisolone) for induction; thiopurines (azathioprine / 6-MP) as steroid-sparing maintenance agents [45] |
| Severe / Refractory | IV corticosteroids (hydrocortisone) for acute severe colitis; if no response in 3-5 days → rescue therapy with ciclosporin or infliximab |
| Biologic therapy | Anti-TNFα (infliximab, adalimumab) for refractory disease; MUST screen for TB (CXR + QuantiFERON-TB Gold) and HBV (HBsAg) before starting [45]; TB prophylaxis with isoniazid/rifampicin; HBV prophylaxis with entecavir |
| Surgery | Total proctocolectomy with IPAA (ileo-pouch anal anastomosis) = curative for UC; indicated for: refractory medical therapy, fulminant colitis, toxic megacolon, dysplasia/CRC |
Why screen for TB and HBV before biologics? Anti-TNFα agents suppress cell-mediated immunity → risk of reactivation of latent TB (granuloma breakdown) and HBV (loss of immune surveillance). This is particularly important in Hong Kong where both TB and HBV are endemic [45].
IBS is a functional disorder — management is reassurance-based, dietary, and pharmacological [11]:
| Component | Details |
|---|---|
| Reassurance and education | Explain that IBS is a real condition, not "in the head", but there is no structural damage |
| Dietary modification | Low-FODMAP diet (fermentable oligosaccharides, disaccharides, monosaccharides, and polyols); adequate fibre; avoid trigger foods |
| IBS-C (constipation-predominant) | Soluble fibre supplements, osmotic laxatives (PEG), lubiprostone, linaclotide |
| IBS-D (diarrhoea-predominant) | Loperamide (antidiarrhoeal); low-dose TCA (amitriptyline — slows transit + central analgesic); alosetron (5-HT₃ antagonist) [11] |
| Pain-predominant | Antispasmodics (hyoscine, mebeverine, peppermint oil); low-dose TCA or SSRI for visceral hypersensitivity |
| Psychological therapies | CBT, hypnotherapy — evidence-based for refractory IBS |
Management principles [27][46]:
| Component | Details |
|---|---|
| Resuscitation | NPO, IV fluids, analgesics [27] |
| Prophylactic IV antibiotics | Anaerobic coverage: IV ceftriaxone + metronidazole [27]; non-complicated: continue until 24h post-op; complicated (abscess/phlegmon): continue 3-7 days post-op [27] |
| Laparoscopic appendicectomy | First-line [27] — lower wound infection, post-op pain, and hospital stay compared to open |
| Open appendicectomy | Indicated if gross sepsis, laparoscopic facilities unavailable, or need for conversion |
| Scenario | Management |
|---|---|
| Present within 72 hours + fit for surgery | Immediate laparoscopic appendicectomy [27] |
| Complicated + unstable | Consider open surgery [27] |
| Present > 72 hours + stable (walled-off mass/abscess) | Interval surgery (Ochsner-Sherren regimen): IV antibiotics (~90% success) ± image-guided drainage of abscess → laparoscopic appendicectomy 6-8 weeks later → colonoscopy if > 40 years old to exclude CA [27] |
Consent risks [27]:
- Immediate: conversion to open, normal appendix (still removed), malignancy requiring right hemicolectomy ± stoma, injury to surrounding organs, bleeding
- Early: wound infection (5-10%), intra-abdominal/pelvic abscess (spiking fever), post-op ileus
- Late: incisional hernia, adhesions, recurrent/stump appendicitis
Conservative management (antibiotics-first strategy) [27]:
- Can be considered if uncomplicated (no perforation/abscess) and not fit for surgery
- Recurrence rate: 30% at 3 months, 40% at 1 year, 50% at 3 years [27]
- Supported by: CODA trial (2020): 10-day antibiotics non-inferior to appendicectomy; 30% chance of appendicectomy in 90 days; increased risk if appendicoliths present [27]
| Condition | Emergency Surgery | Elective Surgery |
|---|---|---|
| Diverticulitis | Hartmann's procedure (Hinchey III-IV) | Sigmoid colectomy with primary anastomosis (interval) |
| Sigmoid volvulus | Laparotomy + resection if gangrenous | Sigmoid colectomy (interval after decompression) |
| Ischaemic colitis | Resection of gangrenous segments | Rarely needed |
| CRC with LBO | Hartmann's or resection ± stoma | Elective resection after stenting |
