Beware of the Ailments of Vitamin B12 Deficiency

Vitamin B12 or cobalamin deficiency is a common problem in adult patients, which is however frequently missed. The most common cause of cobalamin deficiency is the food cobalamin malabsorption syndrome (> 60% of all cases). Neuropsychiatric manifestations can be the presenting and only early sign of cobalamin deficiency even in the absence of hematologic abnormalities. The deficiency can occur despite serum cobalamin levels at low normal values; thus, normal vitamin B12 levels have been revised upward to >350 pg/ml. Early detection and treatment are important to prevent structural and irreversible damage. The causes and ailments of vitamin B12 deficiency are herein overviewed and a diagnostic and therapeutic strategy is outlined.