Reversal of apparent AIDS dementia complex following treatment with vitamin B12

The human immunodeficiency virus (HIV)-associated dementia complex is characterized by difficulties in concentration and memory followed by apathy, social withdrawal and motor dysfunction. Decreased serum vitamin B12 levels occur in up to 20% of patients with acquired immune deficiency syndrome (AIDS) and may adversely contribute to the haematologic and neurologic dysfunction which is frequently attributed to the human immunodeficiency virus. We describe a patient with AIDS who presented with an apparent advanced AIDS dementia complex. There was an associated low serum vitamin B12 resulting from malabsorption due to low gastric intrinsic factor secretion. Following treatment with vitamin B12 the symptoms resolved over a 2-month period. We believe that the AIDS dementia complex represented a reversible adverse synergistic interaction between the human immunodeficiency virus and vitamin B12 deficiency.