1468: Fat Embolism Syndrome: A Rare Complication of Sickle Cell Disease

Introduction: Fat embolism syndrome (FES) is a rare complication of sickle cell disease that results from bone marrow necrosis and release of fat globules into the venous circulation. Despite high mortality and potentially devastating neurologic sequelae, FES is underrecognized. Here, we describe the experience of diagnosing and treating two pediatric patients with FES. Description: Patient A was a 16 year-old male with Hemoglobin SS disease admitted for vaso-occlusive crisis. On hospital day 2 he was transferred to the ICU for altered mental status, fever, and hypoxemia. Labs showed stable hemoglobin, leukocytosis with mild left shift, hyperferritinemia (3,379 ng/mL), elevated LDH, increased fraction of nucleated red blood cells, and notable thrombocytopenia (144,000 to 40,000 per microliter). CT head and CTPA were normal. Due to concern for FES, he received an urgent red cell exchange (RCE) transfusion and 3 days of therapeutic plasma exchange (TPE). His mental status returned to baseline. Patient B was a 20 year-old male with Hemoglobin/beta-zero thalassemia disease who was admitted with vaso-occlusive crisis. On day 1 of hospitalization, he developed chest pain, fever, and hypoxemia and was transferred to the ICU for respiratory support. CXR did not show infiltrate and CTPA was negative for pulmonary embolism. Labs were notable for a decrease in his hemoglobin, hyperleukocytosis, a relative thrombocytopenia (from 295,000 to 180,000 per microliter), hyperferritinemia (4,493 ng/mL), and increased fraction of nucleated red blood cells. He underwent a simple transfusion but his clinical symptoms did not improve and he developed mental status changes that prompted RCE. Brain MRI demonstrated innumerable punctate lesions in the anterior and posterior circulations, suggestive of fat emboli. Treatment with 5 days of TPE resulted in an improved mental status. He was discharged home on hospital day 16 with outpatient rehabilitation. Discussion: Patients with sickle cell disease who present with severe pain, mental status changes, and laboratory findings including thrombocytopenia and hyperferritinemia should raise suspicion for FES and prompt exchange transfusion and plasma exchange.