(445) Extensive Fat Emboli Syndrome in Mild Sickle Cell Disease From HPV B19-Induced Bone Marrow Necrosis

Introduction: Non-traumatic Fat Emboli Syndrome (FES) is a rare condition in Sickle Cell Disease (SCD) with devastating sequelae and high mortality rate (~33%) resulting from bone marrow necrosis and failure. It is associated with milder forms of SCD, predominantly HbSC and HbSB+ (~68%), and Human Parvovirus B19 (HPV B19) infection (~22%). FES in SCD is under-recognized and lacks specific diagnostic criteria warranting further discussion of case specific characteristics to improve early diagnosis.

Description: A 55 year-old female with Hb-SC and no history of vasoocclusive crisis (VOC) was found unresponsive in her room and presented with altered mental status and hypoxic respiratory failure. Her labs revealed leukocytosis, lactic acidosis, acute kidney injury, transaminitis and positive HPV B19 titers. She was admitted to the ICU for multiorgan failure and shock. CT Head was unremarkable and CTA Chest showed multifocal groundglass opacities concerning for acute chest syndrome versus pneumonia. She was intubated and stabilized with pressors and broad-spectrum antibiotics followed by (1) red cell exchange and (5) plasma exchanges with high dose steroids. Despite interventions, she remained obtunded. MRI Brain showed innumerable punctate foci of infarction and micro-hemorrhage with cerebral edema favoring FES. Her hospital course was complicated by prolonged intubation due to neurological symptoms requiring tracheostomy and hyperfiltration for volume overload. Labs revealed high ferritin (13,902 ng/ml), elevated ESR and low platelets consistent with documented cases of FES. Secondary to HPV B19, she had low reticulocytes, along with increased LDH and reduced haptoglobin. She has yet to make a full neurological recovery.

Discussion: Bone marrow necrosis releases fat globules into the bloodstream resulting in massive cytokine release and tissue toxicity. Early identification of patient characteristics, such as lack of VOC, mild form of SCD, HPV B19 infection and elevated inflammatory markers may be key in early treatment. Bone marrow biopsy does not exclude the diagnosis of FES in the context of consistent imaging and non-homozygous SCD. Furthermore, literature suggests near complete recovery rate (63%) in patients with long term follow up warranting further investigation and studies.