Trigeminal Neuralgia

What is Trigeminal Neuralgia

Trigeminal neuralgia is a nerve disorder that causes attacks of severe facial pain.

The attacks last from a few seconds to several minutes.

They can happen for days, weeks, or months and then go away for months or years. Trigeminal neuralgia is also called tic douloureux.

Trigeminal neuralgia (TN) is a chronic condition characterized by nonpainful stimuli to the face, leading to intense pain. It is most common in women older than 50, although men and younger adults can also be affected. Patients report intermittent, shooting pain to the face that lasts seconds to minutes. The pain usually follows one distribution of the trigeminal nerve: V1, V2, or V3. These are the ophthalmic, maxillary, and mandibular dermatomes, respectively, carrying sensory information from the defined areas of coverage.

How is Trigeminal neuralgia classified

Trigeminal neuralgia can be classified into several subtypes. Type 1 is characterized by predominantly episodic pain, and type 2 is characterized by constant pain.

To be defined as trigeminal neuropathic pain, it must result from injury to the nerve due to trauma or surgery. Another classification is trigeminal deafferentation pain, which results from damage due to peripheral nerve ablation, gangliolysis, or rhizotomy attempted to treat facial pain. Postherpetic neuralgia can also occur in the trigeminal distribution. Lastly, atypical facial pain produces facial pain due to a somatoform pain disorder and requires psychological examination for an accurate diagnosis.

How common is trigeminal neuralgia? 

The estimated prevalence is 1 per 20,000 people suffer from this disorder.

What are the common causes?

This condition is caused by damage to a nerve in the face that is called the trigeminal nerve. An attack can be triggered by:

• Talking.
• Chewing.
• Putting on makeup.
• Washing your face.
• Shaving your face.
• Brushing your teeth.
• Touching your face.

The most common cause is a tortuous vessel compressing the trigeminal ganglia.

Other causes include aneurysm, tumor, and multiple sclerosis.

It may also be idiopathic.

In most cases, TN is caused by vascular compression of the nerve, most commonly the superior cerebellar artery (SCA), followed by the anteroinferior cerebellar artery and the basilar artery. Nerve compression may also be due to tumors, dural arteriovenous fistulas, and an ectactic basilar artery. Additionally, the pathophysiology of TN in multiple sclerosis (MS) is different. In MS it is common for demyelination to be present at the root entry zone of the trigeminal nerve in the pons, whereas compression may take place anywhere along the whole course of the nerve for TN in other pathologies.

What increases the risk?

This condition is more likely to develop in:

• Women.
• People who are 50 years of age or older.

What are the symptoms of Trigeminal Neuralgia?

The main symptom of this condition is pain in the jaw, lips, eyes, nose, scalp, forehead, and face. The pain may be intense, stabbing, electric, or shock-like.

Typical manifestation is a paroxysmal pain that is described as either lancinating, boring, hot poker-like, or intense electrical “zap” in the trigeminal neural distribution.

Which division of the trigeminal nerve is most commonly affected? 

The maxillary division (V2) is affected most, then mandibular (V3), followed by the ophthalmic division (V1) in about 5% of cases. Bilateral involvement occurs in 10% of individuals. Involvement of all three divisions rarely occurs.

How is this diagnosed?

This condition is diagnosed with a physical exam. A CT scan or MRI may be done to rule out other conditions that can cause facial pain.

Magnetic resonance imaging (MRI) and magnetic resonance angiogram of the brain are suggested in order to exclude tumors, aneurysms, arachnoid cysts, multiple sclerosis plaque, or anomalous vasculature.

A medical history and neurological examination in combination with magnetic resonance imaging is used to determine whether the patient has TN and if there is vascular compression of the nerve. The branch of the trigeminal nerve involved is determined by inspection based on dermatomes V1, V2, and V3 and presence of reflexes in these distributions.

How is Trigeminal Neuralgia treated?

This condition may be treated with:

• Avoiding the things that trigger your attacks.
• Pain medicine.
• Surgery. This may be done in severe cases if other medical treatment does not provide relief.

Anticonvulsant therapy is a mainstay.

The drug of first choice is carbamazepine or its congener, oxcarbazepine. Other alternatives include phenytoin, valproate, baclofen, and lamotrigine.

Lacosamide is a relatively new and promising addition to the armamentarium. If pharmacotherapy fails, then microvascular decompression (Janetta procedure) is the preferred step.

Balloon compression, rhizotomy, and gamma knife therapy are other options.

Treatment of TN begins with medication, most commonly carbamazepine or other anticonvulsants, including gabapentin. Patients prescribed carbamazepine must undergo weekly blood testing during the initial 2 months to monitor levels of carbamazepine therapy. Once an adequate dose has been reached, testing is less frequent but regular to ensure the drug is within acceptable levels in the blood.

These medications are generally effective in alleviating nerve pain with side effects, including fatigue, headaches, and nausea. Doses vary based on the drug of choice, with the dose for pain mediation commonly being less than the recommended for epileptic patients prescribed the same pharmacologic agent. There have also been multiple reports of the efficacy of antidepressants, muscle relaxants, and steroids in treating TN.

How effective are medications as treatments for trigeminal neuralgia?

Medications are not ubiquitously helpful, or may diminish in effectiveness after use for a certain period of time. In these cases, other treatment options may be considered in dealing with TN, such as physical therapy, holistic options, or invasive options. Physical therapies involving heat treatment, ultrasound, craniosacral manipulation, and massage have been beneficial to some patients. For others, acupuncture, yoga, and meditation have provided relief. Lastly, invasive options such as botulinum toxin type-A, percutaneous procedures, radiosurgery, and open surgery may be considered.

What is microvascular decompression and when is it an appropriate treatment?

In cases in which there is vascular compression, the gold standard of surgical treatment is microvascular decompression. Commonly alleviating pain in 70% to 80% of patients at 10 years after treatment, this procedure involves creating an incision behind the ear and displacing the artery in contact with the nerve. Although uncommon, risks of this procedure include potential facial numbness, partial hearing loss, double vision, and in severe cases, stroke.

What are additional procedures to treat trigeminal neuralgia?

Percutaneous procedures include balloon compression, radiofrequency ablation, and glycerol rhizotomy. Each of these methods uses a needle to reach the trigeminal nerve through the face and uses glycerol, an inflated balloon, or an electrical current to damage the nerve. These procedures are beneficial and often reduce pain for years. However, problems associated with this type of procedure include recurrent pain, with the patient sometimes experiencing facial numbness and facial muscle weakness. Radiosurgery is another treatment option offered to many patients, which uses a dose of radiation aimed at the root entry zone of the nerve.

Follow these instructions at home:

• Take over-the-counter and prescription medicines only as told by your health care provider.
• If you wish to get pregnant, talk with your health care provider before you start trying to get pregnant.
• Avoid the things that trigger your attacks. It may help to:
  • Chew on the unaffected side of your mouth.
  • Avoid touching your face.
  • Avoid blasts of hot or cold air.

Contact a health care provider if:

• Your pain medicine is not helping.
• You develop new, unexplained symptoms, such as:
  • Double vision.
  • Facial weakness.
  • Changes in hearing or balance.
• You become pregnant.

Get help right away if:

• Your pain is unbearable, and your pain medicine does not help.