GC195 Lower And Diffuse Abdominal Pain RLQ Problems; Pelvic Inflammatory Disease; Peritonitis And Abdominal Emergencies
Lower and diffuse abdominal pain encompasses right lower quadrant pathologies such as appendicitis, pelvic inflammatory disease caused by ascending genital tract infection, and peritonitis resulting from inflammation of the peritoneal cavity, all of which may present as acute abdominal emergencies requiring urgent evaluation and management.
Lower & Diffuse Abdominal Pain, RLQ Problems, Pelvic Inflammatory Disease, Peritonitis & Abdominal Emergencies
Lecturer: Dr. Foo Chi Chung, Chief of Colorectal Surgery, HKU (MBBS IV WCS 053) [1]
The Big Idea: This lecture is a systematic framework for approaching a patient who presents with lower abdominal pain, diffuse abdominal pain, or signs of peritonitis. You must be able to (1) describe the pain using a structured approach, (2) formulate a differential diagnosis based on location, (3) choose appropriate investigations, and (4) institute definitive treatment — including recognizing surgical emergencies that require immediate intervention.
Learning Objectives (from Case 5 Study Guide) [2]:
- Understand common aetiologies of abdominal pain in adults
- Understand pathophysiology of peritonitis
- Derive differential diagnoses from signs/symptoms of peritonitis
- Learn investigation approach and management
- Appreciate progressive process of abdominal emergencies and need for monitoring
- Understand rationale of conservative vs operative treatment in perforated peptic disease
- Understand implications of laparoscopic surgery in surgical emergencies
How it fits into exams: This is a perennial exam favourite. Past papers test RLQ pain differentials, peritonitis management, imaging choices for appendicitis, ectopic pregnancy workup, and diverticulitis management. The lecture directly feeds MCQ EMQs, SAQs, and mini-cases.
Core Concepts: Origin of Abdominal Pain
Understanding why pain localizes where it does is the foundation of the entire lecture.
| Type | Mechanism | Character | Localization | Example |
|---|---|---|---|---|
| Visceral pain | Stretching/distension of hollow or solid organ; innervated by autonomic (bilateral) nerves | Dull, vague, poorly localized | Midline — depends on embryonic origin (see below) | Early appendicitis → periumbilical |
| Parietal (somatic) pain | Irritation of pain fibres in parietal peritoneum; innervated by somatic (unilateral) nerves | Sharp, well-localized | Dermatome at the site of stimulus | Late appendicitis → RLQ |
| Referred pain | Pain felt at site different from pathology — shared segmental innervation | Sharp, well-localized but remote | Distant site sharing same spinal cord segment | R diaphragm irritation → R shoulder tip |
High Yield — Visceral Pain Localization by Embryonic Origin [1]:
- Foregut (stomach, biliary, D1 & D2) → Epigastrium
- Midgut (D2 to proximal 2/3 transverse colon) → Periumbilical
- Hindgut (distal 1/3 transverse colon to rectum) → Hypogastrium
Why this matters: This is exactly why early appendicitis (appendix = midgut structure) causes periumbilical pain, and why the pain shifts to the RLQ once the inflamed appendix irritates the overlying parietal peritoneum. The shift from visceral → parietal pain is the classical migratory pain of appendicitis. [1] [3]
Pain and spasm resulting from contraction of a hollow organ against an obstruction [1]
- Examples: biliary colic, ureteric colic, small and large bowel obstruction
This is different from constant inflammatory pain. Colicky pain has crescendo-decrescendo waves with pain-free intervals. True colic (e.g., ureteric) is excruciating, gripping, with the patient unable to lie still — the opposite of peritonitis where patients lie motionless.
