Trigeminal neuralgia

Trigeminal neuralgia (TN), also known as tic douloureux, is a type of chronic pain disorder that involves sudden, severe facial pain. It affects the trigeminal nerve, or fifth cranial nerve, which provides feeling and nerve signaling to many parts of the head and face. TN is a type of neuropathic pain, typically caused by a nerve injury or nerve lesion.

Symptoms

• Sudden, intense pain, typically on one side of the face
• Pain attacks that can last for a few seconds to about two minutes
• Numbness or a tingling sensation

• A burning, throbbing, shock-like, or aching sensation
• Attacks of pain that occur regularly for days to weeks or longer, sometimes several times a day

Trigeminal nerves

The trigeminal nerves are a pair of cranial nerves that connect your brain and brain stem to different parts of the brain, head, torso, and neck. Each of the 12 nerves splits to serve the two sides of your body and brain. Each nerve also has three branches that conduct sensations from the upper, middle, and lower portions of your face.

• The ophthalmic, or upper, branch supplies sensation to most of the scalp, forehead, and front of your head.
• The maxillary, or middle, branch stimulates your cheek, upper jaw, top lip, teeth and gums, and to the side of the nose.
• The mandibular, or lower, branch supplies nerves to your lower jaw, teeth and gums, and bottom lip.

More than one nerve branch can be affected by the disorder. In some rare cases, both sides of your face may be affected at different times, or even more rarely at the same time (bilateral TN).

There are two main types of TN:

Type 1—This is the typical or "classic" form of the disorder. It causes extreme, intermittent, sudden burning or shock-like facial pain. The pain lasts anywhere from a few seconds to two minutes per episode. These attacks can occur very close together, in stretches that can last up to two hours.

The intense flashes of pain can be triggered by vibration or contact with the cheek (such as when shaving, washing your face, or applying makeup), brushing teeth, eating, drinking, talking, or being exposed to the wind. The pain may affect a small area of your face or it may spread. Bouts of pain rarely occur when you are sleeping. Due to the intensity of the pain, some people may avoid daily activities or social contacts because they fear an impending attack.

Type 2—This is an “atypical” form of the disorder that is characterized by constant aching, burning, stabbing pain. This pain is usually less severe than in Type 1.

It's possible for you to have both forms of trigeminal neuralgia, sometimes at the same time. The intensity of pain can be physically and mentally devastating. TN attacks typically stop for a period of time and then return. In some cases, the condition can be progressive, meaning that the attacks can get worse over time, with fewer and shorter pain-free periods before they recur.

In progressive TN, the pain-free intervals eventually disappear and medication to control the pain becomes less effective.

Who is more likely to get trigeminal neuralgia?

TN occurs most often in people over age 50, although it can occur at any age, including infancy. The disorder is more common in women than in men.

TN can be caused by several other conditions:

• A blood vessel pressing on the trigeminal nerve as it exits the brain stem. This compression causes the wearing away or damage to the protective coating around the nerve (the myelin sheath)
  
• Multiple sclerosis, a disease that causes deterioration of the trigeminal nerve's myelin sheath
• Nerve compression from a tumor
  
• A tangle of arteries and veins called an arteriovenous malformation
  
• Injury to the trigeminal nerve (perhaps the result of sinus surgery, oral surgery, stroke, or facial trauma)

How is trigeminal neuralgia diagnosed and treated?

Diagnosing TN. TN diagnosis is based primarily on your medical history and description of symptoms, along with results from physical and neurological examinations.

Other disorders that cause facial pain should be ruled out before TN is diagnosed. Some other disorders that cause facial pain include:

• Post-herpetic neuralgia (nerve pain following an outbreak of shingles)
• Cluster headaches
• Temporomandibular joint disorder (TMJ, which causes pain and dysfunction in the jaw joint and muscles that control jaw movement).

You may be asked to have a magnetic resonance imaging (MRI) brain scan to rule out a tumor or multiple sclerosis as the cause of your pain. This scan may or may not clearly show a blood vessel compressing the nerve. Special MRI imaging procedures can reveal the presence and severity of compression of the nerve by a blood vessel.

If doctors suspect that you have TN1, they may ask you to try a short course of an antiseizure medication. If the medication helps, it helps to support a diagnosis of TN1.

