A Rare Case of Severe Vitamin B12 Deficiency Presenting as Pancytopenia and Neuropsychiatric Manifestations in a Young Adult: A Case Report

Abstract

Vitamin B12 deficiency commonly presents with megaloblastic anemia and neurological symptoms; however, severe pancytopenia with neuropsychiatric manifestations in young adults is relatively uncommon and may mimic hematological malignancies or bone marrow failure syndromes.

Case Presentation

A 28-year-old male presented with progressive generalized weakness, exertional breathlessness, tingling and numbness of both lower limbs, memory disturbances, and loss of appetite for three months. Clinical examination revealed pallor, mild icterus, impaired vibration sense, and gait instability. Laboratory investigations demonstrated severe pancytopenia with hemoglobin 5.8 g/dL, total leukocyte count 2,100/mm3, platelet count 72,000/mm3, and macrocytosis with mean corpuscular volume of 118 fL. Peripheral smear showed macro-ovalocytes and hypersegmented neutrophils. Serum vitamin B12 level was markedly reduced (78 pg/mL). Bone marrow examination revealed megaloblastic erythropoiesis. The patient was treated with parenteral vitamin B12 therapy, folic acid supplementation, and supportive care. Significant hematological and neurological improvement was observed within six weeks.

Conclusion

Vitamin B12 deficiency should be considered in the differential diagnosis of pancytopenia and neuropsychiatric manifestations, particularly in young adults. Early diagnosis and prompt treatment can result in complete clinical recovery and prevent irreversible neurological damage.