Clinical outcomes and safety of botulinum toxin injections for X-linked dystonia parkinsonism: a five-year experience from a tertiary center in the Philippines

Botulinum toxin (BoNT) is established as a first-line treatment for focal and segmental dystonias, yet longitudinal real-world data on its efficacy and barriers to care in resource-limited settings like the Philippines remain scarce. The objective of this study was to describe the five-year clinical outcomes, safety profile, and socioeconomic barriers to treatment continuity among patients with X-linked Dystonia-Parkinsonism (XDP) receiving BoNT injections. We conducted a retrospective descriptive study of 159 genetically confirmed XDP patients (558 injection sessions) at a tertiary center from 2021 to 2025. Besides pedigree confirmation and adequate follow-up data extraction, at least two cycles of BoNT were mandated. Outcomes were evaluated using the Global Dystonia Rating Scale (GDRS), Patient Global Impression of Improvement (PGI-I), and treatment-related adverse events (TRAE). Muscle localization was mainly achieved using electromyography (EMG) and/or ultrasound (US) guidance. There were 558 unique injection sessions and each XDP patient came for 2–8 sessions. The anatomical areas injected were cervical (49%), oromandibular/lingual (32%), facial (18%), upper/lower limb (15%), and truncal (8%). The overall mean GDRS improvement was 65.5% at four weeks post-injection. The highest clinical responses by region were observed in facial (69.6%) and focal upper/lower limb (64.7%) dystonias, followed by oromandibular/lingual (55.6%), cervical (55.6%), and truncal involvement (48.9%). Overall, the mean PGI-I score was 2.4 ± 0.6 (“Much better”) in all combined regions injected. TRAEs occurred in 30% of patients and included dysphagia, localized muscle weakness, bruising, and pain. Financial constraints were the leading barrier to reinjection (53%), followed by distance or travel difficulties (33%) and pandemic-related disruptions (24%). BoNT therapy is an effective and safe intervention for XDP, across various dystonic regions, including drooling. While precision targeting through instrumentation optimizes outcomes, significant socioeconomic barriers persist, highlighting the need for sustainable funding models to maintain functional stability in this vulnerable population.