What is ‘hemifacial spasm’?
Hemifacial spasms are types of involuntary myoclonic contractions of a segment of the facial muscles that are usually supplied by the facial nerve. These movements can begin as twitching movements around the eye and can progress to other muscles of the face, usually on one side. The condition is commonly seen in the 5th and 6th decade of life and in most instances, identifying an underlying cause would not be possible.
What can cause this condition?
Hyper-excitability of the facial nerve is considered to be one of the contributors for such spasms and there are many ways in which such excitability can take place. In most instances, it is postulated that, a blood vessel can be chronically pressed against the nerve and would cause irritation that leads to the development of involuntary action potential. At the same time, tumors, irritations and injury can also lead to such spasmic movements. Apart from the compression effects, events such as strokes, meningitis of specific locations as well as plaques built up in multiple sclerosis can also lead to the development of hemifacial spasms.
What are the treatment options that are available?
When considering the treatment options, surgery and medications would be playing a vital part. But, use of medications is limited to early disease states as well as when a person declines to take stronger agents such as ‘botulism toxin’.
In surgery, the surgeons will want to remove any compression effects caused by blood vessels, tumors or any other tissue elements. In case there is no apparent nerve entrapment, surgeons would undertake posterior fossa exploration in order to find a possible cause. At the same time, myectomy can also be tried in unresponsive cases to alleviate the symptoms.
When considering medical treatment, use of toxins such as botulinum toxin A and B are well recognized. It will inhibit the contractions through binding to receptors of neuromuscular junctions and would exert there effect for many months. Apart from toxins, use of drugs such as benzodiazepines to relax muscular movements by acting on the spinal cord along with the use of other muscle relaxing agents are also been used with good effect. Anticonvulsive medications are also a valuable player in the medical management of hemifacial spasms and drugs such as carbamazapine has been used by clinicians in combination with other treatment modalities.
What is the prognosis of such treatment strategies?
When considering the outcome of these treatment strategies, it almost always responds favorably to most of the treatment. But, if no treatment is initiated, the condition can be progressive but would not have fatal outcomes as well.