DLB

Dementia with Lewy bodies (DLB) is a neurodegenerative dementia defined by the accumulation of Lewy bodies—alpha-synuclein–containing inclusions—in cortical and subcortical neurons. The distribution of pathology is variable, and DLB often coexists with Alzheimer's disease pathology or Parkinsonian changes. It is a common cause of degenerative dementia after Alzheimer’s disease.

Symptoms typically begin after age 60 and progress over several years. Core features include fluctuations in attention and alertness, recurrent visual hallucinations, and spontaneous parkinsonism such as bradykinesia, rigidity, and slowed movement. REM sleep behavior disorder and autonomic dysfunction are common, and patients are often sensitive to antipsychotic medications.

Diagnosis is clinical, using criteria that require two core features or one core feature plus a suggestive feature (for example REM sleep behavior disorder, reduced striatal dopamine uptake on SPECT imaging, or low cardiac uptake on MIBG scintigraphy). Imaging such as MRI or PET is supportive but not diagnostic.

Treatment is symptomatic and multidisciplinary. Cholinesterase inhibitors (donepezil, rivastigmine) may help cognition and neuropsychiatric symptoms; memantine is used selectively. Levodopa can improve parkinsonian symptoms but may worsen confusion or hallucinations. Antipsychotics are used with caution; quetiapine or clozapine are often preferred at low doses when psychosis is troublesome. Nonpharmacologic care, sleep management, and caregiver support are important. The illness is progressive and varies in duration, with greater impairment over time.