Diagnosis of TN2 is more complex and difficult, but doctors may ask you to try low doses of a tricyclic antidepressant medication (such as amitriptyline and nortriptyline) to see if it will help. If so, the positive response to treatment supports a diagnosis of TN2.

Treating TN. People with TN require effective medical or surgical treatment for their pain. Treatment options include medicines, surgery, and complementary approaches.

Medications

There are several types of medication that can help treat TN:

• Anticonvulsant medicines. Anticonvulsants are used to block nerve firing. They are usually effective in treating TN1 but often less effective in TN2. These drugs include carbamazepine, oxcarbazepine, topiramate, gabapentin, pregabalin, clonazepam, phenytoin, lamotrigine, and valproic acid.
• Antidepressants. Tricyclic antidepressants such as amitriptyline or nortriptyline can be used to treat pain.

Common pain-relieving medications (such as aspirin and ibuprofen) and opioid medications such as hydrocodone are not usually helpful in treating the sharp, recurring pain caused by TN1. However, some individuals with TN2 do find opioids helpful.

Surgery

If medication fails to relieve pain or produces intolerable side effects such as cognitive disturbances, memory loss, excess fatigue, bone marrow suppression, or allergy, your doctor may recommend surgical treatment. Since TN can be a progressive disorder that becomes resistant to medication over time, people often seek surgical treatment.

Several neurosurgical procedures are available to treat TN. The choice of procedure depends on the nature of the pain; your preference, physical health, blood pressure, and previous surgeries; presence of multiple sclerosis, and the distribution of trigeminal nerve involvement (particularly when the upper/ophthalmic branch is involved).

You can expect some degree of facial numbness after many of these procedures, and TN will often return even if the procedure is initially successful. Depending on the procedure, other risks of TN surgery include hearing loss, balance problems, leaking of the cerebrospinal fluid (the fluid that bathes the brain and spinal cord), infection, anesthesia dolorosa (a type of nerve pain that causes both surface numbness and deep burning pain), and (in rare cases) stroke.

Some procedures are done on an outpatient basis, while others may involve a more complex operation that is performed under general anesthesia and requires a hospital stay.

Rhizotomy techniques

A rhizotomy (rhizolysis) is a procedure in which nerve fibers are damaged in order to block pain. A rhizotomy for TN always causes some degree of sensory loss and facial numbness. Several forms of rhizotomy are available to treat trigeminal neuralgia:

• Balloon compression uses a small balloon tip on a catheter to squeeze part of the trigeminal nerve against the hard edge of the brain covering (the dura) and the skull. This injures the insulation on nerves that are involved with the sensation of light touch on the face and can relieve trigeminal neuralgia pain. Pain relief from balloon compression usually lasts one to two years. Balloon compression is usually an outpatient procedure. It is performed in an operating room under general anesthesia.
  
• Glycerol injection uses a medicine to damage the insulation of trigeminal nerve fibers in order to relieve pain. Glycerol injection requires that the person be sedated with intravenous medication. It is usually an outpatient procedure. Pain relief from glycerol injection usually lasts for one to two years. The procedure can be repeated multiple times.
  
• Radiofrequency thermal lesioning (also known as "RF Ablation" or “RF Lesion”) uses an electrode to apply heat to injure the nerve fibers that cause trigeminal neuralgia pain. Under anesthesia, a needle is placed near the trigeminal and gradually heated with an electrode, injuring the nerve fibers. More than one procedure may be needed to reduce pain to an acceptable level, while preserving the sensation of touch. The pain relief may be permanent, but about half of the people treated this way have pain that comes back within three to four years The procedure is usually performed on an outpatient basis.
  
• Stereotactic radiosurgery (Gamma Knife, Cyber Knife) uses computer imaging to direct highly focused beams of radiation at the site where the trigeminal nerve exits the brain stem. It does not require an anesthetic or involve cutting into the cheek. It damages the nerve in a way that disrupts the transmission of pain signals to the brain. Relief from pain often takes several weeks (or sometimes several months) to develop following the procedure. About half of those who were successfully treated with this procedure have the pain come back within three years. People usually leave the hospital the same day or the next day after this treatment.

