Clinical Pearls & Morning Reports
The differential diagnosis for enterocolitis and guaiac-positive diarrhea in a neonate includes necrotizing enterocolitis, very-early-onset infantile inflammatory bowel disease, and a non–IgE-mediated gastrointestinal food allergy. Read the Case Record of the Massachusetts General Hospital.
Q. How common is necrotizing enterocolitis in full-term infants?
A. Necrotizing enterocolitis is a severe inflammatory disease of the intestine that is typically seen in premature infants. Less than 10% of cases occur in full-term infants, and in such cases, coexisting conditions such as perinatal hypoxia, congenital heart disease, and endocrinopathies are commonly present.
Q. What is very-early-onset inflammatory bowel disease?
A. Children younger than 6 years of age who present with clinical, imaging, endoscopic, or histopathological evidence of inflammatory bowel disease are considered to have very-early-onset disease. Although the incidence of very-early-onset inflammatory bowel disease is increasing, it remains exceptionally rare. Infants and children with this disease typically present with isolated colonic disease. Infantile inflammatory bowel disease is related to an underlying immunodeficiency in up to 25% of cases.
Figure 1. Imaging Studies.
A: Non–IgE-mediated food allergies — including food protein–induced enteropathy (FPE), food protein–induced allergic proctocolitis (FPIAP), and the food protein–induced enterocolitis syndrome (FPIES) — can occur in infants. The most common trigger for these conditions is exposure to milk or soy protein contained in infant formula. The inflammation associated with FPE is limited to the small bowel, and it results in malabsorption, vomiting, nonbloody diarrhea, and failure to thrive. FPIAP typically occurs during the first 6 months of life and accounts for 60% of cases of rectal bleeding in infants. Infants with FPIAP often appear well, and their symptoms resolve after the diet is switched to a partially hydrolyzed formula or an amino acid–based formula. FPIES is a severe non–IgE-mediated food allergy that can occur within the first few days of life on exposure to cow’s milk–based or soy-based formula; this syndrome is unlikely to occur in exclusively breast-fed infants. The clinical presentation is often a combination of protracted emesis, diarrhea (often with guaiac-positive or grossly bloody stools), and severe dehydration. Up to 15% of infants with FPIES present with shock and need intensive care.
A: Among patients in whom the use of a cow’s milk–based formula results in FPIES, the use of a soy-based formula is also associated with a high rate of FPIES, and therefore, an extensively hydrolyzed casein (EHC)–based formula is recommended. However, 10 to 15% of infants in whom the use of cow’s milk–based formula results in FPIES will also have persistent symptoms with use of an EHC-based formula. Current recommendations for the management of FPIES include the avoidance of trigger foods for a minimum of 12 to 18 months after a reaction occurs. Although FPIES is a non–IgE-mediated food allergy, up to 25% of patients with FPIES also have an IgE-mediated sensitization to the foods that triggered the initial reaction, and some will have symptoms of immediate hypersensitivity on exposure to the food. Such patients have delayed resolution of FPIES.