Hemophagocytic lymphohistiocytosis is a rare but possible complication of infectious conditions. It is potentially fatal if left untreated, which highlights its clinical importance.

E.M.S.S., female, 22 years old, living with HIV for 8 years, with a history of poor treatment adherence, progressed to AIDS. She presented with asthenia, followed by productive cough and episodes of fever, associated with unquantified weight loss. Past medical history: smoking and alcohol use. Initial laboratory results showed Hb 10.1, WBC 2330, Platelets 122,000, AST 4022, ALT 165, GGT 102, LDH 3,798. Chest X-ray: diffuse ground-glass opacities and miliary-pattern nodules; urinary LAM antigen: reactive. Initial diagnostic hypotheses included pulmonary tuberculosis, AIDS, acute alcoholic liver disease, and mild pancytopenia secondary to immunodeficiency. Review of previous tests revealed a viral load above the upper limit and CD4 count of 19 cells/mm³, with negative TB molecular test and negative sputum culture for Mycobacterium tuberculosis. Treatment for tuberculosis (hepatopathy regimen) was initiated, with ART reintroduction scheduled for two weeks later. Despite these measures, the patient deteriorated – daily high fever, worsening pancytopenia (severe anemia refractory to transfusion), ferritin > 50,000, persistently elevated hepatic enzymes, and progressive skin lesions (erythematous and scaly papules and plaques on face, upper limbs, trunk, and back). A blood smear collected on 08/28/2024 revealed Histoplasma capsulatum within neutrophil and monocyte cytoplasm. Disseminated histoplasmosis was diagnosed, complicated by severe hematologic syndrome of unspecified etiology. Treatment with Amphotericin B was initiated for 14 days, leading to improvement in fever, asthenia, liver enzyme levels, and reduction in CRP and LDH. However, hematologic abnormalities persisted, along with prolonged PT/INR. Literature review confirmed that the clinical picture met criteria for secondary hemophagocytic lymphohistiocytosis. The HLH-94 protocol was implemented, resulting in hematologic recovery and normalization of all blood counts.

Although severe, this complication is treatable, and recognizing it can drastically change patient outcomes.