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Trigeminal neuralgia, or Tic Douloureux, is a neuropathic disorder of the trigeminal nerve that causes episodes of intense pain in the eyes, lips, nose, scalp, forehead, and jaw. Trigeminal neuralgia is considered by many to be among the most painful of conditions and has been labeled the "suicide disease," due to the significant numbers of people taking their own lives because they were unable to have their pain controlled with medications or surgery. An estimated one in 15,000 people suffers from trigeminal neuralgia, although numbers may be significantly higher due to frequent misdiagnosis. It usually develops after the age of 40 and affects women in a 2:1 ratio.
Pathophysiology
The trigeminal nerve is the fifth cranial nerve, a mixed cranial nerve responsible for sensory data such as tactition (pressure), thermoception (temperature), and nociception (pain) originating from the face above the jawline; it is also responsible for the motor function of the muscles of mastication, the muscles involved in chewing but not facial expression. Several theories exist to explain the possible causes of this pain syndrome. Among the structural causes, damage to the myelin sheath of this nerve causes the electrical impulses traveling along it to be erratic or excessive, activating pain regions or deactivating pain inhibitory regions in the brain. The damage may be caused by an aneurysm (an outpouching of a blood vessel) or abnormally coursing artery compressing the nerve, most frequently at the area of its cerebellopontine nerve root; the superior cerebellar artery has been an oft-cited culprit. 2 to 4% of patients with TN, usually younger, have evidence of multiple sclerosis, which may damage either the trigeminal nerve or other related parts of the brain. Trigeminal Neuralgia may also be caused by a tumor or a traumatic event such as a car accident. When there is no structural cause, the syndrome is called idiopathic. Postherpetic Neuralgia, which occurs after shingles, may cause similar symptoms if the trigeminal nerve is affected.
Symptoms
The episodes of pain occur paroxysmally, or suddenly, sometimes triggered by common activities or cold exposure, and are said to feel like stabbing electric shocks. Individual attacks affect one side of the face at a time, last several seconds, and may come and go throughout the day, or for periods as long as several months. Three to 5% of cases are bilateral, and attacks may increase in frequency or severity over time. Although trigeminal neuralgia is not fatal, successive recurrences may be incapacitating, and the fear of provoking an attack may make sufferers reluctant to engage in normal activities.
There is a variant of trigeminal neuralgia called, "atypical trigeminal neuralgia." In some cases of atypical trigeminal neuralgia, the sufferer experiences a severe, relentless underlying pain similar to a migraine in addition to the stabbing pains. In other cases, the pain is stabbing and intense, but may feel like burning or prickling, rather than a shock. Sometimes, the pain is a combination of shock-like sensations, migraine-like pain, and burning or prickling pain.
Treatment
There is no cure for trigeminal neuralgia, but it can be treated with anticonvulsants such as carbamazepine (Tegretol), phenytoin, or gabapentin (Neurontin). Low doeses of some antidepressants such as Nortriptyline can also be effective in treating neuropathic pain. Surgery may be recommended, either to relieve the pressure on the nerve or to damage it further to prevent the transmission of pain. Surgery is effective in greater than 75% of people with classic trigeminal neuralgia. The nerve can also be damaged to prevent pain signal transmission using a fine beam of radiation, so-called gamma knife. This is used especially for those people who are medically unfit for a long general anaesthetic, or who are taking medications for prevention of blood clotting (e.g., warfarin). Excellent success rates using a cost effective percutaneous surgical procedure known as balloon compression have been reported. This technique has been helpful in treating the elderly for whom surgery may not be an option due to coexisting health conditions. Balloon compression is also the best choice for patients who have ophthalmic nerve pain or have experienced recurrent pain after microvascular decompression (MVD).
Atypical trigeminal neuralgia is more difficult to treat, both with medications and surgery. Surgery may result in areas of numbness bothersome to the patient and lead occasionally to "anesthesia dolorosa," which is numbness with intense pain. It should, however, be noted that many people do find dramatic relief with minimal side effects from the various surgeries that are available.
Capsaicin can be helpful in short term temporary pain control of trigeminal neuralgia. It works by over stimulating the nerve endings at the site of current trip points on the face.
Sources
External links
- Trigeminal Neuralgia Association
- Facial neuralgia
- About surgery for trigeminal neuralgia
- My Trigeminal neuralgia - a personal story.
- Centre for Cranial Nerve Disorders.
"Trigeminal neuralgia"