necrotizing

necrotizing enterocolitis (NEC) the development of necrotic patches in the intestine that interfere with digestion and absorption and can lead to a paralytic ileus, perforation, and peritonitis. The entire bowel may be affected, or the ischemic necrosis may be localized.

NEC is a serious condition that occurs most often in preterm and very immature neonates; it develops in about 5 per cent of all neonates in neonatal intensive care units. The exact cause of the condition is not known, but it is related to ischemia or poor perfusion of blood vessels in sections of the bowel. The ischemia is thought to occur when an earlier oxygen depletion in the heart and brain, as in anoxia or shock, causes blood to be shunted away from less vital organs such as the intestine.

Since the incidence of NEC is low in neonates who are breast-fed, it is likely that the necrotizing process is initiated by a response to the protein in cow's milk and the profuse multiplication of bacteria that thrive more readily in cow's milk than in breast milk. The gas-forming bacteria invade the damaged intestinal cells, causing them to rupture and producing pneumatosis intestinalis, that is, the presence of air in the submucosal or subserosal surfaces of the colon.

Abdominal x-rays will show a characteristic invasion of air in the intestinal wall. If perforation has occurred, the x-ray will reveal free air in the abdominal cavity. Nonspecific symptoms of NEC usually appear in the first week of life and may be overlooked when caregivers are preoccupied with more obvious life-threatening problems. Typically, the neonate exhibits lethargy, vomiting, distended abdomen, signs of intestinal bleeding, and absence of bowel sounds.

Once the condition is diagnosed, all oral feedings are stopped to rest the intestinal tract. Feeding must then be accomplished intravenously. Gastrointestinal decompression via nasogastric suction may be instituted to relieve distention, and antibiotics administered to limit secondary bacterial infection. Progressive deterioration or evidence of perforation are indications for surgery to remove the diseased portion of the bowel. If damage is extensive an ileostomy or colostomy may be necessary.

Causing the death of a specific area of tissue. Human bites frequently cause necrotizing infections.

A. Tumors and not only in the brain tend to develop necrosis the longer they exist because the tumor cells divide so rapidly so the blood supply can't keep up with its' own cells demands, so some cells within the tumor die (therefore are seen as necrotic). This does not usually predict prognosis, but only means that the tumor is longstanding.