| Strangulated hernia | Hernia repair ± bowel resection | Elective mesh repair |
| Ruptured ectopic | Emergency salpingectomy | N/A |
| Ovarian torsion | Laparoscopic detorsion / oophorectomy | N/A |
| Testicular torsion | Scrotal exploration + bilateral orchidopexy | N/A |
High Yield Summary
Management of LLQ Pain — Key Exam Points:
- Initial management for all: NPO + IV fluids + NGT decompression ("drip and suck") + analgesia + antibiotics if infection suspected + type and screen [37][38]
- Diverticulitis management by Hinchey stage: I = antibiotics ± drainage; II = antibiotics + drainage; III-IV = surgery (Hartmann's or primary anastomosis) [24]
- Abscess cut-off: < 4-5 cm → antibiotics; ≥ 4-5 cm → percutaneous drainage [40]
- Recurrent uncomplicated diverticulitis is NO longer an indication for surgery [39][40]
- Colonoscopy 6 weeks after diverticulitis to rule out CRC (2.8% positive rate) [40]
- Sigmoid volvulus: endoscopic decompression first → interval colectomy (50% recurrence rate) [41]
- Ureteric colic: NSAIDs first-line; MET with tamsulosin for distal stones > 5 mm; ESWL/URS/PCNL for definitive removal [34][43]
- Testicular torsion: emergency scrotal exploration + bilateral orchidopexy; irreversible damage after ~12h [22]
- Ruptured ectopic: emergency surgery if unstable; methotrexate if stable + meets criteria [22]
- Before starting biologics for IBD: MUST screen for TB and HBV (Hong Kong endemic) [45]
- Hartmann's procedure = sigmoid resection + end colostomy + closure of rectal stump → safest in septic/unstable patient with faecal peritonitis
Active Recall - Management of LLQ Pain
References
[2] Senior notes: maxim.md (Diverticular disease — Hinchey classification, Diverticular bleeding management) [4] Senior notes: Ryan Ho GI.pdf (p146 — Ischaemic Colitis management) [11] Senior notes: Ryan Ho GI.pdf (p118 — IBS management) [22] Senior notes: Ryan Ho Urogenital.pdf (p233 — Testicular Torsion management, Manual detorsion) [24] Senior notes: maxim.md (Diverticular disease — Hinchey classification with mortality and treatment; CT for abscess drainage; Colonoscopy after resolution) [27] Senior notes: maxim.md (Acute appendicitis — Management: antibiotics, laparoscopic appendicectomy, Ochsner-Sherren, consent risks, CODA trial) [34] Senior notes: Ryan Ho Urogenital.pdf (p140 — Ureteric colic acute management: NSAIDs, alpha-blockers, JJ stent, PCN, EAU guidelines) [37] Senior notes: felixlai.md (Intestinal obstruction — Supportive management: NPO, IV fluids, NGT, antibiotics) [38] Senior notes: Ryan Ho GI.pdf (p138 — Supportive management of IO: drip and suck, NPO, NGT, IVF) [39] Senior notes: felixlai.md (Diverticulitis — Treatment: emergency surgery indications, elective surgery indications, antibiotic regimens, diverticular bleeding management) [40] Senior notes: Ryan Ho GI.pdf (p158 — Conservative treatment of diverticulitis, abscess size cut-off, interval colectomy indications, WSES 2016) [41] Senior notes: Ryan Ho GI.pdf (p139 — LBO management: sigmoid volvulus decompression, endoscopic stenting, surgical management) [42] Senior notes: Ryan Ho GI.pdf (p147 — Ischaemic colitis management: conservative vs surgical, risk factors for poor outcome, features of severe ischaemia) [43] Senior notes: Ryan Ho Urogenital.pdf (p141 — Conservative Tx and MET, spontaneous passage rates, ESWL, URS) [44] Senior notes: Ryan Ho Urogenital.pdf (p225 — Femoral hernia: early repair, surgical approaches, strangulation risk) [45] Senior notes: felixlai.md (IBD — Biologic therapies: TB and HBV screening, contraindications) [46] Senior notes: Ryan Ho GI.pdf (p152 — Appendicectomy approach, timing, Ochsner-Sherren, unexpected findings)
Complications of Conditions Causing LLQ Pain
This section covers the complications of the major causes of LLQ pain — both complications of the diseases themselves and complications of their treatments. Understanding complications requires understanding the natural history of each disease and what happens when pathological processes are left unchecked.
