Urological dysfunction in synucleinopathies: epidemiology, pathophysiology and management

Objective Parkinson's disease (PD) and multiple system atrophy (MSA) are major neurogenerative diseases characterized pathologically by abnormal alpha-synuclein aggregation. PD and MSA are clinically characterized by motor disorder and bladder dysfunction (mainly urinary urgency and frequency, also called overactive bladder). However, few literatures are available concerning bladder dysfunction in PD or MSA. Method A systematic review. Results The bladder dysfunction in MSA is more severe than that in PD for large post-void residual or urinary retention. These bladder dysfunctions presumably reflect the different nervous system pathologies. Overactive bladder in PD reflects lesions in the brain, e.g., in the prefrontal-nigrostriatal D1 dopaminergic bladder-inhibitory pathway. Overactive bladder in MSA reflects lesions similar to PD and the cerebellum (bladder-inhibitory), and the urinary retention in MSA presumably reflects lesions in the pontine micturition center and the sacral intermediolateral nucleus of the spinal cord (bladder-facilitatory). Bladder dysfunction not only impairs an individual's quality of life, it can also cause emergency hospitalizations due to acute retention and early institutionalization. Anticholinergics are the first-line treatment for bladder dysfunction in PD and MSA patients, but care should be taken for the management of bladder dysfunction-particularly in MSA patients due to the high prevalence of difficult emptying, which needs clean, intermittent catheterization. Conclusions This review summarizes the epidemiology, pathophysiology, and management of bladder dysfunction in individuals with PD or MSA.