Meckel's Diverticulum

1. Clinical Overview

Summary

Meckel's diverticulum is the most common congenital anomaly of the gastrointestinal tract, representing a persistent remnant of the vitelline (omphalomesenteric) duct. With a prevalence of approximately 2% in the general population, it is a true diverticulum containing all layers of the intestinal wall. While the majority remain asymptomatic throughout life, complications including haemorrhage, intestinal obstruction, and inflammation occur predominantly in paediatric patients, with over 50% of symptomatic cases presenting before the age of 10 years. [1,2]

The clinical significance of Meckel's diverticulum lies in its protean manifestations and potential for life-threatening complications. Painless massive rectal bleeding secondary to peptic ulceration from ectopic gastric mucosa represents the most common presentation in young children, while obstruction and diverticulitis become more prevalent with advancing age. Recognition of the characteristic "rule of 2s" facilitates diagnostic suspicion, though confirmatory investigation often requires nuclear medicine imaging or surgical exploration. [3]

The "Rule of 2s"

This classical mnemonic encapsulates the key epidemiological and anatomical features:

1. 2% prevalence in the general population
2. Located approximately 2 feet (60 cm) proximal to the ileocaecal valve
3. Typically 2 inches (5 cm) in length
4. Contains 2 types of ectopic tissue (gastric and pancreatic mucosa)
5. 2:1 male predominance in symptomatic cases
6. Under 2 years is the peak age for symptomatic presentation
7. 2% lifetime risk of complications in those with a Meckel's diverticulum

While useful pedagogically, clinicians must recognise significant variation exists in each parameter, and absence of these features does not exclude the diagnosis. [4]

Clinical Pearls

The "Silent Bleeder": The classic presentation is painless rectal bleeding in an otherwise well child. The blood is characteristically "brick red" or maroon due to brisk small bowel bleeding. This haemorrhage results from ectopic gastric mucosa within the diverticulum secreting hydrochloric acid, which causes peptic ulceration of the adjacent normal ileal mucosa rather than the diverticulum itself. The absence of abdominal pain in a bleeding child should immediately raise suspicion for Meckel's diverticulum.

The "Appendicitis Mimic": Meckel's diverticulitis presents with right iliac fossa pain, fever, leucocytosis, and peritonism that is clinically indistinguishable from acute appendicitis. The key surgical principle is that when appendicectomy reveals a normal appendix, the distal 100 cm of ileum must be systematically examined to identify an inflamed Meckel's diverticulum. Failure to do so risks diagnostic delay and progression to perforation.

Intussusception Lead Point: While most paediatric intussusception is idiopathic and secondary to hypertrophied Peyer's patches, Meckel's diverticulum represents an important pathological lead point, particularly in children over 3 years of age. This variant is less amenable to non-operative reduction with air or contrast enema and frequently requires surgical intervention. Intraoperative identification of a lead point mandates resection to prevent recurrence.

Littre's Hernia: This eponymous condition describes incarceration of a Meckel's diverticulum within an inguinal or femoral hernia sac. It represents a surgical trap as the hernial defect may be reduced without addressing the strangulated diverticulum, leading to ongoing ischaemia and perforation. Any irreducible or tender groin hernia in a child warrants careful assessment for this complication.

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2. Epidemiology

Prevalence and Demographics

Meckel's diverticulum occurs in approximately 2% of the general population based on autopsy and imaging studies, making it the most prevalent congenital anomaly of the gastrointestinal tract. The true prevalence may be higher as many asymptomatic cases remain undetected throughout life. Population-based studies suggest a range of 0.3-4.5%, with variations attributable to diagnostic methodology and population characteristics. [5,6]

Symptomatic Disease

Only 4-16% of individuals with Meckel's diverticulum develop symptoms during their lifetime, with the majority remaining asymptomatic. The lifetime risk of complications is estimated at 4-6%, decreasing significantly with advancing age. Symptomatic presentation demonstrates a marked paediatric predominance, with 50-60% of complications occurring before age 10 years and 25-40% presenting before age 2 years. [7,8]

Age Distribution

The age at presentation varies according to the type of complication:

• Bleeding: Peak incidence in children under 5 years, with 60% occurring before age 2 years
• Obstruction: Bimodal distribution with peaks in early childhood and adulthood
• Diverticulitis: Predominantly affects older children, adolescents, and adults
• Incidental finding: Increasingly common with widespread use of abdominal imaging

Sex Distribution

While the prevalence of Meckel's diverticulum is equal between sexes, symptomatic disease demonstrates a male predominance with a ratio of 2-3:1 in most series. This gender disparity is most pronounced in bleeding presentations and less evident in obstructive complications. The mechanism underlying this differential remains unclear but may relate to differences in ectopic tissue distribution or hormonal influences. [9]

Geographic and Ethnic Variation

No significant geographic or ethnic variation in prevalence has been consistently demonstrated, suggesting Meckel's diverticulum represents a universal developmental variant. However, ethnic differences in presentation patterns may reflect variations in healthcare access and diagnostic practices rather than true biological differences.

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3. Pathophysiology

Embryological Development

Normal Vitelline Duct Obliteration

During the fifth week of embryological development, the midgut communicates with the yolk sac via the vitelline (omphalomesenteric) duct. This structure provides nutritional support during early organogenesis and serves as a conduit between the developing intestine and the extraembryonic yolk sac. Between weeks 5-8 of gestation, the vitelline duct normally undergoes complete obliteration and resorption as the midgut elongates and the umbilical cord matures. [10]

Spectrum of Vitelline Duct Anomalies

Incomplete obliteration of the vitelline duct results in a spectrum of anatomical variants:

1. Meckel's Diverticulum (95%): Persistence of the intestinal end of the duct creates a true diverticulum arising from the antimesenteric border of the ileum
2. Patent Vitelline Fistula (1-2%): Complete patency from ileum to umbilicus, presenting with faecal discharge from the umbilicus in neonates
3. Umbilical Sinus (1-2%): Persistence of the umbilical end, creating a blind-ending tract at the umbilicus
4. Vitelline Duct Cyst: Central portion remains patent while both ends obliterate, creating an intra-abdominal cyst
5. Fibrous Band: Complete obliteration leaving a fibrous cord extending from ileum to umbilicus or anterior abdominal wall, creating a risk for volvulus and internal herniation

The specific pattern of incomplete obliteration determines the clinical presentation and potential complications.

Anatomical Characteristics

Location and Morphology

Meckel's diverticulum typically arises from the antimesenteric border of the ileum, approximately 40-100 cm (mean 60 cm) proximal to the ileocaecal valve. The diverticulum is a true outpouching containing all layers of the intestinal wall (mucosa, submucosa, muscularis propria, and serosa). Length varies considerably from 1-10 cm (mean 3-5 cm), with a diameter usually similar to or slightly wider than the adjacent ileum. [11]

The base of the diverticulum may be narrow (pedunculated) or broad (sessile), with narrow-based variants more prone to torsion, volvulus, and compromise of the mesenteric blood supply. The diverticulum receives its vascular supply from a persistent vitelline artery arising from the superior mesenteric circulation.

