Vitamin B12 Deficiency-Induced Massive Schistocytosis and Hemolytic Anemia Due to Pseudo-Thrombotic Microangiopathy: A Case Report

A 37-year-old male presented with complaints of fatigue, weight loss, and decreased appetite. Laboratory examinations revealed hemolytic anemia, an elevated lactate dehydrogenase (LDH) level, and marked schistocytosis. His other laboratory hematological findings included nucleated red blood cells with abnormal morphologies in the peripheral blood, as well as a small peak that was indicative of schistocytes on a red blood cell histogram. A bone marrow examination demonstrated megaloblastic changes; therefore, a preliminary diagnosis of vitamin B12 deficiency was made. Intramuscular vitamin B12 injections were started, and it was later reported that the patient's serum vitamin B12 level was below the reference range. Hence, the diagnosis of vitamin B12 deficiency was confirmed. Thereafter, the hemolysis and anemia improved within five weeks. It has been reported that megaloblastic anemia accompanied by schistocytosis demonstrates similar laboratory hematological findings to thrombotic microangiopathy (TMA) and is therefore called pseudo-TMA. In such cases, it is important to identify and rule out other concomitant abnormalities based on laboratory findings, to make a prompt and accurate diagnosis and choose an appropriate treatment strategy.