Pernicious Anemia Presenting With Severe Hemolytic Anemia

Pernicious anemia is an autoimmune disease characterized by vitamin B12 deficiency due to antibodies that target intrinsic factor and/or parietal cells in the stomach. Hemolytic anemia is rarely seen in vitamin B12 deficiency. This case report highlights a patient with a history of autoimmune thyroid disease who presented with severe hemolytic anemia and vitamin B12 deficiency from pernicious anemia. This report discusses the association of hemolytic anemia with vitamin B12 deficiency, the association of pernicious anemia with other autoimmune diseases, and the treatment of pernicious anemia.