Levodopa/carbidopa intestinal gel therapy for advanced Parkinson Disease: AN early toxic effect for small nerve fibers?

Introduction: Peripheral neuropathy related to levodopa/carbidopa intestinal gel (LCIG) therapy for advanced Parkinson disease (PD) is under investigation and is debated in the literature. The purpose of the study was to detect whether small nerve fibers are damaged during LCIG infusion. Methods: Five advanced PD patients were enrolled prior to starting LCIG infusion. Six PD patients on oral levodopa (LD) treatment and 6 PD patients naïve to LD were also enrolled. Clinical examination, the Quantitative Sensory Testing battery testing, nerve conduction studies, and intraepidermal nerve fiber density examinations were collected at baseline and at 3, 6, and 12 months after LCIG infusion was started in the study cohort. Results: After 3, 6, and 12 months, severe skin denervation and increased thermal thresholds were observed in the LCIG group. Conclusions: Significant damage to small nerve fibers was detected in PD patients soon after LCIG infusion had started, suggesting careful monitoring of small fiber impairment during LCIG is needed. Muscle Nerve, 2016 Muscle Nerve 54: 970–972, 2016.