Merck Manual

Please confirm that you are a health care professional

honeypot link

Hemifacial Spasm


Michael Rubin

, MDCM, New York Presbyterian Hospital-Cornell Medical Center

Last full review/revision Sep 2020| Content last modified Sep 2020
Click here for Patient Education

Hemifacial spasm refers to unilateral painless, synchronous contractions of facial muscles due to repetitive involuntary electrical impulses from the 7th cranial (facial) nerve and/or its motor nucleus.

Hemifacial spasm usually results from nerve compression by a pulsating blood vessel that causes ectopic impulse generation (ephaptic nerve impulses), 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 of hemifacial spasm is ultimately clinical. Focal seizures, blepharospasm, and tics cause similar symptoms and should be considered.

The most effective treatment for hemifacial spasm is

  • Injection of botulinum toxin (botulinum toxin type A or botulinum toxin type B) into affected muscles

Treatments for trigeminal neuralgia (eg, antiseizure drugs, baclofen, amitriptyline, microvascular decompression) can also be used.

Click here for Patient Education
NOTE: This is the Professional Version. CONSUMERS: Click here for the Consumer Version
Professionals also read

Test your knowledge

Thiamine Deficiency
Thiamin deficiency causes beriberi. It is most common among patients with alcoholism and people subsisting on white rice or highly refined carbohydrates. Early symptoms of all types of beriberi are nonspecific and include fatigue, poor memory, anorexia, and abdominal discomfort. As beriberi progresses, different forms of this condition cause different symptoms. Of these symptoms, which of the following is most indicative of dry beriberi?
Download the Manuals App iOS ANDROID
Download the Manuals App iOS ANDROID
Download the Manuals App iOS ANDROID

Also of Interest