1st August 2023

Diagnosis

The general approach to diagnosis should incorporate a detailed history, including collateral history if available, using a valid structured cognitive assessment tool and undertaking investigations to exclude reversible causes of cognitive decline. This would include blood tests and structural imaging. The person should be referred to a specialist dementia diagnostic service.

The main causes of dementia are the subtypes of Alzheimer’s disease, vascular dementia, dementia with Lewy bodies and frontotemporal dementia. In addition to this, there are some rarer causes, such as Huntington’s disease and prion disease, and there are some reversible causes of dementia, for example, normal pressure hydrocephalus.

Differential diagnoses to consider include delirium, depression, mild cognitive impairment, vitamin deficiency, metabolic disorders such as hypothyroidism and Addison’s disease, infections, including HIV and syphilis, and adverse drug effects.