A syndrome characterized by tremor, rigidity, bradykinesia (slow movement) and postural disturbances, due to primary degeneration or damage to particular areas of the brain (basal ganglia).


Primary Parkinsonism:

  • Cause is unknown

Secondary Parkinsonism:

  • Infections e.g. sleeping sickness, syphilis
  • Poisoning e.g. manganese, carbon monoxide
  • Drugs e.g. chlorpromazine, haloperidol
  • Vascular disorders, intracranial tumour, trauma

Clinical features

  • Non intentional tremor
  • Muscle rigidity
  • Slowness of voluntary movement
  • Walking with short quick steps (shuffling gait)
  • Vacant facial expression (mask face)
  • Excessive salivation
  • Urinary incontinence (sometimes occurs)
  • Variable cognitive impairment

Differential diagnosis

  • Essential tremor (isolated intentional tremor, benign)
  • Thyrotoxicosis
  • Dementia, depression


  • Good history and clinical examination


  • Levodopa-carbidopa 100/25 mg
  • Start with 1 tablet every 8 hours (specialist only management)

Only for drug-induced parkinsonism

  • Benzhexol 2-15 mg daily in 1-3 divided doses
    • Initially: 1 mg/day; increase by 2 mg increments at intervals of 3 to 5 days
    • Usual dose: 6 to 10 mg/day in 3 to 4 divided doses; doses of 12 to 15 mg/day may be required
  • Benzhexol side effects: dry mouth, constipation, palpitations, urinary retenton, confusion and agitation
    (especially in the elderly)
  • Do not give benzhexol routinely to patients on antipsychotic medicines in the absence of parkinsonlike
    side effects
  • Use lower doses in elderly