Severe Pancytopenia Secondary to Combined Vitamin B12 and Folate Deficiency Mimicking Bone Marrow Failure: A Case Report

Vitamin B12 and folate are essential cofactors for DNA synthesis and red cell maturation. Severe combined deficiency is rare but can mimic bone marrow failure by causing profound pancytopenia and intramedullary haemolysis. This report describes the case of a 65-year-old woman who presented with profound pancytopenia and jaundice caused by severe combined vitamin B12 and folate deficiency. The identification of megaloblastic changes and prompt administration of vitamin replacement led to complete recovery. This case underscores the importance of considering nutritional deficiencies when diagnosing pancytopenia. The report highlights the continued prevalence of such deficiencies among older adults in the United Kingdom and the subsequent associated morbidity.