Know Trigeminal Neuralgia

by Dr. Archana Nankar

Trigeminal Neuralgia (TN), also called tic douloureux (French for unbearable painful twitch or spasm), is a chronic pain condition often described as the most atrocious suffering known to mankind. It typically involves the lower face and jaw, but may also involve the area around the nose and above the eye. The pain is described to be intense, stabbing, electric shock like and is usually limited to one side of your face. It is said to be caused by irritation of the trigeminal nerve, which carries sensation from your face to the brain.

Although tic douloureux cannot be cured, there are treatments available to alleviate the debilitating pain. Normally, anticonvulsive medications are the first treatment of choice. Fluoroscopy guided radiofrequency ablation of the trigeminal ganglion and microvascular decompression surgery are among other treatment options.

The Trigeminal Nerve
The trigeminal nerve is the fifth cranial nerve out of 12 pairs of cranial nerves within the head. It is the nerve liable for providing sensation to the face. There are 2 nerves supplying each side of the face. As the name suggests, (‘tria’ meaning three and “geminus” meaning twin), the nerve divides into three branches, controlling sensations throughout the face.

Prevalence of TN
• According to a most recently published study performed from year 1992 to 2002 in the United Kingdom, reported an incidence of 26 per 100,000 per year.
• The condition affects women more frequently than men and the onset is usually after age 40 with peak occurrence between ages 50 and 80.
• It can occur in younger individuals (age < 40), in which cases, it may be due to a brain tumour compressing the nerve or a disease known as multiple sclerosis.
Causes
There can be multiple pathologies that can cause this condition, some of them could include compression of the trigeminal nerve by a healthy artery or vein at the base of the brain, which causes the nerve to misfire.
Other causes include pressure of a tumour on the nerve or multiple sclerosis, which damages the myelin sheaths or coverings of the nerve, sometimes there may be damage to the blood vessels supplying the nerve.

Symptoms
• Most patients report that their pain begins spontaneously.
• It is characterized by attacks of intense, sharp, electrical shock like or stabbing pain which may be accompanied by uncontrollable muscular spasms on the affected side of the face.
• Attacks are reported to be set off by activities such as washing the face, shaving, talking, chewing, brushing of the hair and scalp, or a light breeze on the face of a patient.
• The attacks generally last from fractions of a second to 2 minutes and are followed by a refractory period during which no pain can be triggered.
• Between attacks, the patient is in dreaded fear of the next flash of pain.
• There might be spontaneous remission of pain for weeks, months, or even years.
• Atypical TN – Characterised by background pain that is constantly present like a burning sensation affecting a more widespread area of the face. With this pain there may not be a remission period, and symptoms are usually more difficult to treat.
• Pre-TN – Patients suffer a dull aching or burning pain involving a part of the upper or lower jaw triggered by jaw movements or liquids, for which they might undergo multiple dental procedures before the it is recognized as an early sign of TN.

Diagnosis:
Trigeminal neuralgia usually is diagnosed based on the description of the symptoms provided by the patient. Magnetic resonance imaging (MRI) can detect if a tumour or MS is irritating the trigeminal nerve. The vessel next to the nerve root is difficult to ascertain even on a high-quality MRI.
Treatment

1. Medications

• Anticonvulsant medicine, is the most common medication used to treat trigeminal neuralgia. Possible side effects include dizziness, drowsiness, constipation, nausea. It can cause bone marrow suppression, liver toxicity and low sodium levels.

2. Radiofrequency ablation of trigeminal nerve

It is a technique that directs high-frequency heat onto the trigeminal nerve, specifically destroying its ability to transmit pain signals to your brain.

It is a procedure to place a needle at cheek to reach the trigeminal nerve at the base of skull. We confirm placement of needle by X-ray, your pain physician will stimulate the nerve and ask if you feel the stimulation in the same place where you experience pain. This step confirms that your doctor has targeted the right location. Then radiofrequency heat is used to block the nerve conduction that is taking the pain to brain.
98% of patients experience pain relief with this technique. Sometimes pain may recur after pain free period of few years, but majority enjoy pain relief for several years.
Complications may include diminished corneal reflex, weakness of jaw muscles, mild numbness and pain in a small percentage of patients in the part of the face supplied by the nerve called anesthesia dolorosa.

3. Balloon compression

In balloon compression, a small balloon is introduced through your cheek, using a needle to compress the nerve.

4. Open Surgery

Microvascular decompression involves exposure of the trigeminal nerve root, identification of a blood vessel that may be compressing the nerve and gentle movement of the blood vessel away from the point of compression. While this is best if there is a blood vessel compressing the nerve, but it is invasive, because it requires opening the skull through a craniotomy. There is a small risk of facial weakness, facial numbness, chances of double vision, stroke or even death.