Autonomic dysfunction in pathologically confirmed multiple system atrophy and idiopathic Parkinson's disease - a retrospective comparison

INTRODUCTION: Autonomic dysfunction (AD) can be a feature of both multiple system atrophy (MSA) and idiopathic Parkinson's disease (IPD), conditions that are frequently misdiagnosed in life. Most studies on AD in MSA and IPD are based on clinical cases without pathological verification. MATERIAL AND METHODS: We retrospectively analysed AD in 135 pathologically confirmed cases of IPD and in 33 of MSA from the UK PD Society Brain Bank. RESULTS: MSA started at a younger age than IPD (54.4 +/- 10.7 yrs versus 60.6 +/- 10.8 yrs), and AD began earlier in the course of the illness All MSA patients had some degree of AD in life whereas AD was absent in 24% of IPD patients. Although each of five autonomic domains was affected in variable numbers of IPD patients, AD in MSA generally involved more autonomic domains than in IPD, and to a more severe degree, in particular with regard to inspiratory stridor. CONCLUSIONS: These results indicate that the presence of autonomic disturbance alone does not distinguish between MSA and IPD in individual cases. However, the presence of severe AD, of AD preceding parkinsonism, or of inspiratory stridor, are all individually suggestive of MSA.