Multiple system atrophy
The term multiple system atrophy (MSA) denotes a sporadic progressive neurodegenerative disorder of adult onset and of unknown aetiology which is clinically characterized by autonomic failure, parkinsonism, cerebellar ataxia, and pyramidal signs in any combination. One recent epidemiological survey has found a prevalence rate of 4.4/100.000, and another an incidence rate of 3/100.000/year.
Two major motor presentations can be distinguished clinically. Parkinsonian features predominate in 80% of patients (MSA-P subtype), cerebellar ataxia is the major motor feature in 20% of patients (MSA-C subtype).
The disease affects both men and women, it usually starts in the 6th decade and relentlessly progresses with death occuring after on average 9 years.
Clinical features in 203 pathologically verified MSA cases
I. Autonomic symptoms | Frequency | CIs (95%) |
Urinary incontinence | 55% | (48-62) |
Postural faintness (incl. syncope) | 51% | (44-58) |
Impotence | 47% | (37-56) |
Recurrent syncope (>2) | 18% | (12-23) |
Urinary retention | 18% | (13-24) |
Faecal incontinence | 12% | (8-17) |
II. Parkinsonism |
|
|
Akinesia | 83% | (77-88) |
*Tremor | 67% | (60-73) |
present at rest | 39% | (32-46) |
pill-rolling | 8% | (5-12) |
jerky | 3% | (1-6) |
not specified | 25% | (18-32) |
Rigidity | 63% | (56-70) |
L-Dopa response |
|
|
best - poor | 72% | (62-83) |
-good | 28% | (17-38) |
Last -poor | 95% | (75-92) |
good | 5% | (1-12) |
Dyskinesias | 27% | (17-38) |
orofacial | 15% | (8-25) |
limbs | 10% | (4-19) |
Fluctuations | 24% | (15-35) |
III. Cerebellar signs |
|
|
Gait ataxia | 49% | (42-56) |
Limb ataxia | 47% | (40-54) |
*Intention tremor | 24% | (18-30) |
Nystagmus | 23% | (18-30) |
IV. Pyramidal signs |
|
|
Hyperreflexia | 46% | (39-53) |
Extensor plantar response | 41% | (34-48) |
Spasticity | 10% | (6-15) |
V. Other features |
|
|
Intellectual deterioration |
|
|
mild | 22% | (17-29) |
moderate | 2% | (1-5) |
severe | 0.5% | (0-3) |
Stridor | 13% | (9-18) |
Dystonia | 12% | (8-17) |
Anisocoria | 8% | (5-12) |
Contractures | 7% | (4-11) |
*Some patients had > 1 type of tremor.
Bradykinesia, rigidity, postural and rest tremor as well as dysequilibrium and gait unsteadiness characterize parkinsonism associated with MSA. Up to 90% of patients with MSA-P treated fail to show a sustained, long-term response to L-dopa. The cerebellar disorder comprises gait ataxia, limb kinetic ataxia and scanning dysarthria as well as cerebellar occulomotor disturbances. Autonomic failure in MSA manifests predominantly as symptomatic orthostatic hypotension, frequently associated with impaired or absent reflex tachycardia upon standing. Erectile dysturbances represent the most common and often the earliest feature of male MSA patients. In addition, patients may note increased constipation and hypo- or anhydrosis. Urological features are common and include urinary urgency, frequency, nocturia and urge incontinence. The clinical diagnosis of MSA rests largely on history and physical examination. Additional investigations are particularly helpful in excluding differential diagnoses, however, they may also support a presumptive clinical diagnosis