Hemifacial spasm refers to unilateral painless, synchronous contractions of facial muscles due to dysfunction of the 7th cranial (facial) nerve and/or its motor nucleus.
Hemifacial spasm usually results from nerve compression by a pulsating blood vessel, similar to that in trigeminal neuralgia.
Unilateral, involuntary, painless contractions of facial muscles usually begin in the eyelid, then spread to the cheek and mouth. Contractions may be intermittent at first but may become almost continuous.
The pulsating blood vessel is often visible on MRI, but diagnosis is ultimately clinical. Focal seizures, blepharospasm, and tics cause similar symptoms and should be considered.
Injection of botulinum toxin (botulinum toxin type A or botulinum toxin type B) is the most effective treatment. Treatments for trigeminal neuralgia (eg, anticonvulsants, baclofen, amitriptyline, surgery) can also be used.
Last full review/revision March 2014 by Michael Rubin, MDCM
Content last modified March 2014