Microvascular decompression

Microvascular decompression (MVD) is the most invasive surgery for TN, but it offers the lowest probability that pain will return. It involves relieving pressure from surrounding blood vessels that either wrap the nerve or are touching it. A small opening is made through the skull and the surgeon places a soft cushion between the nerve and the blood vessel (usually an artery) that is compressing the nerve. Unlike rhizotomies, the goal is not to produce numbness in the face after this surgery. MVD is inpatient procedure, performed under general anesthesia. People generally stay in the hospital for several days following the procedure, and it usually takes them several weeks after the procedure to fully recover. Pain relief is permanent in about half of people who undergo MVD. Others have their pain come back within 12 to 15 years.

A neurectomy (also called partial nerve section), which involves cutting part of the nerve, may be performed near the entrance point of the nerve at the brain stem during MVD if the surgeon finds that no vessel is pressing on the trigeminal nerve. Neurectomies also may be performed by cutting superficial branches of the trigeminal nerve in the face. A neurectomy will cause more long-lasting numbness in the area of the face that is supplied by the nerve or nerve branch that is cut. However, the nerve may grow back and in time sensation may return. With neurectomy, there is a risk of causing anesthesia dolorosa.

Surgical treatment for TN2 is usually more problematic than for TN1, particularly when brain imaging prior to the surgery does not show vascular compression of the trigeminal nerve. Many neurosurgeons advise against the use of MVD or rhizotomy if TN2 symptoms predominate over TN1, unless vascular compression has been confirmed. MVD for TN2 is less successful than it is for TN1.

Complementary treatments

Some people manage trigeminal neuralgia using complementary treatments, usually in combination with drug treatment. These therapies have varying degrees of success. Complementary treatments for TN include:

• Low-impact exercise
• Yoga
• Creative visualization
• Aroma therapy
• Meditation
• Acupuncture

• Chiropractic treatment of the upper cervical area of the spine
• Biofeedback
• Vitamin therapy
• Nutritional therapy
• Injections of botulinum toxin to block activity of sensory nerves

What are the latest updates on trigeminal neuralgia?

The National Institute of Neurological Disorders and Stroke (NINDS), a part of the National Institutes of Health, supports a variety of research on TN. These studies are exploring the mechanisms involved with chronic pain and TN, as well as novel diagnostic methods and treatments. Other research addresses TN through studies associated with pain research. NIH research on TN is also funded by the National Institute of Dental and Craniofacial Research.

Women are at a greater risk of pain from TN and several other chronic pain disorders, but the reasons for this are unclear. Researchers are looking at how estrogen hormones may affect nerve pain activity, including the pain of TN. Understanding estrogen activity on pain nerves may increase the knowledge of why women are at greater risk for pain. This research also may lead to the development of medications that dampen the activity of estrogen on nerves that send pain signals to the brain and spinal cord.

More information about TN and facial pain research supported by NINDS and other NIH Institutes and Centers can be found using NIH RePORTER, a searchable database of current and past research projects supported by NIH and other federal agencies. RePORTER also includes links to publications and resources from these projects. Additional research projects on TN and facial pain can be found on the Facial Pain Research Foundation website.

How can I or my loved one help improve care for people with trigeminal neuralgia?

Consider participating in a clinical trial so clinicians and scientists can learn more about TN and facial pain. Clinical research uses human volunteers to help researchers learn more about a disorder and perhaps find better ways to safely detect, treat, or prevent disease.

All types of volunteers are needed—those who are healthy or may have an illness or disease—of all different ages, sexes, races, and ethnicities to ensure that study results apply to as many people as possible, and that treatments will be safe and effective for everyone who will use them.

For information about participating in clinical research visit NIH Clinical Research Trials and You at. Learn about clinical trials currently looking for people with TN at Clinicaltrials.gov.

Where can I find more information about trigeminal neuralgia?

Information may be available from the following organizations:

Facial Pain Association (formerly the Trigeminal Neuralgia Association)
Phone: 352-384-3600 or 800-923-3608

Facial Pain Research Foundation
Phone: 352-332-1653

Content source: https://www.ninds.nih.gov/health-information/disorders/trigeminal-neuralgia Accessed July 17, 2023.

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