The lecture provides this systematic approach [1]:
- Location: localized vs diffuse vs vague
- Onset: sudden vs gradual
- Severity: mild to excruciating
- Character: colicky vs persistent
- Duration
- Aggravating and relieving factors
- Radiation / Shifting / Referred pain
- Symptoms associated with pain
Key Pain Radiation/Shifting/Referred Examples from the Lecture [1]
| Origin | Pain Location |
|---|---|
| R diaphragm | R shoulder tip |
| Gallbladder | R scapula tip |
| Pancreatitis / Ruptured AAA | Back |
| Ureteric colic | Ipsilateral testicle |
| Testicular pain | Ipsilateral flank |
| Acute appendicitis | From periumbilical to RLQ (shifting pain) |
Exam Trap: Shifting vs Referred vs Radiation
These are three DIFFERENT concepts. Shifting = pain moves from one site to another over time (appendicitis: periumbilical → RLQ). Referred = pain felt at a different site from pathology simultaneously (diaphragm → shoulder). Radiation = pain spreading from one site to another (pancreatitis → through to back). Don't confuse them — examiners love testing this distinction.
From the lecture [1]:
- Vomiting, diarrhoea
- Abdominal distension
- Fever
- Dysuria, haematuria
- Rectal bleeding or mucus
- Change of bowel habit
- Vaginal discharge
- Loss of appetite and weight change
- Family history
- Surgical history (adhesions!)
- Menstrual history (ectopic pregnancy!)
- Sexual history (PID, STDs!)
Lecture checklist [1]:
- General: Fever, vital signs, hydration status
- Abdomen: Distension, tenderness, guarding, rebound tenderness, mass, bowel sound, hernia (check hernial orifices!)
- Rectal and vaginal examination
Why check hernial orifices? A strangulated inguinal or femoral hernia is a commonly missed cause of bowel obstruction and abdominal pain. The lecture explicitly reminds you not to forget this. [1]
Key Clinical Signs for Appendicitis (from supporting notes) [3] [4]:
- Pointing sign: maximal tenderness at McBurney's point (junction of lateral 1/3 and medial 2/3 of line from ASIS to umbilicus)
- Rovsing's sign: RLQ pain upon pressing LLQ (shifting peritoneal contents irritates inflamed appendix)
- Psoas sign: pain on extending hip against resistance (retrocecal appendix)
- Obturator sign: pain on internal rotation of flexed hip (pelvic appendix)
Lecture framework [1]:
- Bedside: Urinalysis, pregnancy test (ALWAYS in females of childbearing age!)
- Blood: CBC (leucocytosis), RFT, LFT, amylase, clotting profile, ABG, type and screen
- Imaging: Erect CXR, erect + supine AXR, USG, CT, contrast studies
- Endoscopy: Colonoscopy, upper endoscopy
Why erect CXR? To detect pneumoperitoneum (free gas under diaphragm) — present in ~70% of perforated peptic ulcers. Its absence does NOT exclude perforation. [5]
Why ABG? Metabolic acidosis suggests bowel ischaemia, severe sepsis, or shock — a red flag for surgical emergency. [1]
Differential Diagnosis by Location
High Yield — The lecture's RLQ differential list:
- Acute appendicitis (most common surgical cause)
- Caecal diverticulitis
- Ureteric colic*
- Ruptured ectopic pregnancy*
- Mesenteric adenitis
- Torsion of ovarian cyst*
- Ileitis
- Meckel's diverticulitis
- Caecal ischaemia
- Cancer of caecum
- Inguinal/femoral hernia*
- Testicular pathology*
- Perforated peptic ulcer (Valentino's sign — gastric contents track down R paracolic gutter)
- Acute cholecystitis
(* = can cause pain at left and right side) [1]
- Sigmoid diverticulitis
- Cancer of sigmoid colon
- Torsion of ovarian cyst*
- Ruptured ectopic pregnancy*
- Ureteric colic*
- Inguinal/femoral hernia*
- Testicular pathology*
- Small bowel obstruction
- Gastroenteritis
- Early acute appendicitis
