Necrotizing enterocolitis: Year of the Zebra 2024

Necrotizing enterocolitis, or NEC for short, is a rare life-threatening condition that involves inflammation and necrosis, or tissue death, of the intestines. This can lead to perforation of the intestinal wall and severe infection.

NEC usually occurs within the first 2 weeks of life and mostly affects premature babies, especially those with very low birth weights, though it can occur in full-term infants too. This is because their immune system and gut barrier are not fully mature, making it easier for harmful bacteria to invade the intestinal wall.

Among premature babies, those fed with formula rather than breast milk seem to be at higher risk. This is likely due to the protective effect of breast milk in the intestines, as it contains a more natural balance of sugars that promote the growth of beneficial bacteria in the baby’s gut, as well as antibodies and other anti-inflammatory compounds that prevent harmful microbes from adhering to the intestinal lining.

Early symptoms of NEC include feeding intolerance, where the baby has difficulty digesting formula or breast milk, and abdominal bloating or swelling. Infants may also present vomiting, sometimes containing bile, along with diarrhea and bloody stools. As the condition progresses, the baby's abdomen may become tender, red, or shiny. In cases of intestinal perforation, crepitus—or a crackling sound—may be heard when lightly pushing on the abdomen due to free air in the abdomen. Infants may also show signs of infection, such as fever, breathing problems, low blood pressure, and poor circulation.

Despite advancements in care, NEC continues to have a high mortality rate, especially in extremely premature infants, meaning those born before 28 weeks’ gestation. Infants who survive usually face many long-term complications including short bowel syndrome, intestinal strictures, and neurodevelopmental delays.