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Necrotizing Enterocolitis (NEC)


Jaime Belkind-Gerson

, MD, MSc, University of Colorado

Reviewed/Revised Oct 2023

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.

  • 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.

  • About 70 to 80% of newborns with this disorder survive.

The cause of necrotizing enterocolitis is not completely understood, but it is in part related to immaturity of the intestine along with low oxygen levels in the blood and/or diminished blood flow to the intestine. 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 Sepsis in Newborns Sepsis is a serious bodywide reaction to infection spread through the blood. Newborns with sepsis appear generally ill—they are listless, do not feed well, often have a gray color, and may have... read more ) and sometimes death. If the injury progresses through the entire thickness of the intestinal wall and the intestinal wall tears (perforates) Perforation of the Digestive Tract Any of the hollow digestive organs may become perforated (punctured), which causes a release of intestinal contents and can lead to sepsis (a life-threatening infection of the bloodstream) and... read more , intestinal contents leak into the abdominal cavity and cause inflammation and usually infection of the abdominal cavity and its lining (peritonitis Peritonitis Abdominal pain is common and often minor. Severe abdominal pain that comes on quickly, however, almost always indicates a significant problem. The pain may be the only sign of the need for surgery... read more ).

Risk factors for necrotizing enterocolitis

Symptoms of Necrotizing Enterocolitis

Newborns with necrotizing enterocolitis may develop swelling of the abdomen and may have difficulty feeding. They may vomit bloody or green- or yellow-stained 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).

Narrowing of the intestine (intestinal stricture) is the most common long-term complication of necrotizing enterocolitis.

Diagnosis of Necrotizing Enterocolitis

  • X-rays of the abdomen

  • Ultrasonography

  • Blood tests

The diagnosis of necrotizing enterocolitis is confirmed by abdominal x-rays X-Rays X-rays are a type of medical imaging that use very low-dose radiation waves to take pictures of bones and soft tissues. X-rays may be used alone (conventional x-ray imaging) or combined with... read more that show gas in the intestinal wall (called pneumatosis intestinalis) or that free air (air outside of the gastrointestinal tract) is in the abdominal cavity if the intestinal wall has perforated. Doctors may also do an ultrasound of the abdomen Ultrasound Scanning (Ultrasonography) of the Abdomen Ultrasound scanning uses sound waves to produce pictures of internal organs (see also Ultrasonography). An ultrasound scan can show the size and shape of many organs, such as the liver and pancreas... read more Ultrasound Scanning (Ultrasonography) of the Abdomen to look at the thickness of the intestinal wall, pneumatosis intestinalis, and blood flow.

Blood samples are taken to look for bacteria and other abnormalities (for example, a high white blood cell count).

Sometimes, blood is detected in the stool.

Treatment of Necrotizing Enterocolitis

  • Feedings stopped

  • Nutrition, fluids, and antibiotics given by vein

  • Sometimes surgery

Feedings are stopped immediately in newborns with necrotizing enterocolitis. 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 and allow the intestine to heal. Antibiotics are given by vein to treat infection.

Over 75% of newborns with necrotizing enterocolitis 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 (about 1 pound or less, or 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 they are in less critical condition. In some cases, infants recover without needing additional surgery.

Prognosis for NEC

Current medical and surgical treatments have improved the prognosis for infants with necrotizing enterocolitis. About 70 to 80% of affected newborns survive.

Strictures occur in 10 to 36% of infants who survive the initial episode of necrotizing enterocolitis and typically cause symptoms 2 to 3 months after the episode. Sometimes strictures need to be corrected surgically.

Prevention of NEC

Feeding premature newborns their mother’s breast milk Breastfeeding Breast milk is the ideal food for newborns and infants. Although babies may be fed breast milk or formula, the World Health Organization (WHO) and American Academy of Pediatrics (AAP) recommend... read more Breastfeeding rather than formula seems to provide some protection against necrotizing enterocolitis. In addition, hospital personnel avoid giving the infant highly concentrated formula and take measures to prevent low oxygen levels in the infant's bloodstream. Antibiotics and acid-supressing medications also should not be given to the infant if possible.

There is some evidence that probiotics (good bacteria) may be helpful in prevention, but this therapy is still experimental.

Pregnant women who are at risk of having a preterm birth may be given corticosteroids to help prevent necrotizing enterocolitis.

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