Meckel's diverticulum

(Johann F. Meckel, the younger, 1781 - 1833, German comparative anatomist and embryologist), persistence of a remnant of the omphalomesenteric duct at its junction with the ileum. The diverticulum is situated on the antimesenteric border of the ileum approximately 30 cm from the ileocaecal valve. Though present at autopsy in 1 - 4% of patients, clinical presentation is less frequent. Clinical symptoms are related to bleeding from the ectopic gastric mucosa within the diverticulum, obstruction due to volvulus around the diverticulum, or from intussusception caused by the diverticulum acting as a lead point.

The radiological investigation of a child with a suspected Meckel's diverticulum is by radionuclide scanning with technetium pertechnetate which is taken up by gastric mucosa (Fig.1). Activity appears in the diverticulum at the same time as in the stomach mucosa, seen best on the anterior abdominal images. False negative scans occur if the diverticulum contains no gastric mucosa (but these are unlikely to bleed), or if the bleeding is very severe or the diverticulum is devascularized. False positive scans are reported with duplication cysts.

Small bowel contrast studies are not indicated.

A rare clinical presentation of a perforated Meckel's diverticulum is abdominal wall swelling (Fig.2). See ileal dysgenesis and gastrointestinal haemorrhage

HC