Sudden Cardiac Arrest Due to Hemophagocytic Lymphohistiocytosis in a Child.

Background: Hemophagocytic lymphohistiocytosis (HLH) is an uncommon hyperinflammatory condition in children that may acutely mimic septic shock. Sudden out-of-hospital cardiac arrest in children is also uncommon and may be of unclear etiology upon initial presentation.

Case Report: A 10-year-old previously healthy child presented with sudden cardiac arrest after an insidious course of throat pain, fever, and progressive altered mental status. He was subsequently diagnosed with Epstein-Barr virus-associated HLH and suffered cerebral edema and death. WHY SHOULD AN EMERGENCY PHYSICIAN BE AWARE OF THIS?: HLH has not previously been described as a cause of sudden out-of-hospital cardiac arrest in children. Rapid diagnosis of underlying cause of an unexpected cardiac arrest may help guide appropriate therapy to salvage organ function.