Relationship between nigrostriatal dopaminergic degeneration, urinary symptoms, and bladder control in Parkinson's disease

Patients with Parkinson's disease (PD) often have lower urinary tract symptoms (LUTS). Studies have indicated a correlation between dopaminergic degeneration and LUTS and presence of overactive bladder. We evaluated 18 patients with Parkinson's disease using single-photon emission computerized tomography (SPECT) imaging of the dopamine transporter with [ 1 2 3 I]-FP-CIT, and bladder symptoms were assessed using questionnaires and full urodynamic evaluation both in medicated state and after cessation. Bladder symptoms correlated with age, stage and severity of disease but not with uptake of the ligand in the striatum. Patients with bladder symptoms had a significant lower uptake in the striatum compared with patients without LUTS. In patients with severe bladder dysfunction, LUTS correlated with putamen/caudate ratio. The specific binding of the ligand did not correlate with urodynamics parameters or any change in these after wash-out. Our findings suggest that the presence of LUTS is associated with the degeneration of the total number of nigrostriatal dopaminergic neurones, whilst the severity of bladder dysfunction is correlated with the relative degeneration of the caudate nucleus. The effects of medication on bladder control, as evaluated by urodynamics are believed to involve structures outside the basal ganglia.