What is Trigeminal Neuralgia?
Trigeminal neuralgia explained by Denver, Golden, Aurora, Boulder, Broomfield, Jefferson, and Littleton Colorado’s top pain doctors
Trigeminal neuralgia (TN) is a term referring to pain that is thought to originate from a major nerve of the brain, the trigeminal nerve, or its main subdivisions or branches. These important nerves mainly control sensation in the face. The etiology of trigeminal neuralgia is most likely to be associated with injury or damage to the nerves, though there are other valid theories on this in its field of research.
Some types of migraine headache, those that are episodic or very frequent, are associated with trigeminal neuralgia. Episodic migraine is often severe pain, usually perceived as located behind or just above the eye. These tend to occur on the same side of the face every time. Episodic migraines can arise as often as once per day, even at the same approximate time every day. 16% of U.S. adults reportedly suffer from this type of headache pain. Women ages 18-44 appear to be at higher risk of developing migraines than men. The symptoms of trigeminal neuralgia may be associated with nausea, vomiting, and light or sound sensitivity. Trigeminal neuralgia is widely regarded as the most severe type of pain a human can experience.
Causes of Trigeminal Neuralgia
Many researchers propose that damage to the trigeminal nerve, or its point of origin in the brain, the trigeminal nucleus, is the cause of trigeminal neuralgia. Facial injury can also trigger migraine headaches. Inflammation of the trigeminal nervous tissue is also associated with episodic migraine. This is associated with autoimmune conditions, such as scleroderma, multiple sclerosis, or lupus. Herpes zoster, a virus, causes damage to nervous tissue, and can result in chronic pain that persists even after the infection has cleared. An alternative theory of trigeminal neuralgia development concerns protective layers that are present around most major nerves. This is based on some evidence that the membranes around the trigeminal nerve or its branches degenerate over time, resulting in pain.
Treatment for Trigeminal Neuralgia
Drugs that treat inflammation, such as non-steroidal anti-inflammatory drugs (NSAIDs, e.g. aspirin), are commonly recommended as migraine treatment. However, they appear to be effective only for episodic migraine patients with headaches every ten days or less per month. Acetaminophen (paracetamol) in high doses is also effective in treating mild episodic migraine. The risks of NSAIDs include gastrointestinal problems and the possibility of organ failure with repeated high doses. As migraine sufferers are often advised to increase the dose of their medication in response to increased pain, this risk is particularly relevant. Acetaminophen can cause liver failure at high or frequent doses.
Patients with severe trigeminal neuralgia sometimes require opioid medications. These drugs activate receptors in the body to inhibit pain signals from affected nerves. Common examples of opioids include morphine, oxycodone, and codeine. Opioids are effective in severe cases of migraine, but carry risks, such as addiction, and side effects, such as respiratory depression and lethargy. Patients taking opioids for migraine may also suffer from withdrawal symptoms if they discontinue treatment. Carbamezapine, an anticonvulsant, is another effective treatment for episodic migraine treatment. They can have severe side effects, including toxic epidermal necrolysis, skin irritation, and allergic reactions. Patients of Asian origin tend to be more susceptible to these risks.
The trigeminal nerve branches extend into the face, from a ‘meeting point’, a ganglion of nervous tissue, located within the skull behind the eye. This is known as the Gasserian semilunar, or trigeminal ganglion. This can be the focus of minimally invasive surgical interventions developed to prevent migraine pain. These treatments are often the next line of options for severe, drug-resistant trigeminal neuralgia.
An example of these is radiofrequency ablation (RFA). This procedure involves probes that emit radiofrequency impulses that disrupt the pain signals sent to the brain by the ganglion. The RFA procedure is carried out under local anesthetic. The probe must be inserted through the mouth or nasal cavity to make contact with the ganglion. This is located with imaging techniques, such as fluoroscopy or MRI, that guide the probe to the correct area. It is possible to accurately pinpoint what parts of the nervous tissue are responsible for pain signaling and disrupt this. RFA is significantly effective in preventing episodes in approximately 97% of cases. There are risks, mostly associated with infections at the insertion site. There is a low incidence of inaccurate probe placement, in which case moderate facial paralysis can occur. In rare cases, the anesthesia administered as part of the procedure fails, resulting in severe pain during the procedure.
Trigeminal neuralgia is a disorder associated with the trigeminal nerve and its branches. It tends to take the form of episodic migraines, which are severe headaches occurring as often as once a day, every day. Migraines are usually felt behind or above one eye, possibly radiating outwards over time if untreated. Trigeminal neuralgia is thought to be the worst pain known to humanity. Initial treatments for trigeminal neuralgia include conventional medications. Minimally invasive surgeries, such as radiofrequency ablation (RFA), are available if no other treatment options are effective.
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