To investigate the relationship between lower urinary tract function and 123I-ioflupane dopamine transporter scintigraphy in Parkinson’s disease(PD).

We had 30 patients with PD who underwent a systematized lower urinary tract symptom (LUTS) questionnaire and a urodynamics, which were performed irrespective of the presence of LUTS. The diagnosis of PD was made according to the published criteria. We evaluated all patients with PD using single-photon emission computerized tomography (SPECT) imaging of the dopamine transporter with 123I-ioflupane. The patients included 18 men and 12 women; mean age 70 (53-83) years; mean disease duration 1.3 (0.4-5) years. All patients had gait difficulty with the mean Hoehn Yahr stage 2.2. Cognitive function was assessed in all patients; and the mean Mini Mental Sate Examination (MMSE) score was 26.5 (less than 24 indicates cognitive decline). Urodynamics/ sphincter electromyography (EMG) was performed according to the International Continence Society methods. Before participating in the study, informed consent was obtained from all subjects and their families. This study was approved in local Ethics Committee.

A questionnaire revealed that all patients had LUTS; comprising night-time urinary frequency in 70%, urinary incontinence in 40%, daytime urinary frequency in 80% and urinary retention (post-void residual > 100 ml) in 2%. A urodynamic study revealed a mean volume at the first sensation 92.3 ml (29-231 ml; 100< normal <300 ml): bladder capacity 200.9 ml (41-351 ml, 200< normal <600 ml); and detrusor overactivity in 50%. Sphincter electromyography (EMG) revealed neurogenic change in 13% on whom the test was performed. By 123I-ioflupane scintigraphy, the average specific binding ratio (SBR) had significant correlation with bladder capacity and Watts factor (Spearman’s correlation coefficients p<0.05. Figure 1,2).

In the present study, EMG-cystometry revealed DO in 50% of the patients studied. The result in the present report was less than those in the previous report (Stocchi et al 1997,Palleschi et al 2006 and Uchiyama et al 2006). The reason why our incidence of DO was not common, presumably reflects the short disease duration of our patients with PD. 123I-ioflupane scintigraphy SBR average had significant correlation with bladder capacity. Abnormal 123I-ioflupane scintigraphy is thought to reflect loss of nigral dopaminergic cells. In addition, it is known that prefrontal-nigrostriatal D1 dopaminergic pathway might regulate bladder function. Therefore, our study result strongly suggests that loss of brain dopaminergic cells directly relates with lower urinary tract dysfunction in PD.

PD has common lower urinary tract dysfunction as indicated by urinary incontinence and detrusor overactivity. our study result suggests that loss of brain dopaminergic cells directly relates with lower urinary tract dysfunction in PD.

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