Although cobalamin (vitamin B12) deficiency was described over a century ago, it is still difficult to make the correct diagnosis and prescribe the right treatment. Symptoms associated with vitamin B12 deficiency can be varied, ranging from neurological to psychiatric. A number of individuals with vitamin B12 deficiency may present with classic megaloblastic anemia.
In clinical practice, many cases of vitamin B12 deficiency are overlooked or sometimes even misdiagnosed. In this review, we describe the heterogeneous spectrum of disease in patients with vitamin B12 deficiency in whom the diagnosis was based either on low serum B12 levels, elevated biomarkers such as methylmalonic acid and/or homocysteine, or improvement in clinical symptoms after the introduction of parenteral vitamin B12 therapy.
We discuss the possible clinical signs and symptoms of patients with B12 deficiency and the various pitfalls of diagnosis and treatment.
