Meckel Diverticulum
Meckel diverticulum is a congenital true diverticulum of the ileum resulting from incomplete obliteration of the vitelline (omphalomesenteric) duct, typically located approximately 2 feet proximal to the ileocecal valve.
Meckel Diverticulum
Meckel diverticulum is the most common congenital anomaly of the gastrointestinal tract (GIT) [1][2][3]. It is a blind, true, congenital diverticulum located on the anti-mesenteric surface of the mid-to-distal ileum [1][3][4].
Let's break down the key terms:
- True diverticulum: contains all four layers of the bowel wall (mucosa, submucosa, muscularis propria, serosa). This distinguishes it from pseudo-diverticula (e.g. colonic diverticula in diverticular disease), which only involve herniation of mucosa and submucosa through the muscular wall.
- Anti-mesenteric surface: the side of the bowel opposite to where the mesentery attaches. This matters because the mesenteric side carries the major blood supply — the anti-mesenteric side is the embryological point where the vitelline duct originally connected.
- Congenital: present from birth, arising from an embryological remnant.
It results from incomplete obliteration of the vitelline (omphalomesenteric) duct during fetal development [1][2][3][4].
Key concept: Meckel diverticulum = true diverticulum (all wall layers) vs. colonic diverticula = false/pseudo-diverticula (mucosa + submucosa only). This is a classic exam distinction.
Epidemiology
Classically described by the "Rule of 2" [1][2][3][4][5]:
| Rule of 2 | Detail |
|---|---|
| 2% of population | Prevalence — most are asymptomatic and discovered incidentally |
| M:F = 2:1 | Males are twice as likely to be symptomatic (possibly related to higher rates of ectopic gastric mucosa) |
| 2 feet (≈60 cm) from ileocaecal valve | Location in distal ileum |
| 2 inches (≈5 cm) in length | Typical diverticulum size; approximately 2 cm wide |
| 2–4% develop complications | Approximate historical risk; presentation can occur at any age |
| 2 types of mucosa | Two classic ectopic tissue types: gastric and pancreatic (neither is obligatory) |
High Yield – Rule of 2
The "Rule of 2" is one of the most commonly tested mnemonics in surgery and paediatrics examinations. Know every component. The numbers are approximate but are consistently asked.
- 25–50% of symptomatic cases present before age 10 [1][4]
- In adults, symptomatic Meckel diverticulum more commonly presents with small bowel obstruction (SBO) rather than bleeding [1][4]
- In children, the classic presentation is painless lower GI bleeding [1][4][6]
- No familial predisposition, but increased incidence in those with other congenital malformations (especially GIT, umbilicus, CNS, CVS) [1][4]
- Presence of ectopic (heterotopic) tissue — most important risk factor
- Age < 50 years
- Male sex
- Long diverticulum ( > 2 cm)
- Broad-based diverticulum
- Fibrous band present (remnant vitelline cord connecting to umbilicus)
Anatomy and Embryological Basis
Understanding Meckel diverticulum requires understanding the vitelline (omphalomesenteric) duct:
- In early fetal life, the midgut communicates with the yolk sac via the vitelline duct (also called omphalomesenteric duct — "omphalo" = umbilicus, "mesenteric" = relating to the mesentery/gut)
- The vitelline duct provides nutrition to the developing embryo from the yolk sac before the placenta takes over
- Normally, the vitelline duct completely regresses (obliterates) by approximately 5–7 weeks of gestation [1][4]
- If this regression is incomplete, a spectrum of vitelline duct remnant abnormalities results
| Anomaly | Description | Clinical Significance |
|---|---|---|
| Meckel diverticulum | Blind-ending pouch at ileal end; may have a fibrous band but no patent fistula | Most common vitelline remnant; risk of bleeding, obstruction, diverticulitis |
| Vitelline cord/band | Fibrous cord from diverticulum to umbilicus | Risk of intestinal obstruction — bowel can twist (volvulus) around the band [1][4] |
| Vitelline cyst | Fluid-filled cyst along the remnant path | Can cause obstruction or infection |
| Vitelline (omphalomesenteric) fistula | Completely patent duct from ileum to umbilicus | Enteric contents discharge from umbilicus — diagnosed in neonates |
| Umbilical sinus | Patent only at the umbilical end | Umbilical discharge |
- Location: anti-mesenteric border of mid-to-distal ileum, approximately 2 feet (60 cm) proximal to the ileocaecal valve [1][2][3][4]
- Size: typically 2 inches (5 cm) long, 2 cm wide [1][4]
- Blood supply: supplied by the vitelline (omphalomesenteric) artery, which is a remnant of the original vitelline circulation. This artery is a branch of the superior mesenteric artery (SMA) and runs in the mesentery of the diverticulum
- Wall structure: true diverticulum → contains mucosa, submucosa, muscularis propria, and serosa [1][3][4]
This is the most clinically important histological feature:
- Heterotopic mucosa is found in approximately 20% of all Meckel diverticula (some sources say up to 50% in symptomatic cases) [1][4][6]
- Ectopic gastric mucosa is especially associated with bleeding, but is not universally demonstrated
- Types of heterotopic mucosa:
Why does ectopic gastric mucosa matter? Because parietal cells secrete HCl into the lumen of the diverticulum and adjacent ileal mucosa. The ileal mucosa has less protection against acid (unlike the stomach which has specialised acid-protective mechanisms). This leads to peptic ulceration of the adjacent ileal mucosa → bleeding. The ulcer forms adjacent to or just downstream from the diverticulum ; it may involve ileal-type mucosa within or adjacent to the diverticulum [5].
Common Exam Pitfall
Gastric heterotopia is the acid source; adjacent ileal-type mucosa is the usual site of peptic ulceration. Surgery may need to include affected adjacent bowel.
Etiology and Pathophysiology
Meckel diverticulum is a congenital anomaly — there are no modifiable or acquired risk factors. The etiology is:
- Failure of vitelline duct regression at approximately 5–7 weeks gestation [1][4]
- The cause of this failure is unknown — no specific genetic mutation has been identified
- No familial predisposition [1][4]
- Increased prevalence in patients with other congenital malformations (GIT, umbilical, CNS, CVS anomalies) [1]
Clinical relevance:
- In the Hong Kong paediatric surgery setting, Meckel diverticulum is an important differential for painless rectal bleeding in children and for lead-point intussusception
- Meckel diverticulum is listed as a possible location for peptic ulcer disease — "if contain ectopic gastric mucosa" — and is a relatively common cause of obscure GI bleed [7][8]
Pathophysiology of Complications
The pathophysiology of symptomatic Meckel diverticulum depends on the specific complication:
- The ectopic gastric mucosa produces acid → results in ulcer formation and bleeding adjacent to, or just downstream from, the diverticulum [5]
- Bleeding can be chronic/insidious (causing iron-deficiency anaemia) or acute/massive [1][4]
- Characteristically painless [1][4]
- The blood is typically dark red/maroon (sometimes described as "brick red" or "currant jelly") because it originates from the ileum and undergoes partial degradation during transit. If massive, it can appear bright red.