1. Complications of Acute Diverticulitis
Diverticulitis is fundamentally an infective/inflammatory process that begins with obstruction of a diverticular neck by a faecolith. If not contained, the infection progressively extends. Each complication represents a stage in this continuum.
| Complication | Incidence | Pathophysiology | Clinical Features | Management |
|---|---|---|---|---|
| Abscess | 17% of acute diverticulitis [47] | Microperforation of diverticulum is walled off by mesentery/omentum/adjacent structures → localized collection of pus | Persistent fever and no improvement in abdominal pain despite 3 days of antibiotics [47]; palpable tender mass; may develop pyogenic liver abscess via portal circulation [47] | < 4-5 cm → IV antibiotics; ≥ 4-5 cm → CT-guided percutaneous drainage [24] |
| Fistula | ~2% of diverticulitis | Chronic inflammation erodes into an adjacent organ, creating an epithelialised tract between two surfaces | Depends on type — see below | Control sepsis → resection of affected sigmoid with fistula → primary repair of secondarily involved organ [47] |
| Obstruction | Variable | Partial: pericolonic inflammation/oedema or abscess compression narrowing the lumen; Complete: recurrent attacks → progressive fibrosis and scarring → stricture formation; Paralytic ileus from localised peritoneal irritation [47] | Colicky abdominal pain, distension, vomiting, constipation; hyperactive bowel sounds with obstruction; absent/sluggish bowel sounds with paralytic ileus [47] | Partial: conservative (bowel rest, NGT); Complete/refractory: surgical resection of strictured segment |
| Perforation | Hinchey III-IV | Rupture of diverticular abscess into peritoneal cavity (purulent peritonitis) or rupture of inflamed diverticulum with faecal contamination (faecal peritonitis) [47] | Haemodynamic instability, peritoneal signs (guarding, rigidity, rebound tenderness), absent bowel sounds, pneumoperitoneum on CXR | Emergency surgery: Hartmann's procedure [24]; mortality up to 50% in Hinchey IV [24] |
| Diverticular bleeding | ~9.5% bleed in 10 years [48] | Vasa recta draped over dome of diverticulum → exposed to luminal injury → eccentric intimal thickening and medial thinning → segmental weakness → rupture [47]; right colon more common source (thinner wall, wider diverticular necks) [47] | Painless massive haematochezia [2]; diverticular bleeding and diverticulitis rarely co-exist [48]; 80% self-limiting [48] | Colonoscopy (diagnostic + therapeutic) → angiography → surgery if all else fails [39][48] |
Types of diverticular fistulae [47]:
| Fistula Type | Frequency | Clinical Features | Why It Happens |
|---|---|---|---|
| Colovesical (most common) [2][47] | Most frequent | Recurrent dysuria, pneumaturia (air in urine), faecaluria (stool in urine) [2] | Sigmoid colon is anatomically adjacent to the bladder dome; chronic inflammation erodes through the intervening tissue |
| Colovaginal | Second most common, especially post-hysterectomy [47] | Vaginal passage of faeces and flatus | After hysterectomy, the vaginal cuff lies directly against the sigmoid with no uterine buffer |
| Colocutaneous | Uncommon | Faeculent discharge from abdominal wall | Usually easy to identify clinically |
| Coloenteric | Uncommon | May be asymptomatic or cause corrosive diarrhoea | Inflammation erodes into adjacent small bowel loop |
Why does the right colon bleed more than the left in diverticular bleeding? Although left-sided diverticula are more common (in Western populations), right-sided diverticula have wider necks and domes that expose a greater length of the vasa recta to mucosal injury. Additionally, the right colonic wall is thinner, providing less protection for the draped artery [47].
