Early-onset drug-induced parkinsonism after exposure to offenders implies nigrostriatal dopaminergic dysfunction
Authors
Seok Jong Chung ; Han Soo Yoo ; Hyojeong Moon ; Jungsu S Oh ; Jae Seung Kim ; Yong Hee Park ; Jin Yong Hong ; Byoung Seok Ye ; Young H Sohn ; Phil Hyu Lee
Citation
JOURNAL OF NEUROLOGY NEUROSURGERY AND PSYCHIATRY, Vol.89(2) : 169-174, 2018
OBJECTIVES: The onset of parkinsonism in patients with drug-induced parkinsonism (DIP) exhibits extensive individual variability following exposure to offending drugs. We investigated whether the individual variations in the onset time of parkinsonism reflected the underlying subtle dopaminergic dysfunction in DIP. METHODS: We enrolled 71 patients with DIP who had visually normal striatal dopamine transporter (DAT) availability in (18)F-FP-CIT positron emission tomography scans. According to their exposure durations to the offending drugs prior to onset of the parkinsonism, the patients were divided into the early-onset group (duration 6 months; n=36). We performed the quantitative analysis of the DAT availability in each striatal subregion between the groups. RESULTS: No patients with DIP had DAT availability that was more than 2 SD below the normal mean of DAT availability. Compared with the delayed-onset group, the early-onset DIP group had decreased DAT availability in the striatal subregions including the posterior putamen (p=0.018), anterior putamen (p=0.011), caudate (p=0.035) and ventral striatum (p=0.027). After adjusting for age, sex and cross-cultural smell identification test scores, a multivariate analysis revealed that the DAT availability in the striatal subregions of the patients with DIP was significantly and positively associated with the natural logarithm of the duration of drug exposure. CONCLUSIONS: These results suggest that a short exposure to the offending drugs before the development of parkinsonism would be associated with subtle nigrostriatal dopaminergic dysfunction in patients with DIP.