ABSTRACT
Vitamin B12 deficiency may lead to demyelinization in the cerebrum, with, among other disturbances, dementia, or in the cord, leading to a syndrome known as subacute combined degeneration; a macrocytic anemia is also common; however, as stressed below, neuropsychiatric symptomatology may occur in patients with normal red blood cell counts and red blood cell indices. Although vitamin B12 deficiency is most commonly due to pernicious anemia, multiple other causes must also be considered.
