Trigeminal neuralgia: Symptoms, causes, and treatment
Also known as tic douloureaux,it is thought to be one of the most painful human conditions.
Neuralgia refers to severe pain along the course of a nerve, due to nerve irritation or damage. Trigeminal neuralgia affects the trigeminal nerve, one of the most wide-reaching nerves in the head.
In the United States (U.S.), approximately 14,000 people develop the condition annually, and 140,000 people currently live with the condition. It is thought to affect about one million people worldwide.
What is trigeminal neuralgia?
Trigeminal neuralgia is a type of non-nociceptive pain.
- Nociceptive pain happens when an external stimulus triggers specific pain receptors in the nervous system, for example, the pain caused by a burn.
- Non-nociceptive pain results from damage or irritation to the nerves or a fault in the nervous system. The nerves themselves are sending pain messages to the brain.
Neuralgia is a type of non-nociceptive pain, and trigeminal neuralgia is non-nociceptive pain caused by the trigeminal or 5th cranial nerve in the face.
People with neuralgia describe it as a short-lived but intense burning or stabbing pain. It may feel as if the pain is shooting along the course of the affected nerve. Although the pain is brief, trigeminal neuralgia is a chronic condition, which gets worse in time.
Bouts of pain can last a few minutes, usually on one side of the face.
Trigeminal neuralgia is twice as common in women than men, and it is more likely after the age of 50 years.
One or more of the following symptoms may occur:
- intermittent twinges of mild pain lasting from a few seconds to several minutes
- severe episodes of searing, shooting, jabbing pain that feel like electric shocks
- sudden attacks of pain triggered by stimuli that are usually not painful, such as by touching the face, chewing, speaking, or brushing the teeth
- spasms of pain which last from a couple of seconds to a couple of minutes
- episodes of cluster attacks, which may last much longer, but between them, there may be no pain
- pain wherever the trigeminal nerve and its branches may reach, including the forehead, eyes, lips, gums, teeth, jaw, and cheek
- pain in one side of the face, or, less frequently, both sides
- pain that is focused in one spot or spreads in a wider pattern
- attacks of pain that occur more regularly and intensely over time
- tingling or numbness in the face before pain develops
Attacks of pain may occur hundreds of times each day in severe cases. Some patients may have no symptoms for months or years between attacks.
Some patients will have specific points on their face that trigger pain when if touched.
Area of pain
The area of pain will be based on the three branches of the trigeminal nerve:
- Ophthalmic: Affects the forehead, nose, and eyes
- Maxillary: Affects the lower eyelid, side of nose, cheek, gum, lip, and upper teeth
- Mandibular: Affects the jaw, lower teeth, gum, and lower lip
Trigeminal neuralgia sometimes affects more than one branch at a time.
Atypical trigeminal neuralgia
Atypical trigeminal neuralgia is a variation on typical trigeminal neuralgia. Pain may be described as burning, aching, or cramping, rather than sharp or stabbing.
It may occur on one side of the face, often in the region of the trigeminal nerve, and can extend into the upper neck or the back of the scalp. The pain can fluctuate in intensity from a mild ache to a crushing or burning sensation.
The atypical presentation of trigeminal neuralgia is harder to diagnose.
The main cause of trigeminal neuralgia is blood vessels pressing on the root of the trigeminal nerve.
This makes the nerve transmit pain signals that are experienced as stabbing pains. Pressure on this nerve may also be caused by a tumor or multiple sclerosis (MS).
Other causes may include:
- Multiple sclerosis: This is due to demyelinization of the nerve. Trigeminal neuralgia typically appears in the advanced stages of multiple sclerosis.
- A tumor presses against the trigeminal nerve: This is a rare cause.
- Physical damage to the nerve: This could be the result of injury, a dental or surgical procedure, or infection.
- Family history: The formation of blood vessels is inherited.
Sometimes the cause remains unknown.
If an individual’s symptoms indicate trigeminal neuralgia, a doctor will examine their face to determine the affected areas.
A magnetic resonance imaging (MRI) scan may help eliminate other conditions with similar symptoms, such as tooth decay, a tumor, or sinusitis. However, an MRI is unlikely to show the exact cause of nerve irritation.
The main treatments for trigeminal neuralgia involve prescribed medications and surgery.
Medications are available to treat trigeminal neuralgia, but these may become less effective over time.
