Lewy body dementia
The relationship between Parkinson's disease and Lewy body dementia is complicated, particularly as dementia is often seen in Parkinson's disease. Also, up to 40% of patients with Alzheimer's have Lewy bodies.
- progressive cognitive impairment
- visual hallucinations (other features such as delusions and non-visual hallucinations may also be seen)
- usually clinical
- single-photon emission computed tomography (SPECT) is increasingly used. It is currently commercially known as a DaTscan. Dopaminergic iodine-123-radiolabelled 2-carbomethoxy-3-(4-iodophenyl)-N-(3-fluoropropyl) nortropane (123-I FP-CIT) is used as the radioisotope. The sensitivity of SPECT in diagnosing Lewy body dementia is around 90% with a specificity of 100%
- both acetylcholinesterase inhibitors (e.g. donepezil, rivastigmine) and memantine can be used as they are in Alzheimer's. NICE have made detailed recommendations about what drugs to use at what stages. Please see the link for more details
- neuroleptics should be avoided in Lewy body dementia as patients are extremely sensitive and may develop irreversible parkinsonism.