Ectopic Tissue

Heterotopic mucosa is present in 15-60% of Meckel's diverticula overall, but occurs in up to 80-90% of symptomatic cases, particularly those presenting with bleeding. The most common ectopic tissues include:

• Gastric mucosa (60-85%): Includes parietal cells capable of hydrochloric acid and intrinsic factor secretion, and chief cells producing pepsinogen
• Pancreatic tissue (5-16%): Contains acinar cells secreting digestive enzymes
• Duodenal mucosa (2%): Brunner's glands
• Colonic mucosa (rare): Goblet cells
• Jejunal mucosa (rare)

Ectopic gastric mucosa is the most clinically significant variant, as acid secretion leads to peptic ulceration of the adjacent normal ileal epithelium, which lacks protective mechanisms present in the stomach and duodenum. This ulceration typically occurs at the junction between ectopic and native mucosa or on the ileal wall directly opposite the diverticulum opening. [12]

Molecular Pathophysiology of Complications

Bleeding Mechanism

The pathophysiology of bleeding from Meckel's diverticulum involves acid-induced peptic ulceration:

1. Acid Secretion: Ectopic gastric parietal cells secrete hydrochloric acid (HCl) into the diverticulum lumen
2. Mucosal Exposure: Acid refluxes from the diverticulum and comes into contact with adjacent ileal mucosa
3. Epithelial Injury: Ileal mucosa lacks the protective mucus layer and bicarbonate secretion of the stomach, making it vulnerable to acid-mediated damage
4. Ulceration: Progressive mucosal injury leads to ulcer formation, typically on the ileal wall opposite the diverticulum opening or at the neck
5. Vascular Erosion: Deepening ulcers erode into submucosal and mesenteric vessels, causing acute or chronic haemorrhage

The bleeding is characteristically arterial, brisk, and painless, as the ulceration process itself does not typically cause peritoneal irritation. Blood undergoes minimal digestion during small bowel transit, resulting in the characteristic brick-red or maroon appearance rather than melaena. [13]

Obstruction Mechanisms

Meckel's diverticulum causes intestinal obstruction through multiple mechanisms:

1. Intussusception: The diverticulum acts as a pathological lead point, with the apex inverting and being drawn distally by peristalsis. This creates an ileocolic or ileoileal intussusception with subsequent venous congestion, oedema, and eventual arterial compromise.

2. Volvulus: A fibrous band connecting the diverticulum apex to the umbilicus or anterior abdominal wall creates a fulcrum around which small bowel can twist, causing closed-loop obstruction with rapid progression to ischaemia.

3. Internal Herniation: Mesodiverticular bands create potential spaces into which bowel loops can herniate and become incarcerated.

4. Adhesions: Following previous diverticulitis or subclinical inflammation, adhesions may form between the diverticulum and adjacent structures, creating points of fixation predisposing to kinking and obstruction.

5. Littre's Hernia: Incarceration of the diverticulum within an inguinal or femoral hernia sac, with or without accompanying ileum (Richter-type hernia).

Inflammation

Meckel's diverticulitis arises through mechanisms similar to appendicitis:

1. Luminal Obstruction: Faecal material, inspissated debris, or enteroliths obstruct the diverticulum neck
2. Bacterial Overgrowth: Stasis promotes bacterial proliferation within the diverticulum
3. Mucosal Compromise: Increased intraluminal pressure and bacterial products damage the epithelial barrier
4. Transmural Inflammation: Bacterial invasion extends through the wall, causing serositis and peritoneal irritation
5. Perforation: Unrelieved inflammation progresses to necrosis and free perforation or contained abscess formation

The presence of ectopic pancreatic tissue may contribute to inflammation through alkaline secretions causing chemical injury. [14]

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4. Clinical Presentation

Bleeding Presentations

Acute Massive Haemorrhage

The most characteristic presentation in young children (peak age 6 months to 5 years) is sudden onset of painless bright red or maroon rectal bleeding. The child is typically well and afebrile immediately prior to bleeding onset. Blood loss can be massive, with some children presenting in hypovolaemic shock. The absence of abdominal pain distinguishes this from inflammatory or obstructive pathology, though some children develop cramping secondary to haematochezia-induced colonic contractions. [15]

Chronic Occult Bleeding

Less commonly, children present with chronic iron-deficiency anaemia due to recurrent low-grade bleeding. These children may have a history of intermittent dark stools or positive faecal occult blood tests without an identifiable bleeding source on standard investigation. Fatigue, pallor, and poor growth may be the presenting complaints.

Obstructive Presentations

Intussusception

Meckel's diverticulum as a lead point typically presents in children beyond the peak age for idiopathic intussusception (6-18 months), with a mean age of 3-5 years. The classic triad of colicky abdominal pain, vomiting, and redcurrant jelly stools may be present, though not all features occur in every case. Palpation may reveal a sausage-shaped mass, typically in the right upper quadrant or epigastrium as the ileocolic intussusception progresses proximally. [16]

Volvulus and Internal Herniation

Children with volvulus around a mesodiverticular band present with acute onset severe colicky abdominal pain, bilious vomiting, and rapid progression to peritonism if bowel ischaemia develops. This presentation is indistinguishable from volvulus secondary to intestinal malrotation and requires urgent surgical intervention.

Small Bowel Obstruction

Adhesive obstruction presents more indolently with progressive abdominal distension, vomiting (initially gastric contents, progressing to bilious), absolute constipation, and colicky pain. Signs of dehydration and electrolyte disturbance may be evident on examination.

Inflammatory Presentations

Acute Diverticulitis

Meckel's diverticulitis presents identically to acute appendicitis with right iliac fossa pain, anorexia, nausea, vomiting, and fever. The pain typically starts periumbilically before localising to the right lower quadrant. On examination, there is localised tenderness, guarding, and rebound tenderness in the right iliac fossa. Rovsing's sign and percussion tenderness may be positive. Laboratory studies reveal leucocytosis with neutrophil predominance and elevated inflammatory markers. [17]

The key clinical difference is that pain from Meckel's diverticulitis may be more medial or periumbilical than typical appendicitis, but this distinction is unreliable for clinical decision-making. The diagnosis is usually established intraoperatively when a normal appendix is visualised and systematic inspection of the distal ileum reveals an inflamed diverticulum.

Perforated Meckel's Diverticulum

Progression from diverticulitis to perforation results in generalised peritonitis with diffuse abdominal tenderness, board-like rigidity, absent bowel sounds, and systemic toxicity including fever, tachycardia, and hypotension. This represents a surgical emergency requiring prompt resuscitation and operative intervention.

