What is necrotizing enterocolitis?

Necrotizing enterocolitis (NEC) is a serious intestinal illness in babies.

• "Necrotizing" means damage and death of cells
• "Entero" refers to the intestine
• "Colitis" means inflammation of the colon (lower part of the intestine)

Although NEC may develop in any newborn, most cases occur in premature babies and in up to 5 percent of babies in newborn intensive care units. NEC is more common in babies weighing less than 1,500 grams (3 pounds, 4 ounces).

What causes necrotizing enterocolitis?

It is not clear exactly what causes NEC. It is thought that the intestinal tissues are somehow weakened by too little oxygen or blood flow. When feedings are started and the food moves into the weakened area of the intestinal tract, bacteria from the food can damage the intestinal tissues. The tissues may be severely damaged and die, which can cause a hole to develop in the intestine. This can lead to severe infection in the abdomen.

Who is affected by necrotizing enterocolitis?

• Premature babies have body systems that are less mature than full-term babies. As a result, they may have difficulty with blood and oxygen circulation, digestion, and fighting infection, thus, increasing their chances of developing NEC.
• High-risk babies, especially premature babies, who are taking milk by mouth or tube feedings are at an increased risk for developing NEC. NEC is much less common in babies who are fed human milk and is rare in babies who have not received feedings.
• Babies who have had a difficult delivery or lowered oxygen levels are at an increased risk for developing NEC. When there is too little oxygen, the body sends the most blood and oxygen to essential organs and away from the intestinal tract. This can result in lowered oxygen in the gastrointestinal circulation.
• Babies with too many red blood cells in the circulation are at an increased risk of developing NEC.
• Babies with gastrointestinal infections are at an increased risk of developing NEC.

Why is necrotizing enterocolitis a concern?

Damage to the intestinal tissues can lead to perforation (a hole) in the intestines. This allows the 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 to large areas of the intestine. The disease can progress very quickly. Infection in the intestines can be overwhelming to a baby and, even with treatment, there may be serious complications. Problems from NEC may include the following:

• Perforation (hole) in the intestine
• Scarring or strictures (narrowing) of the intestine
• Problems with food absorption if large amounts of intestine must be removed
• Severe, overwhelming infection

What are the symptoms of necrotizing enterocolitis?

The following are the most common signs of necrotizing enterocolitis. However, each child may experience symptoms differently. Symptoms usually develop in the first two weeks and may include the following:

• Abdominal distention (bloating or swelling)
• Feedings stay in the stomach instead of moving through to the intestines as normal 
• Bile-colored (green) fluid in the stomach
• Bloody bowel movements
• Signs of infection such as apnea (stopping breathing), low heart rate, lethargy (sluggishness)

The symptoms of necrotizing enterocolitis may resemble other digestive conditions or medical problems. Always consult your child's doctor for a diagnosis.

How is necrotizing enterocolitis diagnosed?

NEC is diagnosed by examining the baby for the signs listed above. An X-ray of the abdomen may show a bubbly appearance in the intestine and signs of air or gas in the large veins of the liver. Air may also be outside the intestines in the abdomen. A needle may be inserted into the abdominal cavity. Withdrawing intestinal fluid from the abdomen is one sign of a hole in the intestines.

Treatment for necrotizing enterocolitis

At The Children's Hospital of Philadelphia, children with necrotizing enterocolitis are evaluated and treated by doctors in the Division of Gastroenterology (GI), Hepatology and Nutrition.

Specific treatment for your baby will be based on the following:

• Your baby's gestational age, overall health, and medical history
• Extent of the disease
• Tolerance for specific medications, procedures, or therapies
• Expectations for the course of the disease
• Your opinion or preference

Treatment may include the following:

• Stopping feedings
• Nasogastric (NG) tube (nose into stomach) to keep stomach empty
• Intravenous fluids (IV) for nutrition and fluid replacement
• Antibiotics for infection
• Frequent X-rays to monitor the progress of the disease
• Extra oxygen or mechanically assisted breathing if the abdomen is so swollen that it interferes with breathing
• Isolation procedures (such as protective gowns and gloves) to keep any infection from spreading

Severe cases of NEC may require:

• Surgery to remove diseased intestine or bowel
• Connecting part of the intestine or bowel to an ostomy (opening on the abdomen)

Prevention of necrotizing enterocolitis

Because the exact causes of NEC are unclear, prevention is often difficult. Studies have found that babies who have had only breast milk (rather than formula) are less likely to develop NEC. Also, starting feedings after a baby is stable and slowly increasing feeding amounts have been recommended.