Adult-onset Still’s disease with secondary hemophagocytic lymphohistiocytosis: a case report

Abstract

Hemophagocytic lymphohistiocytosis (HLH) is an aggressive and life-threatening syndrome of excessive immune activation causing multi-organ dysfunction. HLH can be inherited genetically, but can also be secondary to infections, malignancy, immunosuppression, and autoimmune conditions. Adult-onset Still’s disease (AOSD) is an autoimmune disorder characterized by fevers, arthritis, and an evanescent rash. It can rarely predispose patients to HLH. Herein, we report a case of a 20-year-old male patient who presented with fever, joint pain, and rash for 1 month. On evaluation, he was diagnosed as a case of AOSD complicated with secondary HLH. A 23-year-old male, with no significant past medical history and family history, presented to our emergency department with complaints of fever with rash for the last 1 month. He had intermittent high-grade fever with chills, which was associated with evanescent rash involving the trunk and proximal upper limbs. There was no history of joint pain, cough, sore throat, burning micturition, or weight loss. On examination, the patient was conscious and oriented with a temperature of 101 °F, pulse rate of 100/min, blood pressure of 120/84 mmHg, and SpO₂ of 98% on room air. Physical examination revealed salmon-colored maculopapular rash, cervical lymphadenopathy, and mild splenomegaly. The rest of the physical examination was unremarkable. Lab investigations revealed pancytopenia, transaminitis, elevated CRP with low ESR, highly elevated ferritin, elevated LDH, hypofibrinogenemia, and sterile blood and urine cultures. ANA by ELISA, rheumatoid factor, IGRA, dengue IgM, rapid malaria Ag, typhoid IgM, Leptospira IgM and scrub IgM were reported negative. The patient met the diagnostic criteria for AOSD and HLH, and a diagnosis of HLH secondary to AOSD was made. He was given pulse iv methylprednisolone for 5 days, His general condition improved over the week. Then he was switched to oral prednisolone 60 mg once daily. There were no more episodes of fever, and he was discharged after one week on a tapering dose of steroids. AOSD is a rare autoinflammatory condition which often presents as a diagnostic challenge. A high index of suspicion is important for the diagnosis of HLH, and prompt initiation of treatment is of utmost importance, as it is a rapidly progressive life-threatening condition.