Synopsis
Recognise the Lewy-body cognitive, visual, sleep, motor and autonomic phenotype, use chronology to distinguish DLB from Parkinson disease dementia, prevent neuroleptic harm and balance cognitive, mobility, function and carer priorities.
- Core DLB features are recurrent well-formed visual hallucinations, marked cognitive fluctuation, spontaneous parkinsonism and REM-sleep behaviour disorder.
- Use the one-year convention: DLB when dementia precedes or occurs within one year of parkinsonism; Parkinson disease dementia when cognitive decline follows established Parkinson disease by more than one year.
- Early attention, executive and visuoperceptual deficits may dominate while memory storage appears less impaired than in typical Alzheimer disease.
Key red flags
Haloperidol and other potent dopamine blockers can cause severe or fatal sensitivity and should be avoided in DLB and Parkinson disease.
Severe rigidity, dysphagia, somnolence or autonomic decline follows dopamine blockade and is an emergency.
Investigation priorities
Apply phenotype and one-year convention.
Management branches
Lewy-body disease is suspected. within the current clinical context.
- Obtain collateral on core features and one-year chronology and exclude delirium, visual and medicine mimics.
- Complete cognitive, neurological, autonomic, blood and structural imaging assessment.
Mild-to-moderate DLB or Parkinson dementia is diagnosed.
Key medicines
RivastigmineStart 1.5 mg orally twice daily with food and increase in 1.5 mg twice-daily steps no more often than every two weeks toward the lowest effective tolerated dose.
MemantineBegin 5 mg orally once daily and increase by 5 mg each week toward 20 mg daily if tolerated, with a lower maximum in significant renal impairment.