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What is necrotizing enterocolitis?
The name of this disease is derived from necrotizing, meaning damage and death of cells, entero, referring to the intestine, and colitis, meaning inflammation of the colon (lower part of the intestine). Necrotizing enterocolitis is the most common gastrointestinal emergency in the neonatal intensive care unit. It develops in 2,000 to 4,000 newborns annually and affects 1% to 8% of all newborns admitted to neonatal intensive care units in the United States. Newborns with birth weights less than 2,000 grams (approximately 4 1/2 pounds) comprise 80% of necrotizing enterocolitis cases.
What causes necrotizing enterocolitis?
While there appears to be no single cause of necrotizing enterocolitis, research has identified a number of risk factors, with prematurity being the most important.
Is my baby at risk for necrotizing enterocolitis?
Necrotizing enterocolitis predominantly affects premature infants, but can also be seen in full-term infants. It can affect any portion of the gastrointestinal tract or the entire gastrointestinal tract but the colon is most often affected. Although necrotizing enterocolitis usually occurs 3 to 12 days after birth, late onset can occur many weeks after birth.
Why is necrotizing enterocolitis a concern?
Damage to the intestinal tissues can lead to perforation (a hole) in the intestines, allowing the bacteria normally present in the intestinal tract to leak out into the abdomen and cause infection known as peritonitis. The damage may exist only in a small area or it may progress quickly to large areas of the intestine.
Infection in the intestines can be life-threatening, and even with treatment there may be serious complications, such as severe infection in the abdomen, perforation (a hole) in the intestine, and scarring or narrowing of the intestine. Patients who must undergo removal of a large segment of intestine also experience problems with food absorption.
What are the signs and symptoms of necrotizing enterocolitis?
Since the early symptoms of necrotizing enterocolitis may resemble other digestive conditions or medical problems, this disease is often difficult to diagnose. However, symptoms may include the following:
- Abdominal distention (swelling)
- Bloody bowel movements
- Poor feeding
- Feeding intolerance
- Bile-colored (green) vomit or gastric drainage
- Signs of infection, such as sluggishness and cessation of breathing (apnea)
- Temperature instability
How is necrotizing enterocolitis diagnosed?
Physical examination generally reveals abdominal distention (swelling). In some cases redness of the abdominal wall can be seen. This may indicate perforation and inflammation of the membrane lining the abdominal cavity (peritonitis).
When necrotizing enterocolitis is suspected, abdominal X-rays are taken. An X-ray may show multiple small bubbles within the wall of the intestine (pneumatosis intestinalis). Repeated X-rays help to 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. If the bowel is perforated, air may be seen outside the intestine, but within the abdominal cavity.
Despite lack of evidence of perforation on X-ray, infants sometimes show no clinical improvement. When this occurs, an ultrasound may assist in the diagnosis of perforation. This diagnostic test allows the detection of an abnormal accumulation of intraperitoneal fluid as well as inflammatory changes in the bowel that are consistent with perforation.
Sampling of infected peritoneal fluid from the abdomen is also useful, since the presence of such fluid is a sign of perforation in the intestine.
How is the condition treated?
The management of necrotizing enterocolitis depends on the severity of the disease, the infant’s response to medical treatment, and the degree of bowel involvement. Sixty to 80 percent of babies with necrotizing enterocolitis are managed medically and symptoms resolve without surgery.
Newborns with necrotizing enterocolitis that does not show indications for surgery are placed on a medical protocol. This protocol includes:
- Stopping regular feedings and supplying nutrition through an intravenous (IV) catheter
- Placing a nasogastric tube into the stomach. The tube suctions air and fluids from the baby’s stomach and intestine
- Antibiotic therapy
- Checking bowel movements for blood
- Taking frequent blood tests to look for signs of infection and changes in the body’s chemistry
- Providing supplemental oxygen or ventilator support if abdominal swelling interferes with breathing
- In severe cases, giving blood transfusions for stabilization
If my baby requires surgery what can I expect?
If medical management fails or if the bowel is perforated, surgery becomes necessary.
During surgery, the pediatric surgeon may find a swollen, discolored bowel with several areas that have died due to a lack of blood supply, or the entire bowel may be involved. The aim of surgery is to remove only the bowel that has died and to leave any segments of the bowel that are likely to recover.
A temporary opening in the wall of the abdomen, which is called an ostomy, is created to allow the bowel to recover and heal. Another operation to re-examine the abdomen may be required 24 to 48 hours later to determine if disease has progressed. In some cases, a drain is initially placed in the abdomen to remove the infected fluid and help stabilize the infant prior to more definitive surgery.
Once the baby has recovered and undergoes a period of growth, the baby is returned to the operating room for closure of the ostomy. Prior to this operation a contrast X-ray of the intestine is performed to identify areas that may be damaged (stricture). If a stricture is present the stricture is removed and the bowel repaired. At times, it will not be possible to repair both a stricture and close the ostomy, requiring another operation in 4 to 6 weeks.
What is the long-term prognosis?
Approximately 50% of infants with necrotizing enterocolitis who are treated without an operation (medical management) have clinical resolution of their disease. They experience good recovery and are able to lead normal lives. Nevertheless, some infants may develop an intestinal stricture (narrowing), usually in the colon due to the injury to the bowel. This complication may require later corrective surgery.
Of the newborns who undergo surgery, approximately two-thirds survive. The mortality rate is higher in infants with very low birth weights, particularly those with extensive necrosis of the bowel and overwhelming infection.
At least 10% of children who are managed surgically have gastrointestinal problems, including short-gut syndrome, fat malabsorption, or intestinal strictures. The severity of these conditions correlates with the severity of their necrotizing enterocolitis.
Source: Cincinnati Children’s Hospital Medical Center