Long-term sequelae of diverticulitis [48]:
- Only 30% remain asymptomatic long-term after first episode
- Recurrence in ~1/3 patients (especially females, younger age), but NOT associated with increased risk of complications
- Chronic abdominal pain from persistent low-grade diverticulitis or IBS-like symptoms
- Diverticular colitis: IBD-like segmental colitis following acute diverticulitis
- Diverticular stricture: progressive fibrosis → chronic/acute obstruction
| Timing | Complication | Pathophysiology | Management |
|---|---|---|---|
| Immediate | Intraoperative organ injury (left ureter, gonadal vessels, iliac artery, spleen during splenic flexure mobilisation) [49] | The left ureter runs in close proximity to the sigmoid mesentery; splenic flexure mobilisation puts the spleen at risk of capsular tears | Intra-operative recognition + repair; conversion to open if needed |
| Early ( < 30 days) | Surgical site infection [49] | Bacterial contamination of wound during colonic surgery; risk increased with emergency procedures and contamination | Wound care, antibiotics; open and drain if collection |
| Post-operative ileus [49] | Normal physiological response to bowel handling + peritoneal inflammation; usually resolves in 24-72h | Supportive: NPO, NGT, IV fluids; usually self-resolving | |
| Anastomotic bleeding [49] | Bleeding from staple/suture line | Blood transfusion + correction of coagulopathy; endoscopic haemostasis if accessible | |
| Anastomotic leak (most feared) [49] | Ischaemia at suture line, tension, inadequate blood supply, technical error; becomes apparent 5-7 days post-op [49]; signs: pain, fever, tachycardia, feculent/purulent drainage [49] | Fluid resuscitation, broad-spectrum IV antibiotics, bowel rest, CT-guided percutaneous drainage of collection, ± temporary faecal diversion, ± resection of anastomosis [49] | |
| Late ( > 30 days) | Anastomotic stricture [49] | Fibrosis and scarring at anastomotic site | Most do not require intervention; if symptomatic → finger dilatation (low) or endoscopic balloon dilatation (high) [49] |
| Fistula (enterocutaneous, rectovaginal, rectourinary) [49] | Anastomotic leak → chronic collection → fistulisation | Enterocutaneous → often closes spontaneously; Rectovaginal/rectourinary → proximal faecal diversion [49] | |
| Incisional hernia | Fascial weakness at surgical incision site | Surgical repair (mesh) |
Stoma-specific complications (if Hartmann's with end colostomy, or diverting stoma) [49]:
| Timing | Complication | Why |
|---|---|---|
| Early | Stomal bleeding, necrosis, retraction, mucocutaneous separation | Ischaemia of the stoma due to tension or inadequate blood supply; technical issues at creation |
| Skin irritation and dermatitis (most common in ileostomy) [49] | High-output alkaline enzymatic effluent from ileostomy erodes peristomal skin | |
| Late | Parastomal hernia, stomal prolapse, stomal stenosis [49] | Weakness of abdominal wall around the stoma tract → herniation; prolapse from redundant bowel; stenosis from fibrosis |
CRC causes LLQ complications through its local growth (obstruction, perforation, invasion) and systemic effects (metastasis, cachexia).
