Hemifacial spasm responsive to single low-dose abobotulinumtoxin A in a patient with relapsing-remitting multiple sclerosis: A case report

Hemifacial spasm (HFS) is a movement disorder characterized by involuntary twitching of the facial muscles of one side of the face. Here, we report the case of a 31-year-old woman with relapsingremitting multiple sclerosis who presented with left-sided HFS while receiving interferon beta. Despite immunosuppressive medications and clonazepam, only a partial response was documented. Near complete resolution of HFS was achieved 6 months after a single low dose of abobotulinumtoxin A was injected into the left periocular muscles; no recurrence was observed after 4 years. Botulinum toxin injection for focal dystonia, such as HFS, may lead to long-term symptomatic benefit in patients with multiple sclerosis who have already received optimum medical treatment.