Necrotizing Enterocolitis (NEC)

What is Necrotizing Enterocolitis (NEC)

Necrotizing enterocolitis is a condition that causes tissue death (necrosis) in the lining of the small intestine. The small intestine is the part of the digestive system that receives food from the stomach. NEC usually:

  • Causes areas of swelling and bleeding at the end of the small intestine.
  • Causes gas to build up inside the intestine.

As the cells of the inner lining of the small intestine begin to die, pieces of the lining fall away. If this condition is not treated, it can lead to problems with blood pressure, breathing, and heart rate.

What causes necrotizing enterocolitis 

Necrotizing Enterocolitis is a multifactorial condition that has traditionally been thought to be caused by hypoxia, infection, and enteral feeding. The pathology of NEC resembles that of ischemic necrosis. It may be that the main pathologic trigger in NEC is injury to the intestinal mucosa, which can be caused by different factors in different patients.

What are the causes?

The cause of Necrotizing Enterocolitis is not known.

What increases the risk of Necrotizing Enterocolitis?

Necrotizing Enterocolitis is more likely to develop in a child who:

  • Is born prematurely.
  • Is born at a very low birth weight.
  • Is sick from another cause at birth or shortly after birth.
  • Is admitted to a newborn or infant intensive care unit (NICU).
  • Is exposed to other babies who have NEC.
  • Has had a blood transfusion in early infancy.

Approximately 80% of patients who develop NEC are premature infants. Older infants who develop NEC usually have severe underlying medical problems, such as Hirschsprung’s disease or congenital heart disease.

Patients with this condition present with abdominal distention, vomiting, increased gastric residuals, blood in the stool, lethargy, apnea, and temperature instability.

What are the symptoms of Necrotizing Enterocolitis?

Symptoms of this condition develop soon after birth. Symptoms may include:

  • Firmness (bloating) and swelling (distension) of the abdomen.
  • A red or blue discoloration of the abdomen.
  • Diarrhea.
  • Vomiting.
  • Bloody stools (feces).
  • Sudden stops in breathing (apnea).
  • Decreased blood pressure (hypotension).
  • Unstable body temperature.
  • Sleepiness and lack of movement (lethargy).

How is this diagnosed?

This condition is diagnosed based on:

  • Your child’s symptoms. NEC may be diagnosed if your child is at high risk for the condition and shows signs and symptoms.
  • A physical exam.

Your child may also have tests, including:

  • Blood tests. These may be done to check for signs of infection or low levels of the blood cells that are needed for clotting.
  • Abdomen (abdominal) X-rays. These may be done to check for gas inside the intestine or air outside the intestine. These may show that there is a hole in your child’s intestine.

What findings of NEC can be seen on X rays?

The radiographic findings of NEC are nonspecific when the condition is initially suspected. Radiographs are obtained serially, and the role of the radiologist is to attempt to diagnose the condition prior to the occurrence of bowel perforation. In early NEC, the most commonly detected abnormality is diffuse gaseous distention of bowel loops.

A more useful sign of early NEC is loss of the normal symmetric bowel gas pattern, with a resultant disorganized or asymmetric pattern. In more advanced NEC, the finding of pneumatosis intestinalis (intramural gas) is virtually pathognomonic for the condition.

Gas in the portal venous system is a pathognomonic finding in NEC, occurring in 10% to 30% of cases. Infants at risk for imminent perforation often have portal venous gas. They may also have the “persistent loop” sign, which is a dilated loop of intestine (focal ileus) that remains unchanged over 24 to 36 hours.

Another grave sign is a shift from a pattern of generalized dilation to asymmetric bowel dilation. Ascites is another sign of impending perforation. When pneumoperitoneum develops, this is a definite sign that the bowel has perforated, and the infant must have surgery (i.e., medical NEC becomes surgical NEC).

How is this treated?

Treatment for Necrotizing Enterocolitis begins by stopping all feedings and removing gas from the intestine. Your child’s health care providers will make sure that your child’s blood pressure and body temperature stay within normal ranges. Other treatments may include:

  • Giving antibiotic medicines, fluids, and liquid nutrition through an IV tube.
  • Inserting a tube through the nose or mouth into the stomach (nasogastric tube, or NG tube) to drain fluids and remove gas.
  • Surgery. This may be done:
    • To remove dead or dying intestinal tissue.
    • To make a temporary opening of the intestine through the abdominal wall (ostomy). The intestine can be reconnected weeks or months after recovery.

Follow these instructions at home:

  • Give over-the-counter and prescription medicines only as told by your child’s health care provider.
  • If your child was prescribed an antibiotic medicine, give it to him or her as told by the health care provider. Do not stop giving the antibiotic even if your child starts to feel better.
  • If your child has had surgery, follow home care instructions as told by your child’s health care provider.
  • Feed your child as told by your child’s health care provider.
  • Keep all follow-up visits as told by your child’s health care provider. This is important.

Contact a health care provider if:

  • Your child has a fever.
  • Your child is having trouble feeding.
  • Your child has frequent constipation, diarrhea, or vomiting.

Get help right away if:

  • Your child is unable to eat.
  • Your child has bloody stools or bloody vomit.
  • Your child is struggling to breathe.


  • Necrotizing enterocolitis is a condition that causes tissue in the small intestine to die (necrosis).
  • Treatment for NEC begins by stopping all feedings and removing gas from the intestine.
  • Contact your child’s health care provider right away if your child has a fever, trouble feeding, or frequent constipation, diarrhea, or vomiting.

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