Trigeminal Neuralgia: Types, Causes, Treatments

Trigeminal neuralgia (TN) is a condition that can cause intense facial pain sometimes so severe it can interfere with the normal activities of daily living. Brief, painful episodes may be triggered by chewing, talking, smiling, brushing teeth, shaving, or light pressure on the face. The pain may be sudden, intense, and sporadic (off and on). It also may be more constant but less severe.

Usually, TN affects only one side of the face. In this case, it is said to be unilateral. If both sides of the face are affected, the condition is bilateral. The right side of the face tends to be affected slightly more often than the left side.

What is the trigeminal nerve?

The trigeminal nerve is responsible for transmitting sensations of touch and pain from the face and head to the brain. The trigeminal nerve has three branches. One branch carries nerve impulses from the forehead, upper eyelids, and eyes to the brain. The second branch is responsible for sensation in the lower eyelids, cheeks, nostrils, upper lip, and upper gum. The third branch serves the lower lip, lower gum, jaws, and some muscles used for chewing.

What are the types of trigeminal neuralgia (TN)?

There are two main forms of TN:

Typical (Type 1) TN: Symptoms include sudden or sporadic periods of intense facial pain or burning. Attacks can last from a few seconds to a few minutes. Painful episodes occur in rapid succession and may continue for a few hours, but there are generally pain-free periods between attacks.
Atypical (Type 2) TN: The atypical form is characterized by constant pain, with stabbing, burning or aching sensations that may be less intense but more widespread than those associated with Type 1. Symptoms may also be more difficult to control.

More about TN

TN may be progressive, meaning that the condition worsens over time. At first, pain may be limited to the upper or lower jaw, and patients might think it is due to dental problems. The intervals between attacks may become shorter or disappear altogether, while efforts to manage pain with medication may be less effective.

Pain that accompanies TN may be so intense that it becomes debilitating. People with TN may avoid normal activities due to concerns that a painful episode will occur.

How common is trigeminal neuralgia (TN)?

About 150,000 new cases of trigeminal neuralgia are diagnosed each year. It is more likely to occur in people over age 50, although people of any age may be affected. Typical trigeminal neuralgia is rare in people less than 40 years old. Multiple sclerosis should be considered in younger patients with TN. The incidence of trigeminal neuralgia in patients with MS is 1% to 2%.

SYMPTOMS AND CAUSES

What causes trigeminal neuralgia (TN)?

There are several conditions that may result in TN, but usually it is caused by pressure on the nerve exerted by a blood vessel near the brain stem. Multiple sclerosis (MS) causes the deterioration of the nerve coating called the myelin sheath, so people with MS may also develop TN.

Less commonly, a tumor or vascular lesion may cause nerve compression. Injury to the trigeminal nerve due to oral or sinus surgery, stroke, or facial trauma are other causes of facial nerve pain that may be similar to TN type pain.

DIAGNOSIS AND TESTS

How is trigeminal neuralgia (TN) diagnosed?

Your doctor will ask questions about your symptoms and medical history. He or she will perform a physical examination of the head and neck areas, including the ears, mouth, teeth, and temporomandibular joint (TMJ).

Other disorders may cause facial pain and mimic TN type pain so they need to be ruled out before a definite diagnosis is made. These include cluster headaches or migraines, post-herpetic neuralgia (pain following an outbreak of shingles), or TMJ disorder. Sinusitis and ear infections must also be ruled out.

A magnetic resonance imaging (MRI) scan may be performed to rule out the presence of a brain tumor, multiple sclerosis, or other causes. The scan might indicate whether a blood vessel is pressing on the nerve.

MANAGEMENT AND TREATMENT

How is trigeminal neuralgia (TN) treated?

Several options can be used to treat TN. These include medications, surgery, and complementary therapies.

Medications

Anticonvulsant drugs: An anticonvulsant drug called carbamazepine is usually the first choice for treating pain associated with typical TN. Other anticonvulsant drugs that may be prescribed include oxcarbazepine, phenytoin, lamotrigine, sodium valproate, gabapentin, clonazepam, and topiramate.
Other medications: Tricyclic antidepressants such as amitriptyline or nortriptyline are used to treat symptoms associated with atypical trigeminal neuralgia. Baclofen is a muscle relaxant that may be used alone or along with carbamazepine or phenytoin. Botulinum toxin injections may be used to block sensory nerves. Nerve blocks are also used in some instances to provide temporary relief.

Surgery

Patients who do not respond to drug therapy or whose condition worsens over time may be candidates for surgery. Several procedures are used to treat TN, depending on the severity of the pain, the patient’s preference, physical health, previous surgeries, and surgeries’ relative risks and benefits.

Percutaneous (through the skin) surgical techniques include

Balloon compression: A surgeon passes a needle through the cheek to the trigeminal nerve. A catheter with a small balloon is inserted through the needle. The balloon is inflated and compresses the nerve, injuring the pain-causing fibers. The balloon and catheter are removed at the end of the procedure.
Glycerol injection rhizotomy: Glycerol is injected through a needle into the area where the nerve divides into three main branches. The procedure causes selective nerve damage that disrupts the transmission of pain signals to the brain.
Stereotactic rhizotomy: Nerve pain is relieved using heat to destroy part of the nerve that causes pain. The surgeon passes a hollow needle through the cheek into the trigeminal nerve. A heating current is passed through an electrode to destroy some of the nerve fibers.

Open (invasive) surgical procedures include

Microvascular decompression: Decompression may reduce sensitivity and allow the trigeminal nerve to recover and return to a more normal, pain-free state. Generally, it is the most effective method to treat TN. However, it is also the most invasive because an opening must be made in the skull to expose the trigeminal nerve root. The surgeon can then locate the blood vessel that may be compressing the nerve and gently move it away from the point of compression. Microvascular decompression is associated with relief of symptoms in over 70% of patients after 10 years. Younger patients who are otherwise in good health are suitable candidates for the procedure.

Stereotactic radiosurgery includes

Radiation procedures: Gamma Knife, Cyberknife or LINAC surgery deliver a single, highly concentrated amount of ionizing radiation to a precise target at the trigeminal nerve root. Over a period of time a lesion forms in the nerve that disrupts transmission of pain signals to the brain.