2269 An Unprovoked Crisis: Hemophagocytic Lymphohistiocytosis

Abstract

INTRODUCTION: Hemophagocytic Lymphohistiocytosis (HLH) is a syndrome of dysregulated immune response due to abnormal immune activation which can be life threatening and very aggressive. Here we report a woman with jaundice found to have hemophagocytosis on a bone marrow aspirate. CASE DESCRIPTION/METHODS: A 48-year-old woman with no past medical history presented with a diffuse erythematous morbilliform rash, fever, chills, and headache for one week. The headache is described as throbbing with associated photophobia. There was no history of travel, or hiking. On physical exam, the patient was afebrile but tachycardic, her BP was 85/64 mmHg, she was ill appearing, lethargic, and had scleral icterus. Her abdomen was tender to palpation with hepatosplenomegaly. She had a diffuse maculopapular rash. Labs were notable for hypoproliferative anemia, bandemia of 36%, thrombocytopenia, elevated AST/ALT, total bilirubin with predominance of direct bilirubin, alkaline phosphatase, and lactate. CT abdomen revealed moderate diffuse colonic wall thickening from the cecum to rectum. In the meantime, a very extensive infectious workup was sent. A bone marrow biopsy revealed a mildly hypercellular marrow with hemophagocytosis. Soluble CD-25 was found to be significantly elevated. The patient’s mental status continued to deteriorate and had to be transferred to MICU for airway protection. She received steroids, etoposide, and was eventually started on emapalumab due to progression in symptoms. The patient significantly improved, and was extubated. Over two weeks her mental status returned back to baseline. DISCUSSION: HLH results from the inability to downregulate active macrophages and lymphocytes. The primary tissue damage mechanism is thought to be due to cytokine release secondary to immune activation. The instigating factor for HLH is typically an infection or an altered immune homeostasis state. The typical presentation of HLH involves fevers, bicytopenia, splenomegaly, hemophagocytosis, elevated soluble CD25, hypertriglyceridema, hepatitis, and elevated ferritin. The dilemma in the case we present remains in the trigger for HLH; the extensive infectious workup was completely unrevealing, with the patient being negative to some of the very common viral pathogens. There is no family history of HLH or any immune related disorders, and she had no past medical history. With that being said, an episode of HLH of unknown etiology seems to have been the cause of her symptoms.