Hemifacial spasm: causes, treatment and what to expect

A spasm is a sudden, involuntary tightening of a muscle or group of muscles. Hemifacial means half of the face. Patient.info explains that all the muscles of the face are controlled by the facial nerve (the seventh cranial nerve), with one nerve for each side of the face. If something presses on the nerve along its course, the signals it carries can be disturbed and the muscles may twitch or go into spasm when you do not want them to.

St George's University Hospitals NHS Foundation Trust says hemifacial spasm affects one side of the face only and may start in the muscles around the eye before spreading to involve the whole half of the face. It may be associated with impaired balance (vertigo) and, less commonly, tinnitus.

Patient.info says twitching usually begins around the eye. At first the spasms may come and go, then gradually become worse and may become permanent. The left side is more often affected than the right. The twitching may spread to other muscles on the same side, and the mouth and jaw are often involved. As time goes on, the corner of the mouth can be pulled up by a permanent spasm.

Some people report distorted hearing, hearing loss, or a clicking sound on the affected side when the spasm comes. Patient.info says some people have a mild condition that causes inconvenience and embarrassment, while for others the spasms affect their vision and ability to drive. Spasms may become worse when you are tired and stressed, and may improve when you lie down.

Patient.info says the cause is not fully understood, but doctors believe the most common cause is a blood vessel pressing on the facial nerve at the base of the brain, the brainstem. St George's similarly says it is commonly caused by compression of the nerve that supplies the facial muscles as it exits the brainstem, like trigeminal neuralgia.

Rarely, other structural abnormalities such as injury to the facial nerve or a tumour can cause it, and there are other causes such as infections or strokes. Sometimes there is no obvious cause and doctors call it idiopathic hemifacial spasm. Patient.info says because the causes are not inherited, it is unlikely that you will pass the condition on to your children.

Patient.info says more temporary twitches of the face are not hemifacial spasm. Habit tics and twitches, and muscle spasms around the eyes (blepharospasm), are different conditions, and in these other conditions both sides of the face are usually affected.

Patient.info says that if you are worried about twitching on one side of the face you should see your GP, who will ask what has happened and how it affects you, and may examine you. If they think it might be hemifacial spasm they will refer you to a neurologist, and some neurologists specialise in movement disorders such as this. A scan of the brain is usually requested to look for a structure or abnormality pressing on the facial nerve, either an MRI scan or an angiography, a type of X-ray used to check the blood vessels.

St George's adds that at a neurosurgery clinic the diagnosis is confirmed, which may involve an MRI scan if you have not had one, and the risks and benefits of surgery are discussed.

Patient.info says that although there is no guaranteed cure currently, various treatments are available.

Patient.info explains that botulinum toxin, made by the bacterium Clostridium botulinum, is safe when given in controlled doses to relax excessive muscle contraction. It is injected into the facial muscles and blocks the signal from the nerve. The injection starts to work within a few days and its effect normally lasts for two to three months.

At least 7 to 8 people out of 10 with hemifacial spasm are helped, but repeated injections are needed every 3 to 4 months as the effect wears off. Patient.info lists drooping of the eyelid and double vision as possible side effects, which usually wear off after one or two weeks.

St George's University Hospitals NHS Foundation Trust says the most effective procedure for treating, and in many cases curing, hemifacial spasm is microvascular decompression surgery. Patient.info says it involves moving the blood vessel that may be pressing on the facial nerve, or placing a small piece of sponge between the vessel and the nerve. It is successful in 9 out of 10 people, but may be unsuitable for some.

Some serious side effects may rarely occur, such as hearing loss or permanent paralysis of the face, so Patient.info says surgery is usually reserved for severe and disabling spasms. It is also used when other treatments have failed, or if you are young and do not want long-term repeated injections.

Patient.info says hemifacial spasm is usually a long-term condition. It is not dangerous or fatal but may affect your quality of life, and it very rarely improves without treatment. Learning relaxation techniques may benefit some people, and educating yourself about the condition and staying positive can also help. Patient.info says complementary therapies such as homeopathy or acupuncture do not seem to help.

Because the spasms can affect vision and, for some people, the ability to drive, discuss this with your doctor if it applies to you.

On the NHS your GP refers you to a neurologist, who arranges a scan and starts treatment, usually botulinum toxin injections in a neurology or movement disorders clinic. If surgery is considered, you are referred to a neurosurgery centre. St George's University Hospitals NHS Foundation Trust says its neurosciences department accepts referrals from anywhere within England, and your GP can ask for this.

Some people consult a neurologist privately for a faster opinion or scan. Treatments such as botulinum toxin are the same in principle, and long-term follow-up is usually coordinated with your NHS team.