What is the diagnosis and management approach for Meckel's (Meckel's diverticulum) diverticulum?

Diagnosis and Management of Meckel's Diverticulum

Diagnostic Approach

For young patients with unexplained lower gastrointestinal bleeding after negative upper endoscopy and colonoscopy, Tc-99m pertechnetate scintigraphy (Meckel's scan) is the diagnostic test of choice, with sensitivity of 89% and specificity of 98% for detecting symptomatic Meckel's diverticulum. 1

Clinical Presentation

• Painless rectal bleeding is the classic presentation, particularly in children and young adults, accounting for more than 50% of unexplained lower GI bleeding in the pediatric population 1, 2
• Meckel's diverticulum is present in approximately 2% of the population, with most symptomatic cases occurring in children and young adults 1, 3
• Other presentations include:
  • Intestinal obstruction from volvulus around a fibrous band connecting the diverticulum to the umbilicus or entrapment of small bowel beneath a mesodiverticular band 1, 3
  • Diverticulitis mimicking appendicitis 4
  • Perforation from peptic ulceration 5, 4
  • Approximately 50% of Meckel's diverticula contain ectopic gastric mucosa, which secretes acid causing peptic ulceration and bleeding 5, 6

Diagnostic Algorithm

Step 1: Initial Evaluation

• Perform upper endoscopy and colonoscopy first to exclude other sources of GI bleeding 1
• If these are negative in a young patient with painless rectal bleeding and anemia, proceed to Meckel's scan 1

Step 2: Meckel's Scan (Tc-99m Pertechnetate Scintigraphy)

• Patient preparation is essential: Premedicate with H2-receptor blockers (cimetidine 20 mg/kg in pediatric patients or 300 mg q.i.d. for adults for 48 hours before the test, or ranitidine 1 mg/kg IV one hour before) to enhance gastric mucosa visualization and reduce false negatives 6, 2
• Defer barium studies and colonoscopy for 2-3 days after examination 6
• Imaging technique: Sequential gamma camera imaging for 1 hour in anterior projection, with complementary lateral, oblique, and upright views for better localization 7, 2
• Administer furosemide IV (0.75 mg/kg) if needed to clear urinary tract activity that may obscure findings 6
• The scan detects ectopic gastric mucosa within the diverticulum, which accumulates pertechnetate, creating a fixed focal area of uptake typically in the umbilical region 1, 5

Step 3: Alternative Imaging if Meckel's Scan is Negative or Unavailable

• CT enterography can identify Meckel's diverticulum when bleeding is not active and help exclude other etiologies, particularly in older patients or atypical presentations 1
• CT scan with contrast is highly accurate for diagnosing complications like diverticulitis or perforation 1

Diagnostic Performance and Pitfalls

• Meckel's scan has positive and negative predictive values approaching 100% in anemic patients with GI bleeding 1
• True positive rate is 84.2% when proper technique and premedication are used 5, 6
• Accuracy exceeds 90% in the pediatric population with careful patient preparation 7, 2
• Common pitfalls include nonspecific tracer accumulation in tumors, intestinal obstructions, arteriovenous malformations, and the urinary tract—these can be recognized through clinical history and complementary imaging 7, 2
• Maximum clustering of positive cases occurs in the 1-2 year age group (52.38% of positive cases) 5

Management

Step 1: Surgical Intervention

• All symptomatic Meckel's diverticula require surgical resection to prevent life-threatening complications including bleeding, obstruction, inflammation, and perforation 4
• Laparoscopic exploration is both diagnostic and therapeutic, allowing direct visualization and resection of the diverticulum 3

Step 2: Incidental Findings

• For asymptomatic Meckel's diverticula discovered incidentally during surgery for other indications, prophylactic resection should be considered based on patient age and risk factors, though this remains controversial 4

Key Clinical Pearls

• The site of ectopic activity on Meckel's scan is mainly in the umbilical quadrant (52.4% of cases) 5
• Meckel's diverticulum contains all intestinal wall layers, including muscularis propria, distinguishing it from other diverticula 1
• In patients with small bowel obstruction and no prior major abdominal surgery, consider Meckel's diverticulum as a potential cause, especially in young patients with concurrent GI bleeding 3
• Do not delay surgical consultation when Meckel's scan is positive, as complications can be life-threatening and result in significant morbidity and mortality 4