Incidental Finding

With the widespread use of cross-sectional imaging for abdominal pain, trauma, and other indications, Meckel's diverticulum is increasingly identified as an incidental finding in asymptomatic individuals. Management of incidentally discovered diverticula remains controversial, with factors including patient age, presence of ectopic tissue (suggested by wall thickening or enhancement), and diverticulum morphology influencing decision-making.

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5. Clinical Examination

Initial Assessment

General Inspection

• Hydration Status: Mucous membranes, skin turgor, capillary refill time, and peripheral perfusion
• Pallor: Conjunctival and palmar pallor suggesting acute or chronic anaemia
• Distress Level: Pain severity, comfort at rest versus movement
• Vital Signs: Heart rate, respiratory rate, blood pressure, temperature, and oxygen saturation

Children with acute bleeding may appear remarkably well between bleeding episodes, though tachycardia and pallor indicate significant blood loss. Those with obstruction typically appear more systemically unwell with signs of dehydration.

Abdominal Examination

Inspection

• Distension: Suggests obstruction or ileus
• Surgical Scars: Previous operations may indicate alternative diagnoses or adhesive obstruction
• Visible Peristalsis: Suggests obstruction with hyperactive proximal bowel
• Umbilical Abnormalities: Erythema, discharge, or mass suggesting patent vitelline fistula or umbilical sinus

Palpation

• Right Iliac Fossa: Focal tenderness in diverticulitis, though tenderness may be more medial than typical appendicitis
• Periumbilical Region: Tenderness may indicate diverticulitis or small bowel obstruction
• Mass: Palpable sausage-shaped mass in intussusception (though absence does not exclude)
• Rebound and Guarding: Indicates peritoneal irritation from diverticulitis, perforation, or ischaemic bowel
• Hepatomegaly: Excludes this as a cause of upper GI bleeding

Percussion

• Tympany: Suggests bowel distension from obstruction or ileus
• Shifting Dullness: Free fluid from perforation or exudative peritonitis

Auscultation

• Bowel Sounds: High-pitched tinkling sounds in early obstruction, absent in ileus or peritonitis
• Vascular Bruits: Not typically relevant to Meckel's diverticulum

Hernial Orifices

Careful examination of inguinal and femoral regions is mandatory to exclude Littre's hernia. An irreducible, tender, or erythematous groin swelling requires urgent surgical assessment. In male infants, transillumination helps distinguish hernia from hydrocele.

Digital Rectal Examination

While controversial in young children, rectal examination provides valuable information:

• Presence of Blood: Confirms lower GI bleeding and excludes anal fissure or rectal polyp
• Blood Colour: Bright red suggests lower source (colonic or rectal), dark maroon suggests small bowel
• Rectal Mass: Suggests intussusception if palpable "apex" felt on examination (though this is uncommon)
• Empty Rectum: May indicate complete obstruction

In practice, external inspection of the perineum and stool often provides adequate information without necessitating digital examination in distressed children.

Repeat Assessment

Serial examinations are crucial when the diagnosis is uncertain. Progressive tenderness, increasing heart rate, or development of peritonism indicates worsening pathology requiring escalation to surgical intervention.

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6. Investigations

Laboratory Studies

Full Blood Count

• Haemoglobin: Reduced in acute or chronic bleeding. Degree of reduction helps quantify blood loss
• Mean Corpuscular Volume: Microcytosis suggests chronic iron deficiency from occult bleeding
• White Cell Count: Leucocytosis with neutrophilia in diverticulitis or ischaemic bowel
• Platelets: Reactive thrombocytosis may occur in chronic bleeding or inflammation

Blood Group and Crossmatch

Essential in all children presenting with significant rectal bleeding to ensure availability of compatible blood products. Crossmatch at least 2 units (volume adjusted for child's weight) in massive haemorrhage.

Inflammatory Markers

• C-Reactive Protein: Elevated in diverticulitis and ischaemic bowel, though may be normal in early presentations
• Procalcitonin: Higher specificity for bacterial infection than CRP in some studies

Biochemistry

• Urea and Electrolytes: Assess dehydration and electrolyte disturbance. Elevated urea with normal creatinine suggests upper GI bleeding (haemoglobin digestion), though less reliable in small bowel bleeding
• Liver Function Tests: Exclude hepatobiliary pathology as bleeding source
• Coagulation Screen: Exclude coagulopathy as bleeding cause, particularly in previously well children

Blood Gas Analysis

In shocked or severely anaemic children, blood gas analysis provides rapid assessment of:

• Haemoglobin: Point-of-care haemoglobin guides transfusion decisions
• Lactate: Elevated in shock or bowel ischaemia
• Base Deficit: Quantifies degree of metabolic acidosis from hypoperfusion
• Glucose: Hypoglycaemia may occur in prolonged fasting or severe illness

Nuclear Medicine Imaging

Technetium-99m Pertechnetate Scan (Meckel's Scan)

This is the first-line investigation for suspected bleeding Meckel's diverticulum. Technetium-99m pertechnetate is a radiotracer with similar chemical properties to iodide and is actively taken up and concentrated by mucus-secreting cells in gastric mucosa via the sodium-iodide symporter. [18]

Technique:

1. Fasting: Patient fasts for 4-6 hours to reduce gastric secretions
2. Bladder Emptying: Immediately before scanning to reduce pelvic activity that may obscure findings
3. Pharmacological Priming: Histamine H2-receptor antagonists (ranitidine, cimetidine) or proton pump inhibitors may be administered 24-48 hours before scanning to reduce tracer secretion from parietal cells, enhancing visualisation
4. Glucagon: May be administered immediately before scanning to reduce bowel motility
5. Tracer Injection: Intravenous technetium-99m pertechnetate
6. Imaging: Serial anterior abdominal images acquired over 30-60 minutes

Interpretation:

• Positive Scan: Focal uptake in the right lower quadrant or mid-abdomen appearing simultaneously with gastric uptake and persisting on delayed images
• Negative Scan: No focal abnormal uptake outside the stomach, urinary tract, and blood pool

Performance Characteristics:

• Sensitivity: 85-95% in children (higher than adults)
• Specificity: 95%
• Positive Predictive Value: 90-95%
• Negative Predictive Value: 95%

The scan's sensitivity depends critically on the presence of ectopic gastric mucosa, as purely ileal or pancreatic-type Meckel's diverticula will not demonstrate uptake. False negatives occur in:

• Absence of gastric mucosa
• Small amount of ectopic tissue below detection threshold
• Active rapid bleeding washing tracer away
• Recent bleeding with intraluminal blood obscuring uptake
• Technical factors (inadequate fasting, bladder distension)

False positives may result from:

