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Trigeminal
neuralgia (tic douloureux) is severe facial pain due to malfunction
of the 5th cranial nerve (trigeminal nerve). This nerve carries sensory
information from the face to the brain and controls the muscles
involved in chewing.
Trigeminal neuralgia usually occurs in middle-aged and older people, although it can affect adults of all ages. It is more common among women.
In most cases, the cause is unknown. A common known cause is an abnormally positioned artery that compresses the trigeminal nerve near where it exits the brain. Occasionally in younger people, trigeminal neuralgia results from nerve damage due to multiple sclerosis. Rarely, trigeminal neuralgia results from damage due to herpes zoster (a viral infection) or compression by a tumor.
Symptoms
The pain can occur spontaneously but is often triggered by touching a particular spot (called a trigger point) on the face, lips, or tongue or by an action such as brushing the teeth or chewing. Repeated short, lightning-like bursts of excruciating stabbing pain can be felt in any part of the lower portion of the face but are most often felt in the cheek next to the nose or in the jaw.
Usually, only one side of the face is affected. The pain usually lasts seconds but may last up to 2 minutes. Recurring as often as 100 times a day, the pain can be incapacitating. Because the pain is intense, people tend to wince, and thus the disorder is sometimes called a tic. The disorder commonly resolves on its own, but bouts of the disorder often recur after a long pain-free interval.
Diagnosis
Although no specific test exists for identifying trigeminal neuralgia, its characteristic pain usually makes it easy for doctors to diagnose. However, doctors must distinguish trigeminal neuralgia from other possible causes of facial pain, such as disorders of the jaw, teeth, or sinuses and trigeminal neuropathy (which is often due to compression of the trigeminal nerve caused by a tumor, stroke, an aneurysm, or multiple sclerosis). Trigeminal neuropathy can be distinguished because it causes loss of sensation and often weakness in parts of the face and trigeminal neuralgia does not.
Treatment
Because the bouts of pain are brief and recurrent, typical analgesics are not usually helpful, but other drugs, especially certain anticonvulsants (which stabilize nerve membranes), may help. The anticonvulsant carbamazepine is usually tried first. Gabapentin or phenytoin , also anticonvulsants, may be prescribed if carbamazepine is ineffective or has intolerable side effects. Baclofen (a drug used to reduce muscle spasms) or a tricyclic antidepressant (such as amitriptyline —see Mood Disorders: Drugs Used to Treat Depression ) may be used instead. A local anesthetic may be injected into or around the nerve (a nerve block) to provide temporary pain relief.
If the pain continues to be severe, surgery may be done. If the cause is an abnormally positioned artery, a surgeon separates the artery from the nerve and places a small sponge between them. This procedure (called vascular decompression) usually relieves the pain for many years. If the cause is a tumor, the tumor can be surgically removed.
If people have pain unrelieved by drugs and surgery seems too risky, a test can be done to determine whether other procedures would help. For the test, alcohol is injected into the nerve to temporarily block its function. If alcohol relieves the pain, disrupting the nerve may relieve the pain, sometimes permanently. The nerve may be cut surgically or with a radiofrequency probe (using heat) or gamma knife (using radiation), or it may be destroyed by injecting a drug such as glycerol into it. However, these treatments are used as a last resort. They often provide only temporary relief—for months to a few years—and afterward, discomfort in the face returns and is even more severe.
Last full review/revision July 2007 by Michael Rubin, MD
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