Multiple mechanisms can cause small bowel obstruction (SBO):
(a) Intussusception
- Meckel diverticulum acts as a pathological lead-point [1][4]
- The diverticulum is "caught" by peristalsis and telescopes into the adjacent bowel, pulling the proximal bowel into the distal bowel
- Should be considered in children with recurrent small bowel intussusception [1][4] — in contrast, most childhood intussusception is "idiopathic" (likely triggered by enlarged Peyer's patches from viral infection) and occurs at the ileocaecal junction
Clinical pearl: In children < 2 years, intussusception is usually idiopathic (ileocolic). But in older children and adults, or in cases of recurrent intussusception, always consider a pathological lead-point such as Meckel diverticulum, polyp, lymphoma, or duplication cyst.
(b) Volvulus around vitelline band
- Small bowel can twist around the fibrous cord/band associated with the diverticulum [1][4]
- The vitelline cord tethers the bowel to the umbilicus → acts as a fixed point around which the mobile small bowel can twist → closed-loop obstruction → ischaemia and strangulation
(c) Incarcerated Littre hernia
- Littre hernia = a hernia containing Meckel diverticulum [1][4]
- "Littre" is eponymous — named after Alexis Littre (French anatomist)
- The diverticulum can become incarcerated and strangulated within an inguinal, femoral, or umbilical hernia
(d) Other mechanisms
- The pathophysiology is analogous to appendicitis — luminal obstruction → bacterial overgrowth → inflammation → ischaemia → potential perforation [1][4]
- Causes of obstruction: enterolith (stone formed within diverticulum), inflammation, food particles, foreign body, tumour (rare — carcinoid is most common tumour in Meckel diverticulum) [1][4]
- Clinical features often mimic acute appendicitis — peri-umbilical or central abdominal pain migrating to RLQ [1]
- Can be difficult to distinguish from appendicitis before surgery [1]
- Can occur secondary to diverticulitis, peptic ulceration, or rarely from foreign body
- Leads to peritonitis with acute abdomen
- Carcinoid tumour is the most common neoplasm found in Meckel diverticulum
- Other rare tumours: adenocarcinoma, GIST, leiomyoma
Classification
There is no formal staging or classification system for Meckel diverticulum itself. However, it can be classified based on:
| Category | Description |
|---|---|
| Asymptomatic | Most; discovered incidentally |
| Symptomatic | Presents with bleeding, obstruction, diverticulitis, or perforation |
| Type | Frequency | Clinical Relevance |
|---|---|---|
| Without ectopic mucosa | ~80% of all Meckel diverticula | Lower risk of bleeding; may present with obstruction or diverticulitis |
| With ectopic gastric mucosa | ~60% of those with ectopic tissue | Acid secretion → peptic ulceration → bleeding |
| With ectopic pancreatic tissue | Less common | Can cause pancreatitis-like inflammation within diverticulum |
| With ectopic duodenal/colonic mucosa | Uncommon (~6% colonic) | Less clinical significance |
As described in the embryology section above — Meckel diverticulum is one of several vitelline duct remnants.
A narrow healthy base may allow diverticulectomy. A broad or diseased base, nearby ulceration or compromised ileum may require wedge or segmental resection. These operations are distinct; there is no universal 2 cm base-width threshold (see Mx tab).
Clinical Features
| Age Group | Most Common Presentation | Why? |
|---|---|---|
| Children ( < 2 years) | Painless lower GI bleeding | Higher rate of ectopic gastric mucosa → acid → ulceration → bleeding from well-vascularized ileal mucosa |
| Older children/adolescents | Bleeding, intussusception, diverticulitis | Ectopic mucosa still present; diverticulum can act as lead-point |
| Adults | Small bowel obstruction | Adhesions, bands, Littre hernia more likely; presentation varies by cohort and anatomy |
Symptoms (with Pathophysiological Basis)
- Mechanism: ectopic gastric mucosa → HCl secretion → peptic ulceration of adjacent ileal mucosa → erosion of vessels → GI bleeding
- Character:
- Variable — can be chronic/insidious or acute/massive [1][4]
- Usually painless [1][4] (because the ulceration is in the ileum, which has visceral innervation only — poorly localized, dull pain at best; and the bleeding itself is painless)
- Colour: typically dark red, maroon, or "brick-red" stools (from ileal origin — undergoes some degradation during transit). Can appear bright red if bleeding is brisk/massive
- Can sometimes present as melena if bleeding is slower and transit time is longer
- In chronic cases: may present insidiously with iron-deficiency anaemia (fatigue, pallor, tachycardia)
Clinical Pearl
Painless lower GI bleeding in a child — the top differentials are Meckel diverticulum, juvenile polyps, and intussusception (though intussusception is usually painful with "redcurrant jelly" stools). Meckel bleeding is classically painless and can be massive.
- If diverticulitis:
- Peri-umbilical or central abdominal pain [1] — because the Meckel diverticulum is in the ileum (midgut), which refers pain to the peri-umbilical region via visceral afferents travelling with the superior mesenteric artery (T10 dermatome)
- May localize to RLQ or lower abdomen as inflammation involves the parietal peritoneum — mimics acute appendicitis [1]
- If perforated → diffuse abdominal pain (peritonitis)
- If obstruction (intussusception): colicky, intermittent abdominal pain with episodes of screaming/distress in young children
- If volvulus: sudden severe colicky pain → constant pain as ischaemia sets in
- Present when there is intestinal obstruction (intussusception, volvulus, adhesive band obstruction)
- Mechanism: proximal bowel distension → reverse peristalsis → vomiting
- Bilious vomiting suggests obstruction distal to the ampulla of Vater (which is nearly always the case in Meckel-related obstruction, as the diverticulum is in the ileum)
- In the context of distal small bowel obstruction
- Mechanism: accumulation of gas and fluid proximal to the obstruction → distension
- Complete obstruction: absolute constipation (no passage of stool or flatus)
- Mechanism: mechanical obstruction prevents onward transit
- Fatigue, exertional dyspnoea, pallor, dizziness
- Mechanism: chronic occult blood loss → depletion of iron stores → iron-deficiency anaemia
- This can be the presenting feature in older children and adults with "obscure GI bleeding"
Signs (with Pathophysiological Basis)
| Sign | Mechanism |
|---|---|
| Fresh blood / dark blood per rectum (PR) | Direct bleeding from ulcerated ileal mucosa into bowel lumen |
| Pallor (conjunctival, palmar creases) | Anaemia from chronic or acute blood loss |
| Tachycardia | Compensatory sympathetic response to hypovolaemia |
| Hypotension (in massive bleed) | Loss of circulating volume exceeds compensatory mechanisms |
| Signs of iron-deficiency anaemia (koilonychia, angular cheilitis, glossitis) | Chronic blood loss → iron depletion → impaired erythropoiesis |
| Sign | Mechanism |
|---|---|
| RLQ or central/peri-umbilical tenderness [1] | Inflammation of diverticulum → parietal peritoneal irritation (somatic pain localises); or visceral pain (peri-umbilical) |
| Peritoneal signs (guarding, rebound tenderness, rigidity) — if perforated [1] | Free perforation → chemical and bacterial peritonitis → parietal peritoneal inflammation |
| Palpable phlegmon (if walled-off) [1] | Walled-off inflammation with omentum/adjacent loops → mass effect |
| Fever | Systemic inflammatory response to infection/inflammation |
| Leucocytosis | Neutrophilic response to bacterial infection |
Exam Pitfall: Meckel Diverticulitis vs Appendicitis
Meckel diverticulitis is often only distinguished intra-operatively — preoperative recognition can be difficult [1]. It is a classic mimicker of appendicitis. If a surgeon finds a normal appendix at laparoscopy/laparotomy for suspected appendicitis, they should inspect the distal ileum for Meckel diverticulum (check approximately 60 cm of ileum proximal to the ileocaecal valve). Key differentials for Meckel diverticulitis also include Crohn ileitis and colonic diverticulitis [1].
