Trigeminal neuralgia
It is probably the most intense pain medicine describes, and it is also the one that most often ends in an unnecessary tooth extraction. Of every ten patients who reach surgery, eight saw a dentist first, and more than half of them had something done in the mouth that was not needed.
Many people arrive at this page without a diagnosis. They search for "pain in half my face", "my jaw hurts on the left side", "electric shock in my face when I chew". They do not yet know that what they have has a name.
If what you are describing is a pain like a lightning bolt, on one side of the face, lasting seconds, set off by talking, chewing, touching your face or feeling the wind, and between attacks nothing hurts at all, there is a good chance it is trigeminal neuralgia. It is a recognised condition, it can be investigated, and it has treatment.
What it actually is
The trigeminal is the nerve that carries sensation from the face. It has three branches: one for the forehead and the eye, one for the cheekbone and the upper lip, and one for the jaw and the lower lip. Neuralgia almost always affects the last two, which are precisely the ones covering the dental area. That is where all the confusion begins.
In 80 to 90 per cent of cases the cause is mechanical and concrete: an artery resting on the nerve right where it leaves the brainstem, wearing it down with every beat. Over the years that rubbing damages the sheath that insulates the fibres, and the nerve starts firing on its own.
That explains two things. It explains why the pain is so electric — it is an abnormal discharge, not an inflammation. And it explains why there is an operation that solves the problem at its source: the artery is lifted off the nerve and a sheet of inert material is placed between them.
What it feels like
The features that set it apart from almost any other facial pain:
- It is on one side only, and it practically never swaps sides.
- It lasts seconds, not hours. The attacks come in volleys.
- It is electric, stabbing, searing. It is not a dull or throbbing pain.
- The triggers are trivial: talking, chewing, brushing your teeth, shaving, cold air, a kiss, putting on make-up. Many people stop eating, or stop talking on one side.
- Between attacks nothing hurts. That normality between episodes is very characteristic.
- It does not usually wake you at night, unlike dental pain.
- And it runs in phases: spells of pain and remissions of weeks or months, which grow shorter over the years.
That last point matters, because it produces false cures. When the pain lifts on its own after some treatment has been started, it is easy to give the treatment the credit.
The numbers worth having
- Compression by an artery accounts for 80 to 90 per cent of cases. The superior cerebellar artery is responsible in three out of every four.
- Only 15 per cent of neuralgias are secondary to another disease. Multiple sclerosis is the cause in 2 to 4 per cent, and it should be suspected above all in young people or when the pain is on both sides.
- It appears mostly after the age of 50, and is somewhat more common in women.
- And the figure that hurts most: in a series of 51 patients who had surgery, 41 — 82 per cent — had gone to a dentist first, and 27 of those 41 received invasive dental treatment for this pain: extractions, root canals, implants. None of those procedures could have worked, because the problem was never in the mouth.
From that comes the most useful practical rule on this page: if the pain did not settle after dental treatment, the problem is probably not dental. And if you are offered a second extraction for the same pain, that is the moment to ask for a neurological opinion first.
When not to wait
Trigeminal neuralgia is not life-threatening, but these situations do call for prompt attention:
- Pain that does not respond to medication and that stops you eating or drinking. Dehydration and weight loss are real complications of severe episodes.
- Persistent numbness of the face. Classic neuralgia does not leave the face numb between attacks; if sensation is lost, another cause has to be looked for.
- Weakness of the chewing muscles, double vision, hearing loss, or pain on both sides.
- Onset before the age of 40.
- And if you are taking carbamazepine: fever, sore throat, easy bruising or a skin rash. These are signs of adverse reactions that need immediate review.
What you will hear that is not true
"It is a dental problem." It is myth number one and the most expensive, in money and in teeth. Eight out of every ten patients go through a dentist before the right diagnosis.
"It is stress, or something emotional." The pain gets worse with tiredness, as almost all pain does. But the cause has been identified and it is anatomical in 80 to 90 per cent of cases: an artery resting on a nerve. This is not a psychogenic pain, and telling someone with trigeminal neuralgia that their pain is emotional is both inaccurate and cruel.