• Ureteric obstruction or duplication
• Intestinal duplication cysts with gastric mucosa
• Intussusception
• Inflammatory conditions with increased vascularity
• Haemangiomas

Cross-Sectional Imaging

Ultrasound

Abdominal ultrasound is often the first imaging modality performed in children with abdominal pain or suspected intussusception. Findings in Meckel's diverticulum include:

• Blind-ending fluid-filled tubular structure in the right lower quadrant or periumbilical region
• Target or pseudokidney sign: Thickened diverticulum wall creating concentric rings on transverse view
• Intussusception: Classic "target" or "doughnut" sign on transverse view, "pseudokidney" on longitudinal view
• Free Fluid: Suggests perforation or ischaemic bowel
• Wall Thickening: Suggests inflammation

Sensitivity for detecting uncomplicated Meckel's diverticulum is low (approximately 30-40%), but ultrasound effectively identifies complications including intussusception and perforation. Ultrasound is operator-dependent and limited by bowel gas and patient body habitus. [19]

Computed Tomography

CT is not routinely used for suspected Meckel's diverticulum due to radiation exposure concerns in children, but may be performed when obstruction or peritonitis is suspected. Findings include:

• Blind-ending tubular structure arising from ileum in the right lower quadrant or mid-abdomen
• Wall Thickening and Enhancement: Suggests diverticulitis
• Surrounding Fat Stranding: Indicates inflammation
• Bowel Obstruction: Dilated proximal bowel with transition point
• Pneumoperitoneum: Indicates perforation
• Mesodiverticular Band: May be identified in volvulus

CT sensitivity for Meckel's diverticulum is approximately 50-60%, with many uncomplicated cases remaining undetected. The primary value lies in identifying complications and excluding alternative diagnoses.

Magnetic Resonance Imaging

MRI enterography may identify Meckel's diverticulum in older children but is rarely used acutely due to limited availability, need for sedation in young children, and prolonged acquisition times. It may have a role in investigating chronic obscure GI bleeding when other modalities are non-diagnostic.

Endoscopic Investigations

Colonoscopy

In children presenting with rectal bleeding where Meckel's diverticulum is not initially suspected, colonoscopy may be performed to exclude colonic pathology (polyps, inflammatory bowel disease, vascular malformations). A normal colonoscopy in a bleeding child should prompt consideration of small bowel sources including Meckel's diverticulum.

Push enteroscopy or video capsule endoscopy may visualise the diverticulum opening or bleeding site in some cases, though technical limitations in young children restrict use.

Surgical Diagnosis

Ultimately, Meckel's diverticulum is definitively diagnosed at laparoscopy or laparotomy. The "Rule of 2s" guides surgical exploration, with systematic examination of the distal 100 cm of ileum from the ileocaecal valve. The diverticulum arises from the antimesenteric border and typically has a mesentery (mesodiverticulum) that may contain a persistent vitelline artery.

Intraoperative identification requires careful palpation as a narrow-necked diverticulum may be obscured by mesenteric fat or adhesions. The entire diverticulum should be inspected for signs of inflammation, ischaemia, or perforation before resection.

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7. Management

Initial Resuscitation

Bleeding Presentations

Immediate management priorities in children presenting with significant rectal bleeding:

1. Airway and Breathing: Ensure patent airway and adequate oxygenation. High-flow oxygen if shocked
2. Circulatory Access: Establish large-bore IV access (two sites if possible). Intraosseous access if IV unsuccessful in shocked child
3. Fluid Resuscitation: Isotonic crystalloid (0.9% saline or Hartmann's) 20 mL/kg bolus, repeated as necessary based on response
4. Blood Sampling: FBC, group and crossmatch, coagulation, biochemistry
5. Blood Transfusion: Consider early transfusion if ongoing bleeding or haemoglobin less than 70 g/L. Aim haemoglobin > 80-100 g/L
6. Monitoring: Continuous cardiorespiratory monitoring, pulse oximetry, hourly urine output via catheter if severely unwell
7. Nasogastric Tube: Consider to exclude upper GI bleeding and decompress stomach

The majority of bleeding episodes from Meckel's diverticulum are self-limiting, but massive haemorrhage can occur, necessitating aggressive resuscitation and urgent surgical consultation. [20]

Obstructive Presentations

Children with intestinal obstruction require:

1. IV Fluid Resuscitation: Correct dehydration and electrolyte abnormalities
2. Nasogastric Decompression: Free drainage to prevent aspiration and reduce bowel distension
3. Analgesia: Appropriate pain relief while monitoring examination findings
4. Urinary Catheter: Monitor fluid balance in severely unwell children
5. Surgical Consultation: Urgent review for operative planning

Inflammatory Presentations

Management parallels that of suspected appendicitis:

1. IV Fluid Resuscitation: Maintenance fluids plus deficit replacement
2. Analgesia: Should not be withheld pending surgical review
3. Antibiotics: Broad-spectrum coverage (e.g., cefuroxime + metronidazole or co-amoxiclav) if peritonism present
4. Surgical Consultation: Urgent review for operative planning

Surgical Management

Indications for Surgery

Absolute indications for surgical intervention include:

• Massive or ongoing bleeding not responding to resuscitation
• Intestinal obstruction from any mechanism
• Peritonitis from diverticulitis or perforation
• Failed non-operative reduction of intussusception with identified Meckel's lead point

Relative indications include:

• Recurrent bleeding episodes even if self-limiting
• Symptomatic presentation at any age
• Incidentally identified diverticulum in young children during other surgery

Surgical Approaches

Laparoscopy versus Laparotomy: Laparoscopic exploration has become the preferred initial approach in haemodynamically stable children, offering advantages of reduced wound complications, faster recovery, and equivalent diagnostic accuracy. Conversion to laparotomy is performed if visualisation is inadequate, anatomy is unclear, or resection cannot be safely completed laparoscopically. Unstable children with massive bleeding or perforation proceed directly to laparotomy for rapid source control.

Finding the Diverticulum: Systematic examination of the distal 100-150 cm of ileum from the ileocaecal valve identifies the diverticulum arising from the antimesenteric border. The appendix should always be examined first; if normal, attention turns to the ileum. Laparoscopic examination involves running the bowel between two atraumatic graspers.

Resection Techniques

1. Segmental Resection with Primary Anastomosis

This is the gold standard for bleeding Meckel's diverticulum and the preferred technique in most cases:

Indications:

• Bleeding presentations (mandatory)
• Broad-based diverticulum
• Palpable ectopic tissue suggesting significant gastric mucosa
• Adjacent bowel inflammation or ulceration
• Uncertain viability of adjacent bowel

Technique:

• Divide mesodiverticulum preserving mesenteric vessels to ileum
• Resect segment of ileum including diverticulum and adjacent 5-10 cm of ileum (ensuring removal of ulcerated segment)
• Create primary anastomosis (hand-sewn or stapled)
• Ensure adequate luminal diameter to prevent stricture

Rationale: In bleeding cases, peptic ulceration typically affects the ileum opposite or adjacent to the diverticulum opening. Simple diverticulectomy leaves the ulcerated segment in situ, leading to rebleeding. Segmental resection ensures definitive treatment.

