Necrotizing enterocolitis | causes, symptoms, diagnosis, treatment & pathology

Necrotizing Enterocolitis (NEC) is a life-threatening, acute inflammatory disease of the gastrointestinal tract primarily affecting neonates. It is characterized by variable ischemic mucosal injury, bacterial invasion, tissue necrosis, and potential full-thickness perforation of the intestinal wall—most commonly in the terminal ileum and colon. Pathophysiology and Disease Cascade Immature Intestinal Barrier: Premature infants possess an underdeveloped gut mucosa with compromised tight junctions, reduced mucosal secretions (such as IgA), and altered vascular autoregulation. Hyper-Reactive Inflammatory Response: When premature intestinal cells encounter bacterial products or formula proteins, they trigger an exaggerated pro-inflammatory response via Toll-like Receptor 4 (TLR4) pathway activation. Ischemia and Bacterial Invasion: Inflammatory cascades impair microvascular blood flow, leading to tissue ischemia. Pathogenic gut bacteria breach the weakened mucosal barrier, producing gas within the intestinal wall. Necrosis and Perforation: Progressive transmural necrosis destroys bowel wall integrity, leading to intestinal perforation, peritonitis, septic shock, and multiorgan failure. Primary Risk Factors Prematurity and Low Birth Weight: The single most critical risk factor; susceptibility increases as gestational age and birth weight decrease. Enteral Formula Feeding: Enteral nutrition—particularly hyperosmolar formula—increases risk compared to exclusive human milk diets. Gut Microbiome Dysbiosis: Abnormal bacterial colonization patterns in neonatal intensive care units (NICUs) or prolonged antibiotic exposure. Hypoxic or Ischemic Insults: Perinatal asphyxia, congenital heart disease, intrauterine growth restriction (IUGR), or anemia that reduces mesenteric perfusion. Diagnostic Staging and Features (Modified Bell's Criteria) #viral #viralvideo #mbbs #mcq #bestmedicalcollegeinindia #neet #biology #mbbsabroad #mbbsmotivation