Hemifacial Spasm

Hemifacial spasm is a disorder characterized by involuntary, intermittent contraction of muscles innervated by the facial nerve on one side of the face. Etiologies include vascular compression at the nerve root exit or idiopathic causes. Pathophysiology involves hyperexcitability of the facial nerve nucleus and ephaptic transmission. Diagnosis is clinical, supported by MRI to identify vascular loops. Management includes botulinum toxin injections, microvascular decompression, or antiepileptic drugs; prognosis is favorable with treatment.