Vitamin B12 deficiency: an unusual presentation. Case report

Abstract

Vitamin B12 or cobalamin is a water-soluble vitamin absorbed in the terminal ileum after binding to intrinsic factor and has important physiologic roles in haematopoiesis, intermediary metabolism, growth, and early brain development. Vitamin B12 deficiency usually causes anaemia, macrocytosis, leukopenia, hyper-segmented neutrophils, and thrombocytopenia. Although most of the vitamin B12-deficient cases have only mild haematological findings, in approximately 10% of patients, life-threatening conditions, such as symptomatic pancytopenia, severe anaemia (haemoglobin level < 6 g/dL), and haemolytic anaemia, have been reported. Since the clinical findings of B12 deficiency are nonspecific, they are often overlooked, leading to a delay in the diagnosis. In this report we describe the case of a 16-year-old boy who presented with severe haemolytic anaemia and pancytopenia secondary to vitamin B12 deficiency, which resolved completely following appropriate replacement therapy.

Keywords

• Vitamin B12 deficiency. Haemolytic anaemia. Pancytopenia. Adolescent. Case report.