| Complication | Pathophysiology | Clinical Features |
|---|---|---|
| Large bowel obstruction | Annular constricting tumour occludes the sigmoid lumen | Colicky abdominal pain, distension, absolute constipation, late faeculent vomiting; competent ileocaecal valve creates a closed-loop obstruction → risk of caecal perforation when caecum dilates > 9-12 cm [37] |
| Perforation | Tumour necrosis → wall breakdown; or caecal perforation from closed-loop obstruction (highest wall tension in the caecum by Laplace's law — largest radius) | Sudden severe pain, peritonitis, pneumoperitoneum; very high mortality |
| Bleeding | Fragile tumour neovascularization | Chronic occult bleeding → iron deficiency anaemia (right-sided); overt PR bleeding (left-sided) |
| Fistula formation | Locally advanced tumour invades adjacent organs | Colovesical, colovaginal fistulae (similar presentation to diverticular fistulae) |
| Metastasis | Haematogenous (liver > lung > bone > brain), lymphatic, transcoelomic (peritoneal carcinomatosis) | Hepatomegaly, jaundice, ascites (peritoneal disease), pulmonary symptoms, bone pain |
Post-surgical complications of colectomy for CRC are similar to those described for diverticulitis surgery above, with the addition of:
- Autonomic nerve injury (especially in rectal surgery): sympathetic damage → incontinence, impaired ejaculation; parasympathetic damage → urinary retention, erectile dysfunction [49]
- Low anterior resection (LAR) syndrome: change in bowel movement (frequency, urgency, faecal incontinence) persisting ≥ 1 month post-surgery [49]; due to colonic dysmotility, neorectal reservoir dysfunction, and anal sphincter dysfunction; managed with pelvic floor muscle exercise, antidiarrhoeal agents, transanal irrigation [49]
| Complication | Pathophysiology | Clinical Features |
|---|---|---|
| Transmural necrosis / Gangrene | Prolonged ischaemia (only 15% of cases) → full-thickness bowel wall death | Worsening pain, peritoneal signs, haemodynamic instability, metabolic acidosis, pneumatosis intestinalis or portal venous gas on AXR [4]; mortality 50-75% [42] |
| Perforation | Necrotic bowel wall → structural failure → free perforation | Pneumoperitoneum, faecal peritonitis → emergency laparotomy |
| Stricture | Chronic ischaemic insult → mucosal ulceration → healing by fibrosis | Progressive obstructive symptoms weeks-months after the acute episode; may require endoscopic dilatation or segmental resection |
| Chronic ischaemic colitis | Incomplete healing of mucosal injury | Persistent bloody diarrhoea, protein-losing enteropathy, iron deficiency anaemia |
| Sepsis and multi-organ failure | Bacterial translocation through ischaemic mucosa → systemic sepsis | Fever, tachycardia, hypotension, confusion, raised lactate, organ dysfunction |
Why is right-sided ischaemic colitis a poor prognostic sign? Right colon involvement implies SMA territory involvement rather than the typical IMA watershed non-occlusive disease. This suggests a more proximal, extensive, and potentially embolic/thrombotic aetiology — associated with higher rates of transmural necrosis and need for surgery [42].
