Parkinson's disease
(Additional)

Background information

Epidemiology

Average onset = 55 years.

1% of people >60yo has the disease.

Male:female=3:2

Predisposition/Association

PD is less prevalent in smokers.

Genetic factor involved in early-onset (<40yo) PD.

Pathophysiology

Cause

Primary (idiopathic) Parkinsonism

• Parkinson's disease
• Juvenile Parkinsonism

 

Secondary (acquired, symptomatic) Parkinsonism

• Infectious:
  - postencephalitic, slow virus
• Drugs:
  - Neuroleptics (antipsychotic, antiemetic drugs)
  - Reserpine
  - Tetrabenazine
  - Alpha-methyldopa
  - Lithium
  - Flunarizine
  - Cinnarizine
• Toxin:
  - MPTP (1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine
  - CO
  - Mn
  - Hg
  - CS2
  - methanol, ethanol
• Vascular:
  - multi-infarct
  - hypotensive shock
• Trauma:
  - pugilistic encephalopathy
• Others:
  - Parathyroid abnormalities
  - Hypothyroidism
  - Hepatocerebral degeneration
  - Brain tumour
  - Normal-pressure hydrocephalus
  - Syringomesencephalia

 

Heredodegenerative Parkinsonism

• Autosomal dominant Lewy body disease
• Huntington's disease
• Wilson disease
• Hallervorden-Spatz disease
• Olivopontocerebellar and spinocerebellar atrophy
• Familial basal ganglia calcification
• Familial Parkinsonism with peripheral neuropathy
• Neuroacanthocytosis

 

Multiple-system degeneration (Parkinsonism PLUS)

• Progressive supranuclear palsy
• Multiple-system atrophy
  - Shy-Drager syndrome
  - Striatonigral degeneration
  - Olivopontocerebellar atrophy
• Parkinsonism-demntia-ALS complex (amyotrophic lateral sclerosis)
• Corticobasal ganglionic degeneration
• Alzheimer's disease
• Hemiatrophy-Parkinsonism

 

 

 

Mechanisms

Progressive cell degeneration and neuronal eosinophillic inclusion bodies (Lewy bodies) in pars compacta of the substantia nigra and other basal ganglia nuclei.

Loss of dopamine (and melanin) in the striatum, correlating with areas of cell loss and degree of akinesia.

 

 

 

 

 

 

Complication

 

 

Clinical information

Diagnostic criteria

Diagnosis is based on clinical pattern.

 

Classification/staging

2 Major subtypes of PD:

• Dominant feature: tremour
  - slower progression, earlier age of onset, more normal mental status
• Dominant feature: postural instability and gail difficulty
  - faster progression, more bradykinesia and dementia

 

Differential diagnosis

Non-Parkinson's disease disorders can be distinguished clinically from Parkinson's disease by the presence of atypical findings, absence or paucity of tremour, and poor response to levadopa.

 

 

 

Followup

Expected course/prognosis

PD worsens over some years (usually 10-15 years). Progression rate is very variable.

Remissions are unknown except for rare and remarkable short-lived periods (e.g. times of great emotion, such as in a fire)

Power and senses tend to remain normal.

Cognitive function is preserved early in the condition, but dementia often develops in the late stages.

Anxiety and depression are common.

Death usually result from bronchopneumonia

 

 

Prevention