What is Necrotizing Enterocolitis (NEC)?
Necrotizing enterocolitis (NEC) affects mainly premature babies. It is the most common surgical emergency in newborns. NEC accounts for 15% of deaths in premature babies weighing less than 1500 grams. Overall death from those babies with NEC is 25%.
What causes Necrotizing Enterocolitis (NEC)?
No single factor has been established as the cause of NEC. It is now thought that NEC is the result of a combination of several factors. The two consistent findings are prematurity and feedings. The premature intestine reacts abnormally and develops an acute inflammatory response to feedings leading to intestinal necrosis (death). Some postnatal issues including heart abnormalities, obstruction of circulation in the bowel, infection or gastroschisis are also associated with NEC.
In the premature infant, NEC usually occurs a week to ten days after the initiation of feedings. In the term baby, NEC occurs within one to four days of life if feeding is started on day one. The risk of NEC is less with later gestational age. Very few unfed infants develop NEC. One theory which connects feeding to bowel mucosa damage involves the overgrowth of bacteria when provided with a carbohydrate source. The digestion of the lactose in formula by premature infant is incomplete and the residual ferments (has a chemical change) that encourages growth of bacteria that cause inflammation.
What are the signs and symptoms of Necrotizing Enterocolitis (NEC)?
NEC is difficult to diagnose. The baby may have lethargy, poor feeding, bilious vomiting, distended abdomen and blood in stools. Physical examination may show the baby to have abdominal tenderness, periumbilical darkening or erythema (redness, or a fixed loop of bowel that can be felt.
How is Necrotizing Enterocolitis (NEC) diagnosed?
Abdominal X-rays are done frequently if NEC is suspected. These films will show the neonatal team if there are any fixed or distended loops of bowel that may indicate an ileus (obstruction). Pneumatosis intestinalis (air in the bowel wall) can be seen early in NEC and can resolve over a number of hours. Pneumoperitoneum (air in the abdomen) is an indicator for immediate surgery. Air in the abdomen shows that the bowel has perforated (torn).
How is Necrotizing Enterocolitis (NEC) managed?
Medical management consists of stopping feeds, nasogastric drainage to suction (tube in baby’s stomach to "suck out" contents), 7-14 days of antibiotics and IV nutrition. Close monitoring of fluid status, electrolytes, coagulation and oxygen requirements are also necessary. 60-80% of babies with NEC are managed medically and symptoms resolve without surgery. Feedings postoperatively are started slowly.
What if surgery is needed?
Surgery is necessary if medical management fails or the bowel is perforated (torn). After opening the abdomen, the surgeon may find a swollen, purple bowel with areas of necrosed (dead) bowel. The usual areas involved are the terminal ileum, cecum and right colon but the whole bowel may be involved. The goal is to remove only that bowel that is fully necrosed (dead) and to leave any marginal areas in the hope that they will survive. This may require an colostomy
and/or another operation within 24-48 hours to evaluate any surviving bowel. The nutritional outcome is roughly based on the remaining intestinal length and the medical and surgical team will discuss this with you.
A note to parents...
Having a baby with NEC is confusing and frightening. Feeding your child is a basic bonding parental experience and a child that can’t be fed probably makes you feel helpless and frustrated. We know that soul searching is inevitable with questions like "What did we do wrong?" The frustration and anxiety are increased with the realization that there is nothing to do but "wait and watch". Your nurse and any other members of the team are here to help you. Ask questions. We are here to support you through this difficult time.
For additional information on necrotizing enterocolitis (NEC) visit the APSA Family and Parent Resource Center's page here »
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Contact us »This information, although based on a thorough knowledge and careful review of current medical literature, is the opinion of doctors at The University of Texas Medical School and is presented to inform you about surgical conditions. It is not meant to contradict any information you may receive from your personal physician and should not be used to make decisions about surgical treatment. If you have any questions about the information above or your child's care, please contact our doctors.