Diffuse Lewy Body Disease

Diseases, , ,

Synonyms:

Dementia with Lewy bodies, a.k.a. Lewy body dementia a.k.a. Diffuse Lewy body disease DLBD, formerly Lewy body varient of Alzheimers:

Clinical features:

  • Dementia: deficits in attention, executive function, visuospatial ability and later on in memory. This is a subcortical dementia i.e. cortical features are spared early in the disease

Core features:

  • Dementia that develops before or within two years after the onset of motor symptoms of parkinsonism.
  • Visual hallucinations
  • Fluctuations in level of consciousness i.e. moments of clarity & moments of confusion

Other features:

  • REM sleep behaviour disorder
  • Severe neuroleptic sensitivity
  • Autonomic dysfunction

Histology:

Gross: pallor of the substantia nigra & locus ceruleus
Microscopically:

  • Affects: Classical types: brainstem, limbic, and diffuse cortical types,
  • Brain stem: Substantia nigra, Amygdala, raphe nuclei, pedunculopontine nuclei, dorsal vagal nucleus
  • Limbic (transitional) i.e. subcortical structures: anterior cingulate, entorhinal, basal forebrain/nucleus basalis of Meynert. Sometime amygdala
  • Diffuse cortical; neocortex (frontal, temporal, insular), sometimes hippocampus.
  • Lewy bodies (see under parkinson disease) in the cortex & brainstem. Levels of involvement brainstem predominant, limbic (transitional) & cortical.
  • Lewy neurites occur.
  • Vacuolar change in the parahippocampal gyrus. Coexisting Alzheimers pathology is frequent.

Immunohistochemistry: Lewy bodies and extracellular Lewy neurites are alpha synuclein positive and also ubiquitin positive.

Findings on Investigations:

SPECT:

  • DAT SPECT (123I-FP-CIT SPECT): images presynaptic dopamine transporters
  • Reduced uptake in putamen & caudate in DLB, normal in Alzheimer’s disease

Other tests:

  • MIBG cardiac scintigraphy: reduced uptake in the myocardium, a sign of postganglionic disease

PET, DAT scan dopamine transporter scan: reduced uptake in the striatum.
FDG PET: reduced uptake in the occipital lobes

Treatment:

General measures of dementia care
Treatment is dependent on presentation
Psychiatric symptoms:

  • Acetylcholine esterase inhibitors e.g. rivastigmine
  • Typical antipsychotics are contraindicated. Avoid anticholingergics including amantadine.

Motor symptoms:

  • Dopamine therapy

Related articles:

References:

  1. McKeith, I.G., et al., Diagnosis and management of dementia with Lewy bodies: third report of the DLB Consortium. Neurology, 2005. 65(12): p. 1863-72.
  2. McKeith, I., et al., Efficacy of rivastigmine in dementia with Lewy bodies: a randomised, double-blind, placebo-controlled international study. Lancet, 2000. 356(9247): p. 2031-6.
  3. McKeith, I., et al., Neuroleptic sensitivity in patients with senile dementia of Lewy body type. Bmj, 1992. 305(6855): p. 673-8.