Hemifacial spasm is a nervous system disorder in which the muscles on one side of your face twitch involuntarily. Hemifacial spasm is most often caused by a blood vessel touching or pulsating against a facial nerve. It may also be caused by a facial nerve injury or a tumor. Sometimes there is no known cause.
Common symptoms of hemifacial spasm include twitching or contracting of muscles in the face that are usually:
- On one side of the face
These contractions often start in the eyelid, then may progress and affect the cheek and mouth on the same side of the face. At first, hemifacial spasms come and go. But eventually, usually over the course of several months to a few years, they occur almost constantly.
Occasionally, hemifacial spasms may occur on both sides of the face. However, the twitching doesn't occur on both sides of the face at the same time.
Hemifacial spasm is most often caused by a blood vessel touching a facial nerve. It can also be caused by a facial nerve injury or a tumor. Sometimes there's no identifiable cause.
Hemifacial spasm may sometimes be triggered by:
- Moving the muscles in the face
To diagnose your condition, your doctor will conduct a physical examination and check for signs of hemifacial spasm. To determine the cause of your condition and develop the most appropriate treatment for your condition, imaging tests may be necessary.
Magnetic resonance imaging (MRI) uses a magnetic field and radio waves to create detailed images of your head and determine the cause of your hemifacial spasm. Your doctor may inject a contrast dye into a blood vessel (magnetic resonance angiogram) to look for any abnormal blood vessel that may be irritating the facial nerve.
You won't always need an MRI scan or other imaging test to diagnose hemifacial spasm. Your doctor may be able to diagnose the condition based on your symptoms and an exam. You may need an imaging test if your symptoms aren't typical or if you're preparing to have surgery.
Treatment for hemifacial spasm may include:
- Botulinum injections. Your doctor may inject botulinum toxin (Botox) into the affected muscles, which temporarily paralyzes those muscles. This treatment is very effective in relieving symptoms in most people. You'll need additional treatments every few months.
- Other medications. Medications, including anticonvulsant drugs, can relieve hemifacial spasm in some people.
Surgery. There are several types of surgery that can help relieve hemifacial spasm. Decompression surgery involves making an opening in your skull and opening the covering of your brain (dura) to expose the facial nerve as it leaves the brainstem.
Your surgeon locates the blood vessel pressing on or irritating the facial nerve and puts a spongelike material between the nerve and blood vessel, removing the pressure on the nerve. This surgery often can relieve hemifacial spasm.
Other procedures include destroying parts of the facial nerve via surgery and radiofrequency thermocoagulation, which uses heat and radio waves.