Chapter 36: Necrotizing Enterocolitis

SCOPE

DISEASE/CONDITION(S)

Necrotizing enterocolitis (NEC) requiring medical and/or surgical treatment.

GUIDELINE OBJECTIVE(S)

Review risk factors and basic mechanisms of necrotizing enterocolitis; provide rationale for defining necrotizing enterocolitis; recommendations for the treatment of both medical and surgical necrotizing enterocolitis; identify areas for quality improvement.

BRIEF BACKGROUND

NEC is an acute acquired intestinal disease of neonates, the most common condition requiring surgical treatment and a leading cause of death in infants requiring care in a neonatal intensive care unit (NICU). The pathophysiology of NEC continues to be elucidated. In preterm infants, NEC is likely acquired through a series of steps. Preterm infants are born in a relative passive immune deficit without active transport of immunoglobulins in the third trimester. Secondly, the premature intestine undergoes excessive stimulation of the innate immune system. Specifically, toll-like receptor-4 is abundant and highly active in cell death−signaling pathways. Repeated exposure of bacterial lipopolysaccharide ramps up these pathways increasing the likelihood of apoptosis-induced necrosis. Finally, in the setting of passive immune deficit and innate immune priming, there is a window of vulnerability. During this window, infants may be exposed to one or more triggers that ultimately precipitate or permit NEC. These triggers may include anemia (transfusion-associated NEC), bacterial or viral pathogens, a hypoxic/ischemic event, cow’s milk formula, or commercial thickening agents.

RECOMMENDATIONS

MAJOR RECOMMENDATIONS

Delineating between medical and surgical NEC requires both clinical and radiographic signs. Surgical treatment of NEC is suggested when there is free intraperitoneal air on radiograph or ultrasound, persistent ileus pattern that is unresponsive to medical management, and deteriorating clinical symptoms (persistent hypotension) or laboratory values (recalcitrant thrombocytopenia).

PRACTICE OPTIONS

Practice Option #1: Management of Medical NEC

Infants with a diagnosis of medical NEC require bowel rest and decompression. Bowel rest should continue for 3 days after radiographic evidence of NEC is absent. Abdominal radiographs, including anteroposterior and left lateral decubitus, should be monitored every 12 hours or until evidence of disease progression is absent. Laboratory studies including white blood cell count and differential, hematocrit, and platelet count should be monitored for disease progression and may aid in diagnosis and prognosis. Blood cultures should be obtained, and consideration should be made for viral cultures of stool. Antibiotics, including coverage of both gram-negative and gram-positive bacteria, should be instituted and continued for 5–7 days, depending on the severity of illness. It is unknown if there are specific antibiotic choices that could best optimize outcomes. When a cluster of NEC cases occur in a given NICU, consideration should be given to quarantining individual cases.

Practice Option #2: Management of Surgical NEC

Infants with a diagnosis of surgical NEC require bowel rest and decompression. ...