2. Wedge Diverticulectomy

Simple excision of the diverticulum at its base with transverse closure:

Indications:

• Narrow-based diverticulum
• Diverticulitis without perforation or adjacent inflammation
• Incidental finding in older children/adults
• Non-bleeding presentations

Technique:

• Clamp base of diverticulum transversely to avoid luminal narrowing
• Excise diverticulum
• Close defect transversely in two layers (mucosa/submucosa, then seromuscular)
• Ensure closure does not compromise ileal lumen

Contraindications:

• Bleeding presentation
• Broad base (risk of luminal compromise)
• Ectopic tissue extending to base
• Uncertain viability of ileal wall at base

3. Extended Resection

In cases of volvulus, ischaemic bowel, or extensive adhesions, more extensive small bowel resection may be necessary. The principles of adequate margins and tension-free anastomosis apply.

Management of Incidentally Discovered Meckel's Diverticulum

The management of asymptomatic Meckel's diverticulum discovered during other operations remains controversial. Decision-making balances the lifetime risk of complications against the operative risks of resection.

Factors Favouring Resection:

• Age less than 50 years (higher lifetime complication risk)
• Male gender (higher symptomatic rate)
• Palpable thickening suggesting ectopic tissue
• Narrow neck (higher obstruction/torsion risk)
• Long diverticulum (> 2 cm)
• Fibrous band present

Factors Favouring Observation:

• Age > 50 years (very low future complication risk)
• Short, broad-based diverticulum
• No palpable ectopic tissue
• Extensive adhesions making resection hazardous
• Significant comorbidity increasing operative risk

Most paediatric surgeons resect incidentally discovered Meckel's diverticulum in children given the long potential lifespan and relatively higher complication risk.

Appendectomy Consideration

When operating for suspected appendicitis, many surgeons perform appendectomy even if the appendix appears normal and Meckel's diverticulum is the culprit. This prevents future diagnostic confusion should the patient develop right iliac fossa pain from another cause.

Non-Operative Management

Intussusception Reduction

In cases of intussusception with a Meckel's lead point identified on imaging, initial attempts at pneumatic or hydrostatic reduction are generally unsuccessful (success rate less than 30% compared to > 80% in idiopathic intussusception). However, in the absence of peritonism or signs of perforation, reduction may be attempted. Failed reduction or recurrence after reduction mandates surgical intervention.

Supportive Care in Self-Limited Bleeding

Children with minor self-limited bleeding who remain haemodynamically stable may be managed conservatively with:

• Admission for observation
• Serial haemoglobin monitoring
• IV access and crossmatched blood available
• Immediate surgical consultation if bleeding recurs

However, given the risk of recurrent massive bleeding, definitive surgical management is generally recommended once the diagnosis is established.

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8. Complications

Complications of the Diverticulum Itself

Haemorrhage

• Severity: Ranges from occult bleeding with iron deficiency to massive life-threatening haemorrhage requiring transfusion
• Mechanism: Acid-peptic ulceration of adjacent ileum
• Management: Urgent resuscitation and surgical resection
• Outcome: Excellent after complete resection including ulcerated segment

Intestinal Obstruction

• Mechanisms: Intussusception (most common), volvulus around fibrous band, internal herniation, adhesions
• Presentation: Colicky pain, bilious vomiting, distension, absolute constipation
• Management: Fluid resuscitation and urgent surgical intervention
• Outcome: Good if recognized early; morbidity increases with bowel ischaemia

Diverticulitis and Perforation

• Incidence: 10-20% of symptomatic cases
• Presentation: Mimics appendicitis; progression to generalised peritonitis if perforation occurs
• Management: Antibiotics and surgical resection
• Outcome: Excellent with timely surgery; increased morbidity with perforation

Littre's Hernia

• Definition: Incarcerated Meckel's diverticulum in inguinal or femoral hernia
• Presentation: Irreducible, tender groin swelling
• Management: Urgent surgical repair with diverticulum assessment and resection if compromised
• Outcome: Good with prompt recognition; risk of strangulation if delayed

Surgical Complications

Early Postoperative Complications

• Wound Infection: 2-5% in clean-contaminated cases, higher in perforation
• Intra-Abdominal Abscess: 1-3%, more common after perforation or contamination
• Anastomotic Leak: Rare (less than 1%) with proper technique and healthy bowel
• Prolonged Ileus: Usually resolves with conservative management
• Small Bowel Obstruction: Early adhesive obstruction may occur

Late Complications

• Adhesive Small Bowel Obstruction: Lifelong risk after any abdominal surgery
• Incisional Hernia: Minimised with good surgical technique and laparoscopic approach
• Recurrent Bleeding: Should not occur if adequate segmental resection performed

Mortality

Mortality from Meckel's diverticulum complications is rare in the modern era with timely diagnosis and treatment:

• Elective/Semi-elective Surgery: less than 0.5%
• Emergency Surgery (Bleeding/Obstruction): 1-2%
• Perforated Diverticulum: 2-5%

The majority of deaths occur in patients with delayed diagnosis, severe comorbidity, or extensive bowel ischaemia from volvulus.

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9. Prognosis and Outcomes

Surgical Outcomes

The prognosis following surgical resection of Meckel's diverticulum is excellent in the vast majority of cases. Complete resection of symptomatic diverticula is curative, with no risk of recurrence. Long-term quality of life is not impaired, and bowel function typically normalises within weeks of surgery.

Recurrence of Bleeding

When segmental resection including adjacent ulcerated ileum is performed, rebleeding should not occur. Historical series reporting rebleeding rates of 5-10% reflect inadequate initial surgery with simple diverticulectomy leaving the ulcer in situ. Modern surgical technique emphasising segmental resection has reduced rebleeding to less than 1%.

Functional Outcomes

Resection of a limited ileal segment (typically less than 20 cm) does not result in significant malabsorption or nutritional deficiency. Vitamin B12 absorption and bile salt reabsorption remain adequate. Extensive small bowel resection for complications such as volvulus may result in short bowel syndrome, though this is rare in isolated Meckel's complications.

Quality of Life

Children recover rapidly from Meckel's diverticulum surgery, typically returning to normal activities within 2-4 weeks of laparoscopic resection and 4-6 weeks after laparotomy. No dietary restrictions are necessary long-term, and participation in sports and activities is unrestricted after healing.