| Sign | Mechanism |
|---|---|
| Abdominal distension | Gas and fluid accumulation proximal to obstruction |
| High-pitched / tinkling bowel sounds | Hyperactive peristalsis attempting to overcome the obstruction |
| Absent bowel sounds (late) | Bowel fatigue → ileus / ischaemia |
| "Sausage-shaped" mass (intussusception) | Telescoped bowel forms palpable mass, classically in RUQ or epigastrium |
| "Redcurrant jelly" stool (intussusception) | Venous congestion of intussuscepted bowel → mucosal ischaemia → bloody mucus (late sign — means vascular compromise) |
| Empty RIF on palpation (Dance sign — intussusception) | Caecum has been drawn up into the intussusceptum, leaving the RIF empty |
| Dehydration signs (dry mucous membranes, sunken fontanelle in infants, reduced skin turgor) | Third-spacing of fluid into obstructed bowel lumen and wall; vomiting-related losses |
| Sign | Mechanism |
|---|---|
| Irreducible inguinal/femoral/umbilical swelling | Meckel diverticulum incarcerated within hernia sac |
| Signs of strangulation (tenderness, erythema over hernia, fever) | Compromised blood supply to incarcerated diverticulum |
- Enteric discharge from umbilicus in a neonate: suggests patent vitelline fistula (not Meckel diverticulum itself, but part of the same spectrum)
- Umbilical polyp/nodule: may represent residual vitelline duct tissue at the umbilicus
| Complication | Typical Age | Key Features | Pathophysiology |
|---|---|---|---|
| GI bleeding | Children < 2y | Painless haematochezia; can be massive or chronic | Ectopic gastric mucosa → acid → peptic ulcer of adjacent ileum |
| Intussusception | Children | Colicky pain, vomiting, sausage mass, redcurrant jelly stool | Diverticulum as pathological lead-point |
| Volvulus | Any age | Acute obstruction, severe pain, signs of ischaemia | Bowel twists around vitelline cord/band |
| Meckel diverticulitis | Older children/adults | Mimics appendicitis — peri-umbilical → RLQ pain | Luminal obstruction → bacterial overgrowth → inflammation |
| Perforation | Any age | Peritonitis, sepsis | Complication of diverticulitis or ulceration |
| Littre hernia | Any age | Incarcerated hernia with SBO features | Diverticulum within hernia sac |
| Chronic anaemia | Older children/adults | Fatigue, pallor, iron-deficiency picture | Chronic occult bleeding from ulcerated mucosa |
High Yield Summary — Overview
A true diverticulum from a vitelline-duct remnant, usually on the antimesenteric distal ileum. The rule of twos is approximate; male predominance chiefly concerns symptomatic cases and presentation is possible at any age. Ectopic gastric tissue can ulcerate neighbouring ileal mucosa. Think painless bleeding, obstruction or an appendicitis mimic.
Active Recall — Overview
[1] Senior notes: Adrian Lui Pediatrics Notes.pdf (pp. 249–250) [2] Senior notes: MBBS Final MB (Pediatrics) (Felix PY Lai).pdf (p. 343) [3] Senior notes: MBBS Final MB (Surgery) (Felix PY Lai).pdf (p. 1040) [4] Senior notes: Ryan Ho GI.pdf (pp. 160–161) [5] Senior notes: Block A - Coffee ground vomitus tarry stool upper GI bleeding.pdf (p. 58) [6] Senior notes: Ryan Ho Diagnostic Radiology.pdf (p. 63) [7] Senior notes: Maksim Medicine Notes.pdf (p. 125) [8] Senior notes: Block A - Upper abdominal pain_ peptic ulcer; pancreatitis and gallstone.pdf (p. 10)
Differential Diagnosis of Meckel Diverticulum
The differential diagnosis of Meckel diverticulum depends entirely on how it presents. Since Meckel diverticulum is a great mimicker, you need to think about differentials organized by the presenting complaint — not by the pathology itself. A patient doesn't walk in saying "I have a Meckel diverticulum." They present with painless rectal bleeding, or RLQ pain, or bowel obstruction. Your job is to work backwards.
This is the classic presentation of Meckel diverticulum in paediatrics — massive painless maroon-coloured stool [9][10]. The key question is: what else causes painless (or near-painless) rectal bleeding in a child?
GC Lecture High Yield: The senior notes and paediatric surgery notes consistently frame Meckel diverticulum in the LGIB differential as: "painless, large amount, altered blood" — contrasted with intussusception ("painful, small amount, mucus") and anal fissure ("painful defecation, outlet type") [10].
| Diagnosis | Age | Pain? | Character of Blood | Key Distinguishing Feature | Pathophysiology |
|---|---|---|---|---|---|
| Meckel diverticulum | Often children; any age possible | Painless [9][10] | Dark red / maroon / "brick-red"; can be massive | Meckel scan +ve for ectopic gastric mucosa; negative OGD and colonoscopy [5] | Ectopic gastric mucosa → acid → peptic ulceration of adjacent ileal mucosa |
| Juvenile polyps | 2–10 years | Painless | Bright red, small amount, often coating stool | Colonoscopy reveals pedunculated polyp; painless, outlet-type bleeding [10] | Hamartomatous polyps with fragile surface vessels → chronic oozing |
| Anal fissure | Any age (common in infants with constipation) | Painful defecation | Bright red, on surface of stool or on wiping | History of constipation/hard stools; visible fissure on inspection; outlet type [10] | Mucosal tear at anal verge → exposed somatic nerve endings (pain) + exposed vessels (bleeding) |
| Intussusception | 6 months – 2 years (peak) | Painful — intermittent colicky pain | "Redcurrant jelly" (blood + mucus); late sign | Classical triad: colicky pain, sausage mass, redcurrant jelly stool; USG shows target sign [10][11] | Invagination of proximal bowel into distal → venous congestion → mucosal ischaemia → bloody mucus |
| Intestinal duplication cyst | Young children | Variable | Variable — can be painless PR bleed | May contain ectopic gastric mucosa (like Meckel); false positive on Meckel scan [10] | Ectopic gastric mucosa within cyst → acid secretion → ulceration (same mechanism as Meckel) |
| Inflammatory bowel disease | Older children / adolescents | Crampy pain, diarrhoea | Bloody diarrhoea (UC > Crohn) | Chronic symptoms, growth failure, extra-intestinal manifestations | Chronic mucosal inflammation → ulceration → bleeding |
| Infectious colitis | Any age | Crampy abdominal pain | Bloody/mucoid diarrhoea | Acute onset, fever, travel/exposure history | Bacterial invasion of mucosa → inflammation → mucosal haemorrhage |
| Henoch-Schönlein Purpura (HSP) | 3–10 years | Abdominal pain (can be severe) | PR bleed or haematemesis | Palpable purpura (vasculitis + bleeding), arthritis, renal involvement; can cause intussusception [11] | IgA-mediated small vessel vasculitis → GI mucosal haemorrhage; bowel wall oedema can cause intussusception |
| Colonic diverticular bleeding (adults) | > 50 years | Painless | Maroon/bright red, can be massive | Most common cause of LGIB in adults; right-sided diverticula more common in Asians [12][13] | Rupture of vasa recta draped over diverticulum dome |
| Angiodysplasia (adults) | > 65 years | Painless | Variable severity | Elderly; associated with aortic stenosis (Heyde syndrome) [13] | Degenerative dilated submucosal vessels → rupture into lumen |
Exam Approach: Painless GI Bleed in a Young Patient with Negative OGD and Colonoscopy
"For your young patient with GI bleed, everything's coming up negative. Negative OGD, negative colonoscopy, negative VCE and CTE. What is your top differential and what is the imaging you would order?" — The answer is Meckel diverticulum → order a Meckel scan [5]. This is a classic exam stem. Meckel diverticulum is a relatively common cause of obscure GI bleed [8] and should be high on the list when standard endoscopic workup is negative in a child or young adult.
