Necrotizing enterocolitis: pathophysiology, clinical presentation, and management

Necrotizing Enterocolitis is one of the serious problems that can affect a premature baby. Necrotizing means the death of the tissue. Entero is a reference to the small intestine, Colo to the large intestine, and itis meaning inflammation. However, knowing what the words means does not mean that the disease is understood. It is a disease of the gastrointestinal tract and generally affects only premature infants. NEC involves inflammation and an infection that causes either partial or complete destruction of the bowel and intestine. Only one infant out of 2000 to 4000 live births will be affected but it is the most serious and the most common gastrointestinal disorder among preterm infants that are hospitalized. It makes up between 1% and 5% of admissions to the neonatal intensive care unit. Typically, NEC occurs within the first two weeks of the baby's life, and this is usually after the baby has begun feeding on milk. When babies are premature the first feedings are generally given through a tube that goes to the baby's stomach (kidshealth.org, 2004).

Approximately 10% of babies that weigh less than 3 lbs. 5 ounces will experience NEC. These premature infants are not only tiny but they have a lack of maturity of many of their organs and systems as well, and this includes the bowels which are very prone to infection and also extremely sensitive to any changes in blood flow. These preterm infants also sometimes have difficulty with oxygen circulation and blood circulation during their digestion and this increases the chances of the development of NEC. The exact cause, however, is still unknown. A weakening of the intestinal tissues of premature infants is one theory that has been suggested, and others include what is in the infant formula, how fast it is delivered, or how much maturity the mucous membranes have in the intestines. Other theories have to do with lowered oxygen levels and there have even been cases were individuals feel that NEC could actually be spread from a baby to another baby, as some nurseries have had what they would consider minor epidemics (kidshealth.org).

It is often very difficult to diagnose NEC. Sometimes the baby will vomit, and it may feed poorly, be lethargic, have a distended abdomen, and have blood in the stool. Upon physical examination, abdominal tenderness may be seen in the baby and periumbilical darkening or redness is sometimes also seen. Occasionally, there is a fixed loop of bowel that can be felt when the abdomen is examined. Generally, if NEC is suspected an abdominal x-ray is done. This x-ray will show individuals whether there are distended or fixed loops of bowel that could possibly indicate some type of obstruction. Having air in the wall of the bowel can also be seen very early on in NEC but often resolves over a period of hours. Having air in the abdomen, however, is indicative of immediate surgery. If there is air anywhere in the abdomen this indicates that the bowel has torn or perforated and this is a life-threatening emergency, especially in a tiny premature infant. If the bowel is not torn and surgery is not necessary, it can be managed medically. Feedings will be stopped and a nasogastric tube will be placed in order to suck up the contents of the baby's stomach. The baby will also require nutrition through an intravenous line and between one and two weeks of antibiotics. Monitoring of electrolytes, coagulation and oxygen requirements, fluid status, and other things are also often necessary with this condition. Sixty to 80% of babies that develop NEC can be managed medically and their symptoms will resolve themselves without resorting to surgery. If operations are necessary, the feedings afterwards will be started very slowly. If the bowel is torn then surgery is required and once the abdomen is opened it is likely that a swollen and dead area of bowel will be found. The goal is to leave as much of the healthy or marginally healthy bowel and intestines as possible, and an ostomy may be required (www.pedisurg.com, n.d.).