Botulinum-A toxin in the treatment of painful post-stroke nocturnal paroxysmal dystonia triggered by periodic limb movements of sleep: case report.

INTRODUCTION Sleep disorders presenting involuntary movements may be very annoying to patients, apart from their negative influence on sleep. OBJECTIVE To report the use of botulinum type-A toxin (BoNT-A) to manage the case of a patient whose sleep was severely disrupted by episodes of dystonic posturing of the right lower limb triggered by periodic limb movements of sleep (PLMS). METHOD A 79-year-old woman with mild post-stroke right hemiparesis presented with recurrent painful episodes of dystonia of the right lower limb, which disrupted her sleep. The dystonic episodes could also be voluntarily triggered by extension of the right hallux. Polysomnography confirmed that the dystonic episodes were triggered by PLMS. Twenty units of BoNT-A (20U/500U vial) were injected into her right extensor hallucis longus. RESULTS Shortly after BoNT-A was injected, the dystonic symptoms abated, and the patient achieved better sleep efficiency. CONCLUSION The PLMS-related involuntary extension of the hallux was probably triggering the nocturnal post-stroke lower limb dystonic paroxysms. BoNT-A injection into the right extensor hallucis longus was effective in managing this condition and thus resolved the associated disruption of sleep.