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ALL / Neurology

Multiple system atrophy

Multiple system atrophy

Multiple System Atrophy (MSA) is a progressive, sporadic, adult-onset neurodegenerative disorder characterised by varying combinations of autonomic failure, parkinsonism, and cerebellar ataxia. It results from widespread neuronal loss and the accumulation of α-synuclein–containing glial cytoplasmic inclusions within multiple regions of the central nervous system. Shy–Drager syndrome is a historical term referring to MSA with severe and early autonomic failure (now encompassed under the umbrella of MSA).

There are 2 predominant types of Multiple System Atrophy (MSA):
  • 1) MSA-P (Parkinsonian type) – characterised by predominant extrapyramidal features such as bradykinesia and rigidity. It clinically resembles idiopathic Parkinson’s disease but typically has a poorer response to levodopa and earlier development of autonomic dysfunction.
  • 2) MSA-C (Cerebellar type) – characterised by predominant cerebellar features such as ataxia, dysarthria, and gait disturbance. This variant is more common in East Asian populations.

Pathophysiology
  • Neurodegenerative disorder involving glial cytoplasmic inclusions (α-synuclein positive).
  • Affects multiple regions: striatonigral (causing parkinsonism), olivopontocerebellar (causing cerebellar ataxia), and autonomic nuclei in the brainstem and spinal cord.
  • Progressive neuronal loss and gliosis lead to combined extrapyramidal, cerebellar, and autonomic dysfunction.

Features
  • Parkinsonism – bradykinesia, rigidity, postural instability, minimal tremor, poor levodopa response.
  • Autonomic disturbance:
    • Erectile dysfunction – often an early and prominent feature.
    • Postural (orthostatic) hypotension – due to failure of baroreflex and sympathetic outflow.
    • Atonic bladder – urinary retention or incontinence from detrusor–sphincter dyssynergia.
    • Constipation and anhidrosis may occur.
  • Cerebellar signs – gait and limb ataxia, dysarthria, intention tremor, nystagmus.
  • Pyramidal signs – brisk reflexes, extensor plantar responses.
  • Sleep-related problems – REM sleep behaviour disorder, stridor from vocal cord palsy.

Investigations
  • MRI brain: may show pontine atrophy ('hot cross bun' sign), putaminal rim hyperintensity, or cerebellar atrophy.
  • Autonomic testing: orthostatic BP drop without compensatory tachycardia.
  • DAT-SPECT: presynaptic dopaminergic deficit similar to Parkinson’s disease.

Management
  • Symptomatic and supportive; no disease-modifying therapy.
  • Trial of levodopa (often limited benefit).
  • Fludrocortisone or midodrine for postural hypotension.
  • Intermittent catheterisation or bladder management for urinary dysfunction.
  • Prognosis: progressive disorder with median survival 6–10 years after onset.
+PassMedicine Notes

Multiple System Atrophy (MSA) is a progressive, sporadic, adult-onset neurodegenerative disorder characterised by varying combinations of autonomic failure, parkinsonism, and cerebellar ataxia. It results from widespread neuronal loss and the accumulation of α-synuclein–containing glial cytoplasmic inclusions within multiple regions of the central nervous system. Shy–Drager syndrome is a historical term referring to MSA with severe and early autonomic failure (now encompassed under the umbrella of MSA).

There are 2 predominant types of Multiple System Atrophy (MSA):
  • 1) MSA-P (Parkinsonian type) – characterised by predominant extrapyramidal features such as bradykinesia and rigidity. It clinically resembles idiopathic Parkinson’s disease but typically has a poorer response to levodopa and earlier development of autonomic dysfunction.
  • 2) MSA-C (Cerebellar type) – characterised by predominant cerebellar features such as ataxia, dysarthria, and gait disturbance. This variant is more common in East Asian populations.
Pathophysiology
  • Neurodegenerative disorder involving glial cytoplasmic inclusions (α-synuclein positive).
  • Affects multiple regions: striatonigral (causing parkinsonism), olivopontocerebellar (causing cerebellar ataxia), and autonomic nuclei in the brainstem and spinal cord.
  • Progressive neuronal loss and gliosis lead to combined extrapyramidal, cerebellar, and autonomic dysfunction.
Features
  • Parkinsonism – bradykinesia, rigidity, postural instability, minimal tremor, poor levodopa response.
  • Autonomic disturbance:
    • Erectile dysfunction – often an early and prominent feature.
    • Postural (orthostatic) hypotension – due to failure of baroreflex and sympathetic outflow.
    • Atonic bladder – urinary retention or incontinence from detrusor–sphincter dyssynergia.
    • Constipation and anhidrosis may occur.
  • Cerebellar signs – gait and limb ataxia, dysarthria, intention tremor, nystagmus.
  • Pyramidal signs – brisk reflexes, extensor plantar responses.
  • Sleep-related problems – REM sleep behaviour disorder, stridor from vocal cord palsy.
Investigations
  • MRI brain: may show pontine atrophy ('hot cross bun' sign), putaminal rim hyperintensity, or cerebellar atrophy.
  • Autonomic testing: orthostatic BP drop without compensatory tachycardia.
  • DAT-SPECT: presynaptic dopaminergic deficit similar to Parkinson’s disease.
Management
  • Symptomatic and supportive; no disease-modifying therapy.
  • Trial of levodopa (often limited benefit).
  • Fludrocortisone or midodrine for postural hypotension.
  • Intermittent catheterisation or bladder management for urinary dysfunction.
  • Prognosis: progressive disorder with median survival 6–10 years after onset.


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