Urinary dysfunction and orthostatic hypotension in multiple system atrophy: which is the more common and earlier manifestation?

Objectives-Urinary dysfunction and orthostatic hypotension are the prominen t autonomic features in multiple system atrophy (MSA). A detailed questionn aire was given and autonomic function tests were performed in 121 patients with MSA concerning both urinary and cardiovascular systems. Methods-Replies to the questionnaire on autonomic symptoms were obtained fr om 121 patients including three clinical variants; olivopontocerebellar atr ophy (OPCA) type in 48, striatonigral degeneration (SND) type in 17, and Sh y-Drager type in 56. Urodynamic studies comprised measurement of postmictur ition residuals, EMG cystometry, and bethanechol injection. Cardiovascular tests included head up tilt test, measurement of supine plasma noradrenalin e (norepinephrine, NA), measurement of R-R variability (CV R-R), and intrav enous infusions of NA and isoproterenol. Results-Urinary symptoms (96%) were found to be more common than orthostati c symptoms (43%) (p<0.01) in patients with MSA, particularly with OPCA (p<0 .01) and SND (p<0.01) types. In 53 patients with both urinary and orthostat ic symptoms, patients who had urinary symptoms first (48%) were more common than those who had orthostatic symptoms first (29%), and there were patien ts who developed both symptoms simultaneously (23%). Post-micturition resid uals were noted in 74% of the patients. EMG cystometry showed detrusor hype rreflexia in 56%, low compliance in 31%, atonic curve in 5%, detrusor-sphin cter dyssynergia in 45%, and neurogenic sphincter EMG in 74%. The cystometr ic curve tended to change from hyperreflexia to low compliance, then atonic curve in repeated tests. Bethanechol injection showed denervation supersen sitivity of the bladder in 19%. Cardiovascular tests showed orthostatic hyp otension below -30 mm Hg in 41%, low CV R-R below 1.5 in 57%, supine plasma NA below 100 pg/ml in 28%, and denervation supersensitivity of the vessels (alpha in 73%; beta 2 in 60%) and of the heart (beta 1 in 62%). Conclusion-It is Likely that urinary dysfunction is more common and often a n earlier manifestation than orthostatic hypotension in patients with MSA, although subclinical cardiovascular abnormalities appear in the early stage of the disease. The responsible sites seem to be central and peripheral fo r both dysfunctions.