Necrotizing enterocolitis, or NEC, is a serious intestinal disease that primarily affects premature infants. The condition involves inflammation and injury to the tissues of the small or large intestine, which can cause the tissue to die and lead to a perforation, or hole, in the intestinal wall. This allows bacteria from the intestine to leak into the abdomen or bloodstream, causing a widespread, life-threatening infection. NEC typically develops within the first two to six weeks after birth.
Risk Factors and Causes
The greatest risk factor for necrotizing enterocolitis is premature birth. Over 90% of cases occur in infants born before 37 weeks of gestation, with babies weighing less than 3.25 pounds being the most vulnerable. This is due to the immaturity of a premature baby’s systems; their underdeveloped intestines and weak immune systems are not well-prepared to manage circulation, digest food, and fight infection. Events that reduce oxygen or blood flow to the gut can injure the intestinal lining, allowing bacteria to invade the damaged tissue and cause an infection known as peritonitis.
The method of feeding also plays a part in the risk of developing NEC. Babies fed infant formula are at a higher risk compared to those fed human breast milk. Breast milk contains substances that help protect the intestinal lining and support the developing immune system. In some instances, NEC cases have appeared in clusters within neonatal intensive care units (NICUs), suggesting a possible link to specific bacteria or viruses.
Symptoms and Diagnosis
The signs of NEC can develop over a few days or appear suddenly. A common initial symptom is abdominal swelling, also known as distension, where the baby’s belly appears bloated and may be tender to the touch. Another indicator is feeding intolerance; the baby may refuse to eat, have trouble digesting, or have green or yellow fluid in the stomach from a previous feeding.
Other symptoms include changes in the stool, which may become bloody. The infant might also show general signs of illness, such as lethargy, an unstable body temperature, and changes in breathing, including periods of paused breathing known as apnea. Some babies may also experience a slowed heart rate or low blood pressure. These symptoms can overlap with other medical issues, so a prompt evaluation is necessary.
To confirm a diagnosis, healthcare providers use an abdominal X-ray. A characteristic finding is the presence of gas bubbles in the wall of the intestine, a condition called pneumatosis intestinalis. In more severe cases, the X-ray might reveal air that has escaped the intestine, which indicates a perforation. Blood tests are also performed to look for signs of infection and inflammation.
Medical and Surgical Treatments
Once NEC is diagnosed, treatment begins immediately to allow the intestines to rest and heal. All oral or tube feedings are stopped, and intravenous (IV) fluids are started for nutrition and hydration. A nasogastric (NG) tube is typically inserted through the baby’s nose into the stomach to suction out air and fluid, which helps decompress the bowel.
Broad-spectrum antibiotics are administered through the IV to combat the infection. The infant is monitored closely with regular physical exams and repeated abdominal X-rays to track the disease’s progression. For many infants with milder cases, this medical treatment is sufficient, and between 60% and 80% of babies with NEC do not require surgery.
Surgical intervention becomes necessary when there are signs of a perforation or if the infant’s condition worsens despite medical treatment. The primary goal of surgery is to remove the sections of the intestine that are dead or dying. After removing the damaged tissue, the surgeon assesses the health of the remaining intestine.
In many surgical cases, the surgeon will perform an ostomy. This procedure involves bringing an end of the intestine to an opening on the abdominal wall, called a stoma. This allows stool to exit the body into a collection bag, bypassing the newly operated and healing sections of the bowel. This is often a temporary measure to give the intestine time to recover fully before a second surgery is performed weeks or months later to reconnect the bowel.
Prognosis and Recovery
The outlook for infants with necrotizing enterocolitis has improved significantly, and a majority of babies recover fully. Many infants treated successfully with only medical management go on to have no further digestive problems. The survival rate for affected newborns is approximately 70% to 80%.
For infants who required surgery to remove a portion of their intestine, the recovery path can be more complex and may require a period of healing before a subsequent operation to reconnect the bowel. While many of these infants also recover well, they face a higher risk of long-term complications. One of the most common issues is the development of intestinal strictures, which are narrowings in the bowel caused by scarring. Strictures occur in 10% to 36% of survivors and may require another surgical procedure to correct.
A smaller number of infants who have had a large section of their intestine removed may develop short bowel syndrome. This condition affects the body’s ability to absorb nutrients properly, leading to diarrhea and malabsorption. These children may require specialized long-term nutritional support, sometimes delivered intravenously, while their remaining intestine adapts and heals. The journey after NEC requires careful follow-up with a medical team to manage any potential long-term effects on growth and development.