- Bowel ischaemia
- Irritable bowel syndrome
- Ruptured AAA
- Acute pancreatitis
- Cystitis
- Pelvic inflammatory disease
- Large bowel obstruction
- Retention of urine
Condition-by-Condition High-Yield Content
Classically presented with periumbilical pain (visceral pain) which later shifted to right lower quadrant (somatic pain) [1]
| Feature | Detail |
|---|---|
| Symptoms | Nausea, loss of appetite, vomiting, diarrhoea, dysuria, fever |
| Onset | Gradual |
| Age | Peak 5–12 years; less common in elderly |
| Examination | Localized tenderness and guarding at McBurney's point |
| Labs | Leucocytosis |
| Diagnosis | Often clinical |
| Imaging | USG and CT may be helpful |
| Treatment | Antibiotics + Appendicectomy (laparoscopic vs open) |
Why is diagnosis often clinical? Because classic migratory pain + anorexia + fever + RLQ tenderness + leucocytosis gives a high pre-test probability. Imaging is used when presentation is atypical (women of childbearing age, elderly, obese patients, children). [1] [6]
Pathology progression: Obstruction (faecolith/lymphoid hyperplasia) → luminal distension → venous congestion → ischaemia → gangrene/perforation → phlegmon/abscess/peritonitis [3]
2016 SAQ Q9 — Imaging for Appendicitis in Children
USG is preferred in children because: (1) no radiation, (2) widely available, (3) good sensitivity in thin patients. CT is the alternative, especially in obese children where USG is limited. [6]
Often misdiagnosed as acute appendicitis [1]
| Feature | Detail |
|---|---|
| Pathology | Enlarged mesenteric lymph nodes |
| Organisms | β-haemolytic Strep, E. coli, Strep viridans, Yersinia, coxsackievirus, rubeola virus, adenovirus |
| Age | Usually in children |
| History | Recent sore throat and high fever |
| Key differentiator | Not much peritoneal sign (unlike appendicitis) |
Why is it important? At laparoscopy for suspected appendicitis, you may find a normal appendix but enlarged mesenteric nodes. The preceding URTI and higher fever without localized peritonism help distinguish it clinically. [1] [3]
True colic, severe, gripping in nature [1]
| Feature | Detail |
|---|---|
| Character | Starts at loin, radiates to groin |
| Urinalysis | RBC present (haematuria) |
| Diagnosis | X-ray or plain CT abdomen (non-contrast CT KUB is gold standard) |
| Treatment | Mostly conservative and pain relief — majority pass spontaneously |
| Key differentiator from appendicitis | Patient writhes in pain (can't keep still) vs peritonitis (lies still) |
2025 MCQ Q56 tests exactly this: RLQ colicky pain radiating to groin, afebrile, soft abdomen, unremarkable AXR + urinalysis → Answer: Ureteric stone [7]
Colonic diverticula are outpouchings of the colon where mucosa herniate through the muscular wall [1]
| Feature | Detail |
|---|---|
| Location of herniation | At site where blood vessels penetrate bowel wall |
| Prevalence | ~60% of elderly > 80 |
| Western pattern | Mostly sigmoid (LLQ pain) |
| Asian pattern | More right-sided diverticula (can mimic appendicitis!) |
| Pathogenesis | Microperforation causes diverticulitis |
| Spectrum | Diverticulitis → localized abscess → purulent peritonitis → faecal peritonitis |
Clinical features: Fever, tenderness, guarding, leucocytosis [1]
Diagnosis: CT scan (confirms diagnosis and assesses severity) [1]
Treatment depends on severity:
- Antibiotics (mild)
- Image-guided drainage (abscess)
- Laparoscopy and lavage
- Laparotomy and bowel resection (severe / faecal peritonitis) [1]
2025 MCQ Q57: Sigmoid diverticulitis with 5cm pelvic abscess → Answer: Radiological guided drainage of abscess [7]
The Rule of '2': [1]
