Meckel Diverticulum
The most common congenital GI defect, caused by a remnant tissue pouch in the lower small intestine that can contain stomach tissue, leading to painless bloody stools or bowel obstruction, especially in children.
Emergency Management: Hypovolemic shock due to acute massive hemorrhage. Requires immediate establishing of 2 large-bore IVs, rapid crystalloid bolus (20 mL/kg), and type-specific or O-negative blood transfusion, followed by emergent exploratory laparotomy.
Meckel diverticulum is a true congenital diverticulum (involving all layers of the intestinal wall) resulting from the incomplete obliteration of the vitelline (omphalomesenteric) duct during embryonic development. It is the most common congenital anomaly of the gastrointestinal tract and frequently contains ectopic gastric or pancreatic mucosa, which can lead to painless rectal bleeding or inflammatory complications.
Detailed Overview
The condition famously follows the 'Rule of 2s': it occurs in approximately 2% of the population, presents within 2 feet of the ileocecal valve, is about 2 inches in length, contains 2 types of ectopic mucosa (gastric and pancreatic), is 2 times more common in males for symptomatic cases, and often presents before age 2. Ectopic gastric mucosa secretes acid, causing ulceration of the adjacent unprotected ileal mucosa, leading to painless lower gastrointestinal bleeding.
Epidemiology & Demographics
Prevalence is roughly 2% of the general population. Most patients are asymptomatic throughout their lives. Symptomatic cases most frequently present in the pediatric population, often before the age of 2 years. Male-to-female ratio for symptomatic cases is 2:1 to 4:1.
Etiological Mechanism
Embryological failure of the vitelline duct to completely obliterate during the 5th to 7th week of fetal gestation.
Primary Causes
Strictly an embryological malformation. Symptoms are specifically caused by the presence of heterotopic gastric mucosa secreting acid, or the anatomical structure acting as a lead point for intussusception.
During weeks 5-7 of gestation, the vitelline duct (connecting the yolk sac to the midgut) normally obliterates. Failure of the intestinal end to obliterate leaves a blind pouch (Meckel diverticulum) on the antimesenteric border of the ileum. In about 50% of symptomatic cases, this pouch contains ectopic gastric mucosa. The parietal cells in this mucosa secrete hydrochloric acid. Because the adjacent ileum lacks protective mechanisms (like mucus production and bicarbonate secretion found in the stomach), the acid rapidly causes peptic ulceration, leading to brisk, painless lower GI hemorrhage. Alternatively, the diverticulum can invert and act as a lead point for ileocolic intussusception, or a persistent fibrous band connecting the diverticulum to the umbilicus can cause volvulus and bowel obstruction.
Diagnostic Criteria & Guidelines
Diagnosis in children with painless lower GI bleeding is established via a positive Technetium-99m pertechnetate scan (Meckel scan). In adults or those with obstructive symptoms, CT abdomen is often the diagnostic modality.
Hemodynamic stabilization: Intravenous fluids (Normal Saline or Lactated Ringer's) and packed RBC transfusion for significant anemia/shock. Definitive treatment is surgical.
Second-Line & Adjunctive Therapy
Not applicable; medical management is only supportive. Asymptomatic Meckel diverticula found incidentally in adults are often left alone unless they have a narrow neck, palpable abnormality, or the patient is young.
Surgical & Procedural Management
Surgical resection (Laparoscopic or open). Options include simple diverticulectomy (if the base is narrow and adjacent ileum is healthy) or segmental ileal resection with primary anastomosis (preferred if there is a broad base, palpable ectopic tissue, or ulceration of the adjacent ileum).
Patient Counseling & Advice
Reassure parents that once the diverticulum is surgically removed, the condition is completely cured and will not recur. Explain that the bleeding was caused by stomach-like tissue in the intestine.
Follow-Up & Monitoring Schedule
Standard post-operative surgical follow-up at 2-4 weeks to assess wound healing and bowel function. No long-term GI surveillance is required.
Preventive Strategies
No prevention is possible as it is a congenital embryological anomaly.
Excellent. Surgical resection is curative. Mortality is near zero with prompt recognition and treatment of complications.