A case of pernicious anemia requiring differential diagnosis of autoimmune hemolytic anemia complication.

An 80-year-old female was admitted to our hospital due to malaise. The initial diagnosis on admission was pernicious anemia (PA), Hashimoto thyroiditis and autoimmune atrophic gastritis. Autoimmune hemolytic anemia was suspected because direct antiglobulin test (DAT) was positive. Treatment with vitamin B12 improved anemia, with the disappearance of hemolysis. In some cases, PA patients with positive DAT may have hemolysis without the involvement of the autoimmune mechanism. Therefore, it is important to carefully assess PA patients with hemolysis and positive DAT for the prevention of unnecessary administration of steroid therapy.