| Complication | Pathophysiology | Clinical Features |
|---|---|---|
| Bowel ischaemia and gangrene | Torsion ≥ 360° compromises mesenteric blood supply [5] → arterial insufficiency → ischaemic necrosis | Worsening constant pain, peritoneal signs, fever, tachycardia, raised lactate |
| Perforation | Gangrenous sigmoid wall → structural failure | Faecal peritonitis → septic shock |
| Recurrence | 50% recurrence rate with endoscopic decompression alone [41] because the anatomical predisposition (long redundant sigmoid, narrow mesentery) persists | Recurrent episodes of volvulus → each episode carries cumulative risk of ischaemia |
| Electrolyte disturbances | Prolonged vomiting → hyponatraemia, hypokalaemia, metabolic alkalosis; bowel ischaemia → metabolic acidosis with raised lactate [5] | Confusion, cardiac arrhythmias, renal impairment |
| Complication | Pathophysiology | Clinical Features |
|---|---|---|
| Obstructive uropathy / Hydronephrosis | Ureteric stone blocks urine flow → backpressure → dilation of renal pelvis and calyces → parenchymal damage | Persistent flank pain, ↑creatinine (bilateral/solitary kidney), hydronephrosis on USS |
| Urinary tract infection / Urosepsis | Stasis of urine proximal to obstruction → bacterial overgrowth; infected obstructed system is a urological emergency | Fever, rigors, tachycardia, hypotension; pyuria; positive urine and blood cultures → requires urgent decompression (JJ stent or PCN) [34] |
| Renal impairment | Prolonged obstruction → tubular atrophy → loss of renal function; especially dangerous if bilateral or solitary kidney | Rising creatinine; kidney with < 15% total renal function on DTPA/MAG3 scintigraphy is not worth salvaging [34] |
| Stone recurrence | Underlying metabolic predisposition (hypercalciuria, hyperoxaluria, hypocitraturia, hyperuricosuria) persists | 50% recurrence within 5 years without preventive measures |
| Post-ESWL complications | Shock wave-induced tissue damage | Steinstrasse ("stone street" — column of stone fragments obstructing the ureter), renal haematoma, haematuria (usually self-limiting) |
| Post-ureteroscopy complications | Instrumentation trauma | Ureteric perforation, stricture, infection, JJ stent symptoms (irritative LUTS, flank pain on micturition) |
| Complication | Pathophysiology | Clinical Features |
|---|---|---|
| Perforation [50] | Transmural inflammation → necrosis → wall breakdown; risk increases once significant inflammation and necrosis occurs [50]; consider when fever > 39.4°C, WBC > 15 × 10⁹/L, imaging shows RLQ fluid collection [50] | Sudden worsening of pain → diffuse peritonitis if not walled off |
| Appendiceal abscess / Phlegmon | Perforation walled off by omentum/adjacent bowel → localized collection | RLQ mass, spiking fever [27], persistent pain despite antibiotics |
| Generalised peritonitis | Perforation not walled off → free contamination of peritoneal cavity | Diffuse abdominal tenderness, guarding, rigidity, sepsis |
| Pylephlebitis (septic portal vein thrombosis) [50] | Septicaemia spreads through portal venous system from appendiceal veins → thrombosis + infection → intrahepatic abscesses | High fever, chills, rigors, jaundice [50]; rare but life-threatening |
Post-appendicectomy complications [27][50]:
- Wound infection (5-10%) [27]
- Intra-abdominal / pelvic abscess (spiking fever post-operatively) [27]
- Post-operative ileus [27]
- Adhesive intestinal obstruction (long-term) [50]
- Enterocutaneous fistula (from intraperitoneal abscess fistulising to skin) [50]
- Stump appendicitis (incomplete appendicectomy → inflammation of residual stump) [27]
- Incisional hernia [27]
| Condition | Complication | Pathophysiology |
|---|---|---|
| Ruptured ectopic pregnancy | Hypovolaemic shock, death | Tubal rupture → intraperitoneal haemorrhage → exsanguination if not treated |
| Infertility | Loss of fallopian tube (salpingectomy); contralateral tubal damage from adhesions | |
| Ovarian torsion | Loss of ovary | Prolonged ischaemia → necrotic ovary → oophorectomy required |
| Recurrence | If the underlying cyst is not removed; oophoropexy may not always prevent re-torsion | |
| PID | Tubo-ovarian abscess | Spread of infection → walled-off pelvic collection → requires drainage |
