Necrotizing enterocolitis - Some things old and some things new: A comprehensive review

Necrotizing enterocolitis (NEC) is the most common gastrointestinal emergency encountered in particular the preterm infants and less often in term and near-term infants. Since its description in the late 1950's and early 1960's, its incidence along with its associated mortality and morbidity has remained unchanged. In babies born < 1500 g or before to 32 weeks of gestation, its incidence ranges between 3% and 12% and mortality is between 20 and 30%, with highest among those requiring surgery. With better understanding of etiology and pathophysiology, it is now being increasingly recognized that NEC as diagnosed by most clinicians in clinical practice may not be a single disease but a spectrum of diseases that present with similar signs and symptoms. NEC is currently thought to be due to dysbiosis of the intestinal microbiome and an uncontrolled exuberant inflammatory response to this microbial imbalance. This comprehensive review discusses the differences between NEC as seen in term and near-term babies as opposed to that seen classically in preterm infants. It also discusses the epidemiology, pathogenesis, and newer diagnostic modalities for the diagnosis of NEC in great depth, because it is only by understanding and appreciation of these dynamics that is likely to lead to the development of successful strategies for prevention, diagnosis, treatment, and improved outcome.