necrotizing enterocolitis (NEC), an acute inflammatory bowel disorder that occurs primarily in preterm or low–birth weight neonates, typically within the first 2 weeks of life. It is characterized by ischemic necrosis of the GI mucosa that may lead to perforation and peritonitis. The cause of the disorder is unknown, although it appears to be a defect in host defenses, with infection resulting from normal GI flora rather than from invading organisms. Formula-fed infants are more susceptible to the disorder, possibly because formula lacks the immunoglobulin A antibodies and macrophages found in breast milk that may protect the GI mucosa from damage and bacterial invasion. Also called pseudomembranous enterocolitis. See also enteritis. ▪ OBSERVATIONS: Significant predisposing factors for the condition include prematurity, hypovolemia, respiratory distress syndrome, sepsis, an indwelling umbilical catheter, exchange transfusion, and feeding with hyperosmolar or high-caloric formulas. The condition results from a reflex shunting of blood away from the GI tract, which leads to convulsive vasoconstriction of the mesenteric vessels supplying the intestines. The diminished blood supply interferes with the normal production of mucus and with other bowel functions and results in severe necrosis with bacterial invasion of the bowel wall. Formula-fed infants are more susceptible to the disorder, possibly because formula lacks the immunoglobulin A antibodies and macrophages found in breast milk that may protect the GI mucosa from damage and bacterial invasion. Initial symptoms, which usually develop after several days of life, include temperature instability (usually hypothermia), lethargy, poor feeding, vomiting of bile, abdominal distension, blood in the stools, and decreased or absent bowel sounds. Signs of deterioration are apnea, pallor, hyperbilirubinemia, oliguria, abdominal tenderness, and erythema and edema of the anterior abdominal wall or palpable masses, with eventual respiratory failure leading to death. Diagnosis is confirmed by x-ray visualization of the intestine or by the presence of increased peritoneal fluid or pneumoperitoneum. ▪ INTERVENTIONS: Treatment includes discontinuation of oral feeding, IV infusion, abdominal decompression by nasogastric suction, hydration, plasma or whole blood transfusion, and administration of broad-spectrum antibiotics. With routine supportive management, improvement usually occurs within 48 to 72 hours. Oral feedings usually are not resumed for 10 days to 2 weeks. Total parenteral nutrition is necessary during that period. Surgical resection of the affected bowel segment may be necessary, especially if signs of intestinal perforation or peritonitis develop. If a large part of bowel is affected, an ileostomy or colostomy may be necessary. Stenosis of the involved bowel segment may present later complications. ▪ PATIENT CARE CONSIDERATIONS: The primary concern of the physician and nurse is to observe high-risk, formula-fed infants for early symptoms of necrotizing enterocolitis, especially for difficulty in feeding, bile-stained regurgitation, bloody stools, temperature fluctuations, or a distended shiny abdomen. After the diagnosis is confirmed, the nurse initiates nasogastric intubation for abdominal decompression and continues to monitor the baby constantly for dehydration and electrolyte balance. Daily weight is taken. Infants who are unable to take fluids by mouth require special oral care. A pacifier helps meet the infant’s need to suck. Parents are encouraged to visit and are helped to meet the emotional needs of the infant and to provide tactile, auditory, and visual stimulation. Consultation with an occupational therapist is appropriate. The health care team explains the usual course of the disease and any procedures and keeps the parents informed of the infant’s progress. Frequent visits to the care unit facilitate family-infant relationships and provide the health care team with an opportunity to teach proper care techniques before discharge. Most infants who develop NEC recover fully and do not have further feeding problems.
