Can We Differentiate Between Organic and Functional Bladder Outlet Obstruction in Males With Parkinson's Disease?

To determine the type of bladder outlet obstruction (BOO) in patients with Parkinson's disease (PD).

A case-control study was carried out in 46 patients divided into two groups. Group 1 formed by 23 PD patients with BOO (a URA parameter ≥ 29 cm H₂O). Group 2 formed by 23 patients with benign prostatic hyperplasia (BPH) and compressive obstruction (an opening pressure > 35 cm H₂O) and URA parameter ≥ 29 cm H₂O). Both groups underwent a pressure-flow study to calculate Dynamic Urethral Resistance Relationship (DURR) patterns. Based on previous research, we describe two types of DURR pattern. Pattern A typical of dynamic or functional obstruction and pattern B typical of static or organic obstruction.

We found that PD patients had a significantly higher frequency of pattern A (70%) than BPH patients (4%). Other significant differences between groups were age (greater in PD group), bladder compliance (greater in PD group), maximum flow rate [Q_max (greater in BPH group)], maximum detrusor pressure [P_max (greater in BPH group)], detrusor pressure at maximum flow rate [PQ_max (greater in BPH group)], opening detrusor pressure (greater in BPH group), and the bladder contractility parameters BCI and W_max (greater in BPH group). There were no significant differences in perineal voiding electromyography (EMG) activity between groups nor relationship between voiding EMG activity and the type of DURR pattern.

Our results are consistent with the usefulness of the DURR pattern to differentiate between functional and organic BOO in PD patients. Most PD patients have functional obstruction although a minority has organic obstruction consistent with BPH.