Trigeminal neuralgia is a descriptive term applied to cases of brief, excruciating, electric-shock-like pains affecting one side or the other of the face. The term derives from combining neuralgia, meaning pain originating aberrantly in a nerve, with trigeminal, the name of the nerve responsible for carrying sensation from the face. It has also been referred to as tic douloureux, a misnomer applied to the facial wincing (mistakenly labeled tics) that often results from the episodic pains. The pains of trigeminal neuralgia typically last only seconds at a time. They are often described by patients as seeming electrical (such as “like a bolt of lightning”), and can be among the most excruciating the person has ever experienced in his or her lifetime. Pains typically occur only in the lower half of the face, in the distribution of the second and third divisions of the nerve. Most people with this condition experience periods of frequent pains, interspersed with other periods of relative quietude. Many people find that they have a “trigger zone,” an area of facial skin or oral mucous membrane in which light touch or other normal sensation can induce paroxysms of pain.
The disorder typically begins when someone is in their 50s or 60s, and affects women slightly more frequently than men. In the overwhelming majority of cases, trigeminal neuralgia arises for unknown reasons; it does not mean that there is an underlying neurological disorder. However, in a very small minority of sufferers, the condition is caused by a small tumor, vascular malformation, or area of inflammation. It is therefore very important that a physician evaluate any sufferer of pain potentially consistent with this disorder, and make note of any symptoms other than the pains. Symptoms that may be particularly important are facial numbness between pains, and current or past episodes of (a) numbness or tingling in the face or elsewhere in the body, (b) loss of vision, blurry vision, or double vision, (c) ringing or rushing noises in the ears, or hearing loss, (d) balance disturbances, (e) weakness or clumsiness of any part of the body, especially of the face or mouth, (f) difficulty speaking or swallowing, or (g) fainting or lightheadedness. Presence of any of these signs is worrisome for the presence of abnormal vein patterns (vascular malformation), tumor, or the inflammation of multiple sclerosis, and should prompt the clinician to proceed with contrasted magnetic resonance imaging (MRI) of the brain, which is far more sensitive than standard CT (computerized assisted tomography—CAT scan) for brainstem disease. Presentation of the disorder before the age of 50 should likewise prompt specialized imaging of the nervous system (neuroimaging). It is also important to be aware of any other symptoms that accompany the pain, such as tearing, excessive salivation, facial flushing, or altered sensation elsewhere besides the face; these signs may suggest that the underlying diagnosis (real problem) is cluster headache.
The first choice (preferred) treatment of trigeminal neuralgia is the antiseizure medication carbamazepine. Many people obtain complete relief from this agent. The drawbacks of carbamazepine are potential damage to the blood-producing apparatus of the bone marrow (bone marrow suppression), potential liver toxicity, and many possible interactions with other medications, particularly oral contraceptive pills. Any woman starting carbamazepine who is taking birth control pills should discuss the issue both with the physician starting the carbamazepine, and with her gynecologist. Carbamazepine may be associated with a higher rate of birth defects among infants of mothers who took car-bamazepine during pregnancy. This increase in risk is moderate and a woman of childbearing age taking car-bamazepine must take extra precautions to avoid pregnancy, and discuss the risks and potential alternative treatments with her physician if she wishes to become pregnant.
Other medications for trigeminal neuralgia have been tried, and reported to be beneficial to some individuals. In particular, a modified form of carbam-azepine, oxcarbazepine, has now been on the market for a few years, and appears to have fewer adverse effects. Other medications that have been tried and found effective in a few individuals include phenytoin, lamotrigine, gabapentin, baclofen, and clonazepam.
In many people for whom medications fail, there is an option of progressing to surgical treatment. In many cases, the abnormal sensory transmission underlying the pains is due to compression of the trigeminal nerve by an abnormal brain artery; surgery to relieve this compression, in those with this cause, can be 80% effective or better. This option must, however, be utilized only after a reasonable trial of medication, and only in individuals who are otherwise without medical illness. This is because the surgery involved, while generally safe in the hands of an experienced neurosur-geon, is nonetheless fairly risky. An alternative procedure does exist, for those in whom medications have been fruitless but are poor candidates for the more risky arterial surgery, but has risks of its own.
Trigeminal neuralgia rarely spontaneously resolves, and treatments are generally not completely curative. In this sense, trigeminal neuralgia is essentially a lifelong, incurable disorder. In most individuals, however, symptoms can be adequately controlled, by medicine or surgery, to permit carrying on in life with minimal disruption from pain.
- Goodman, J. M. (2002). Approach to the patient with facial pain. In J. Biller (Ed.), Practical neurology (2nd ed.). Philadelphia: Lippincott, Williams & Wilkins.
- Rozen, T. D., Capobianco, D. J., & Dalessio, D. J. (2001). Cranial neuralgias and atypical facial pain. In S. D. Silberstein, R. B. Lipton, & D. J. Dalessio (Eds.), Wolff’s headache and other head pain (7th ed.). New York: Oxford University Press.