Twitching may occur only occasionally at first but may become almost constant.
Doctors diagnose hemifacial spasm based on symptoms but do magnetic resonance imaging to check for other disorders that can cause similar symptoms.
Hemifacial spasm is treated with botulinum toxin or another drug, but if drugs are ineffective, surgery may be necessary.
(See also Overview of the Cranial Nerves Overview of the Cranial Nerves Twelve pairs of nerves—the cranial nerves—lead directly from the brain to various parts of the head, neck, and trunk. Some of the cranial nerves are involved in the special senses (such as seeing... read more .)
Hemifacial spasm affects men and women but is more common among middle-aged and older women.
The spasms may be caused by
An abnormally positioned artery or loop of an artery that puts pressure on (compresses) the facial cranial nerve where it exits the brain stem
Symptoms of Hemifacial Spasm
Muscles on one side of the face twitch involuntarily, usually beginning with the eyelid, then spreading to the cheek and mouth. Twitching may be intermittent at first but may become almost continuous.
Hemifacial spasm is essentially painless but can be embarrassing and look like a seizure.
Diagnosis of Hemifacial Spasm
A doctor's evaluation
Magnetic resonance imaging
Hemifacial spasm is diagnosed when doctors see the spasms.
Magnetic resonance imaging (MRI) should be done to rule out tumors, other structural abnormalities, and multiple sclerosis, which can cause similar symptoms. Also, MRI can usually detect the abnormal loop of artery pressing against the nerve.
Treatment of Hemifacial Spasm
Botulinum toxin (used to paralyze muscles or to treat wrinkles) is the drug of choice for hemifacial spasm. It is injected into the affected muscles. The same drugs used to treat trigeminal neuralgia Trigeminal Neuralgia Trigeminal neuralgia is severe facial pain due to malfunction of the 5th cranial nerve (trigeminal nerve). This nerve carries sensory information from the face to the brain and controls the... read more —carbamazepine, gabapentin, phenytoin, baclofen, and tricyclic antidepressants Heterocyclic (including tricyclic) antidepressants Agomelatine, a new type of antidepressant, is a possible treatment for major depressive episodes. Several types of drugs can be used to treat depression: Selective serotonin reuptake inhibitors... read more —can also be used.
If drug treatment is unsuccessful, surgery (called vascular decompression) may be done to separate an abnormal artery, if present, from the nerve by placing a small sponge between them.
Taking the Pressure Off a Nerve
When pain results from an abnormally positioned artery pressing on a cranial nerve, the pain can be relieved by a surgical procedure called vascular decompression. This procedure may be done to treat trigeminal neuralgia, hemifacial spasms, or glossopharyngeal neuralgia.
If the trigeminal nerve is compressed, an area on the back of the head is shaved, and an incision is made. The surgeon cuts a small hole in the skull and lifts the edge of the brain to expose the nerve. Then the surgeon separates the artery from the nerve and places a small sponge between them.
A general anesthetic is required, but the risk of side effects from the procedure is small. Side effects include facial numbness, facial weakness, double vision, infection, bleeding, alterations in hearing and balance, and paralysis.
Usually, this procedure relieves the pain, but in about 15% of people, pain recurs.