| Chronic pelvic pain | Adhesion formation from repeated episodes of pelvic inflammation | |
| Infertility | Tubal damage from scarring and adhesions → ectopic pregnancy risk also increased | |
| Fitz-Hugh-Curtis syndrome | Perihepatitis — gonococcal/chlamydial infection spreads to liver capsule → "violin string" adhesions → pleuritic RUQ pain |
| Complication | Pathophysiology | Clinical Features |
|---|---|---|
| Irreducibility (incarceration) | Contents trapped in the hernia sac by narrow neck or adhesions | Hernia cannot be reduced; mild-moderate discomfort; ± features of bowel obstruction |
| Obstruction | Incarcerated bowel loop → luminal obstruction without vascular compromise | Colicky pain, vomiting, distension, constipation; hernia is tender but not acutely inflamed |
| Strangulation | Compromised blood supply to contents → ischaemia → gangrene as early as 5-6 hours [44] | Acutely tender, tense, irreducible hernia; loss of cough impulse; signs of IO; ± overlying erythema [44]; progresses to perforation, peritonitis, sepsis |
| Richter's hernia | Only the anti-mesenteric border of bowel wall is trapped → ischaemia without complete luminal obstruction | Can strangulate WITHOUT features of intestinal obstruction — easily missed; higher risk in femoral hernias (narrow rigid ring) |
| Maydl's hernia | Two loops of bowel enter the sac with the intervening loop remaining intra-abdominal; the intra-abdominal loop strangulates | The strangulated loop is inside the abdomen — external examination may be misleading |
Why does strangulation happen so quickly in femoral hernias? The femoral ring is bounded by rigid structures (inguinal ligament superiorly, lacunar ligament medially, femoral vein laterally, pectineal ligament posteriorly) — there is no "give." Once bowel enters this ring, even slight distension from luminal gas causes the rigid boundaries to compress the mesenteric vessels → ischaemia within hours [44].
| Complication | Pathophysiology | Clinical Features |
|---|---|---|
| Stricture [51] | Repeated episodes of inflammation → muscle hypertrophy and fibrosis → luminal narrowing | Obstructive symptoms; should be considered malignant until proven otherwise by endoscopy and biopsy [51] |
| Fulminant colitis [51] | Severe, extensive inflammation extending beyond the mucosa to involve the muscle layers | ≥ 10 stools/day, continuous bleeding, abdominal pain, distension, acute severe toxic symptoms (fever, anorexia) |
| Toxic megacolon [51] | Inflammatory process extends to the muscularis → loss of colonic tone → massive non-obstructive dilatation (≥ 6 cm or caecum > 9 cm) [51] | Fever, tachycardia, hypotension, dehydration, electrolyte disturbances, altered mental status; diagnosis by plain AXR [51]; high risk of perforation |
| Perforation [51] | Most commonly occurs as a consequence of toxic megacolon [51] | Peritonitis; associated with high mortality [51] |
| Colorectal cancer [51] | Chronic inflammation → dysplasia → carcinoma sequence; risk increases with duration and extent of disease (5-15× risk after 8-10 years in pancolitis, 15-20 years in left-sided colitis) | May be asymptomatic until advanced; regular endoscopic surveillance recommended |
Post-surgical complications of UC (total proctocolectomy with IPAA) [51]:
- Pouchitis (most common long-term complication): inflammation of the ileal pouch; treated with metronidazole + ciprofloxacin
- Pouch-vaginal / perineal fistula
- Anastomotic stricture / dehiscence
- Sexual dysfunction / Infertility (especially in females — pelvic dissection can damage tubal patency)
These are general post-operative complications that apply across all surgical conditions causing LLQ pain [52]:
| Timing | Complication | Examples |
|---|---|---|
| Immediate ( < 1h) | Bleeding (primary haemorrhage), organ injury, anaesthesia-related (hypotension, arrhythmia, aspiration) | Laparoscopy-specific: organ puncture, vascular injury, port-site hernia, pneumothorax from pneumoperitoneum [52] |
| Early (24-48h) | Reactionary haemorrhage (within 24h — stress-related vasoconstriction masks bleeding vessel intra-op → bleeds when BP normalises) [52]; post-op ileus; wound infection; AROU; UTI; atelectasis → pneumonia | |
