Parkinsonism

From Ganfyd

Definition

A clinical syndrome characterised by :

Parkinsonism is not the same as Parkinson's disease and has a distinctly different prognosis given its multiple causes

• Bradykinesia - slow movements and one or more of:
• Tremor - pill rolling rest tremor
• Rigidity - lead pipe or with tremor becomes cogwheel
• Postural Instability - poor balance on standing

(after Quinn, with some others depreciating Postural Instability as it has poor diagnostic specificity)

Aetiology

Neurotransmitter imbalance in the basal ganglia. Parkinsonism is not just related to a single neurotransmitter, dopamine or a single pathology of neuron drop out in the substantia nigra.

Frequency

There is a marked increase in Parkinsonism in human populations with age related to the increased neuropathological burden from multiple causes. In the very old, over 85, it may be found in more than 50% of the community population. Because common enviromental exposure with variable genetic susceptibility may be a factor in many conditions, parkinsonism can be found in spouses more commonly than others. Certain reasonably common environmental exposures are all but predictive. These included a designer drug mistake in California, exposure to neuroleptic drugs and repetitive head injury as in boxing.

"Primary" Parkinsonian disorders

• Idiopathic Parkinson's Disease
• Multiple system atrophy
• Dementia with Lewy Bodies
• Progressive Supranuclear Palsy

Other Conditions with Parkinsonism

• Genetic Disorders
  • Familial Parkinsons and Movement Disorder conditions - these are proving useful in understanding the polygenetic background to idiopathic Parkinson's Disease. A gene pathway of the relevant characterised genes exists
• Neurodegenerative (in many cases this is a final common pathway so one of the other conditions may be a factor as well as neurodegeneration in a presentation)
  • Alzheimer's disease
  • Cortico-basilar degeneration
• Toxin induced
  • All drugs with dopaminergic neuron blocking properties
    • Major tranquilisers (eg prochlorperazine, haloperidol, risperidone)
    • Metoclopramide
    • Selective Serotonin Reuptake Inhibitors
    • Lithium
    • Valproate
    • MPTP
  • Other drugs reported to induce Parkinsonism include
    • Amiodarone
    • Losartan
  • Carbon monoxide poisoning
  • Heavy metal toxicity
  • Many other organic neurotoxins
• Infective/Post infective
  • Encephalitis
  • CJD
• Sub-cortical ischaemia
  • Global ischaemia
  • Localised stroke disease affecting basal ganglia
• Trauma
  • Repetitive head injury
  • Single severe head injury

Non-Parkinsonian disorders to consider

• Tremor
  • Essential tremor
  • Dystonic tremor
  • Tremor secondary to a midbrain stroke
• Bradykinesia and/or rigidity
  • Upper motor neurone lesion
    • Sub-acute presentation of stroke
    • Space occupying lesion
  • Motor neurone disease
  • Myasthenia gravis
• Gait disturbance
  • Isolated gait disorder (usually cerebrovascular in origin)
  • Normal pressure hydrocephalus

Prognosis

This has been studied in community populations of the elderly. It appears that the risk of dying over the next 3 years odd in those over 75 years with parkinsonism is doubled within wide confidence intervals -OR=2.65 (1.18–5.94)^[1]. This may not the case where the Parkinsonism is due to Parkinson's disease as twenty year follow up of a large cohort meeting the definition for this condition in the same community showed that mortality for Parkinson's disease was actually less than age matched controls for the first 3 years of the disease^[2].

Treatment

The classic problem, is that with the exceptions of some of genetic causes and to a degree multiple systems atrophy, the common out of license (off label) use of drugs licensed to treat Parkinson's disease does not work that well. Indeed, if a patient fails to respond to levodopa containing preparations the prescriber is likely to induce net deterioration with any other agent. Always treat underlying conditions where possible.

References