A Rare Presentation of Mixed Warm and Cold Autoimmune Hemolytic Anemia

Mixed autoimmune hemolytic anemia (mAIHA) is a rare clinical condition where both warm and cold antibodies lead to autoimmune red cell destruction and progressive anemia. Herein, we report a rare case of combined warm and cold agglutinin-mediated autoimmune hemolytic anemia in a 61-year-old male who initially presented with incidental macrocytic anemia during a preoperative evaluation for pterygium surgery. Investigations showed the presence of both warm (IgG) and cold (IgM) autoantibodies, evidenced by a positive direct Coombs test (both anti-IgG and anti-C3), and elevated serum IgM levels. Type and cross-isolate revealed two distinct autoantibodies with different thermal amplitudes. Further workup did not reveal a definitive underlying etiology for the hemolysis. Mycoplasma pneumoniae and Epstein-Barr virus antibody panels were not suggestive of active infection. He was treated with corticosteroids and rituximab, resulting in an improvement in his hemoglobin levels, a reduction in splenomegaly, and ultimately remission of his autoimmune hemolytic anemia. This case emphasizes the need for a thorough workup to identify the cause of anemia, even in the context of seemingly unrelated surgical procedures.