Trigeminal neuralgia 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.
A common cause of trigeminal neuralgia is
Occasionally in younger people, trigeminal neuralgia results from nerve damage due to multiple sclerosis. Rarely, trigeminal neuralgia results from damage due to compression by a tumor, an abnormal connection between arteries and veins (arteriovenous malformation), or a bulge (aneurysm) in an artery supplying a nerve near the brain.
Pain due to 4th cranial nerve palsy 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.
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). Other trigeminal nerve disorders can be distinguished because they cause loss of sensation and often weakness in parts of the face, and trigeminal neuralgia does not.
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. Oxcarbazepine, 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 amitriptyline (an tricyclic antidepressant) may be used instead. If amitriptyline has intolerable side effects, another tricyclic antidepressant may be tried.
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, an anesthetic is injected into the nerve to temporarily block its function. If the injection relieves the pain, disrupting the nerve may relieve the pain, sometimes permanently. Disruptions may involve
However, treatment that relieves pain often results in facial numbness. Also, pain often recurs. As a result, people may require many procedures. Having many procedures may increase the risk of developing severe pain that is difficult to treat.
Taking the Pressure Off a Nerve
When pain results from an abnormally positioned artery pressing on a cranial nerve, the pain can be relieved by a surgical procedure called vascular decompression. This procedure may be done to treat trigeminal neuralgia, hemifacial spasms, or glossopharyngeal neuralgia.
If the trigeminal nerve is compressed, an area on the back of the head is shaved, and an incision is made. The surgeon cuts a small hole in the skull and lifts the edge of the brain to expose the nerve. Then the surgeon separates the artery from the nerve and places a small sponge between them.
A general anesthetic is required, but the risk of side effects from the procedure is small. Side effects include facial numbness, facial weakness, double vision, infection, bleeding, alterations in hearing and balance, and paralysis.
Usually, this procedure relieves the pain, but in about 15% of people, pain recurs.