Why each differential is included — first principles reasoning:
- Juvenile polyps: Most common cause of painless rectal bleeding in children aged 2–10. The polyps are hamartomatous (not neoplastic in most cases) and bleed from surface erosion. Distinguished from Meckel because the blood is typically bright red and small-volume (outlet bleeding), and colonoscopy identifies the polyp.
- Anal fissure: Key distinguishing feature is pain on defecation. Meckel bleeding is painless. Fissures are associated with constipation and hard stools in children. Blood is bright red, on surface.
- Intussusception: Overlaps with Meckel diverticulum in two ways — (a) it is itself a DDx for Meckel bleeding, and (b) Meckel can actually cause intussusception as a lead-point. The combination of colicky pain, vomiting and bloody mucus supports it; the classic triad is often incomplete, so absence of these findings does not exclude it. This differs from the painless bleeding of Meckel. However, if Meckel diverticulum is the lead-point, the presentation is intussusception, not isolated bleeding.
- Intestinal duplication cyst: Important because it can also contain ectopic gastric mucosa → same mechanism as Meckel → can give a false positive on Meckel scan [10]. Distinguished by imaging (USG/CT showing cystic structure).
- HSP: Important paediatric DDx for abdominal pain + PR bleed. The presence of palpable purpura on lower extremities/buttocks is the clinical clue [11].
Meckel diverticulitis has a similar presentation as acute appendicitis [14]. This is directly from the GC lecture slide and is high yield.
GC 195 Lecture Slide — HIGH YIELD: "Meckel's Diverticulitis: Similar presentation as acute appendicitis. Diagnosis by CT scan. Incidental finding during appendicectomy. Treatment: Antibiotics, Diverticulectomy / small bowel resection." [14]
The differential here is essentially the DDx of RLQ pain / acute abdomen in children and young adults:
| Diagnosis | Key Distinguishing Features | Why it mimics / differs from Meckel diverticulitis |
|---|---|---|
| Acute appendicitis | Classic migration from periumbilical → RIF; McBurney's point tenderness; anorexia, nausea | Most important DDx — Meckel diverticulitis is often only distinguished intra-operatively (preoperative recognition can be difficult) [1]. Both involve an inflamed blind-ending structure, but the appendix arises from the caecum and Meckel from the ileum. |
| Crohn ileitis | Chronic diarrhoea, weight loss, perianal disease; skip lesions on imaging; young patient | Terminal ileal inflammation can mimic Meckel diverticulitis. Distinguished by chronicity and extra-intestinal features. Listed as DDx alongside appendicitis and colonic diverticulitis [1]. |
| Colonic diverticulitis | Usually older patients ( > 40); LLQ pain in Westerners (may be RLQ in Asians with right-sided diverticula) | Listed as DDx for Meckel diverticulitis [1]. Distinguished by age and CT findings (colonic wall thickening + pericolonic fat stranding vs. small bowel diverticulum). |
| Mesenteric adenitis | Often preceded by viral illness prodrome; USG shows mesenteric lymphadenopathy [11] | Common mimic of appendicitis in children. Distinguished by viral prodrome and imaging. |
| Ovarian pathology (in females) | Ruptured ovarian cyst, ovarian torsion, ectopic pregnancy; always check β-hCG and LMP in reproductive-age females [11] | RLQ pain in females — must exclude gynaecological causes before attributing to Meckel or appendicitis. |
| Testicular torsion (in males) | Acute scrotal pain ± referred to RIF; high-riding testis, absent cremasteric reflex | Can present with referred abdominal pain in boys. Always examine the scrotum. |
| HSP (Henoch-Schönlein Purpura) | IgA-mediated small vessel vasculitis; palpable purpura, arthritis, abdominal pain, renal involvement [11] | Abdominal pain in HSP can mimic surgical abdomen. Distinguished by purpuric rash. Can also cause intussusception. |
| Intestinal obstruction (adhesions, hernia, volvulus) | Previous surgical scars (adhesions); irreducible groin lump (hernia); bilious vomiting | Meckel-related obstruction (volvulus around band, Littre hernia) is one cause; other causes must be considered. |
Critical Teaching Point
Meckel diverticulitis is often only distinguished intra-operatively — preoperative recognition can be difficult [1]. If a surgeon performs appendicectomy and finds a normal appendix, they must inspect the distal ileum for Meckel diverticulum. Conversely, if Meckel diverticulitis is found, concomitant appendicectomy is an individual operative decision rather than mandatory treatment.
When Meckel diverticulum presents as intestinal obstruction, the differential includes all causes of small bowel obstruction (SBO) in children [10][11]:
| Diagnosis | Mechanism | Distinguishing Features |
|---|---|---|
| Incarcerated inguinal hernia | Important cause, particularly in infants [11] | Irreducible inguinal swelling; more common in premature infants (patent processus vaginalis) |
| Intussusception | Invagination of proximal into distal bowel | Typical age 6 months – 2 years; ileocaecal (85%); classical triad; USG target sign [11] |
| Adhesive intestinal obstruction | Post-operative adhesions | History of previous abdominal surgery; AXR shows distended SB [11] |
| Malrotation with midgut volvulus | Failure of normal gut rotation → shortened mesentery → volvulus | Often presents in infancy with bilious vomiting, but may occur later; displaced DJ flexure on imaging; emergency Ladd procedure [1] |
| Congenital bands | Fibrous bands (including vitelline band from Meckel) | Can present at any age; band compresses or causes volvulus of small bowel |
| Intestinal duplication cyst | Mass effect or lead-point for intussusception | USG/CT shows cystic structure adjacent to bowel |
| Foreign body / bezoar | Mechanical luminal obstruction | History of ingestion; X-ray or CT may show foreign body |
| Pyloric stenosis | Hypertrophied pyloric muscle → gastric outlet obstruction | Non-bilious projectile vomiting in 3–6 week old infant; "olive" mass; different mechanism from SBO |
4. DDx When Meckel Diverticulum Is Found as Part of a Broader Differential
"Obscure GI bleeding" = bleeding that persists or recurs after negative upper endoscopy (OGD) and colonoscopy [5][8]. The DDx includes:
| Source | Cause |
|---|---|
| Small bowel | Meckel diverticulum (esp. in young patients), angiodysplasia, small bowel tumours (GIST, carcinoid, lymphoma, adenocarcinoma), NSAID-induced small bowel ulcers, Crohn disease, TB enteritis, aortoenteric fistula |
| Missed upper GI | Cameron ulcer (hiatal hernia), Dieulafoy lesion, gastric antral vascular ectasia (GAVE/"watermelon stomach") |
| Missed colonic | Right-sided lesion missed on colonoscopy |
Meckel diverticulum is listed under peptic ulcer disease as a possible location — "2% of population, have acid producing cells producing peptic ulcers (relatively common cause of obscure GI bleed)" [8].
