TRIGEMINAL NEURALGIA

'Trigeminal neuralgia', or ''Tic Douloureux'', ( also known as prosopalgia ) is a neuropathic disorder of the trigeminal nerve that causes episodes of intense pain in the eyes, lips, nose, scalp, forehead, and jaw.^[1] 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, although there have been cases with patients being as young as three years of age ^[2].

Contents

Pathophysiology

Symptoms

Treatment

Medications

Surgery

Other

References

External links

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. Two to four percent 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, an arachnoid cyst in the cerebellopontine angle^[3], or a traumatic event such as a car accident or even a tongue piercing.[1] 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. A number of patients develop TN after a root canal and may go repeatedly to dentists as the pain can radiate through the teeth. Extractions do not help for the pain is originating in the trigeminal nerve and not in an individual nerve of a tooth. Because of this difficulty, many patients may go untreated for long periods of time before a correct diagnosis is made.
To describe the pain sensation, patients describe a trigger area on the face, so sensitive that touching or even air currents can trigger an episode of pain. It affects lifestyle as it can be triggered by common activities in a patient's daily life, such as toothbrushing. Breezes, whether cold or warm, wintry weather or even light touching such as a kiss can set off an attack. The attacks are said to feel like stabbing electric shocks or shooting pain that becomes intractable. Individual attacks affect one side of the face at a time, last several seconds or longer, and repeats up to hundreds of times throughout the day, or may go on for periods as long as several months or years. 3-5% of cases are bilateral, and attacks may increase in frequency or severity over time. A great deal of patients develop the pain in one branch, then over years the pain will travel through the other nerve branches.
Signs of this can be seen in males who may deliberately miss an area of their face when shaving, in order to avoid triggering an episode. 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. This variant is sometimes called "trigeminal neuralgia, type 2"[2], based on a recent classification of facial pain^[4]. 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. It can also feel as if a boring piercing pain is unrelenting.

Treatment

There is no cure for trigeminal neuralgia, but several intervention strategies exist which can alleviate suffering in some cases. Atypical trigeminal neuralgia is more difficult to treat, both with medications and surgery. Surgery may result in areas of numbness to the patient and lead occasionally to ''"anesthesia dolorosa,"'' which is numbness with intense pain. Many people do find dramatic relief with minimal side effects from the various surgeries that are available.

Medications

★ Some treatments have involved anticonvulsants such as carbamazepine, topiramate, phenytoin, or gabapentin. Anticonvulsant effects may be potentiated with an adjuvant such as baclofen or clonazepam. Baclofen may also help some patients eat more normally if jaw movement tends to aggravate the symptoms.

★ Pain may be treated long-term with an opioid such as methadone in some patients, but due to the nature of the neuralgia, traditional analgesics typically have negligible effect.

★ Low doses of some antidepressants such as nortriptyline can also be effective in treating neuropathic pain.

★ Botox can be injected into the nerve by a physician, and has been found helpful using the "migraine" pattern adapted to the patient's special needs.
Many patients can not tolerate medications for years, and an alternate treatment is to take a drug such as gabapentin and place it in an externally applied cream base by a pharmacist who compounds drugs.

Surgery

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 more than 75% of people with classic trigeminal neuralgia.
The nerve can also be damaged to prevent pain signal transmission using a 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^[5]. 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.

Other

Alternative and complementary health care treatments such as chiropractic or acupuncture are sometimes used either in combination with drugs or alone to help manage pain. Capsaicin can be helpful in short term temporary pain control of trigeminal neuralgia. It works by overstimulating the nerve endings at the site of current trip points on the face .
Some patients have found relief with keeping the face covered.
In one case of trigeminal neuralgia associated with tongue-piercing, the condition resolved after the jewelry was removed.^[6]

References

1. Trigeminal neuralgia: an overview, Bayer DB, Stenger TG, , , Oral Surg. Oral Med. Oral Pathol., 1979
2. Emily Garland: A young girl's painful problem took more than a year to diagnose
3. Babu R, Murali R. "Arachnoid cyst of the cerebellopontine angle manifesting as contralateral trigeminal neuralgia: case report", ''Neurosurgery'' 1991 Jun;28(6):886-7. (PMID 2067614)
4. Burchiel KJ. "A new classification for facial pain", ''Neurosurgery'' 2003 Nov;53(5):1164-6; discussion 1166-7. (PMID 14580284)
5. Percutaneous trigeminal ganglion balloon compression: experience in 40 patients, , M, Natarajan, Neurology (Neurological Society of India), 2000
6. Atypical trigeminal neuralgia associated with tongue piercing, , R, Gazzeri, JAMA, 2006

External links

★ Trigeminal Neuralgia Association

★ About surgery for trigeminal neuralgia

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