Multiple Systems Atrophy (Shy-Drager Syndrome)
Clinical Hallmarks
Multiple Systems Atrophy (MSA) involves the clinical triad of:
- Autonomic dysfunction
- Key features are orthostatic hypotension, urinary retention/incontinence, erectile dysfunction, anhidrosis, and other features.
- Note that there is no MSA-A, since prominent autonomic dysfunction is always required.
- Extrapyramidal disease
- Akinesia, rigidity, and postural instability most often without tremor; it resembles PD more-so than PSP.
- We use MSA-P (formerly striatonigral degeneration, SDN), if parkinsonian symptoms predominate.
- Cerebellar dysfunction
- Ataxia and possible cerebellar speech.
- We use MSA-C (formerly, olivopontocerbellar atrophy, OPCA), if cerebellar symptoms predominate.
- Inspiratory stridor is a common, important clinical manifestation in MSA.
Pathological Hallmarks
- "Hot cross buns sign" is a vommon radiographic finding in MSA.
- We show the pons in cross-section with a hot cross bun on top.
- The white strips represent degenerated pontine white matter pathways within the pons (for more on these tracts, see our tutorial on the cortico-ponto-cerebello-thalamo-cortical pathway).
- Oligodendrocytes comprise glial cytoplasmic inclusions (GCI)
- These are flame-shaped inclusions of alpha-synuclein.
- Lewy bodies in PD also comprise alpha-synuclein but in PD the accumulation occurs in neurons; here, the accumulation is most notably in glial cells (namely, oligodendroctyes).