Congenital mesenteric defect: Description of a rare cause of distal intestinal obstruction in a neonate.

INTRODUCTION: Internal hernias are a rare cause of bowel obstruction in the neonate and present with bilious vomiting. Newborns may be at risk of loss of significant length of bowel if this rare condition is not considered in the differential diagnosis of bilious emesis.

PRESENTATION OF CASE: We report a case of a twin with an internal hernia through a defect in the ileal mesentery who presented with neonatal bowel obstruction. The patient had a microcolon on the contrast enema suggesting that the likely etiology was an intra-uterine event most likely a vascular accident that prevented satisfactory meconium passage into the colon.

DISCUSSION: An internal hernia is rarely considered in the differential diagnosis of distal bowel obstruction in a neonate with a microcolon. Congenital trans-mesenteric hernias constitute only 5-10% of internal hernias. True diagnosis of trans-mesenteric hernias is difficult due to lack of specific radiology or laboratory findings to confirm the suspicion.

CONCLUSION: When clinical and radiological findings are not classical, rare possibilities such as an internal hernia must be considered in the differential diagnosis, to avoid catastrophic bowel loss.