The mechanism of focal intestinal perforations in neonates with low birth weight

Among 36 neonates with intestinal perforations (IP) between 1975 and 1996, 5 had necrotizing enterocolitis (NEC IP) and 10 had focal IPs (FIP). A hist ologic review of the bowel near the perforations was made to see if there w as any difference between cases of NEC IP and FIP. In 1 case of NEC IP, a d efect in the musculature was found in addition to disappearance of the muco sal villi and dilated vessels or hemorrhage in the submucosa. Thinning or a bsence of the intestinal musculature and short villi in the mucosa was obse rved in 3 cases of FIP, but the acute ischemic changes in FIP were much les s than in NEC IP. Hypothesizing that the defective musculature in FIP may b e acquired by a vascular accident either before or after birth, we examined the histology of the latest consecutive infants diagnosed as having meconi um peritonitis (MP) due to inutero volvulus and perforation. In the tissue near the perforation, there was an identical focus of thinning and interrup tion of the musculature while the acute ischemic changes were minimal. We s peculate that thinning or absence of the intestinal musculature in FIP may be a result of a transient ischemic event occurring in-utero and that FIP m ay develop in the damaged intestine after birth when it is fully dilated.