NECROTIZING ENTEROCOLITIS ELBW INFANTS

Necrotizing enterocolitis
NEC is a disease of the premature gastrointestinal tract that represents injury to the intestinal mucosa and vasculature. Incidence of NEC is associated with decreasing gestational age, and it is a dreaded complication of premature birth. NEC accounts for 7.5% of all neonatal deaths. Risk factors include asphyxia or any ischemic insult to the gastrointestinal blood supply. The role of enteral feeding is controversial. Breast milk may have a protective effect but has not been shown to prevent NEC.

Presenting symptoms may be vague and include apnea, bradycardia, and abdominal distention. These symptoms can quickly progress to indicators of increasing sepsis, such as large gastric residuals, metabolic acidosis, and lethargy. Radiographic findings include stacked bowel loops, pneumatosis intestinalis (presence of gas in the bowel wall), portal venous gas, and free air, which indicates perforation of the bowel and is an ominous sign of impending deterioration. NEC usually presents close to the time that the infant is taking full enteral feedings, usually between the second and third weeks of life.

NEC is commonly managed with antibiotics, elimination of oral intake, gastric decompression by nasogastric tube, and supportive measures to correct complications such as metabolic acidosis, thrombocytopenia, and hypotension.

Surgical intervention may be necessary if evidence of perforation exists (presence of free air on radiographs) or medical treatment fails. Long-term complications include those related to bowel resection (short gut syndrome), bowel strictures, and risk of abdominal adhesions.

Spontaneous bowel perforation often occurs in the first week of life, presenting earlier than a typical case of NEC. Stark et al showed a strong interaction between postnatal use of dexamethasone and indomethacin on incidence of perforation (19%) in ELBW infants in a trial designed to determine if a 10-day course of postnatal dexamethasone would reduce the risk of CLD or death.