Levodopa Induced Dystonia in Parkinson's Disease

Kim, Jong Kuk; Cha, Jae Kwan; Kim, Sang Ho; Kim, Jae Woo

Abstract

BACKGROUND: Various types of dystonia may be associated with Parkinson's disease (PD). This dystonic phenomenon is sometimes observed in untreated parkinsonian patients. However, it more commonly emerges as a side effect to long term levodopa (LD) therapy. We studied several factors which influence the risk of the occurrence of LD-induced dystonia (LID) in patients with PD. The types and involved sites in LID were also studied.
METHODS
Ninety-six patients diagnosed as PD were evaluated. We analyzed the contribution of several factors such as sex, age at onset of parkinsonian symptoms, disease durations, H & Y stages, average LD doses, LD durations, and types of initial symptoms (tremor vs non-tremor) to the occurrence of LID. The types of LID were divided into: wearing-off, morning-off, peak-dose, and diphasic groups.
RESULTS
LID was observed in 29 patients (30.2%). Among the 29 patients with LID, 11 were categorized as wearing-off dystonia, 10 as morning-off, 6 as peak-dose, and 2 as diphasic. LID occurred in the feet or toes of 23 patients, upper extremities of 3, and in the heads or necks of 3. Sixteen patients had dystonias on the same side of their initial symptoms, 4 on the opposite side, and 6 on both sides. Among the several factors, the types of initial symptoms, average LD doses, LD durations, age at onset of parkinsonian symptoms, and H & Y stages were found to significantly contribute to the occurrence of LID.
CONCLUSIONS
Dystonia often appeared as a side effect to anti-parkinsonian medications. Wearing-off dystonia was the most common type of LID. LID was commonly seen on the same side of initial symptoms. Initial parkinsonian symptoms were thought to be the most important contributing factor of LID.