Vitamin B12 deficiency as a cause of hemolytic anemia

Vitamin B 12 deficiency can manifest with various hematological abnormalities including hemolysis. In rare instances, it can become severe enough to mimic thrombotic thrombocytopenic purpura. This report discusses a 58-year-old male who had recently returned from a trip to the Philippines and was admitted with severe anemia, with a hemoglobin level of 2.7, signs of hemolysis with blood film showing schistocytes, and thrombocytopenia. He experienced nonspecific symptoms for approximately 4 months before presenting at the hospital with worsening fatigue, shortness of breath, and a new fever. Comprehensive investigations were done aimed to rule out infectious causes, primary hematologic disorders, autoimmune conditions, and malignancies yielded negative results. The patient’s initial blood smear showed changes consistent with Vitamin B 12 deficiency; however, no baseline Vitamin B 12 level was obtained before treatment. Blood markers improved following Vitamin B 12 replacement therapy. The first Vitamin B 12 level recorded at our hospital was elevated, likely due to a recent parenteral replacement, but a repeat test revealed a low Vitamin B 12 level. This highlights the importance of considering Vitamin B 12 deficiency as a potential cause of megaloblastic anemia, even when Vitamin B 12 levels appear normal. The patient was discharged in stable condition with a plan for continued Vitamin B 12 injections and follow-up to investigate the underlying cause of the deficiency.