| Late ( > 48h) | Secondary haemorrhage (7-10 days — due to pseudoaneurysm from infection; "warning bleed" before torrential haemorrhage) [52]; anastomotic leak; wound infection; DVT/PE; adhesive intestinal obstruction; incisional hernia |
High Yield Summary
Complications of LLQ Pain Conditions — Key Exam Points:
- Diverticulitis complications: Abscess (17%), fistula (most common = colovesical → pneumaturia, faecaluria), obstruction (partial from oedema, complete from fibrosis/stricture), perforation (Hinchey III-IV), diverticular bleeding (painless, usually right-sided source)
- Diverticular bleeding and diverticulitis rarely co-exist [48] — different pathophysiological mechanisms
- Anastomotic leak is the most feared surgical complication — appears 5-7 days post-op with pain, fever, tachycardia, feculent drainage [49]
- Toxic megacolon in UC: total/segmental non-obstructive dilatation ≥ 6 cm, diagnosed on AXR, high risk of perforation [51]
- UC strictures should be considered malignant until proven otherwise [51]
- Sigmoid volvulus recurrence rate = 50% with endoscopic decompression alone → interval colectomy needed [41]
- Ischaemic colitis: transmural necrosis in 15%, gangrene mortality 50-75% [42]; right colon involvement is an ominous sign
- Infected obstructed urinary system = urological emergency → urgent decompression (JJ stent or PCN) [34]
- Strangulated hernia: gangrene can occur within 5-6 hours; Richter's hernia can strangulate without IO features — easily missed [44]
- Pylephlebitis (septic portal vein thrombosis) is a rare but life-threatening complication of appendicitis → high fever, rigors, jaundice, intrahepatic abscesses [50]
Active Recall - Complications of LLQ Pain Conditions
References
[2] Senior notes: maxim.md (Diverticular disease — Fistula types, colovesical) [4] Senior notes: Ryan Ho GI.pdf (p146 — Ischaemic Colitis, pneumatosis, portal venous gas) [5] Senior notes: felixlai.md (Volvulus — Pathogenesis: torsion degrees, electrolyte disturbances) [24] Senior notes: maxim.md (Diverticular disease — Hinchey classification with mortality; abscess drainage cut-off) [27] Senior notes: maxim.md (Acute appendicitis — Post-operative complications, consent risks) [34] Senior notes: Ryan Ho Urogenital.pdf (p140 — Ureteric colic: urgent decompression indications, PCN vs JJ stent, DTPA/MAG3) [37] Senior notes: felixlai.md (Intestinal obstruction — Strangulation, complications) [39] Senior notes: felixlai.md (Diverticulitis — Management of diverticular bleeding) [41] Senior notes: Ryan Ho GI.pdf (p139 — Sigmoid volvulus recurrence rate, endoscopic stenting) [42] Senior notes: Ryan Ho GI.pdf (p147 — Ischaemic colitis: mortality in gangrene, features of severe ischaemia) [44] Senior notes: Ryan Ho Urogenital.pdf (p215, p225 — Hernia classification, strangulation timing, Richter's hernia, femoral hernia) [47] Senior notes: felixlai.md (Diverticulitis — Complications: abscess, fistula, obstruction, perforation, bleeding) [48] Senior notes: Ryan Ho GI.pdf (p160 — Diverticulitis prognosis, recurrence, diverticular bleeding epidemiology) [49] Senior notes: felixlai.md (Colorectal surgery — Post-operative complications: anastomotic leak, stricture, fistula, stoma complications); maxim.md (Post-operative complications of CRC surgery: autonomic nerve injury, LAR syndrome) [50] Senior notes: felixlai.md (Acute appendicitis — Complications: perforation, pylephlebitis, post-op complications) [51] Senior notes: felixlai.md (Ulcerative colitis — Complications: stricture, fulminant colitis, toxic megacolon, perforation, CRC; IPAA complications) [52] Senior notes: maxim.md (Post-op complications: timing classification, reactionary vs secondary haemorrhage)
Haematuria
Haematuria is the presence of red blood cells in the urine, which may be visible (macroscopic) or detectable only on microscopy or dipstick testing (microscopic), indicating potential urological or nephrological pathology.
Lower Gi Bleed
Lower gastrointestinal bleeding is hemorrhage originating distal to the ligament of Treitz, most commonly from colonic sources such as diverticulosis, angiodysplasia, or colorectal neoplasms.