Microcolon with Features of Low Intestinal Obstruction

Barium enema in a 2-day old boy shows diffuse small caliber of the colon (arrows). Retained barium is noted in the stomach from a recent upper GI study (which was normal). Note the presence of air in the rest of the small bowel (tubular lucent areas in the background) indicating that this is a low intestinal obstruction.

Differential Diagnosis: Microcolon with Features of Low Intestinal Obstruction

• Pathology of colon itself: colonic atresia, diffuse Hirschsprung's disease
• Pathology of distal small bowel (no bowel content can pass into colon resulting in small colon caliber): ileal atresia, meconium ileus

Approach: when seen evidence of bowel obstruction in a neonate, one needs to distinguish between high and low intestinal obstruction. High obstruction presents with little amount of gas in the bowel, dilated stomach and/or duodenum. If high obstruction due to midgut volvulus is suspected, upper GI study is the next step. If low obstruction is suspected, barium enema is performed. In this case, we see a lot of bowel gas in the neonate with clinical intestinal obstruction and a barium enema shows diffuse microcolon - the differential diagnoses are either diseases of distal small bowel or of the colon itself.

Our case: distal ileal volvulus with possible meconium ileus producing distal intestinal obstruction and microcolon

Reference:

Davies SG. Chapman & Nakielny's Aids to Radiological Differential Diagnosis, 5th edition, 2009.