- 2% of population
- 2 feet (60 cm) from ileocaecal junction
- 2 inches (5 cm) long
- Usually presents at age of 2
| Feature | Detail |
|---|---|
| Embryology | Remnant of omphalomesenteric (vitelline) duct |
| Anatomy | Apex or fibrous cord adherent to umbilicus |
| Ectopic mucosa | May contain gastric or pancreatic mucosa (detected by Meckel's scan = Tc-99m pertechnetate) |
| Complications | Bleeding, perforation, volvulus, intussusception |
| Presentation | Similar to acute appendicitis; incidental finding during appendicectomy |
| Treatment | Antibiotics + diverticulectomy / small bowel resection |
Why gastric mucosa matters: Ectopic gastric mucosa secretes acid → ulceration → painless lower GI bleeding (classically dark red/maroon stool in a child). This is the classic paediatric presentation. [1] [8]
Commonest age 10–15 [1]
| Feature | Detail |
|---|---|
| Symptoms | Severe pain in testis and groin; may be preceded by vague abdominal pain; may radiate to loin |
| Examination | Tender and high-lying testis |
| Treatment | Surgical exploration ± orchidopexy ± orchidectomy |
| DDx | Epididymo-orchitis, testicular tumour |
| Time window | Best salvage if within 6 hours — true urological emergency |
Why can it present as abdominal pain? The testis shares embryological innervation with the retroperitoneum (T10 dermatome), so pain can be referred to the abdomen, especially in young boys who may not volunteer testicular symptoms. Always examine the scrotum in any boy with abdominal pain. [1]
Fertilized ovum implants outside uterus. Most common site: Fallopian tube [1]
| Feature | Detail |
|---|---|
| Risk factors | Previous PID, previous ectopic pregnancy, IUCD |
| Timing | Causes rupture at ~6 weeks |
Ruptured Ectopic Pregnancy [1]
Presents with sudden severe pain, bleeding and circulatory collapse
Investigations: Pregnancy test, CBC, type and screen, USG
Treatment: Large bore IV cannula and resuscitation → Urgent laparoscopy and salpingotomy/salpingectomy
High Yield — Ruptured Ectopic Pregnancy
Any female of childbearing age with lower abdominal pain + haemodynamic instability = ruptured ectopic until proven otherwise. Always do a pregnancy test. This is a life-threatening surgical emergency. [1]
2020 SAQ Q9: 28-year-old lady, sudden lower abdominal pain, dizziness, vaginal bleeding, LMP 6 weeks ago, BP 98/53, pulse 103, HaemoCue 8.4 → Tests: pregnancy test, CBC/type & screen, USG → Treatment: IV resuscitation + urgent laparoscopy [9]
Commonly affects age < 40 [1]
Ascending infection from vagina
Risk factors: History of gynaecological procedure, IUCD, STD
Organisms: Chlamydia trachomatis / Neisseria gonorrhoeae
Symptoms: High fever, lower abdominal pain, dysuria, dyspareunia, vaginal discharge
Key sign: Cervical excitation (chandelier sign — pain on moving the cervix during bimanual exam)
Treatment:
- Antibiotics
- Drainage of tubo-ovarian abscess (image-guided / laparoscopic) [1]
Why ascending infection? Organisms from the vagina/cervix ascend through the cervical canal to infect the endometrium → fallopian tubes (salpingitis) → ovaries → pelvic peritoneum. This is why risk factors include anything that opens the cervical barrier (instrumentation, IUCD). [1] [10]
PID vs Appendicitis discriminators [4] [5]:
- PID pain is lower and usually bilateral
- PID has vaginal discharge and cervical excitation
- PID worsened by coitus (dyspareunia) and menses
- Appendicitis has migratory pain and is unilateral
11. LARGE BOWEL OBSTRUCTION
Common causes: [1]
- Cancer of colon
- Volvulus
- Diverticular stricture
- Pseudo-obstruction
| Feature | Detail |
|---|---|
