Parkinson`s Disease

1817 Paralysis agitans

Aetiology

Exposure to toxic agents, eg insecticides, herbicides

Minute doses of MPTP

Subtle genetic factor

Head trauma

Encephalitis

Idiopathic

Cigarette smoking is probably protective

Clinical features

Progressive onset of features in late middle life

Progression over 10 - 15 years

1 in 200 people over 70 years

Rigidity, lead pipe and/or cog wheel

Tremor, 4-7 Hz.

Pill rolling

Bradykinesia

Speech becomes monotonous

Constipation common

Postural changes, eg stoop and shuffling gait

Balance is impaired

Mask like expression

Gastrointestinal symptoms

Urinary difficulties

Depression is common and dementia may occur

Diagnosis is on clinical grounds only

Pathophysiology

Loss of dopaminergic neurones of the substantia nigra

Imbalance between acetylecholine and dopamine

This correlates well with cell loss and degree of akinesia.

Treatment

Anticholinergics eg benzhexol

Dopamine agonists, eg. levodopa.

Clinical forms

Idiopathic

Drug induced

Post-encephalitic