Trigeminal neuralgia: Causes, symptoms, diagnosis, treatment
What is trigeminal neuralgia?
Trigeminal neuralgia (TN), also called tic douloureux, is a condition that is characterised by intermittent, shooting pain in the face.
TN affects the trigeminal nerve, one of the largest nerves in the head. The trigeminal nerve sends impulses of touch, pain, pressure, and temperature to the brain from the face, jaw, gums, forehead, and around the eyes.
What causes TN?
The precise cause of trigeminal neuralgia is unknown. There are a number of theories as to why the trigeminal nerve is affected.
The most commonly accepted theory is compression of the trigeminal nerve, usually by a blood vessel, causing it to become irritated. This irritation causes the outer covering of the nerve (the myelin sheath) to erode over time. The irritated nerve then becomes more excitable and erratically fires pain impulses.
Tumours and bony abnormalities of the skull may also press on and irritate the trigeminal nerve.
Trauma, infections and multiple sclerosis can also cause damage to the trigeminal nerve.
What are the symptoms of TN?
TN causes a sudden, severe, electric shock-like, or stabbing pain that lasts several seconds to a few minutes. The pain can be felt on the face around the lips, cheek, jaw, eyes, nose, scalp, and forehead. Symptoms can be brought on when a person is brushing the teeth, putting on makeup, touching the face, swallowing, or even feeling a slight breeze.
The pain is so severe that people can become afraid to talk, eat, or move during periods of attacks.
There is usually no pain or numbness between attacks and no dysfunction of the muscles of the face.
TN is often considered one of the most painful conditions seen in medicine. Usually, the pain is felt on one side of the jaw or cheek, but some people experience pain at different times on both sides. The attacks of pain may be repeated one after the other. They may come and go throughout the day and last for days, weeks, or months at a time. At times, the attacks can disappear for months or years. The disorder is more common in women than in men and rarely affects anyone younger than 50.
How is TN diagnosed?
Magnetic resonance imaging (MRI) can be used to determine whether a tumour or multiple sclerosis is irritating the trigeminal nerve. Otherwise, no test can determine with certainty the presence of trigeminal neuralgia. Tests can, however, help rule out other causes of facial disorders. TN usually is diagnosed based on the patient's description of the symptoms.
How is TN treated?
The primary treatment of trigeminal neuralgia is medication to control the pain. Surgery may be necessary when drug therapy is not effective or side effects from the medications are not tolerable.
A number of medications are effective in helping control the pain of trigeminal neuralgia. The most commonly prescribed medications are anticonvulsants (anti-seizure medications). Anticonvulsants help to stop the irritated trigeminal nerve from firing pain impulses.
TN can be treated with anticonvulsant medications such as carbamazepine or gabapentin. The medications clonazepam and sodium valproate may also be effective and may be used in combination with other medicines to achieve pain relief. Some antidepressant medicines also have significant pain relieving effects.
Opioid pain medications can be useful during episodes of severe pain.
If medications are ineffective or if they produce undesirable side effects, neurosurgical procedures are available to relieve pressure on the nerve or to reduce nerve sensitivity.
Some patients report having reduced or relieved pain by means of complementary medical therapies such as acupuncture, chiropractic adjustment, self-hypnosis or meditation.
Trigeminal neuralgia cannot be prevented.