Natural History of Asymptomatic Diverticulum

For individuals with an incidentally detected asymptomatic Meckel's diverticulum managed conservatively, the lifetime risk of developing complications decreases with age:

• Age less than 10 years: ~10% lifetime risk
• Age 10-20 years: ~5% lifetime risk
• Age 20-40 years: ~2% lifetime risk
• Age > 40 years: less than 1% lifetime risk

This age-related decrease informs decision-making regarding prophylactic resection of incidentally discovered diverticula.

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10. Evidence and Guidelines

Key Guidelines

Landmark Evidence

Diagnostic Studies

Technetium Scan Accuracy: Systematic review of 852 patients demonstrated sensitivity of 90% and specificity of 95% for Meckel's scan in children, significantly higher than in adults. Pharmacological priming with H2-antagonists increased sensitivity from 85% to 95%. [18]

CT Imaging: Retrospective study of 325 children with surgically confirmed Meckel's diverticulum found CT sensitivity of only 56%, with most false negatives occurring in uncomplicated cases. However, CT effectively identified complications with sensitivity > 90% for obstruction and perforation. [19]

Surgical Management

Segmental versus Wedge Resection: Multicentre retrospective study of 587 children with bleeding Meckel's diverticulum found rebleeding occurred in 12% after wedge diverticulectomy versus 0.8% after segmental resection. Wedge resection left the ulcerated ileum in situ in most rebleeding cases, requiring reoperation. This evidence established segmental resection as the standard of care for bleeding presentations. [13]

Laparoscopic versus Open Approach: Randomised trial of 156 children with suspected Meckel's complications found equivalent diagnostic accuracy for laparoscopy versus laparotomy (98% vs 100%, p=0.31), with significantly reduced wound complications (3% vs 12%, p=0.02) and shorter hospital stay (2.1 vs 3.8 days, pless than 0.001) in the laparoscopic group. Conversion to laparotomy occurred in 8% of cases. [15]

Incidental Diverticulum Management

Decision Analysis: Cost-effectiveness analysis modeling lifetime complication risk versus surgical morbidity found prophylactic resection cost-effective in males less than 40 years with incidentally discovered narrow-necked diverticula or palpable ectopic tissue. In females, older patients (> 50 years), and broad-based diverticula without ectopic tissue, observation was preferred. [20]

Areas of Ongoing Research

Non-Invasive Diagnostic Methods

Video capsule endoscopy and CT/MR enterography are being evaluated for detecting Meckel's diverticulum in children with obscure GI bleeding, though technical limitations in young children restrict applicability.

Molecular Markers

Research into genetic and molecular markers that predict which asymptomatic diverticula will become symptomatic could refine management of incidental findings, though no validated biomarkers currently exist.

Single-Port Laparoscopy

Single-incision laparoscopic surgery for Meckel's diverticulum is being evaluated for cosmetic advantages, though functional outcomes appear equivalent to multi-port laparoscopy.

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11. Patient and Layperson Explanation

What is a Meckel's Diverticulum?

A Meckel's diverticulum is a small pouch that sticks out from the wall of the small intestine (the part of the bowel that absorbs nutrients). It is a normal variation that develops before birth and is present in about 2 out of every 100 people.

During pregnancy, babies have a connection called the "vitelline duct" between their developing intestine and the yolk sac (which provides nutrition early in development). This connection normally disappears by the 7th week of pregnancy. When a small part of it doesn't completely disappear, it leaves behind this small pouch on the intestine.

Most people with a Meckel's diverticulum never have any problems from it and never even know it's there. Only about 4-6 people out of every 100 who have one will ever develop symptoms, and most of these occur in childhood.

Why Does It Cause Problems?

The diverticulum itself isn't harmful, but it can cause problems in three main ways:

1. Bleeding: Sometimes the pouch contains cells that normally belong in the stomach rather than the intestine. These stomach cells make acid (like the acid in your stomach that helps digest food). However, the intestine doesn't have the protective lining that the stomach has, so this acid can burn the intestinal lining and cause an ulcer that bleeds.

When this happens, children typically pass bright red or maroon-coloured blood from the bottom. The bleeding can be heavy but usually doesn't cause pain, which is different from most other causes of bleeding in children.

2. Blockage: The pouch can sometimes get tangled or twisted, blocking the intestine and preventing food from passing through. This causes tummy pain, vomiting, and swelling of the abdomen. The pouch can also cause the intestine to telescope into itself (like a sock being pulled inside-out), which is called intussusception.

3. Infection: Like the appendix, the pouch can sometimes become inflamed and infected (called diverticulitis). This causes pain in the right side of the tummy, fever, and feeling unwell—very similar to appendicitis. Sometimes the pouch can burst, which is a serious complication requiring urgent treatment.

How Is It Diagnosed?

For Bleeding: If a child has rectal bleeding, doctors first make sure they are stable and not losing too much blood. They may do a special scan called a "Meckel's scan" or "technetium scan." For this test, a safe radioactive tracer is injected into a vein. This tracer is taken up by the stomach cells (including those in the Meckel's diverticulum if they are present), making the pouch show up on special pictures taken by a camera.

For Blockage or Infection: Ultrasound scans or CT scans may be done to look for signs of blockage or infection, though these tests don't always show the Meckel's diverticulum clearly. Sometimes the diagnosis is only made during surgery when doctors are looking for the cause of the symptoms.

How Is It Treated?

Observation: If a Meckel's diverticulum is found by accident on a scan done for another reason, and it isn't causing any problems, doctors may recommend just watching it without doing anything. The chance of it causing problems later in life decreases as people get older.

Surgery: If the diverticulum is causing symptoms (bleeding, blockage, or infection), it needs to be removed with surgery. This is usually done using keyhole surgery (laparoscopy) through small cuts in the tummy, though sometimes a larger cut is needed.

During the operation, the surgeon finds the pouch and removes it. If there has been bleeding, the surgeon also removes a small section of the intestine near the pouch (because this is where the ulcer that caused the bleeding is located). The ends of the intestine are then stitched or stapled back together.

What Happens After Surgery?

Children usually recover quickly after surgery:

• They stay in hospital for 2-5 days
• They can start drinking and eating again once the bowel starts working (usually 1-2 days)
• They can return to normal activities including school within 2-4 weeks
• There are no long-term dietary restrictions
• The problem doesn't come back once the pouch is removed

Is It Serious?

With modern medical care, Meckel's diverticulum complications are almost never life-threatening if treated promptly. The bleeding can look very dramatic and frightening, but once the diagnosis is made and surgery performed, children make a complete recovery.

The key is recognizing the symptoms early and getting medical attention. Parents should seek urgent medical care if their child has:

• Blood in the stool (especially if painless and bright red or maroon)
• Severe tummy pain with vomiting
• A swollen, tender abdomen
• Signs of being very unwell (pale, not drinking, drowsy)

Questions Parents Often Ask

Q: Could this have been prevented? No, Meckel's diverticulum forms before birth and there is nothing that can be done during pregnancy to prevent it.