Understanding false results helps you think about overlapping differentials:
| Result | Cause | Explanation |
|---|---|---|
| False positive | Intestinal duplication cyst [10] | Also contains ectopic gastric mucosa → takes up 99mTc pertechnetate |
| False positive | Inflamed bowel (e.g. Crohn, intussusception) | Hyperaemic mucosa can concentrate tracer non-specifically |
| False positive | Urinary tract anomalies | Tracer excreted by kidneys → renal pelvis/bladder can mimic |
| False negative | No or inadequate heterotopic gastric mucosa [10] | 99mTc pertechnetate only detects gastric mucosa — a Meckel without it will be missed |
| False negative | Rapid bleeding causing dilution of radiotracer [10] | Active brisk haemorrhage dilutes the concentrated signal |
Important Distinction for Exams
Intestinal duplication cyst is the most important false positive on Meckel scan because it also contains ectopic gastric mucosa. If you see an abnormal focus on Meckel scan in a child with GI bleeding, consider both Meckel diverticulum and duplication cyst. CT or surgical exploration will distinguish them.
High Yield Summary — Differential Diagnosis of Meckel Diverticulum
-
Organise DDx by presenting complaint: painless PR bleeding, acute abdominal pain, or intestinal obstruction
-
Painless PR bleeding in children: top DDx = Meckel diverticulum, juvenile polyps, anal fissure (painful — distinguishing feature), intussusception (painful + redcurrant jelly). Intestinal duplication cyst can mimic Meckel and give false positive on Meckel scan
-
Acute abdominal pain (RLQ): Meckel diverticulitis has similar presentation to acute appendicitis (GC 195) — often only distinguished intra-operatively (preoperative recognition can be difficult). Other DDx: Crohn ileitis, colonic diverticulitis, mesenteric adenitis, gynaecological causes
-
Intestinal obstruction in children: include incarcerated hernia, intussusception, adhesions and malrotation; frequency depends on age and setting; Meckel causes obstruction via intussusception (lead-point), volvulus around band, or Littre hernia
-
Obscure GI bleed (negative OGD + colonoscopy in young patient): think Meckel diverticulum → order Meckel scan
-
Meckel scan pitfalls: false positive = intestinal duplication cyst; false negative = no gastric mucosa, or dilution from rapid bleeding
Active Recall - Meckel Diverticulum: Differential Diagnosis
References
[1] Senior notes: Adrian Lui Pediatrics Notes.pdf (pp. 249–250) [5] Senior notes: Block A - Coffee ground vomitus tarry stool upper GI bleeding.pdf (pp. 57–58) [8] Senior notes: Block A - Upper abdominal pain_ peptic ulcer; pancreatitis and gallstone.pdf (p. 10) [9] Senior notes: Maksim Surgery Notes.pdf (pp. 96, 336–338) [10] Senior notes: Maksim Surgery Notes.pdf (pp. 337–338) — Paediatric surgery section [11] Senior notes: Maksim Surgery Notes.pdf (pp. 336–338) — Paediatric surgical abdomen DDx [12] Senior notes: MBBS Final MB (Medicine) (Felix PY Lai).pdf (p. 651) [13] Senior notes: Ryan Ho Fundamentals.pdf (p. 281) [14] Lecture slides: GC 195. Lower and diffuse abdominal pain RLQ problems; pelvic inflammatory disease; peritonitis and abdominal emergencies.pdf (p. 22)
Diagnosis and investigations
There is no diagnostic score for Meckel diverticulum. The investigation depends on whether the presentation is bleeding, inflammation or obstruction. A negative test does not exclude every form of Meckel disease.
Assess perfusion, vital signs, abdominal tenderness/peritonism, vomiting and hernias. Obtain FBC, group and crossmatch when bleeding is significant, coagulation, electrolytes and renal function. CRP and blood gas/lactate help assess inflammation or hypoperfusion. Normal haemoglobin early in haemorrhage and normal lactate early in bowel ischaemia are not reassuring exclusions. Pregnancy testing is relevant when pregnancy is possible.
| Presentation | Investigation strategy |
|---|---|
| Stable child with painless rectal bleeding | Consider a Meckel scan early, alongside assessment for common causes; routine OGD and colonoscopy need not precede it |
| Ongoing substantial bleeding | Resuscitate with urgent surgical/GI/radiology involvement; CT angiography may rapidly localise an active source when feasible |
| Shock, peritonitis or suspected strangulation | Resuscitation and urgent source control; do not delay necessary surgery for scintigraphy |
| Abdominal pain/possible diverticulitis | Ultrasound often first in children; contrast CT when indicated can identify an inflamed distal-ileal pouch and complications |
| Intussusception/obstruction | Ultrasound for suspected childhood intussusception; additional imaging according to age and concern for obstruction/ischaemia |
| Persistent unexplained bleeding | Reconsider the source and scan quality; selected enterography, capsule/balloon enteroscopy or surgical exploration after specialist assessment |
The scan detects functioning ectopic gastric mucosa, not blood extravasation. Gastric mucin-secreting cells concentrate the tracer; acid-secreting parietal cells explain ulceration but are not the tracer-uptake mechanism. An ectopic focus appearing with gastric activity supports the diagnosis. H₂-blocker preparation reduces tracer release/washout into bowel, improving retention; follow the nuclear-medicine protocol. [20]
| Finding or pitfall | Meaning |
|---|---|
| Ectopic focus with gastric-like uptake | Gastric mucosa outside the stomach; often Meckel, but not specific for it |
| Duplication cyst | May contain gastric mucosa and produce a false-positive Meckel interpretation |
| Urinary activity or inflammation | Can mimic abnormal bowel uptake |
| No or too little gastric mucosa | False-negative scan despite a diverticulum |
| Brisk bleeding, motion or technical limitations | Can reduce sensitivity even when gastric tissue is present |
Performance varies with technique and patient selection; the society guideline reports approximately 85% sensitivity and 95% specificity in an appropriate setting. It is generally less reliable in adults. A negative scan neither rules out Meckel disease nor proves that gastric mucosa is absent. [20]
Contrast CT may show a blind-ending pouch arising from the distal ileum, wall thickening, adjacent fat stranding, fluid, obstruction or perforation. Identifying a separate normal appendix helps. A calcified enterolith is a clue, not independently pathognomonic. Ultrasound avoids radiation and can show a thick-walled bowel pouch or intussusception, but a normal examination does not exclude Meckel.
Plain radiographs may show bowel dilatation or free air; normal films do not exclude obstruction or perforation. A fixed adult bowel-diameter cutoff should not be applied uncritically to infants.
CT angiography is rapid and can guide catheter angiography or surgery. Catheter angiography may demonstrate extravasation or a persistent vitelline artery and permits selected embolisation, with a risk of bowel ischaemia. Tagged red-cell scintigraphy can detect intermittent bleeding but localises less precisely and does not identify its cause. The choice depends on bleeding rate, stability, age, radiation considerations and local expertise. [21]
- Capsule endoscopy may reveal a double-lumen appearance or ulceration in unexplained small-bowel bleeding, but cannot biopsy or treat. Avoid it in suspected obstruction/stricture without a safe patency strategy.
- Balloon enteroscopy can inspect and sometimes treat a small-bowel lesion; definitive management of symptomatic Meckel is usually surgical.
- Laparoscopy/exploration may establish the diagnosis when imaging is inconclusive or an acute complication requires surgery.
