Pancytopenia Secondary to Vitamin B12 Deficiency in Older Subjects

Vitamin B12 (cobalamin CBL) is a water-soluble vitamin required to form hematopoietic cells (red blood cells, white blood cells, and platelets). It is involved in the process of synthesizing DNA and myelin sheath. Deficiencies of vitamin B12 and/or folate can cause megaloblastic anemia (macrocytic anemia with other features due to impaired cell division). Pancytopenia is a less frequent exordium of severe vitamin B12 deficiency. Vitamin B12 deficiency can also cause neuropsychiatric findings. In addition to correcting the deficiency, an essential aspect of management is determining the underlying cause because the need for additional testing, the duration of therapy, and the route of administration may differ depending on the underlying cause.

Here, we present a series of four patients hospitalized for megaloblastic anemia (MA) in pancytopenia. All patients diagnosed with MA were studied for a clinic-hematological and etiological profile.

All the patients presented with pancytopenia and megaloblastic anemia. Vitamin B12 deficiency was documented in 100% of cases. There was no correlation between the severity of anemia and deficiency of the vitamin. Overt clinical neuropathy was present in none of the cases of MA, while subclinical neuropathy was seen in one case. The etiology of vitamin B12 deficiency was pernicious anemia in two cases and low food intake in the remaining cases.

This case study emphasizes the role of vitamin B12 deficiency as a leading cause of pancytopenia among adults.