| Symptoms | Cramping pain, vomiting, abdominal distension, constipation |
| Examination | Hydration status, tachycardia & hypotension, abdominal tenderness, hernial orifices, bowel sounds, rectal examination |
- Initial: NPO, nasogastric tube decompression, fluid resuscitation
- Definitive: Colonic stenting, endoscopic decompression, bowel resection, stoma
Causes: [1]
- Thromboembolism
- Venous occlusion
- Non-obstructive mesenteric ischaemia
- Chronic mesenteric ischaemia
- Mechanical (volvulus, hernia)
Clinical features: [1]
- Elderly, history of AF or IHD
- Constant severe non-specific abdominal pain
- Rectal bleeding or bloody diarrhoea
- Lack of peritoneal sign (early — "pain out of proportion to physical findings")
- Leukocytosis, metabolic acidosis, renal failure
- Ileus
Treatment: Resuscitation, resect non-viable bowel
Classic Exam Point — Pain Out of Proportion
2023 MCQ Q18: 66-year-old lady, AF, diffuse abdominal tenderness, absent bowel sounds, fresh blood PR → Answer: Mesenteric ischaemia [11]
Diffuse Abdominal Pain & Peritonitis
One of the commonest surgical emergencies [1]
Inflammation of peritoneum
Classifications:
- Localized vs generalized (diffuse)
- Bacterial vs chemical
- Primary vs secondary vs tertiary
- Burning pain, initially localized and later spread
- Movement and coughing exacerbate pain
- Tenderness, rebound tenderness, and guarding
- Absence of bowel sounds (paralytic ileus)
- Fever, tachycardia, tachypnoea
- Septic shock
Pathology:
- Peritoneum becomes oedematous, hyperaemic, covered with fibrinous exudates
- Sequestration of large amounts of protein-rich fluid (third-spacing → intravascular depletion)
- Septicaemia, endotoxaemia
- Hypovolaemia and shock
From first principles: The peritoneum has a massive surface area (~equal to skin). When inflamed, it becomes highly permeable. Protein-rich fluid pours into the peritoneal cavity (third-spacing), depleting intravascular volume → hypovolaemic shock. Simultaneously, bacteria and endotoxins cross into the bloodstream → septicaemia → distributive shock. The combination of hypovolaemia + sepsis makes peritonitis rapidly lethal without intervention.
Subtypes:
- Spontaneous bacterial peritonitis (SBP)
- Tuberculous peritonitis
- Peritonitis associated with CAPD (chronic ambulatory peritoneal dialysis)
Usually monomicrobial (Strep. pneumoniae, Group A Streptococcus, Enteric organisms)
Risk factors: ascites, malnutrition, intra-abdominal malignancy, immunosuppression, splenectomy, chronic liver & renal disease
Key concept: Primary = no identifiable intra-abdominal source of infection. The bacteria reach the peritoneum via haematogenous spread or translocation from the gut (in SBP, portal hypertension → impaired gut immunity → bacterial overgrowth → translocation). [1] [12]
SBP vs Secondary bacterial peritonitis discriminator [12]:
| Feature | SBP | Secondary |
|---|---|---|
| Culture | Monomicrobial | Polymicrobial |
| Source | No identifiable perforation | Bowel perforation/leak |
| Ascitic fluid PMN | > 250/μL (diagnostic) | Often > 250/μL |
| Treatment | Antibiotics alone | Surgery + antibiotics |
| Treatment response | Usually responds | Fails to respond if surgical cause not addressed |
- Character: serous, blood-stained, purulent, bile-stained, faeculent
- Cell counts: Neutrophil count > 500/μL
- Biochemistry: Low glucose, high protein, high LDH compared to serum
- Microbiology: Gram stain, cultures (aerobic, anaerobic, AFB, fungal)
- Special: Amylase (pancreatitis), creatinine (bladder perforation — ascitic creatinine > serum creatinine)
- Considered rare in developed countries (but NOT rare in Hong Kong's context!)
