Necrotizing Entercolitis (NEC)

What Is Necrotizing Enterocolitis?

Necrotizing enterocolitis (NEC) is a gastrointestinal disease that involves infection and inflammation that causes damage and the death of cells in some or all of the intestine. Although it affects only one in 2,000 to 4,000 births, necrotizing enterocolitis is the most common gastrointestinal (GI) emergency in U.S. neonatal intensive care units.

Who Is Affected by Necrotizing Enterocolitis?

Necrotizing enterocolitis occurs mostly in premature infants (newborns with birth weights of less than 4.5 pounds make up about 80 percent of necrotizing enterocolitis cases), but full-term babies have also been diagnosed. Necrotizing enterocolitis often develops within the first two weeks of life, usually after milk feeding has begun (at first, feedings are usually given through a tube that goes directly to the baby's stomach). About 10 percent of infants weighing less than 3 pounds, 5 ounces (or 1,500 grams) experience necrotizing enterocolitis. The immature bowels of these babies are sensitive, and prone to infection. They may have difficulty with blood and oxygen circulation and digestion, which increases their chances of developing necrotizing enterocolitis.

Damage to the intestinal tissues can lead to perforation (a hole) in the intestines, allowing bacteria normally present in the intestinal tract to leak out into the abdomen and cause infection. The damage may only exist in a small area, or it may progress quickly to large areas of the intestine.

Necrotizing Enterocolitis Risk Factors

While there appears to be no single cause of necrotizing enterocolitis, risk factors include premature birth and early feedings in premature babies with an immature gut. Babies who have had difficult deliveries with lowered oxygen levels can also develop necrotizing enterocolitis.

Some experts believe that necrotizing enterocolitis causes have to do with the makeup of infant formula, the rate of delivery of the formula, or the immaturity of the mucous membranes in the intestines. Babies who are fed breast milk can also develop necrotizing enterocolitis, but their risk is lower.

Another pattern experts have noticed with necrotizing enterocolitis is that it sometimes seems to occur in "epidemics," affecting several infants in the same nursery. Of course, nurseries have very strict precautions to prevent the spread of infection, so this may be coincidence. However, it does suggest the possibility that necrotizing enterocolitis could in some cases be spread from one baby to another.

Necrotizing Enterocolitis Symptoms in Children

Although necrotizing enterocolitis usually occurs in babies between three and 12 days after birth, late onset may occur many weeks after birth. Each baby experiences the necrotizing enterocolitis symptoms differently, which may include:

  • Abdominal distention (swelling)
  • Bloody stools
  • Poor feeding, or feeding intolerance
  • Bile-colored (green) vomiting or gastric drainage
  • Signs of infection such as lethargy (sluggishness) and apnea (cessation of breathing)
  • Temperature instability

Necrotizing Enterocolitis Diagnosis

During a physical examination, your child's doctor may notice swelling and tenderness in the belly. In some cases, a mass can be felt, indicating a perforation in that area. In other cases, a redness of the abdominal wall can be seen. This may also indicate perforation, as well as inflammation of the membrane lining the abdominal cavity.

To confirm or rule out necrotizing enterocolitis, the doctor will order an abdominal X-ray. An X-ray may show multiple small bubbles in the wall of the intestine (pneumatosis intestinalis). Serial films help assess disease progression. In severe cases, the X-ray may reveal air or gas in the large veins of the liver. This air is produced by bacteria in the wall of the bowel.

Necrotizing Enterocolitis Treatment

Necrotizing enterocolitis treatment can be either medical or surgical for pediatric patients. If the intestine is not already perforated, and if only a small area of intestine is affected, medical treatment is usually tried first. Sixty to eighty percent of babies with necrotizing enterocolitis do not need surgery to resolve their symptoms. Many of them recover and are able to lead normal lives. Medical treatment includes:

  • Stopping all regular feedings. The baby receives nutrients through an intravenous (IV) catheter.
  • Placement of a nasogastric tube extending from the nose into the stomach. The tube suctions air and fluids from the baby's stomach and intestine, relieving swelling and discomfort.
  • Starting antibiotic therapy.
  • Checking stools for blood.
  • Taking frequent blood tests. These can detect early signs of infection and imbalances in the body's chemistry.
  • If abdominal swelling interferes with breathing, providing oxygen or mechanically assisted breathing.
  • In severe cases, platelet and red blood cell transfusion may be necessary.

If a child does not respond to medical treatment, or if the intestine is perforated, surgery is needed. A pediatric surgeon examines the intestine and removes only the destroyed parts, leaving as much intestine as possible so that less damaged segments have an opportunity to regain function. In some cases, a drain is placed in the abdomen to remove the infected fluid.

A temporary ostomy (opening in the wall of the abdomen) is created to allow the bowel to recover and heal. Another operation to reexamine the abdomen may be required 24 to 48 hours later to determine if disease has progressed.

Necrotizing enterocolitis diagnosis can be extremely frightening to parents. It's frustrating not to be able to feed your baby, especially when he or she is so small. It may not be possible to do the holding and bonding that is so important for babies and parents. Try to keep in mind that, with medical treatment, there is a good chance your baby will be back on regular feedings within a short time. Infants who need surgery have a tougher road ahead, but many of them survive. Higher birth weight improves the chances of a good outcome.