Hemifacial spasm

Hemifacial spasm is a rare debilitating nerve-muscle disorder that effects the one side of the face. It is characterized by spontaneous twitching and spasms of some of the facial muscles that are supplied by the facial nerve. The incidence is 0,8 per 100 000 and it occurs more frequently in middle aged and older females. In rare cases it can be inherited based on a genetic disorder.

Hemifacial spasm

Yellow arrow showing compression of part of the facial nerve.

There are basically two types namely the typical more common form where contractions start in the muscles of the eyelid and later spread down to involve the muscles around the mouth and cheekbone. The other atypical form starts around the mouth and cheekbone and then spreads over time to the eye. In both forms all the muscles on the affected side of the face are eventually affected. Although extremely rare it is possible to get it on both sides of the face.

The main cause of primary hemifacial spasm is the compression and irritation of the facial nerve by a blood vessel near the brainstem. In less frequent cases, secondary HFS may be caused by trauma, tumours, cholesteatoma, Bell’s palsy and multiple sclerosis(MS). This is the reason that patients who present with HFS will usually be assessed with MRI to rule these out these conditions. Other tests that may be conducted include computerized tomography (CT) and electromyography (EMG). An EMG is a test where the electric activity in a muscle is recorded in response to a contraction.

The management of HFS may consist of the medical treatment such as anti-epileptic drugs, the administration of botulinum toxin or surgery. In the case of a tumour or a cholesteatoma surgical removal may likely be indicated. In the primary form of HFS (blood vessel compression) and where symptoms are severe and not responding well the other treatment, microsurgical decompression may be the only option. This is risky surgery but may be very effective. During this procedure the blood vessel is carefully separated from the nerve and kept away by a sponge. It is worthwhile getting an opinion on all the treatments that are available.