- Non-specific presentation: low-grade fever, weight loss, insidious onset abdominal pain
- Peritoneal sign not florid
- Peritoneal fluid: AFB smear often negative, culture takes 4–6 weeks (may be falsely negative)
- Diagnosis often made by laparoscopy and biopsy of peritoneum
Accounts for most peritonitis
Can be localized (e.g., intra-abdominal abscess) or generalized
May be preceded by chemical peritonitis (gastric juice, bile, pancreatic juice, urine, blood)
Causes:
- Severe inflammation of abdominal organ (diverticulitis, cholecystitis, appendicitis)
- Perforations of GI tract (spontaneous, trauma, iatrogenic)
- Anastomotic leakage
- Ischaemia of abdominal organ (e.g., bowel)
Microbiology: Polymicrobial [1]
- Gram negative: E. coli, Enterobacter, Proteus, Pseudomonas
- Gram positive: Streptococci, Enterococci
- Anaerobes: Bacteroides
Resuscitation:
- IV fluid replacement
- NG tube / urinary catheter / oxygen
- Pain relief
- Broad spectrum antibiotics
- Close monitoring
Definitive:
- Percutaneous drainage of abdominal abscess
- Laparoscopic surgery / Laparotomy
- PPU repair, cholecystectomy, bowel resection [1]
2023 SAQ Q7: Perforated peptic ulcer causing peritonitis → Irritants: gastric acid and bile (chemical peritonitis) → Supportive: IV fluids, NG tube decompression, antibiotics, pain relief [13]
2019 SAQ Q7: Diffuse abdominal pain, guarding, board-like rigidity, free gas under diaphragm → Most likely: perforated peptic ulcer → Chemical irritants: gastric juice, bile, pancreatic juice → Treatment: IV PPI + antibiotics → Definitive: laparotomy/laparoscopy with omental patch repair [14]
- Poor historian, confused or dementia
- History inaccurate (rely on care-provider)
- Peritoneal signs may be mild
- High index of suspicion: abdominal pain, abdominal distension, fever, leucocytosis, acidosis, sepsis of unexplained cause
Why are signs mild? Elderly patients have thinner, less muscular abdominal walls → less impressive guarding. Immunosenescence means less robust fever response. Comorbidities (diabetes, steroids) blunt inflammatory response. This makes elderly peritonitis a diagnostic trap — always think of it when an elderly patient has unexplained sepsis. [1]
The lecture explicitly warns about these:
- Hernia — inguinal or femoral (always check hernial orifices!)
- Ruptured AAA or aortic dissection — tearing epigastric pain radiating to back + shock
- Herpes zoster — dermatomal hyperaesthesia + vesicular eruption (can mimic acute abdomen!)
- Pancreatitis
- Retention of urine (palpable bladder, suprapubic discomfort)
- Non-specific abdominal pain (most common discharge diagnosis in young patients with abdominal pain)
Don't Forget the Hernias!
A strangulated femoral hernia in an elderly woman presenting with small bowel obstruction is an exam classic. The hernia lump may be small and hidden in the groin crease. Always examine hernial orifices in any patient with abdominal pain or obstruction. [1]
Exam Intelligence
| Trap | Correct Reasoning |
|---|---|
| Appendicitis vs mesenteric adenitis | Mesenteric adenitis: children, recent URTI, not much peritoneal sign, higher fever |
| Appendicitis vs PID | PID: bilateral, lower location, vaginal discharge, cervical excitation, sexually active |
| Appendicitis vs ectopic pregnancy | Always do pregnancy test in women of childbearing age; ectopic = amenorrhoea + shock |
| LLQ diverticulitis vs RLQ diverticulitis | Asians have more right-sided diverticula — can mimic appendicitis |
| Ureteric colic vs appendicitis | Ureteric colic: true colic (writhing), haematuria on urinalysis, afebrile, no peritoneal sign |
| Mesenteric ischaemia: pain out of proportion | Severe pain, minimal initial signs, AF/IHD history, metabolic acidosis, bloody diarrhoea |
| SBP vs secondary peritonitis | SBP = monomicrobial, ascites background; Secondary = polymicrobial, surgical cause |
| Perforated peptic ulcer | Free gas under diaphragm on erect CXR (but 30% no free gas — absence doesn't exclude!) |
| Testicular torsion in child | May present as abdominal pain only — always examine scrotum |
- "List the differential diagnoses of RLQ pain" — must include surgical AND gynaecological AND urological causes
- "What is the pathophysiology of peritonitis?" — third-spacing, septicaemia, endotoxaemia, hypovolaemic shock
- "Describe the shifting pain of appendicitis and explain why" — visceral (periumbilical, midgut) → somatic (RLQ, parietal peritoneum irritation)
- "Name conditions that mimic appendicitis at laparoscopy" — mesenteric adenitis, Meckel's diverticulitis, ileitis (Crohn's, Yersinia), ovarian pathology, PID
Past Paper Questions
Stem: 7-year-old boy, fever, increasing abdominal pain 2 days, diffuse tenderness + guarding RLQ, temp 39°C, WCC 15 × 10⁹/L.
