Clinical and physiological characteristics of autonomic failure with Parkinson's disease.

We analyzed the clinical and physiological features of autonomic failure with Parkinson's disease (AF-PD) in seven patients and compared them with those of autonomic failure with multiple system atrophy (AF-MSA). In AF-PD, parkinsonism was more gradually progressive than in AF-MSA, and symptoms were responsive to L-dopa. All seven patients with AF-PD had orthostatic hypotension, postprandial hypotension, and constipation, but no urinary retention. Of these, three had hypohidrosis and five had frequent urination; five patients had subnormal plasma norepinephrine (NE) concentrations. Supersensitivity to NE infusion was observed in all patients. Head-up tilting (HUT) test resulted in no increase of plasma NE concentrations in both groups, but a significant increase of the plasma arginine vasopressin (AVP) concentrations in the patients with AF-PD. Urodynamic studies revealed that urinary bladder function was relatively well preserved in AF-PD in contrast to AF-MSA. In conclusion, there exists some clinical and physiological differences in autonomic features between AF-PD and AF-MSA, and postganglionic involvement predominates in AF-PD.