GASTROINTESTINAL TRANSIT IN PATIENTS WITH IDIOPATHIC MEGARECTUM

PURPOSE: In patients with idiopathic megarectum, it is unknown whether abnormality is limited to the dilated large bowel or whether the uppe r gut is abnormal, as in the various forms of chronic intestinal pseud o-obstruction. This has important implications for treatment, especial ly surgery. METHODS: Ten patients (4 females; median age, 18 (range, 1 7-26) years) with idiopathic megarectum had contrast studies of the up per and lower gut, radioisotope (technetium-99m liquid and indium-111 solid phase) measurement of gastric, small-bowel, and colonic regional transit, and radiopaque marker colonic studies. RESULTS: All patients had a dilated large bowel. No patient had radiographic evidence of up per gut dilation. Four patients had normal and six patients had abnorm ally slow gastric emptying. Both the radioisotope scans and radiopaque marker studies showed abnormal colonic transit. Regions of delay corr esponded with the region of dilated bowel. Symptoms of abdominal diste ntion and bloating did not correspond to abnormalities of gastric empt ying but rather with effectiveness of rectal evacuation. CONCLUSION: P atients with idiopathic megarectum have abnormal colonic transit, dela y occurring predominantly in the dilated gut. Marker studies are less sensitive than isotope studies but provide adequate information for cl inical purposes. Although motility abnormalities of the upper gut are common, symptoms correlate with large-bowel abnormalities.