Unexplained Thrombocytopenia as a Sentinel Manifestation of Undiagnosed HIV Infection

Abstract Background Thrombocytopenia is a common hematological abnormality in people living with human immunodeficiency virus (HIV) and may occur at any stage of infection. In a subset of patients, isolated thrombocytopenia may represent a sentinel clinical manifestation of previously undiagnosed HIV infection, even in the absence of typical symptoms or an evident risk history. Objective To highlight unexplained isolated thrombocytopenia as a presenting clinical manifestation of HIV infection and to emphasize its diagnostic and clinical implications in routine practice. Methods We evaluated adult patients in whom isolated thrombocytopenia was the dominant clinical finding leading to the diagnosis of HIV infection. Isolated thrombocytopenia was defined as a platelet count < 100 × 10 9 /L in the presence of normal hemoglobin and leukocyte counts. Secondary causes were assessed through clinical history, physical examination, routine laboratory testing, and targeted serological investigations. Medication use, alcohol intake, liver disease, and viral hepatitis were specifically evaluated. Given the overall clinical context and subsequent confirmation of advanced HIV infection, HIV-associated immune thrombocytopenia (HIV-ITP) was considered the most likely underlying mechanism. Clinical presentation, laboratory and immunological findings, and response to antiretroviral therapy (ART) and adjunctive ITP-directed treatment were analyzed. Results Severe isolated thrombocytopenia was the initial laboratory abnormality prompting further diagnostic evaluation. Despite minimal bleeding manifestations, both patients exhibited advanced immunosuppression at the time of HIV diagnosis. Initiation of ART resulted in rapid virological suppression and gradual immunological recovery; however, normalization of platelet counts required additional corticosteroid therapy. Conclusion Unexplained isolated thrombocytopenia may serve as a sentinel manifestation of undiagnosed HIV infection. These findings support consideration of HIV testing in adults presenting with unexplained thrombocytopenia, regardless of reported risk factors, as early diagnosis enables timely initiation of antiretroviral therapy and appropriate hematological management.