Hemifacial Spasm

What is it?

Hemifacial spasm is a rare condition, affecting on average 4,000 people in the UK. A spasm is when a muscle, or group of muscles, contracts involuntarily, when they’re not supposed to. The word ‘hemifacial’ describes the area affected by the spasm – half of the face; most commonly the left side. Both men and women are equally affected and, while this condition is not dangerous, it can become disruptive and affect your quality of life.

What are the causes

This condition is not inheritable – so you won’t pass it on to your children if you have it. The exact cause is not fully understood, but most commonly arises from pressure on your fifth cranial nerve – the facial nerve. This pressure is most often a result of a blood vessel pushing on the nerve where it exits the brain – potentially as an aneurism or atrio-venous malformation – but can also be due to stroke, infection, or have no precise cause (in this latter case, we describe it as ‘idiopathic’). Hemifacial spasm may also develop as a side effect of a tumour or Bell’s Palsy – compression of the seventh cranial nerve.

What are the key clinical features

These usually appear in middle age and often start with twitching around one eye (specifically in the periorbital muscles), occasionally causing it to well up, or close completely. Over time, the spasm may spread to other areas of the face, including:

• Eyebrow
• Mouth – one corner may eventually be pulled up into permanent spasm
• Cheek
• Jaws
• Chin
• Upper neck

Spasms may occur during sleep as well as while awake and might be worse if tired or anxious. Additionally, there can be other effects alongside them, such as:

• Hearing changes
• Tinnitus – ringing in the ear
• Pain behind the ear

How is it diagnosed

At a GP appointment, you may be examined and, if a hemifacial spasm is suspected, referred to a neurologist – a doctor who specialises in conditions of the nervous system. They may want to perform a test, such as an MRI to examine your brain, and potentially an angiogram. This is where special contrast dye is injected into your blood vessels, so the scanner can detect if any blood vessels are pressing on your facial nerve.

How is it treated

Depending on the impact and extent of the hemifacial spasm severity, we can use several methods to treat hemifacial spasm.

Medications:

Anti-epileptic drugs in the form of tablets may be prescribed to help soothe the nerve impulses that are triggering the spasm. Responses to this method are variable and it can take time to find the dosage that is right for the patient. These medications will need to be taken long term to manage the spams

Injection:

Injections of Botulinum type A toxin, better known as Botox (the same injection as the cosmetic procedure), can be injected near the site of the twitching muscles in order to relax them and relieve the spasm. The effect of the injection usually lasts around 2-3 months, with positive effects showing within the first few days. The side effects are the same as cosmetic Botox – drooping eyelid and double vision – and wear off within the first week or two. Like medications, injections will have to be repeated long term to manage the symptoms

Surgery:

For more serious spasms that affect quality of life more severely – such as impacting the ability to drive – surgery may be considered. The procedure a neurosurgeon will perform is known as microvascular decompression; in cases where the cause is a blood vessel pressing on the nerve, the area where the facial nerve emerges from the brain is opened, in a procedure called a craniotomy and a sponge-like substance is placed between the nerve and the vessel to relieve the pressure. This procedure has an  80-97% success rate, but complications such as hearing damage and paralysis may occur (though are rare).

Prognosis

Hemifacial spasm is unlikely to improve without treatment and usually requires long term management; while it is not dangerous, symptoms can be disruptive to quality of life.

Summary

Hemifacial spasm can have a variety of causes, usually all related to compression of the facial nerve; there are several effective treatment options available to manage each individual case.

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References:

Chaudhry, N., Srivastava, A. & Joshi, L. 2015, “Hemifacial spasm: The past, present and future”, Journal of the neurological sciences, vol. 356, no. 1, pp. 27-31.

Kong, D. and Park, K., 2007. Hemifacial Spasm: A Neurosurgical Perspective. Journal of Korean Neurosurgical Society, 42(5), p.355.

****Revuelta-Gutierrez, R., Soriano-Baron, H., Vales-Hidalgo, O., Arvizu-Saldana, E. and Moreno-Jimenez, S., 2015. Hemifacial spasm: 20-year surgical experience, lesson learned. Surgical Neurology International, 6(1), p.83.

****Wang, A. and Jankovic, J., 1998. Hemifacial spasm: Clinical findings and treatment. Muscle & Nerve, 21(12), pp.1740-1747.

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