Disseminated histoplasmosis is a progressive granulomatous disease caused by Histoplasma capsulatum, which is an intracellular dimorphic fungus endemic to the Ohio and Mississippi River valleys in the United States. It is usually thought to be due to the failure of the activation of the T-cell-mediated immune response. Hemophagocytic lymphohistiocytosis (HLH) is a rare but potentially fatal condition, in which histiocytes and lymphocytes build up in and damage organs and other blood cells. We present a 37-year-old man with a past medical history of systemic lupus erythematosus (SLE) complicated by lupus nephritis on immunosuppressive therapy who presented to the emergency department with hypotension and was admitted for acute kidney injury. Prior to the presentation, he had persistent fever, myalgias, cough, mild shortness of breath, and back pain. Computed tomography (CT) chest shows "eggshell" calcification; microbiology evaluation of peripheral blood smear revealed intracellular organism, morphologically consistent with H. capsulatum; and urine histoplasmosis antigen test confirmed the diagnosis of histoplasmosis. HLH diagnosis was made clinically after "clinical and testing criteria" were evaluated. Despite further management, he developed coagulopathy and sepsis, which led to his death. At autopsy, we found organomegaly of the liver, spleen, and kidneys. Microscopically, these enlarged organs show old fibrotic granulomas and granulomatous inflammation with suspected fungal organisms. Gomori's methenamine silver special stain confirmed these fungal organisms to be consistent with Histoplasma species (3-5 micron budding yeasts). This case highlights that physicians should be aware of the diagnostic challenge that disseminated histoplasmosis with HLH could pose in a patient with SLE, especially in patients on immunosuppression. Failure to recognize the infection promptly could lead to grievous complications and possibly death.
Keywords: disseminated histoplasmosis; hemophagocytic lymphohistiocytosis; immunosuppressive; organomegaly; systemic lupus erythematosus.
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