Necrotizing Enterocolitis (NEC)
Necrotizing enterocolitis is injury to the inner surface of the intestine. This disorder occurs most often in newborns who are premature and/or seriously ill.
The abdomen may be swollen, stools may be bloody, and the newborn may vomit a greenish, yellow, or rust-colored fluid and appear very sick and sluggish.
The diagnosis is confirmed by abdominal x-rays.
About 70 to 80% of newborns with this disorder survive.
Treatment involves stopping feedings, passing a suction tube into the stomach to remove stomach contents to relieve pressure, and giving antibiotics and fluids by vein (intravenously).
In severe cases, surgery is required to remove the damaged intestine.
The cause of necrotizing enterocolitis is not completely understood, but it is in part related to low oxygen levels in the blood. Diminished blood flow to the intestine in a sick premature newborn may result in injury to the inner surface of the intestine. The injury allows bacteria that normally exist within the intestine to invade the damaged intestinal wall and then enter the newborn’s bloodstream, causing infection (sepsis). If the injury progresses through the entire thickness of the intestinal wall and the intestinal wall tears (perforates), intestinal contents leak into the abdominal cavity and cause inflammation and usually infection of the abdominal cavity and its lining (peritonitis).
Over 85% of cases of necrotizing enterocolitis (NEC) occur in premature newborns.
Besides prematurity, some disorders that put infants at risk include
Infants who are small for gestational age or who have been fed very concentrated formula through a tube also are at increased risk.
Newborns with necrotizing enterocolitis may develop swelling of the abdomen and may have difficulty feeding. They may vomit bloody or bile-stained intestinal fluid, and blood may be visible in the stools. These newborns soon appear very sick and sluggish (lethargic) and have a low body temperature and repeated pauses of breathing (apnea).
The diagnosis of necrotizing enterocolitis is confirmed by abdominal x-rays that show gas in the intestinal wall (called pneumatosis intestinalis) or that free air is in the abdominal cavity if the intestinal wall has perforated.
Blood samples are taken to look for bacteria and other abnormalities (for example, a high white blood cell count).
Current medical and surgical treatments have improved the prognosis of infants with necrotizing enterocolitis. About 70 to 80% of such newborns survive. Intestinal stricture, narrowing of the intestine, is the most common long-term complication. Strictures occur in 10 to 36% of infants who survive the initial episode of necrotizing enterocolitis. Strictures typically cause symptoms several weeks to several months after the episode of NEC. Sometimes strictures need to be corrected surgically.
Feeding premature newborns their mother’s breast milk rather than formula seems to provide some protection against necrotizing enterocolitis. In addition, it is important to avoid highly concentrated formula and to prevent low oxygen levels in the infant's bloodstream. There is some evidence that probiotics (good bacteria) may be helpful in prevention, but this therapy is still experimental.
Feedings are stopped in newborns with NEC. A suction tube is passed into the newborn's stomach to remove its contents, which decreases pressure and helps prevent vomiting. Nutrition and fluids are given by vein to maintain hydration and nutrition. Antibiotics are given by vein to treat infection.
Over 75% of newborns with NEC do not need surgery. However, surgery is needed if there is intestinal perforation or part of the intestine is severely affected. The surgery involves removing the part of the intestine that has not been receiving enough blood. The ends of the healthy intestine are brought out to the skin surface to create a temporary opening to allow the intestines to drain (ostomy). Later, when the infant is healthy, the ends of the intestine are reattached and the intestine is put back into the abdominal cavity.
In extremely small (less than 600 grams) or seriously ill infants, who may not survive more extensive surgery, doctors may place peritoneal drains into the abdominal cavity. Peritoneal drains allow the infected material in the abdomen to drain out of the body and may lessen symptoms. The procedure helps stabilize these infants so that an operation can be done at a later time when the newborns are in less critical condition. In some cases, newborns recover without needing additional surgery.