A hemifacial spasm occurs when muscles on one side of the face frequently involuntarily frequently spasm. Twitching of the eyelid muscle that leads to forced closure of the eye is generally the first symptom. Spasms will then continue to muscles lower in the face, often forcing the mouth to one side. The spasms will eventually become constant and involve all the muscles of the face.
Though hemifacial spasms may often have no apparent cause, they can be brought on by nerve damage in the face or a facial tumor. Botox treatments are the most frequent treatment, though surgery may be required to repair nerve damage and stop the spasms permanently.