- If a normal appendix is found during surgery for unexplained right-sided pain, inspect the distal ileum. The “two feet” location is approximate and should not impose an absolute limit on exploration.
- Histopathology of the resection confirms the wall structure, ectopic tissue, inflammation and any neoplasm.
High Yield Summary — Investigations
Meckel scan detects gastric mucosa; tagged RBC imaging detects bleeding. A negative Meckel scan does not exclude the disease. CT/ultrasound evaluate inflammatory or obstructive presentations. Unstable patients need resuscitation and rapid source control, with imaging only when it helps without harmful delay.
Active Recall — Investigations
References
[20] SNMMI/EANM practice guideline for Meckel diverticulum scintigraphy 2.0. [21] ACG/SAR consensus: imaging of gastrointestinal bleeding (2024). [22] Blouhos et al. Meckel diverticulum: surgical concerns (2018).
Management of Meckel diverticulum
Symptomatic Meckel disease usually needs surgical resection after resuscitation. Timing and extent depend on bleeding, inflammation, bowel viability and physiological stability. The decision for an asymptomatic incidental diverticulum is individualised.
| Problem | Initial care |
|---|---|
| Haemorrhage/shock | ABC, IV/IO access, crossmatch, age-appropriate resuscitation and early blood products for significant haemorrhage; activate the local major-haemorrhage pathway when appropriate |
| Obstruction/vomiting | Nil by mouth, IV fluids/electrolytes, analgesia and nasogastric decompression when indicated |
| Diverticulitis/perforation | IV antibiotics covering enteric Gram-negative organisms and anaerobes, resuscitation and urgent surgical source control |
| Suspected ischaemia | Immediate senior surgical assessment; a normal lactate does not exclude it |
In children, use weight-based local resuscitation and electrolyte protocols, reassessing after each bolus rather than repeatedly giving fixed large volumes. With substantial blood loss, crystalloid is not a substitute for blood. Monitor perfusion, urine output, temperature, glucose, calcium and coagulation as appropriate. Treat hypoperfusion and its cause; bicarbonate is not a routine response to a low pH.
Acid suppression may be an adjunct while treating a bleeding diverticulum, but does not replace haemostasis or resection. Routine combined H₂-blocker/PPI treatment is not required. H₂-blocker scan preparation is a separate diagnostic use.
Procedure choice depends on the base and adjacent ileum, tissue viability, suspected location of ectopic mucosa, and ulceration, not a universal two-centimetre base-width cutoff. [22]
| Operation | What it means | Typical considerations |
|---|---|---|
| Diverticulectomy | Excise the pouch and close the ileal defect | Suitable when the base and adjacent bowel are healthy and closure preserves the lumen |
| Wedge resection | Remove the diverticulum with a wedge of adjacent ileal wall; close the local defect, often transversely | Can include tissue near the base while preserving lumen calibre |
| Segmental ileal resection | Remove an ileal segment containing the diverticulum, then usually anastomose bowel ends | Diseased base/adjacent ulcer, ischaemia, extensive inflammation, problematic morphology or neoplasm |
Wedge and segmental resections are different operations. Bleeding may arise from adjacent ileal ulceration, so removing only the tip may leave the source. In severe instability or contamination, the surgeon may need a staged procedure or diversion instead of immediate anastomosis. Laparoscopic, assisted or open access is chosen according to physiology and operative findings.
| Presentation | Definitive approach |
|---|---|
| Significant or recurrent bleeding | Localise where feasible and resect the diverticulum with affected adjacent bowel as needed |
| Diverticulitis | Antibiotics plus diverticulectomy or bowel resection; perforation/peritonitis increases urgency |
| Intussusception with a Meckel lead-point | Reduction when appropriate, assessment of viability and treatment of the lead-point; successful enema reduction does not remove a persistent pathological lead-point |
| Volvulus/band obstruction | Urgent release of the band/twist, resection of the diverticulum as appropriate and assessment/resection of nonviable bowel |
| Strangulated Littre hernia | Treat the hernia and compromised diverticulum/bowel urgently |
Concomitant removal of a normal appendix is an operative judgement, not mandatory treatment for every Meckel diverticulum.
Routine prophylactic resection remains debated. Younger age, male sex, length over 2 cm, an abnormal appearance or fibrous band may favour resection when operative risk is low. Age is one factor, not a rigid “never after 50” rule. Ectopic tissue cannot always be excluded by visual inspection or palpation. [22]
An imaging-only incidental finding does not automatically justify an operation; assess confidence in the diagnosis, symptoms and individual risk. At surgery for another indication, consider contamination, instability, comorbidity and the additional procedure required. In a child, discuss the balance with the paediatric surgical team; longer remaining lifetime does not make resection risk-free. [23]
Historical percentages for lifetime disease risk and postoperative morbidity come from different populations and should not be directly compared as if they decide treatment for an individual patient.
Review histopathology; monitor for bleeding, infection, ileus, leak and bowel obstruction. Nutrition, analgesia and mobilisation follow the clinical course. Give return advice for worsening pain, fever, persistent vomiting/distension or recurrent bleeding. Long-term adhesive obstruction is possible; extensive bowel loss after ischaemia can rarely cause short-bowel syndrome.
High Yield Summary — Management
Resuscitate first and obtain surgical source control for symptomatic disease. Diverticulectomy, wedge and segmental resection are distinct. Base health, ectopic tissue/ulceration and bowel viability guide the operation. Incidental asymptomatic disease requires risk–benefit assessment, not absolute age or imaging rules.
Active Recall — Management
References
[22] Blouhos et al. Meckel diverticulum: surgical concerns (2018). [23] Yagnik et al. Should an incidental Meckel diverticulum be resected? Systematic review (2024).
Complications of Meckel Diverticulum
Most of Meckel diverticula remain asymptomatic throughout life. When complications do occur, they are the very reason the condition becomes clinically significant. The complications of Meckel diverticulum can be divided into:
- Complications of the disease itself (i.e. what happens when Meckel diverticulum becomes symptomatic)
- Complications of the surgical treatment (postoperative complications)
As listed in the senior notes [15][16]:
Complications of Meckel's diverticulum:
Let's work through each from first principles, explaining why each complication occurs and what its downstream consequences are.
A. Complications of the Disease Itself
Frequency: Most common complication in children (especially < 2 years) [1][5][10]
Pathophysiology chain:
Ectopic gastric mucosa within diverticulum → parietal cells secrete HCl → acid contacts unprotected adjacent ileal mucosa (less acid protection than the stomach) → peptic ulceration of adjacent/downstream ileal mucosa → erosion into submucosal vessels (branches of the vitelline artery) → haemorrhage into bowel lumen [5]
Clinical spectrum:
| Severity | Presentation | Pathophysiological Basis |
|---|---|---|
| Acute massive bleeding | Massive painless maroon-coloured stool (haematochezia) [9][10]; haemodynamic instability (tachycardia, hypotension) | Erosion into a sizeable vitelline artery branch → rapid intraluminal blood loss |
| Chronic occult bleeding | Iron-deficiency anaemia (fatigue, pallor, koilonychia); positive faecal occult blood | Slow, intermittent oozing from a shallow ulcer → gradual iron depletion over weeks to months |
| Recurrent episodes | Intermittent PR bleeding with spontaneous resolution between episodes | Ulcer heals partially between bleeds; acid secretion persists → re-ulceration |
Consequences of uncontrolled bleeding:
- Hypovolaemic shock: loss of circulating volume → ↓cardiac output → ↓tissue perfusion → organ failure
- Severe anaemia: ↓oxygen-carrying capacity → tissue hypoxia → cardiac compensation (tachycardia) → eventual high-output cardiac failure if severe
- Coagulopathy: massive transfusion → dilutional coagulopathy; hypothermia and acidosis from shock worsen clotting (the "lethal triad" of trauma — hypothermia, acidosis, coagulopathy)
- Death if untreated — though mortality from Meckel bleeding is very low with timely surgical intervention
Why Is Meckel Bleeding Typically Painless?
