Urodynamic study for distinguishing multiple system atrophy from Parkinson disease

To evaluate the differences in urodynamic findings between multiple system atrophy (MSA) and Parkinson disease (PD) and to identify the differential diagnostic ability of urodynamic study.

We reviewed patients with MSA or PD who underwent urodynamic studies between January 2011 and August 2018. Patients with probable MSA and PD determined by movement disorder specialists at our center were included. Patients with alleged MSA or PD from outside hospitals, atypical or secondary parkinsonism, and any history of pelvic operation or radiation therapy were excluded.

A total of 219 patients, 107 with MSA (male:female 50:57) and 112 with PD (male:female 57:55), were included. Patients with MSA had shorter disease duration and were referred for urologic evaluation earlier (p < 0.001). Detrusor overactivity and associated urine leakage were prominent in PD (p < 0.001). Patients with MSA showed lower maximal flow rate (4.0 ± 5.8 vs 9.1 ± 8.3 mL/s, p < 0.001) and larger postvoid residual (290.8 ± 196.7 vs 134.0 ± 188.1 mL, p < 0.001) with decreased compliance (44.9% vs 10.7%, p < 0.001) and impaired contractility (24.9 ± 33.8 vs 65.7 ± 51.1, p < 0.001). Postvoid residual from a pressure-flow study had the highest sensitivity and specificity (74.8% and 75.9%), followed by detrusor pressure at maximal uroflow (72.6% and 70.5%), bladder contractility index, and postvoid residual from uroflowmetry (71.0% and 70.5%, respectively).

Patients with MSA showed lower maximal flow rate, larger postvoid residual with decreased compliance, and impaired contractility, whereas patients with PD had higher incidence of detrusor overactivity and associated leakage. For differential diagnosis, postvoid residual from a pressure-flow study provided the best sensitivity and specificity.

This study provides Class III evidence that urodynamic measures can distinguish patients with MSA from those with PD.