NECROTIZING ENTEROCOLITIS IN PREMATURE INFANTS

Necrotizing enterocolitis in term infants

Despite the fact that necrotizing enterocolitis is considered a disease of premature infants, 20% of all affected infants at Babies Hospital over the past 20 years were products of term gestations. Two distinct subgroups of such infants were noted (1) five infants with congenital heart disease and/or congestive heart failure (e.g.hypoplastic left heart syndrome), all but one of whom developed the disease in the first week of life; (2) eight infants who developed the disease at a much later age after a protracted period of diarrhea. This histopathologic features of the disease in term infants are the same as those in premature infants. Further, the pathogenesis of the disease in term infants does not appear to differ basically from that in premature infants. These facts, lead away from the concept of NEC as a disease of simple etiology.

Fulminant neonatal sepsis and necrotizing enterocolitis associated with a "nonenteropathogenic" strain of Escherichia coli

During 1973 a nonendemic mucoid strain of Escherichia coli entered the nursery of a hospital in Houston. This organism caused septicemia and was associated with a high incidence of necrotizing enterocolitis. The illness was fulminant and characterized by apnea, abdominal distension, and shock. Diarrhea was not a feature of the symptom complex. The epidemic organism was nontypable. Assays for invasiveness, enterotoxin production, and Kl antigen were negative. Surveillance revealed a colonization rate of 14%, an attack rate in colonized infants of 19.5%, and a mortality rate of 87.5%. These data suggest that in certain instances the specific bowel flora may increase the incidence and severity of NEC.

Enterocolitis in low-birth-weight infants associated with milk and soy protein intolerance

Two low-birth-weight infants developed a syndrome of vomitting, distension, septic appearance, and bloody diarrhea. Both infants developed symptoms after ingestion of cow milk-based formula initially, and, later, soy-based formulas. These symptoms resolved with intravenous fluids and alimentation. Vomiting, diarrhea, melena, and polymorphonuclear leukocytosis recurred with reintroduction of either milk- or soy-based formulas. This sensitivity persisted throughout the neonatal period and was still present at seven to eight months of age. It appears from these data that intolerance to whole protein formulas can cause a syndrome similar clinically to neonatal necrotizing enterocolitis.

Necrotizing enterocolitis

The clinical course of 54 patients with necrotizing enterocolitis has been compared to a matched group of 98 control patients. On the day of life that NEC occurred, all 54 NEC patients and 63% of controls were receiving standard formula feedings, both at 80/cal/kg/day. Stool cultures at the time revealed a significantly increased frequency of Klebsiella in NEC as compared to control patients. Our data suggest that the combined presence of certain intestinal bacteria and enteric feedings, perhaps requiring a background of mucosal ischemia, may be of etiologic significance in the development of NEC and its radiologic hallmark, pneumatosis intestinalis.

Gastroenteritis with necrotizing enterocolitis in premature babies

Eleven premature babies developed necrotizing enterocolitis in an epidemic of gastroenteritis and salmonella infection. This occurred in one of two premature baby wards over a period of 10 weeks. All affected babies had severe gastroenteritis and six had salmonella infection. No cases of necrotizing enterocolitis occurred in the unaffected ward during the same period. All other possible factors which might have predisposed to necrotizing enterocolitis occurred with equal frequency in both wards.There seems little doubt that infection was the significant factor in the pathogenesis.