There is also a risk of undesirable side effects. In these cases, surgery may be the best option.
Painkillers, such as paracetamol, will not relieve the pain of trigeminal neuralgia. Doctors, therefore, prescribe anticonvulsant medication. These are normally used to prevent seizures, but they can also reduce or block the pain signals sent to the brain. They do this by calming the nerve impulses.
The most common anticonvulsants for trigeminal neuralgia are:
- carbamazepine (Tegretol, Carbatrol, Epitol)
- phenytoin (Dilantin)
- gabapentin (Neurontin)
- topiramate (Topamax)
- valproic acid (Depakene, Depakote)
- lamotrigine (Lamictal)
Sometimes the anticonvulsant loses its effectiveness over time. If this happens, the doctor might increase the dosage or switch to another anticonvulsant.
Side effects of anticonvulsants include:
Make sure that you are not allergic to these medications, and consult with your doctor about any allergies.
Baclofen is a muscle-relaxing agent. It can be prescribed alone or combined with anticonvulsants. Adverse effects include nausea, drowsiness, and confusion.
This numbs the affected areas of the face and provides temporary pain relief. The doctor injects alcohol into the painful part of the face. The patient may require either further injections or a more permanent solution later on.
Surgery for trigeminal neuralgia aims to:
- stop a vein or artery from pressing against the trigeminal nerve
- damage the trigeminal nerve so that the uncontrolled pain signals stop
Damaging the nerve may lead to temporary or permanent facial numbness. Surgery can provide relief, but symptoms may return months or years later.
There are a number of surgical options for trigeminal neuralgia.
Microvascular decompression (MVD) involves relocating or removing the blood vessel that is pressing on the root of the trigeminal nerve.
The surgeon makes a small incision behind the ear on the side of the head near the location of the pain. A small hole is made in the skull, and the brain is lifted, exposing the trigeminal nerve. A pad is placed between the nerve and any touching arteries, effectively redirecting them away from the nerve.
If no blood vessels are pressing against the nerve, the nerve may instead be severed.
MVD can be effective at eliminating or reducing pain, but sometimes the pain returns. There is also a small risk of some hearing loss, facial weakness, facial numbness, and double vision.
The procedure carries a very small risk of stroke and fatality.
Percutaneous glycerol rhizotomy
Percutaneous glycerol rhizotomy (PGR) is also known as a glycerol injection. A needle is inserted through the face and into an opening at the base of the skull. Imaging techniques guide the needle to the joining point of the three branches of the trigeminal nerve.
A small amount of sterile glycerol is injected. Within a few hours, the trigeminal nerve is damaged, and pain signals are blocked.
Most people experience significant pain relief with PGR, but pain may recur later. Many patients experience facial tingling or numbness.
Percutaneous balloon compression of the trigeminal nerve
A balloon is sent down a hollow needle for inflation next to the nerve. This damages the nerve and blocks uncontrolled signals.
The procedure is effective, but the pain may return. Most patients experience some facial numbness and over half experience temporary or permanent weakness of the muscles used for chewing.
Percutaneous stereotactic radiofrequency thermal rhizotomy
This procedure uses electrical currents to destroy specifically selected nerve fibers linked to pain.
An electrode is attached to the nerve root under sedation. The patient is woken from sedation to identify whether they can feel the electrical pulses and put back under while the electrodes heat up and destroy the nerve.
Most patients undergoing PSRTR will experience some facial numbness afterward.
Partial sensory rhizotomy
The doctor makes a small hole in the skull and severs the nerve. As the base of the nerve is severed, the patient will have permanent facial numbness. Sometimes the doctor rubs the nerve instead of severing it.
A high dose of radiation is aimed at the root of the trigeminal nerve, gradually resulting in nerve damage and pain reduction. The patient will experience slowly improving pain relief over several weeks. Initial benefits may take several weeks to appear.
GKR is effective for most patients. However, some may experience a recurrence of pain later on.
There are no guidelines for preventing the development of trigeminal neuralgia. However, the following steps may help prevent attacks once diagnosed:
- eating soft foods
- avoiding foods that are too cold or hot
- washing your face with lukewarm water
- using cotton pads when washing your face
- if tooth brushing triggers an attack, rinsing your mouth with lukewarm water after eating
- as far as possible, avoiding known triggers
Trigeminal neuralgia can be debilitating, but managing the symptoms can drastically improve the quality of life.