An Atypical Presentation of Vitamin B12 Deficiency with Hemolytic Anemia

Vitamin B12 deficiency is a common nutritional deficiency in both developed and developing countries. This water-soluble vitamin is synthesized by bacteria and archaea and plays a major role in DNA synthesis and effective hematopoiesis. Most common etiologies of B12 deficiency include pernicious anemia and dietary deficiency. Hematological manifestations including anemia, leukopenia, thrombocytopenia, and macrocytosis can commonly be seen with vitamin B12 deficiency. Vitamin B12 deficiency is a rare cause of hemolytic anemia with approximately 1.5% of cases. Hemolysis with vitamin B12 deficiency remains a rare entity that has not been well described in the literature. Here we present a case of a 49-year-old male presenting with presyncope and fatigue who was found to have hemolytic anemia secondary to severe vitamin B12 deficiency with clinical improvement after vitamin supplementation therapy and provide a brief review of literature.