Abstract
Vitamin B12 deficiency is a well-known and overall common disease. While the etiology of vitamin B12 deficiency varies from post-surgical changes to inadequate dietary consumption, pernicious anemia should be considered as it is a common cause. Pernicious anemia is an autoimmune atrophic gastritis impairing the absorption of vitamin B12. Manifestations include neurological changes, macrocytic anemia, glossitis, and nail changes. Hemolytic anemia is an unusual complication of vitamin B12 deficiency and an even more unusual initial presentation. This case identifies a patient with previously undiagnosed pernicious anemia with severe vitamin B12 deficiency compounded by hemolytic anemia as the presenting symptom. Overall, this case highlights the importance of considering vitamin B12 deficiency-related hemolytic anemia and the need for further research into the causes and pathophysiology of vitamin B12-induced hemolysis due to its potential for fatal outcomes despite being easily treatable with cost-effective methods to treat.