Diffuse gastrointestinal hemorrhage associated with emapalumab treatment of macrophage activation syndrome: A case report

Abstract Macrophage activation syndrome (MAS) is a complex hyperinflammatory syndrome and continues to have evolving treatment options. This case discusses a 19‐month‐old with MAS associated liver failure and multiorgan dysfunction. Her course was complicated by gastrointestinal (GI) bleed. Emapalumab was administered (6 mg/kg) and within 24 h, her hemoglobin dropped dramatically and there was evidence of upper and lower GI bleed. Esophagogastroduodenoscopy and flexible sigmoidoscopy were performed at the bedside but did not demonstrate any source of the bleed. This case further discusses the association of emaplumab and the massive GI hemorrhage we observed as well as a review of MAS, particularly in the setting of liver failure.