The ileal mucosa has only visceral innervation (via T10 sympathetic afferents). Visceral pain is triggered by stretch, distension, or ischaemia — not by mucosal ulceration per se. The ulcer erodes into the mucosa and vessels without causing significant stretching of the bowel wall. This is analogous to why duodenal ulcers can bleed massively before any significant pain develops. Only when complications like obstruction, distension, or peritonitis arise does pain become prominent.
2. Intestinal Obstruction (IO)
Frequency: Most common complication in adults [1][4]
Meckel diverticulum causes IO through multiple distinct mechanisms, each with its own pathophysiology:
- Meckel diverticulum acts as a pathological lead-point [1][4][9][10]
- The diverticulum protrudes into the bowel lumen → peristaltic waves "catch" the diverticulum and pull the proximal bowel (intussusceptum) into the distal bowel (intussuscipiens) [1]
- This drags the mesentery along with it → compression of mesenteric vessels → venous and lymphatic congestion → bowel wall oedema → arterial compromise → ischaemia → if untreated, gangrene, perforation, peritonitis [1]
- The classic "redcurrant jelly stool" is actually a late sign — it means venous congestion is severe enough to cause mucosal ischaemia and haemorrhage mixed with mucus
- Key point: unlike idiopathic intussusception (which is ileocolic and occurs in infants due to enlarged Peyer patches), Meckel-related intussusception is often ileoileal and occurs in older children — always suspect a pathological lead-point in recurrent intussusception or atypical age [1]
Consequences if untreated:
- Closed-loop obstruction → bowel necrosis → perforation → faecal peritonitis → septic shock → death
- Short bowel syndrome if extensive bowel resection is required for gangrenous bowel
- A persistent fibrous cord (vitelline band) connects the diverticulum to the umbilicus [1][4]
- This band acts as a fixed pivot point → mobile small bowel loops twist around the band → volvulus
- Volvulus = closed-loop obstruction from the outset → both afferent and efferent limbs are obstructed → rapid bowel distension → mesenteric vessel compression → ischaemia develops very quickly
- This is a surgical emergency — delay leads to bowel necrosis
- Littre hernia = hernia containing Meckel diverticulum [1][4][15][16]
- Named after Alexis Littre (1658–1726), French anatomist
- The diverticulum can herniate through any hernia orifice (inguinal, femoral, umbilical)
- If the hernia becomes incarcerated (cannot be reduced) → venous congestion → oedema → strangulation → ischaemia → gangrene of the diverticulum within the hernia sac
- Because only the diverticulum (not the entire bowel loop) is in the hernia, there may be no complete bowel obstruction initially — making the diagnosis tricky
- Downstream consequences: localised gangrene → perforation within the hernia sac → localised abscess or spreading peritonitis if bowel wall breaches
| Mechanism | Explanation | Consequence |
|---|---|---|
| Meckel diverticulitis with oedema | Inflamed, swollen diverticulum causes extramural compression of adjacent ileum [1][4] | Partial or complete SBO |
| Inversion of the diverticulum | The diverticulum turns inside-out into the ileal lumen → acts as an intraluminal mass [1][4] | Mechanical obstruction; can also act as lead-point for intussusception |
| Adhesions | Inflammation from diverticulitis or previous surgery involving the Meckel area → fibrous adhesions form between bowel loops | Adhesive SBO (same mechanism as any post-surgical adhesion) |
Pathophysiology — directly analogous to appendicitis:
Obstruction of diverticular orifice (by enterolith, food particle, foreign body, inflammation, or rarely tumour) → stasis of contents → bacterial overgrowth within the obstructed diverticulum → mucosal inflammation → oedema → vascular compromise of the wall → ischaemia → potential gangrene and perforation [1][4]
Clinical consequences:
| Stage | Clinical Picture | Mechanism |
|---|---|---|
| Early diverticulitis | Periumbilical or central abdominal pain (visceral), low-grade fever, anorexia | Visceral inflammation → afferents via SMA plexus (T10) → periumbilical pain |
| Localised peritonitis | Pain migrates to RLQ; localised guarding and rebound tenderness | Inflamed diverticulum contacts parietal peritoneum → somatic pain (sharp, localised) |
| Walled-off phlegmon/abscess | Palpable phlegmon if walled off [1] | Omentum and adjacent loops wall off the inflammation → inflammatory mass |
| Perforation → generalised peritonitis | Peritoneal signs if perforated [1]; diffuse guarding, rigidity, sepsis | Diverticular wall necroses → bowel contents leak into peritoneal cavity → chemical + bacterial peritonitis |
| Septic shock | Hypotension, tachycardia, fever, oliguria, altered consciousness | Bacterial translocation → systemic inflammatory response → multi-organ dysfunction |
Often only distinguished intra-operatively — recognition before surgery can be difficult [1][4]. This is because the clinical picture is virtually identical to acute appendicitis.
Perforation can result from:
| Cause | Mechanism |
|---|---|
| Meckel diverticulitis (most common) | Transmural inflammation → necrosis → full-thickness wall breach |
| Peptic ulceration | Deep ulceration from acid erosion through all 4 wall layers |
| Foreign body | Sharp FB ingested orally lodges in or perforates the diverticulum |
| Trauma | Blunt/penetrating abdominal trauma involving the diverticulum |
Consequences of perforation:
- Localised peritonitis: if the perforation is small and the omentum/adjacent loops wall it off → localised abscess
- Generalised (faecal) peritonitis: if the perforation is free → ileal contents contaminate the entire peritoneal cavity → massive bacterial load (Gram-negative aerobes: E. coli, Klebsiella; anaerobes: Bacteroides fragilis) → systemic sepsis
- Pneumoperitoneum: free air visible on erect CXR/AXR (subdiaphragmatic air)
- Septic shock and multi-organ failure if untreated
- This is a surgical emergency requiring laparotomy, bowel resection, peritoneal lavage, and broad-spectrum antibiotics
Already discussed above under intestinal obstruction, but worth noting as a standalone complication [15][16]:
- Can occur in inguinal, femoral, or umbilical hernia sacs
- May present as an incarcerated hernia without classic SBO features (because only the diverticulum, not the entire bowel loop, is trapped)
- Strangulation of the Meckel diverticulum within the hernia → gangrene → perforation → localised or spreading sepsis
Although not listed in the standard complication list from the lecture slides, neoplasms arising within Meckel diverticulum are a recognised rare complication:
| Tumour Type | Frequency | Key Points |
|---|---|---|
| Carcinoid tumour | Most common neoplasm in Meckel diverticulum | Usually incidental finding at surgery; can secrete serotonin → carcinoid syndrome (flushing, diarrhoea, wheezing, right-sided cardiac valve fibrosis) if liver metastases present |
| Adenocarcinoma | Rare | Arises from the intestinal or ectopic mucosa |
| GIST | Rare | Gastrointestinal stromal tumour; arises from interstitial cells of Cajal |
| Leiomyoma / leiomyosarcoma | Very rare | Smooth muscle tumour |
The risk is low, but any Meckel diverticulum resected at surgery should be sent for histopathological examination to exclude occult neoplasia.
