The commonest facial pain

Summarized by Robert W. Griffith, MD
August 24, 1999 (Reviewed: January 21, 2005)

Trigeminal neuralgia, although uncommon in itself, is the commonest cause of facial pain. The name results from "trigeminal" = the nerve involved, and "neuralgia" = pain in a nerve. It occurs in people age 50 to 70 as an acute knife-like pain in one side of the face -- usually the right side. The episode may last a few seconds or even several minutes, and sufferers find that attacks are triggered by a touch, exposure to the wind, eating, or tooth cleaning. Sometimes the muscles of the face twitch, so that the condition has been called by its French name: tic doloureux. A recent article has reviewed the diagnosis and current treatment options.¹

The cause of trigeminal neuralgia is unknown. Careful examination by a physician should exclude known possible causes for similar episodes of pain -- a dental problem, middle ear infection, sinusitis, herpes, or glaucoma. Similar episodic pain that occurs without an obvious trigger is seen in patients who suffer from cluster headaches.

Sometimes the condition will disappear for months or even years at a time. Usually, however, the attacks become more frequent, so that treatment is necessary.

A drug called carbamazepine is usually so effective that if it doesn't work the physician may question whether he has made the right diagnosis. The drug should be started at a low dose (100 mg twice daily) and then increased gradually. After the pain has been controlled for 6 to 6 weeks, the drug can be gradually reduced in dose, or even finally stopped altogether. Carbamazepine is not without its drawbacks. It sometimes interferes with other drugs that are broken down in the liver. This means that the concentration of the drug in the blood may have to be measured from time to time, and the dose adjusted accordingly. Also, carbamazepine can cause disturbances of blood cell formation and liver function, so that blood tests must be done at intervals during treatment, especially if the drug is taken for a long period.

If carbamazepine fails to control the painful episodes, there are two other drugs that can be tried, often with success. Phenytoin is a drug usually used in epilepsy, but it is often effective in trigeminal neuralgia. As well as an oral form, it can be given intravenously if there is an acute crisis. Baclofen is another drug that is effective in patients who have become unresponsive to carbamazepine. Both these drugs can cause drowsiness and other mild side effects, and phenytoin can produce the same problems with blood cell formation and liver function that carbamazepine does. Baclofen occasionally causes hallucinations and raised blood sugar levels.

Other drugs have been tried with varying degrees of success in treating this condition. However, if there is obvious failure of medical treatment, surgical intervention should be considered. In its simplest form, this consists of blocking the affected nerve (or its branches) with injections of alcohol, glycerol or intense localized heat production. More drastic intervention involves a surgical approach to the root of the nerve that involves opening the brain cavity, and this obviously carries additional operative and postoperative risks.

While the search for new drugs to treat trigeminal neuralgia is not a high priority for drug companies, experience has shown that drugs developed for other conditions may be useful in this condition. We can expect that new drugs will be found that will reduce the need for surgery, except in the most resistant cases.

Source

• Trigeminal neuralgia. New treatment options for a well-known cause of facial pain. JE. Delzell , AR.  Grelle , Arch Fam Med , 1999, vol. 8, pp. 264--268

Related Links
The Trigeminal Neuralgia Association

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