- (a) Most likely diagnosis: Acute appendicitis (2 marks)
- (b) Most appropriate imaging: Ultrasound (1 mark). Reasons: no ionizing radiation, readily available, good sensitivity in thin children (3 marks)
- (c) USG findings: distended non-compressible appendix > 6mm diameter, appendicolith, peri-appendiceal fluid (2 marks)
- (d) Alternative cross-sectional imaging in obese child: CT abdomen (2 marks)
Stem: 25-year-old male, 3-day RLQ pain, febrile 38.5°C, RLQ tenderness + guarding, leucocytosis. Laparoscopy shows non-inflamed appendix. Name four conditions mimicking acute appendicitis.
- Answer: (1) Mesenteric adenitis, (2) Meckel's diverticulitis, (3) Terminal ileitis (Crohn's disease / Yersinia), (4) Ureteric colic. Other acceptable: PID (if female), testicular torsion, caecal diverticulitis, PPU (Valentino's sign). (10 marks — 2.5 each)
Stem: 65-year-old smoker, sudden severe diffuse abdominal pain, on NSAIDs, generalised guarding and board-like rigidity, afebrile, erect CXR shows free gas.
- (a) Most likely cause: Perforated peptic ulcer (2 marks)
- (b) DDx: Perforated diverticulitis (1 mark)
- (c) Chemical irritants causing peritonitis: gastric acid (HCl), bile, pancreatic juice (3 marks)
- (d) Medications: IV PPI + broad-spectrum antibiotics (2 marks)
- (e) Definitive treatment: Laparotomy (or laparoscopy) with omental patch repair (2 marks)
Stem: Typhoid fever patient develops shock and severe diffuse abdominal pain on Day 2 of antibiotics → emergency laparotomy.
- Rationale: Intestinal perforation (of Peyer's patches in terminal ileum) is the feared complication of typhoid fever — a form of secondary peritonitis.
Stem: 10-year-old boy, acute abdominal pain starting periumbilical → migrating to RLQ, febrile, marked RIF tenderness.
- Answer: A. Acute appendicitis
Stem: 28-year-old lady, sudden severe lower abdominal pain, dizziness, vaginal bleeding, LMP 6 weeks ago, BP 98/53, pulse 103, HaemoCue 8.4.
- (a) Investigations: Urine pregnancy test, CBC + type & screen, USG pelvis (6 marks)
- (b) Treatments: IV fluid resuscitation (large bore cannula) + urgent laparoscopy with salpingotomy/salpingectomy (4 marks)
Stem: 66-year-old lady, AF, abdominal pain + distension, diffuse tenderness, absent bowel sound, fresh blood PR.
- Answer: G. Mesenteric ischaemia
Stem: 45-year-old smoker, sudden severe epigastric pain, hypotension, tachycardia, diffuse tenderness + guarding, free gas under diaphragm. Perforated peptic ulcer suspected.
- (a) Cause of hypotension: Hypovolaemia from third-space fluid loss / septic shock (2 marks)
- (b) Irritants: Gastric acid (HCl), bile (4 marks)
- (c) Supportive measures: IV fluid resuscitation, NG tube decompression (also: IV PPI, urinary catheter, pain relief, antibiotics) (4 marks)
Stem: 55-year-old man, acute RLQ pain, severe colicky, radiates to R groin, afebrile, soft non-tender abdomen, AXR unremarkable, urinalysis sent.
- Answer: C. Ureteric stone
Stem: 70-year-old man, acute lower abdominal pain, LLQ tenderness + guarding + fever 38.5°C, CT: sigmoid diverticulitis with mesenteric stranding, small gas pockets, 5 cm pelvic abscess, on IV antibiotics.
- Answer: D. Radiological guided drainage of abscess
- Intestinal Obstruction & Colorectal Cancer (GC 194): Large bowel obstruction differentials, AXR features (haustra vs valvulae conniventes), and the role of colonic stenting overlap directly [18].
- Complications of Early Pregnancy (GC 223): Ectopic pregnancy workup and management [19].
- Vaginal Discharge & OG Infections (GC 119): PID organisms (Chlamydia, Gonorrhoea), treatment regimens [10].
- Diverticular Diseases (Dr. J Tsang): Hinchey classification of diverticulitis (I = pericolic abscess, II = pelvic/distant abscess, III = purulent peritonitis, IV = faecal peritonitis) — determines management [20].
