Warm Autoimmune Hemolytic Anemia in an Elderly Patient With a History of Chronic Idiopathic Thrombocytopenic Purpura: A Case Report.

Warm autoimmune hemolytic anemia (AIHA) is a rare immune-mediated disorder characterized by IgG-mediated hemolysis and laboratory evidence of anemia, reticulocytosis, elevated lactate dehydrogenase (LDH), indirect hyperbilirubinemia, decreased haptoglobin, and a positive direct antiglobulin test (DAT). In elderly patients, diminished bone marrow reserve may limit compensatory erythropoiesis, resulting in more severe presentations. We report the case of an 82-year-old man with a history of chronic idiopathic thrombocytopenic purpura (ITP) who presented with profound anemia without overt bleeding. Laboratory findings were consistent with warm AIHA. He required multiple packed red blood cell (pRBC) transfusions and initiation of high-dose corticosteroids, with subsequent hematologic improvement. His course was complicated by new-onset atrial flutter, managed with rate control, as anticoagulation was deferred due to severe anemia and bleeding risk. Prior evaluation, including bone marrow biopsy, excluded malignancy. This case highlights the diagnostic and therapeutic challenges of warm AIHA in elderly patients with prior autoimmune cytopenias. The sequential occurrence of ITP and AIHA raises concern for Evans syndrome and reflects underlying immune dysregulation. This case was further complicated by new-onset atrial flutter, creating a management dilemma regarding anticoagulation in the setting of severe anemia and bleeding risk. Management requires careful coordination to balance hemolysis, comorbidities, and competing thrombotic and hemorrhagic risks.