How does Meckel's diverticulum typically present in pediatric patients?

Clinical Presentation of Meckel's Diverticulum in Children

Painless lower gastrointestinal bleeding is the most common presentation of Meckel's diverticulum in children, followed by intestinal obstruction and intussusception. 1, 2

Primary Clinical Manifestations

Gastrointestinal Bleeding (Most Common)

• Painless rectal bleeding or melena is the classic presentation, particularly in younger children and represents the most frequent symptomatic manifestation 1, 2, 3
• Bleeding occurs due to ectopic gastric mucosa within the diverticulum causing peptic ulceration of adjacent ileal tissue 2, 3
• Can present with hemorrhagic shock requiring emergent resuscitation, even in adolescents beyond the typical "rule of two's" age range 4
• Bleeding episodes may be intermittent or massive, and are more common in children under 5 years of age 2

Intestinal Obstruction (Second Most Common)

• Obstruction mechanisms include: 2, 3, 5
  • Intussusception (the diverticulum acts as a lead point) 2, 3, 5
  • Volvulus around a fibrous band connecting the diverticulum to the umbilicus 1, 5
  • Entrapment of small bowel beneath a mesodiverticular band 1, 6
  • Kinking or knotting of bowel loops 5
• In some series, obstruction was the predominant presentation (86% of cases), particularly in certain geographic regions 5

Inflammatory Complications

• Meckel's diverticulitis mimics acute appendicitis clinically, presenting with right lower quadrant pain, fever, and peritoneal signs 2, 3, 6
• Perforation can occur, leading to peritonitis and sepsis 2, 3
• Isolated gangrene of the diverticulum may occur with obstruction, associated with increased morbidity 5

Incidental Finding

• In 10-27% of cases, Meckel's diverticulum is discovered incidentally during laparotomy or laparoscopy for other indications (commonly during appendectomy) 2, 3, 6

Age-Related Patterns

• Most symptomatic cases occur in children and young adults, with a median age of presentation around 5-6 years 2, 3
• Male predominance is evident (approximately 2-3:1 male-to-female ratio) 2, 3, 6
• While the "rule of two's" suggests presentation before age 2, significant numbers of cases present in older children and adolescents 4

Diagnostic Approach

First-Line Imaging

• Technetium-99m pertechnetate scintigraphy (Meckel scan) is the gold standard diagnostic test for suspected bleeding Meckel's diverticulum 1, 7, 2
• The scan detects ectopic gastric mucosa with sensitivity of 89% and specificity of 98% in symptomatic patients 1
• Positive predictive value approaches 100% in anemic patients with GI bleeding 1
• Among patients with bleeding who underwent Meckel scan, approximately 70% showed positive tracer uptake 3

When to Suspect Meckel's Diverticulum

• Young patient with painless rectal bleeding and anemia after negative upper endoscopy and colonoscopy 1, 7
• Unexplained lower GI bleeding in children under 10 years 1, 7
• Intestinal obstruction with intussusception as lead point 2, 5
• Right lower quadrant pain mimicking appendicitis but with atypical features 3, 6

Alternative Imaging

• CT enterography can identify Meckel's diverticulum when bleeding is not active and helps exclude other etiologies such as Crohn disease, celiac disease, and abdominal malignancy 8, 1, 7
• CT with contrast is highly accurate for diagnosing complications like diverticulitis or perforation 1

Pathological Features

• Ectopic gastric mucosa is present in approximately 44-45% of resected specimens 2, 3
• Ectopic pancreatic tissue is found in 35-37% of cases 2, 3
• Heterotopic tissue is significantly more common in symptomatic versus incidentally discovered diverticula 3
• The diverticulum contains all intestinal wall layers including muscularis propria 1

Common Pitfalls

• Misdiagnosis as acute appendicitis is frequent, leading to negative appendectomy 3, 6
• Negative Meckel scan does not exclude the diagnosis (approximately 30% false negative rate in some series) 3
• Hemorrhagic shock can occur even in adolescents, requiring aggressive volume resuscitation 4
• Isolated gangrene of the diverticulum may be missed if not specifically sought during laparotomy for obstruction 5