Parkinsonism

Introduction

Parkinsonism is synonyms to ‘shaking palsy’; ‘paralysis agitans’; ‘akinetic-rigid syndrome’.
A common neuro degenerative disease that results from deficiency of the
neurotransmitter dopamine, in the striato nigral pathway. The idiopathic variety is called Parkinson’s disease while parkinsonism is used when an aetiologic agent is found

Causes:

Drugs

  • Antipsychotics e.g. phenothiazines
  • Antihypertensives: alpha methyl dopa, reserpine

Infections:

  • Encephalitis.
  • Typhoid fever

Vascular diseases:

  • Arteriosclerosis

Neurotoxins

  • Carbon monoxide
  • Manganese
  • Cyanide
  • Heroin analogues e.g. MPTP

Head trauma as in boxing Tumours
Metabolic diseases (Wilson’s disease)
Idiopathic:- Parkinson’s disease

Clinical features

Classical disease:

  • Rest tremors: coarse, distal tremors.
    described as pill-rolling type
  • Rigidity
  • Slowness of movement; loss of arm swinging when walking
  • Retropulsion, propulsion, turning en bloc
  • Postural instability with frequent falls
  • Gait changes: shuffling gait with flexed posturing

Parkinsonism in association with other neurodegenerative diseases

  • Dementia with Parkinsonism
  • Parkinsonism with Amyotrophic Lateral Sclerosis
  • Parkinsonism with Spinocerebellar degeneration
  • Parkinsonism with Dementia

Atypical Parkinsonism

  • Multi-system atrophy -Parkinsonism with postural hypotension – Shy Dragger Syndrome.
  • Progressive supranuclear palsy
  • Corticobasal Ganglionic Degeneration
  • With brain stem and cerebellar degeneration (Olivo-ponto-cerebellar syndrome)

Dementia

  • Diffuse Lewy Body Disease with
    fluctuating confusion and Phenothiazine sensitivity.

Differential diagnoses

  • Multi-infarct dementia
  • Alzheimer’s disease
  • Normal pressure hydrocephalus
  • Brain tumour
  • Benign essential tremor
  • Depression
  • Creutfeldt-Jakob disease

Complications

  • Recurrent falls with attendant complications e.g. fractures, subdural haematoma
  • Dementia
  • Depression

Investigations

  • Diagnosis is essentially clinical
  • Neuro-imaging: CT scan/MRI for exclusion of possible differentials

Management

Treatment objectives

  • Replace dopamine
  • Ensure mobility and avoidance of falls.

Non drug treatment

  • Physiotherapy for postural adjustment

Drug treatment

  • L-dopa/carbidopa (dose expressed as levodopa) 50 mg orally every 6-8 hours increased by 100 mg once or twice weekly depending on response
  • Anti-cholinergic drugs for tremors.
  • Trihexyphenidyl (benzhexol) 1 mg orally daily, increased gradually (usually 5-15 mg in 3- 4 divided doses up to a maximum of 20 mg)
  • Dopamine receptor agonists
    • Bromocriptine 1-1.25 mg orally nocte in the first week; 2-2.25 mg nocte in the 2 week-25 mg twice daily in the 3 week, 2.5 mg three times daily in the 4 week, increasing by 2.5 mg every 1-2 weeks according to response (usual range is 10 – 40 mg daily)
  • Ropinirole 1-3 mg orally once daily (in resistant cases)

Supportive measures

  • Physiotherapy for postural adjustments
  • Antidepressants
    • Amitryptiline for pain (which could be quite incapacitating) especially with dopamine-replacement drugs

Notable adverse drug reactions, caution and contraindications

Dopamine replacement drugs:

  • dyskinesia, pain
  • Advisable to start with small doses and gradually increase
  • There is need for dosage and timing
    adjustments when side effects manifest

Dopa-agonists:

  • postural hypotension; may cause vomiting
  • Caution is advised to avoid falls

Anticholinergic drugs:

  • constipation;
  • memory problems
  • Contraindicated in the presence of glaucoma

Prevention

  • Avoid identified causative agents where feasible
  • Timely and appropriate treatment to prevent/reduce complications