- Abdominal Exam (KM Chu): Systematic examination including inspection, auscultation, percussion, palpation, DRE, hernial orifices [21].
- Emergency Radiology (GC 013): Erect CXR for pneumoperitoneum, AXR for obstruction [22].
High Yield Summary
1. Pain types: Visceral (dull, midline, embryonic origin) → Parietal (sharp, localized) → Referred (remote site, shared innervation).
2. RLQ DDx top 5: Acute appendicitis, caecal diverticulitis (Asians!), ureteric colic, ectopic pregnancy, mesenteric adenitis.
3. Appendicitis: Periumbilical → RLQ shift, clinical diagnosis, leucocytosis, appendicectomy.
4. PID: Age < 40, Chlamydia/GC, cervical excitation, vaginal discharge, treat with antibiotics ± drainage.
5. Diverticulitis: Asians = right-sided; Severity spectrum from antibiotics → image-guided drainage → surgery.
6. Peritonitis: Primary (monomicrobial, SBP) vs Secondary (polymicrobial, surgical). Pathology = third-spacing + septicaemia → shock. Treatment = resuscitate + antibiotics + surgery.
7. Ischaemic bowel: Pain out of proportion, AF/IHD, metabolic acidosis, resect non-viable bowel.
8. Always check: Pregnancy test in females, hernial orifices in all, scrotum in males.
9. Elderly peritonitis: Mild signs, atypical presentation, high index of suspicion.
10. Ectopic pregnancy: Sudden pain + shock + positive pregnancy test = urgent laparoscopy.
Active Recall - Lecture Notes
[1] Lecture slides: GC 195. Lower and diffuse abdominal pain RLQ problems; pelvic inflammatory disease; peritonitis and abdominal emergencies.pdf [2] Lecture slides: Case 5 - Abd-Pain (Adult).pdf (p2) [3] Senior notes: Maksim Surgery Notes.pdf (p89) [4] Senior notes: Ryan Ho Fundamentals.pdf (p272-274) [5] Senior notes: Ryan Ho GI.pdf (p92, 98, 100, 151) [6] Past papers: 2016 Fourth Summative SAQ.pdf (Q9) [7] Past papers: 2025 Fourth Summative MCQ.pdf (Q56, Q57) [8] Senior notes: Adrian Lui Pediatrics Notes.pdf (p246) [9] Past papers: 2020 Fourth Summative SAQ.pdf (Q9) [10] Lecture slides: GC 119. Vaginal discharge obstetric and gynaecological infections.pdf [11] Past papers: 2023 Fourth Summative MCQ.pdf (Q18) [12] Senior notes: Block A - Abdominal distension_ ascites and cirrhosis.pdf (p15, 17) [13] Past papers: 2023 Fourth Summative SAQ.pdf (Q7) [14] Past papers: 2019 Fourth Summative SAQ.pdf (Q7) [15] Past papers: 2017 Fourth Summative SAQ.pdf (Q8) [16] Past papers: 2019 Fourth Summative Mini Case.pdf (Section 4) [17] Past papers: 2020 Fourth Summative Assessment MCQ paper.pdf (Q19) [18] Lecture slides: GC 194. Intestinal obstruction colorectal cancer.pdf [19] Lecture slides: GC 223. Complications of Early Pregnancy.pdf [20] Lecture slides: Diverticular diseases - Dr. J Tsang.pdf [21] Lecture slides: Abdominal exam KM Chu.pdf [22] Lecture slides: GC 013. Emergency radiology.pdf
GC194 Intestinal Obstruction Colorectal Cancer
Intestinal obstruction caused by colorectal cancer occurs when a malignant tumor partially or completely occludes the colonic or rectal lumen, preventing the normal passage of intestinal contents and leading to proximal bowel distension, pain, and obstipation.
GC196 Minimally Invasive Thoracic Surgery
Minimally invasive thoracic surgery encompasses video-assisted thoracoscopic surgery (VATS) and robotic-assisted techniques that use small incisions and camera guidance to perform diagnostic and therapeutic procedures within the chest, reducing surgical trauma and recovery time compared to open thoracotomy.