Lesson of the week: a new cause of treatable dementia.

CASE REPORT: A 69-year-old married British man presented with 4 months of falls and confusion. HIV antibody test, performed after exclusion of other diagnoses, was positive. Institution of triple antiretroviral therapy resulted in an almost complete recovery.

DISCUSSION: HIV infection is now far more common than syphilis. It may be highly amenable to treatment and needs to be considered in the differential diagnosis of the older person with dementia.