Evaluation of neurogenic bladder outlet obstruction mimicking sphincter bradykinesia in male patients with Parkinson’s disease

BACKGROUND: Lower urinary tract symptoms are one of the most common groups of non-movement symptoms in patients with Parkinson’s disease (PD). Storage symptoms are well-acknowledged, but neurogenic voiding dysfunction caused by PD remains a knowledge gap. This study aimed to evaluate the neurogenic bladder outlet obstruction in male patients with PD and its clinical significance. METHODS: Male patients who were diagnosed with PD and underwent urodynamic studies were retrospectively reviewed. The patients with prostate size < 30 ml and bladder outlet obstruction index ≥40 were included in the study. Lower urinary tract symptoms were evaluated by International Prostate Symptom Score (IPSS). Free flowmetry was performed and post void residual (PVR) volume was measured by ultrasound at follow-up. RESULTS: Six patients were included in the final analysis. The mean age was 68.2 and the mean movement symptom duration was 70.7 months. The patients had a mean IPSS of 12.5 and mean PVR volume of 70.8 ml. All patients had slow stream but none of them reported significant voiding difficulty. Urodynamic studies showed the delayed urinary sphincter relaxation and the special trace pattern. After a mean follow-up of 20 months, they had a mean IPSS of 12.5 and mean PVR volume of 73.3 ml. None of them complained of significant voiding difficulty at follow-up. CONCLUSION: The delayed urinary sphincter relaxation is a rare but repeatable phenomenon in male patients with PD. It is unlikely to cause disturbing voiding dysfunction, as reported by the patients, and does not progress prominently during the course of PD. Further studies are needed to investigate the nature of this special type of neurogenic BOO and whether it is peculiar to PD in a larger patient cohort. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1186/s12883-021-02153-4.