These apply to both diverticulectomy and segmental bowel resection [1][4][15][16]:
| Complication | Incidence | Mechanism | Prevention / Management |
|---|---|---|---|
| Wound infection [15][16] | Most common postop complication | Contamination during bowel surgery → bacterial colonisation of wound | Prophylactic antibiotics; meticulous wound care; laparoscopic approach (smaller wound) |
| Postoperative paralytic ileus [15][16] | Common; usually self-limiting | Handling of bowel during surgery → temporary loss of coordinated peristalsis (bowel "stunned" by manipulation); also contributed by opioid analgesia, electrolyte disturbance (especially hypokalaemia) | Minimise bowel handling; early mobilisation; correct electrolytes; restrict opioids; exclude mechanical obstruction |
| Anastomotic leak [15][16] | Uncommon but serious; risk varies | Ischaemia or tension at the anastomosis → breakdown of suture/staple line → bowel contents leak into peritoneal cavity → peritonitis | Ensure tension-free, well-vascularised anastomosis; adequate resection margins; nutritional optimisation |
| Adhesive SBO | Long-term risk | Any abdominal surgery creates peritoneal adhesions (fibrous bands between bowel loops) → can cause future mechanical SBO | Minimise with laparoscopic approach (less peritoneal trauma); anti-adhesion barriers (limited evidence) |
| Intra-abdominal abscess | Rare | Localised collection of infected fluid/pus post-surgery | CT-guided percutaneous drainage; antibiotics |
| Bleeding (from staple/suture line) | Rare | Incomplete haemostasis at the diverticulectomy site or anastomosis | Meticulous surgical technique; check haemostasis before closing |
Surgical outcomes depend on elective versus emergency presentation, contamination, bowel viability, comorbidity and the extent of resection. Avoid applying a single mortality or complication percentage to every patient. Incidental resection requires individual risk–benefit assessment (see Mx tab).
| Age Group | Most Common Complication | Why? |
|---|---|---|
| Infants and young children ( < 2y) | GI bleeding | Highest prevalence of ectopic gastric mucosa; active acid secretion → early ulceration |
| Older children and adolescents | Bleeding + intestinal obstruction (intussusception) | Diverticulum large enough to act as lead-point; still high rates of ectopic mucosa |
| Adults | Intestinal obstruction [1][4] | Adhesions, volvulus around bands, Littre hernia more common; the distribution of presentations varies between cohorts |
| Elderly | Complications are rare | Most symptomatic cases have already declared themselves by middle age; risk decreases with age |
Because Meckel diverticulum is difficult to diagnose pre-operatively (especially diverticulitis), delayed diagnosis is common and carries its own cascade of complications:
- Delayed bleeding → progressive anaemia → transfusion-dependent; or → hypovolaemic shock if massive
- Delayed obstruction → bowel ischaemia → necrosis → perforation → peritonitis → sepsis
- Delayed diverticulitis → perforation → peritonitis → sepsis → multi-organ failure
- Diagnostic delay also means longer hospital stay, more interventions, and higher overall morbidity
This is why the clinical teaching point is repeatedly emphasised: always inspect the distal ileum if the appendix is normal at surgery [1][14]. Failure to do so means missing the Meckel, and the patient may re-present with recurrent symptoms or a more advanced complication.
High Yield Summary — Complications
Disease complications include bleeding, obstruction, diverticulitis, perforation and a Littre hernia. A Littre hernia contains Meckel diverticulum and may become incarcerated or strangulated; it need not obstruct the whole ileal lumen. Surgical complications include infection, ileus, leak and later adhesive obstruction. Risks depend on the clinical setting.
Active Recall — Complications
References
[1] Senior notes: Adrian Lui Pediatrics Notes.pdf (pp. 248–250) [4] Senior notes: Ryan Ho GI.pdf (pp. 160–162) [5] Senior notes: Block A - Coffee ground vomitus tarry stool upper GI bleeding.pdf (p. 58) [9] Senior notes: Maksim Surgery Notes.pdf (pp. 96–97) [10] Senior notes: Maksim Surgery Notes.pdf (pp. 337–338) [13] Senior notes: Ryan Ho Fundamentals.pdf (pp. 257, 281) [14] Lecture slides: GC 195. Lower and diffuse abdominal pain RLQ problems; pelvic inflammatory disease; peritonitis and abdominal emergencies.pdf (p. 22) [15] Senior notes: MBBS Final MB (Pediatrics) (Felix PY Lai).pdf (p. 347) [16] Senior notes: MBBS Final MB (Surgery) (Felix PY Lai).pdf (p. 1044)
Revision summary
High Yield Summary — Overview
A true diverticulum from a vitelline-duct remnant, usually on the antimesenteric distal ileum. The rule of twos is approximate; male predominance chiefly concerns symptomatic cases and presentation is possible at any age. Ectopic gastric tissue can ulcerate neighbouring ileal mucosa. Think painless bleeding, obstruction or an appendicitis mimic.
High Yield Summary — Differential Diagnosis of Meckel Diverticulum
-
Organise DDx by presenting complaint: painless PR bleeding, acute abdominal pain, or intestinal obstruction
-
Painless PR bleeding in children: top DDx = Meckel diverticulum, juvenile polyps, anal fissure (painful — distinguishing feature), intussusception (painful + redcurrant jelly). Intestinal duplication cyst can mimic Meckel and give false positive on Meckel scan
-
Acute abdominal pain (RLQ): Meckel diverticulitis has similar presentation to acute appendicitis (GC 195) — often only distinguished intra-operatively (preoperative recognition can be difficult). Other DDx: Crohn ileitis, colonic diverticulitis, mesenteric adenitis, gynaecological causes
-
Intestinal obstruction in children: include incarcerated hernia, intussusception, adhesions and malrotation; frequency depends on age and setting; Meckel causes obstruction via intussusception (lead-point), volvulus around band, or Littre hernia
-
Obscure GI bleed (negative OGD + colonoscopy in young patient): think Meckel diverticulum → order Meckel scan
-
Meckel scan pitfalls: false positive = intestinal duplication cyst; false negative = no gastric mucosa, or dilution from rapid bleeding
High Yield Summary — Investigations
Meckel scan detects gastric mucosa; tagged RBC imaging detects bleeding. A negative Meckel scan does not exclude the disease. CT/ultrasound evaluate inflammatory or obstructive presentations. Unstable patients need resuscitation and rapid source control, with imaging only when it helps without harmful delay.
High Yield Summary — Management
Resuscitate first and obtain surgical source control for symptomatic disease. Diverticulectomy, wedge and segmental resection are distinct. Base health, ectopic tissue/ulceration and bowel viability guide the operation. Incidental asymptomatic disease requires risk–benefit assessment, not absolute age or imaging rules.
High Yield Summary — Complications
Disease complications include bleeding, obstruction, diverticulitis, perforation and a Littre hernia. A Littre hernia contains Meckel diverticulum and may become incarcerated or strangulated; it need not obstruct the whole ileal lumen. Surgical complications include infection, ileus, leak and later adhesive obstruction. Risks depend on the clinical setting.
See the corresponding tabs for explanations, active-recall questions and references.