Use of extracorporeal support in hemophagocytic lymphohistiocytosis secondary to ehrlichiosis

Abstract

Ehrlichiosis, caused by transmission of Ehrlichia chaffeensis to humans through the bite of an infected lone star tick, can lead to secondary hemophagocytic lymphohistiocytosis (HLH), a life-threatening condition caused by uncontrolled activation of the cellular immune system. We describe a child with HLH secondary to ehrlichiosis who developed multiorgan failure and was successfully managed with extracorporeal membrane oxygenation (ECMO). A 9-year-old boy developed headaches, fever, and sore throat after suspected tick exposure. He presented with pancytopenia, elevated ferritin, and soluble interleukin-2 receptor levels, all consistent with HLH. Bone marrow biopsy revealed hemophagocytosis. Polymerase chain reaction was positive for E chaffeensis. He developed acute kidney injury, coagulation failure, hepatic insufficiency, and progressive respiratory failure requiring intubation. Due to refractory hypoxemia, he was cannulated for veno-venous ECMO. Continuous venovenous hemofiltration was used to manage acute kidney injury and fluid overload. He received doxycycline and dexamethasone/etoposide for treatment of ehrlichiosis and HLH, respectively. Plasma exchange was used for thrombocytopenia-associated multiple organ failure. The patient was decannulated after 140 hours of ECMO and subsequently transferred for inpatient rehabilitation after extubation. Review of the Extracorporeal Life Support Organization Registry database identified 6 patients with tickborne diseases who received ECMO for organ support (survival in 3 of 6); ehrlichiosis was not reported in any of these cases. ECMO likely allowed a platform for stabilization and additional therapeutic interventions in this patient.