Hemifacial spasm

Hemifacial spasm (HFS), similar to trigeminal neuralgia (CN V) and glossopharyngeal neuralgia (CN IX), is characterised by episodic discharges of the facial nerve (CN VII).

As in the two other aforementioned conditions, irritation of the nerve at the root exit zone by an aberrant vascular structure is usually a cause. Up to 100% of cases had a vessel contacting the nerve in symptomatic patients, whereas up to 30% of asymptomatic patients had a similar finding. This matches day to day experience, where an elongated and ectatic vertebrobasilar system is commonly seen incidentally. The vessels most commonly implicated are the AICA, PICA and vertebral artery (decreasing order of frequency).

Other causes of HFS have been reported including:

Often the condition begins insidiously with spasm of the orbicularis oculi gradually spreading in extent and severity to involve the majority of the face, although often sparing the frontalis muscle. It is not a painful condition (after all it is a motor nerve!).

Hemifacial spasm should be distinguished from myokymia a fine undulating fascicular tremor of facial musculature. The two conditions may co-exist.

Microvascular decompression is a useful treatment, with up to 80% complete and immediate resolution of symptoms.

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Article Information

rID: 1438
Synonyms or Alternate Spellings:

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