A Rare Case of Warm Autoimmune Hemolytic Anemia With Intravascular Hemolysis: A Case Report.

This case report highlights a rare presentation of warm autoimmune hemolytic anemia (AIHA) with an atypical manifestation of intravascular hemolysis. The case underscores the diagnostic complexity and therapeutic challenges involved when AIHA presents with unusual features in the context of multiple underlying risk factors like infection, autoimmune markers, and occupational exposure. A 53-year-old male with a history of mining-related environmental exposure and a single previous episode of syncope presented to the emergency department with weakness, fatigue, and a syncopal event. Laboratory findings revealed severe anemia with hemoglobin of 4.4 g/dL, elevated lactate dehydrogenase, low serum haptoglobin, and positive direct antiglobulin test (DAT) for IgG, consistent with warm AIHA. Intravascular hemolysis was noted despite a negative DAT for complement C3 and normal complement levels. The patient was treated with high-dose corticosteroids and blood transfusions, resulting in stabilized hemoglobin levels and discharge in stable condition. Further outpatient follow-up was recommended to evaluate potential underlying autoimmune or neoplastic etiologies. This case highlights the importance of considering atypical mechanisms in warm AIHA presentations. Factors such as high antibody titers, IgG subclass variations, connective tissue disorders, infection, and potential neoplastic processes should be explored. This case contributes to the growing understanding of AIHA variants and underscores the need for individualized assessment in cases with complex presentations.