Hemifacial spasms are caused by neuromuscular irregularities. Involuntary muscle contractions that happen in the face result in hemifacial spasms. It can happen either in one side of the face or in both sides. The earliest symptom of this disorder is an intermittent tic of the eyelid muscle. Gradually, the eye muscles get severely affected and might even result in the complete closure of the eye. In extreme cases, the entire muscles of the affected side get damaged.
Hemifacial spasms are usually found in middle-aged and older people. Compared to men, hemifacial spasms are more common in women. Left-sided spasms are found to be slightly more common than right- sided spasms. It is estimated in the medical circles that eight out of every one-lakh men and fifteen out of one lakh women are affected with hemifacial spasms.
If a person who is less forty suffers from an instance of severe hemifacial spasm, it is generally considered as a pointer towards some serious neurological disorder. Hemifacial spasms can be an initial symptom of multiple sclerosis.
Apart from neurological irregularities, hemifacial spasms may also be caused as an after effect of some injury to the seventh cranial. A blood vessel or a tumour that exerts abnormal pressure on a facial nerve can also lead to this disorder.
Physicians suggest a complete neurological exam, if a patient approaches them with irregular eyelid movements. If hemifacial spasm is suspected, an electromyogram will be done. An electromyogram, that approximately takes two hours, effectively diagnose muscle problems caused by nerve irregularities. In this case, a small needle will be inserted into each muscle that needs to be examined.
If an artery that presses hard on the facial nerve causes the irregularity, magnetic resonance imaging (MRI), computed tomography (CAT scan), or angiographies will not be able to detect the cause. If a tumour or lesion is behind the trouble, these methods will give a clearer picture.