Vitamin B12 Deficiency in Pernicious Anemia: A Hemolytic Anemia Mimic.

Vitamin B12 deficiency can lead to a wide range of clinical symptoms and may resemble hemolytic anemia due to ineffective red blood cell production and hemolysis occurring within the bone marrow. Identifying this deficiency as a possible cause of hemolysis is essential to prevent misdiagnosis, especially when distinguishing it from thrombotic microangiopathy. We present a case involving a 60-year-old woman with a history of hypertension and type 2 diabetes who came in with symptoms of generalized weakness, dizziness, nausea, and abdominal pain. Laboratory tests showed pancytopenia, macrocytosis, and signs of hemolysis. Further investigation confirmed a severe vitamin B12 deficiency linked to pernicious anemia. After starting weekly intramuscular cyanocobalamin injections for the first month and then switching to monthly injections for four months post-discharge, her blood parameters showed significant improvement. This underlines the vital role of timely diagnosis and following established treatment protocols. This case emphasizes the importance of considering vitamin B12 deficiency as a reversible cause of hemolysis. It highlights the need to differentiate it from more serious hematologic disorders such as thrombotic microangiopathy to ensure proper management.