Reference Work Entry

Encyclopedia of Molecular Mechanisms of Disease

pp 583-584

Enterocolitis, Necrotizing

  • Alexander K. C. LeungAffiliated withDepartment of Pediatrics, Alberta Children’s Hospital, The University of Calgary
  • , Reginald S. SauveAffiliated withDepartment of Pediatrics, Health Sciences Center, The University of Calgary
  • , Andrew L. WongAffiliated withDepartment of Surgery, Alberta Children’s Hospital



Definition and Characteristics

Necrotizing enterocolitis (NEC), characterized by intestinal necrosis (Fig. 1), typically presents with abdominal distension, occult or fresh blood in stools, and bilious emesis [1].
Enterocolitis, Necrotizing. Figure 1

A neonate with necrotizing enterocolitis. Note the necrotic bowel found at laparotomy.

Non-specific clinical features include lethargy, poor feeding, temperature instability, apnea, respiratory distress, and bradycardia [1]. Other manifestations such as abdominal wall erythema, abdominal tenderness and guarding, shock, metabolic acidosis, and disseminated intravascular coagulopathy are seen in severe cases.


NEC most commonly presents in the first 2 weeks of life [1]. The incidence is estimated to be 3 per 1,000 live births and 50 to100 per 1,000 in very low birthweight infants (<1,500 g) [2]. The male to female ratio is approximately equal.

Molecular and Systemic Pathophysiology

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