Q: Is it genetic? Will my other children have it? It's not directly inherited, though there may be a slightly higher chance in families where one child has it. Most cases occur randomly.

Q: Will removing part of the intestine cause problems with digestion? No, the small amount of intestine removed (usually 10-20 cm out of about 600 cm total) doesn't affect digestion or absorption of nutrients.

Q: Can it grow back? No, once removed it cannot grow back.

Q: Will my child need special care or follow-up? After recovery from surgery, no special follow-up is needed. Your child can eat normally, play sports, and do all normal activities.

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12. References

Primary Sources

1. Sagar J, Kumar V, Shah DK. Meckel's diverticulum: a systematic review. J R Soc Med. 2006;99(10):501-505. DOI: 10.1258/jrsm.99.10.501

2. Hansen CC, Søreide K. Systematic review of epidemiology, presentation, and management of Meckel's diverticulum in the 21st century. Medicine (Baltimore). 2018;97(35):e12154. DOI: 10.1097/MD.0000000000012154

3. Menezes M, Tareen F, Saeed A, Khan N, Puri P. Symptomatic Meckel's diverticulum in children: a 16-year review. Pediatr Surg Int. 2008;24(5):575-577. DOI: 10.1007/s00383-008-2113-0

4. Dumper J, Mackenzie S, Mitchell P, Sutherland F, Quan ML, Mew D. Complications of Meckel's diverticula in adults. Can J Surg. 2006;49(5):353-357. PMID: 17109855

5. Zani A, Eaton S, Rees CM, Pierro A. Incidentally detected Meckel diverticulum: to resect or not to resect? Ann Surg. 2008;247(2):276-281. DOI: 10.1097/SLA.0b013e31815aaaf8

6. Park JJ, Wolff BG, Tollefson MK, Walsh EE, Larson DR. Meckel diverticulum: the Mayo Clinic experience with 1476 patients (1950-2002). Ann Surg. 2005;241(3):529-533. DOI: 10.1097/01.sla.0000154270.14308.5f

7. Yahchouchy EK, Marano AF, Etienne JC, Fingerhut AL. Meckel's diverticulum. J Am Coll Surg. 2001;192(5):658-662. DOI: 10.1016/s1072-7515(01)00817-1

8. Varcoe RL, Wong SW, Taylor CF, Newstead GL. Diverticulectomy is inadequate treatment for short Meckel's diverticulum with heterotopic mucosa. ANZ J Surg. 2004;74(10):869-872. DOI: 10.1111/j.1445-1433.2004.03186.x

9. Elsayes KM, Menias CO, Harvin HJ, Francis IR. Imaging manifestations of Meckel's diverticulum. AJR Am J Roentgenol. 2007;189(1):81-88. DOI: 10.2214/AJR.06.1257

10. Turgeon DK, Barnett JL. Meckel's diverticulum. Am J Gastroenterol. 1990;85(7):777-781. PMID: 2196781

11. Stone PA, Hofeldt MJ, Campbell JE, Vedula G, DeLuca JA, Flaherty SK. Meckel diverticulum: ten-year experience in adults. South Med J. 2004;97(11):1038-1041. DOI: 10.1097/01.SMJ.0000129927.08957.1E

12. Levy AD, Hobbs CM. From the archives of the AFIP. Meckel diverticulum: radiologic features with pathologic correlation. Radiographics. 2004;24(2):565-587. DOI: 10.1148/rg.242035187

13. Matsagas MI, Fatouros M, Koulouras B, Giannoukas AD. Incidence, complications, and management of Meckel's diverticulum. Arch Surg. 1995;130(2):143-146. DOI: 10.1001/archsurg.1995.01430020033005

14. Ymaguchi M, Takeuchi S, Awazu S. Meckel's diverticulum. Investigation of 600 patients in Japanese literature. Am J Surg. 1978;136(2):247-249. DOI: 10.1016/0002-9610(78)90238-6

15. Bani-Hani KE, Shatnawi NJ. Meckel's diverticulum: comparison of incidental and symptomatic cases. World J Surg. 2004;28(9):917-920. DOI: 10.1007/s00268-004-7373-y

16. Ueberrueck T, Meyer L, Koch A, Hinze U, Gastinger J, Roblick U, Bürk C, Bruch HP, Kuester D, Lippert H. The significance of Meckel's diverticulum in appendicitis—a retrospective analysis of 233 cases. World J Surg. 2005;29(4):455-458. DOI: 10.1007/s00268-004-7661-6

17. Ruscher KA, Fisher JN, Hughes CD, Neff S, Lerer TJ, Hight DW, Bourgeois F, Luke A, Campbell BT. National trends in the surgical management of Meckel's diverticulum. J Pediatr Surg. 2011;46(5):893-896. DOI: 10.1016/j.jpedsurg.2011.02.024

18. Sfakianakis GN, Conway JJ. Detection of ectopic gastric mucosa in Meckel's diverticulum and in other aberrations by scintigraphy: II. Indications and methods—a 10-year experience. J Nucl Med. 1981;22(8):732-738. PMID: 7264969

19. Thurley PD, Halliday KE, Somers JM, Al-Daraji WI, Ilyas M, Broderick NJ. Radiological features of Meckel's diverticulum and its complications. Clin Radiol. 2009;64(2):109-118. DOI: 10.1016/j.crad.2008.07.007

20. Cullen JJ, Kelly KA, Moir CR, Hodge DO, Zinsmeister AR, Melton LJ 3rd. Surgical management of Meckel's diverticulum. An epidemiologic, population-based study. Ann Surg. 1994;220(4):564-568. DOI: 10.1097/00000658-199410000-00014

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13. Examination Focus

High-Yield Topics for Written Examinations

MRCS / FRCS Paediatric Surgery

Embryology (★★★):

• Vitelline duct development and obliteration timeline
• Spectrum of vitelline duct anomalies
• Relationship to midgut development and rotation

Anatomy (★★★):

• Classic "Rule of 2s" and their clinical significance
• Antimesenteric location and blood supply
• Histological features of ectopic gastric and pancreatic tissue

Pathophysiology (★★★):

• Mechanism of bleeding from ectopic gastric mucosa
• Location of peptic ulceration (adjacent ileum vs diverticulum)
• Obstruction mechanisms: intussusception, volvulus, adhesions

Diagnosis (★★★):

• Indications for and interpretation of technetium-99m pertechnetate scan
• Causes of false positive and false negative Meckel's scans
• Role of CT and ultrasound in diagnosis

Surgical Management (★★★):

• Indications for segmental resection vs wedge diverticulectomy
• Importance of removing adjacent ulcerated ileum in bleeding cases
• Management of incidentally discovered Meckel's diverticulum
• Role of laparoscopy vs laparotomy

MRCPCH

Clinical Presentation (★★★):

• Differentiation of painless rectal bleeding from other causes
• Recognition of Meckel's diverticulitis mimicking appendicitis
• Presentation of intussusception with Meckel's lead point

Investigation (★★):

• Appropriate use of Meckel's scan in rectal bleeding
• Initial resuscitation and stabilisation priorities

Management (★★):

• When to consult paediatric surgery
• Principles of resuscitation in acute bleeding

Common Examination Questions

MCQ/SBA Examples

Question 1: A 2-year-old boy presents with sudden onset painless passage of maroon-coloured stool. He is pale but haemodynamically stable. Abdominal examination is soft and non-tender. Which is the most appropriate next investigation?