"It is facial palsy." No. Bell's palsy is motor: the face does not move. Neuralgia is sensory: the face moves perfectly well and hurts.
"There is no cure, you have to put up with it." False, and it is the belief that causes the most years of unnecessary pain. Carbamazepine controls the pain in most patients at the start. And when medication stops being enough, or the side effects become intolerable, there are procedures — microvascular decompression, radiosurgery, percutaneous procedures — with solid results.
"Acupuncture cures it." There is no evidence supporting acupuncture as a primary treatment. And because neuralgia has spontaneous remissions, whatever is being done when the remission arrives looks as though it worked.
"If I am young, it must be multiple sclerosis." Multiple sclerosis accounts for 2 to 4 per cent of cases. In someone young, or with pain on both sides, it has to be ruled out, but it is the exception, not the rule.
What will happen at the appointment
The history is almost everything. You will be asked how long each attack lasts, what sets it off, whether it hurts between episodes, whether you responded to carbamazepine — responding is itself a diagnostic clue — and which side it is on.
The examination has one aim: looking for what should not be there. Sensation intact, normal chewing strength, the rest of the cranial nerves normal. If any of that fails, the picture is no longer a classic neuralgia and a cause has to be found.
The MRI is requested with a particular sequence, aimed at showing the nerve and the vessels around it. It serves to rule out other causes and to see whether a vessel is resting on the nerve.
And on treatment, the order matters: medication first, surgery when medication fails or is not tolerated. If you are offered an operation straight away, without medical treatment having been tried, ask why.
Questions worth writing down before you go
- Is this a classic neuralgia, or is there something suggesting a secondary cause?
- Does the MRI show a vessel resting on the nerve?
- Are we at the right dose of medication before considering surgery?
- Of the surgical options, which one suits me for my age and general health, and why?
- What is the chance of ending up pain-free with each one, and how long does that usually last?
- What is the risk of facial numbness with each option?
The questions people ask most
Can trigeminal neuralgia be cured?
Yes, in many cases. Medication controls the pain in most people at first. And when it stops being enough, microvascular decompression addresses the cause — it lifts the artery off the nerve — and achieves lasting relief in a high proportion of patients. Radiosurgery and percutaneous procedures are also available.
Is trigeminal neuralgia a tooth problem?
Almost never, however much it looks like one: the neuralgia affects the branches of the nerve that supply precisely the dental area. In one series of patients who had surgery, 82 per cent had gone to a dentist first, and more than half of them had an extraction, a root canal or an implant they did not need. If the pain did not settle with dental treatment, the problem is probably not in the mouth.
Is trigeminal neuralgia caused by stress?
No. In 80 to 90 per cent of cases the cause is an artery compressing the nerve where it leaves the brainstem. Tiredness can make it harder to bear, as with any pain, but the origin is not emotional.
How long does the pain last?
Each attack lasts from seconds to a couple of minutes, and they come in volleys. Between attacks, characteristically, nothing hurts. The condition runs in phases, with remissions that can last weeks or months and that tend to grow shorter over the years.
Is trigeminal neuralgia dangerous? Is it cancer?
It is not cancer and it does not put life at risk. What can become dangerous is the intensity: some patients stop eating and drinking during an episode, and that does need attention. Classic neuralgia is not a sign of a tumour either, although the MRI is requested partly to rule that out.
What is microvascular decompression?
It is the operation that corrects the cause. Through a small opening behind the ear, the surgeon reaches the point where the nerve leaves the brainstem, lifts off the artery compressing it and places inert material between them so that it cannot rest there again. It is the only option that does not damage the nerve in order to relieve the pain, and that is why it leaves the least facial numbness.
How long does carbamazepine take to work?
It usually begins to act within days, and the dose is raised gradually to avoid dizziness and drowsiness. Responding well to carbamazepine supports the diagnosis. It requires regular blood tests, and you should seek advice without delay if there is fever, a skin rash or easy bruising.
Can you fly with trigeminal neuralgia?
Yes. Cabin pressure changes do not set off attacks. What is worth planning for is the cold air blowing straight from the vents, which is a trigger in some people, and carrying your medication in your hand luggage.