B12 deficiency

摘要

Vitamin B12 (cobalamin) deficiency is an important cause of macrocytic anaemia. It often presents insidiously, with some patients developing neurological and psychiatric sequalae. Pernicious anaemia is the most common cause of B12 deficiency in the Western world. However, with rising numbers of strict vegans, an ageing population and patients undergoing bariatric surgery, clinicians need to be aware of other causes and likely patient groups who may present with features of B12 deficiency.