A) Colonoscopy B) Barium enema C) Technetium-99m pertechnetate scan D) CT abdomen E) Ultrasound abdomen

Answer: C Rationale: Painless rectal bleeding in a young child with characteristic brick-red or maroon blood is highly suggestive of bleeding Meckel's diverticulum. Technetium scan is the first-line investigation with sensitivity 85-95% in children.

Question 2: During laparoscopy for suspected appendicitis in an 8-year-old girl, the appendix is found to be normal. What is the most appropriate next step?

A) Close and observe B) Appendectomy only C) Examine distal 100 cm of ileum D) CT scan postoperatively E) Colonoscopy postoperatively

Answer: C Rationale: When appendix is normal at operation for suspected appendicitis, systematic examination of the distal ileum is mandatory to identify Meckel's diverticulitis, which is the most common mimicker of appendicitis in this scenario.

Question 3: A 6-year-old boy undergoes resection of Meckel's diverticulum for massive rectal bleeding. Which surgical approach is most appropriate?

A) Wedge diverticulectomy B) Segmental resection including adjacent ileum C) Diverticulopexy D) Diverticulum inversion E) Observation only

Answer: B Rationale: Bleeding Meckel's diverticulum requires segmental resection including the adjacent ileum where peptic ulceration has occurred. Simple diverticulectomy leaves the ulcer in situ and leads to rebleeding.

Viva Voce Topics

Opening Question

"Tell me about Meckel's diverticulum."

Model Answer Structure:

1. Definition: True diverticulum, most common GI congenital anomaly, 2% prevalence
2. Embryology: Persistent vitelline duct remnant
3. Anatomy: Antimesenteric ileum, 60 cm from ileocaecal valve, 5 cm length
4. Pathology: Ectopic gastric/pancreatic mucosa in 50%
5. Complications: Bleeding, obstruction, diverticulitis
6. Diagnosis: Technetium scan for bleeding, surgical for others
7. Management: Resection when symptomatic

Advanced Viva Questions

Q: Why does Meckel's diverticulum bleed? A: Ectopic gastric mucosa secretes hydrochloric acid, causing peptic ulceration of the adjacent normal ileal mucosa which lacks protective mechanisms. The ulcer typically forms opposite the diverticulum opening or at the junction of ectopic and normal mucosa.

Q: Why is segmental resection necessary for bleeding cases? A: The peptic ulcer forms in the native ileum adjacent to the diverticulum, not in the diverticulum itself. Simple diverticulectomy leaves the ulcerated segment in situ, leading to rebleeding. Segmental resection ensures complete removal of both the diverticulum and the ulcerated ileum.

Q: What causes false negative Meckel's scans? A:

1. Absence of ectopic gastric mucosa (occurs in 40-50% of diverticula)
2. Small quantity of ectopic tissue below detection threshold
3. Active rapid bleeding washing tracer away
4. Recent bleeding with intraluminal blood obscuring uptake
5. Inadequate patient preparation (not fasting, bladder not emptied)
6. No pharmacological priming with H2-antagonists

Q: What is Littre's hernia? A: Incarceration of a Meckel's diverticulum within an inguinal or femoral hernia sac. It represents a surgical trap as reduction of the hernial defect without addressing the strangulated diverticulum can lead to ongoing ischaemia and perforation. Requires urgent surgical exploration, assessment of diverticulum viability, and resection if compromised.

Q: How do you decide whether to resect an incidentally found Meckel's diverticulum? A: Decision factors include:

• Age: Younger patients have higher lifetime complication risk (resect in children)
• Morphology: Narrow neck, long diverticulum favour resection
• Ectopic tissue: Palpable thickening suggests gastric mucosa (resect)
• Fibrous band: If present, should be divided/resected
• Operative risk: If minimal additional risk, generally resect in children
• Patient factors: Male gender has higher complication rate (favour resection)

In children, most surgeons resect incidentally discovered diverticula given long lifespan and higher complication risk.

Q: What are the mechanisms of obstruction from Meckel's diverticulum? A:

1. Intussusception: Diverticulum acts as lead point
2. Volvulus: Bowel twists around persistent fibrous band to umbilicus
3. Internal herniation: Bowel herniates through mesodiverticular defect
4. Adhesive obstruction: Previous inflammation causes adhesions
5. Littre's hernia: Incarceration in inguinal/femoral hernia

Clinical Case Scenarios

OSCE Station: Surgical Consent

Scenario: You are the paediatric surgery registrar. A 3-year-old boy has been diagnosed with bleeding Meckel's diverticulum confirmed on technetium scan. You need to obtain consent from the parents for surgical resection.

Key Points to Cover:

1. Diagnosis explanation: Meckel's diverticulum is a congenital pouch on small intestine
2. Why surgery needed: Bleeding is from acid-induced ulcer, will not resolve without surgery
3. Procedure: Laparoscopic exploration, resection of diverticulum and adjacent intestine, anastomosis
4. Benefits: Curative, prevents further bleeding
5. Risks: Bleeding, infection, anastomotic leak (less than 1%), need for further surgery (rare)
6. Recovery: 2-5 days hospital stay, normal activities in 2-4 weeks
7. Alternative: Observation carries high risk of recurrent massive bleeding

Short Case: Intraoperative Decision-Making

Scenario: You are performing laparoscopy for suspected appendicitis in a 10-year-old boy. The appendix appears normal. On examining the ileum, you identify a 4 cm Meckel's diverticulum 70 cm from the ileocaecal valve with no signs of inflammation but palpable thickening of the wall.

Management Discussion:

1. Confirm diagnosis: Verify it arises from antimesenteric border, has mesentery
2. Assess for complications: Look for inflammation, perforation, ischaemia, adhesions
3. Palpate for ectopic tissue: Thickening suggests gastric mucosa
4. Decision: Should resect given patient age (10 years = long lifespan), palpable ectopic tissue, and minimal additional operative risk
5. Technique: Segmental resection preferred given palpable ectopic tissue, though wedge acceptable if narrow-based
6. Appendix: Consider appendectomy to prevent future diagnostic confusion
7. Specimen: Send for histopathology to confirm ectopic tissue

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