Trigeminal neuralgia

What is trigeminal neuralgia?

Trigeminal neuralgia is sudden, severe facial nerve pain.

The pain in the face has been described as stabbing, piercing or like an electric shock. The pain can last from just a few seconds to two minutes each time.

In most cases it only affects one side of the face (unilateral), more commonly the right side. Rarely, people with trigeminal neuralgia have pain on both sides of their face (bilateral).

Read more about the

.

In 80-90% of cases the pain is caused by pressure on the trigeminal nerve, the largest nerve inside the skull.

Read more about the trigeminal nerve and the

.

Types of trigeminal neuralgia

Trigeminal neuralgia can be split into different categories depending on the type of pain. These are described below.

• Trigeminal neuralgia type 1 (TN1) is the classic form of trigeminal neuralgia. The piercing and stabbing pain only happens at certain times and is not constant. This type of neuralgia is known as idiopathic (when no cause can be identified)
• Trigeminal neuralgia type 2 (TN2) can be referred to as atypical (not typical) trigeminal neuralgia. Pain is more constant and involves aching, throbbing and burning sensations
• Symptomatic trigeminal neuralgia (STN) is when pain results from an underlying cause, such as
  multiple sclerosis

When

, your doctor may test to rule out other conditions.

Who is affected?

Trigeminal neuralgia is rare.

Almost twice as many women are affected as men. The condition becomes more common with age and is rare in people under 40 years of age. Trigeminal neuralgia is most commonly seen in people between 60 to 70 years of age.

Treatment for trigeminal neuralgia

Trigeminal neuralgia is a chronic (long-term) condition that often gets worse over time. There is currently no cure.

Living with trigeminal neuralgia can be difficult and can interfere with a person's quality of life. However, medication usually provides temporary relief.

If medication is not effective or causes unpleasant side effects, surgery may be recommended. The aim of surgery is to either stop your blood vessels putting pressure on the trigeminal nerve, or to damage the nerve just enough to stop the pain signals.

Research suggests that surgery provides effective long-term pain relief and that around 70-90% of people are unlikely to experience recurring pain.

However, the chance of the pain returning will vary depending on the type of surgery used.

There are also potential side effects to consider before having surgery, such as hearing loss or facial numbness. You should discuss this with the specialist in charge of your care before deciding which treatment to have.

Read more about

.

Trigeminal neuralgia symptoms

The main symptom of trigeminal neuralgia is a severe stabbing or piercing pain in your face that comes on suddenly.

The pain is almost always on one side of your face, although in rare cases it is on both sides. It can be in the lower jaw, upper jaw, cheek, and less often the eye and forehead.

The pain may last from a few seconds to two minutes each time and you may also feel:

• tingling or numbness in your face before the pain develops
• a slight ache or burning feeling during the attack

You may have spasms of pain regularly for days, weeks or months at a time. In severe cases, you may feel pain hundreds of times a day. Some people experience a constant dull ache in certain areas between episodes of pain. However, it is possible for pain to disappear completely and not reoccur for months or years.

Triggers of trigeminal neuralgia

Episodes of trigeminal neuralgia can be triggered by certain actions or movements, such as:

• talking
• smiling
• chewing
• brushing your teeth
• a light touch
• shaving
• swallowing
• a cool breeze
• head movements

Living with trigeminal neuralgia can be difficult, and it can interfere with your quality of life. You may feel like avoiding activities such as washing, shaving or eating in order to avoid triggering pain.

Living with pain, especially if it affects your quality of life, can also lead to

(feelings of extreme sadness or despair that last a long time).

Atypical trigeminal neuralgia

Atypical means irregular or not typical. If you have this type of trigeminal neuralgia, you will feel prolonged pain between attacks. It may be a constant throbbing, aching or burning sensation. This form of trigeminal neuralgia responds less well to treatment than classic trigeminal neuralgia.

Trigeminal neuralgia causes

Although the exact cause is not always known, trigeminal neuralgia is often caused by compression of the trigeminal nerve or an underlying disease.

The trigeminal nerve

The trigeminal nerve (also called the fifth cranial nerve) is the largest nerve inside the skull. You have two trigeminal nerves, one in each side of your face. Each nerve splits into three branches:

• the upper branch (ophthalmic) – supplies the skin above the eye, forehead and front of the head
• the middle branch (maxillary) – supplies the skin through the cheek, side of the nose, upper jaw, teeth and gums
• the lower branch (mandibular) – supplies the skin through the lower jaw, teeth and gums

Between them, these three branches transmit sensations of pain and touch from your face, teeth and mouth to your brain. Trigeminal neuralgia can involve one or more branches of the trigeminal nerve. The maxillary branch is affected most often and the ophthalmic branch is least affected.

Pressure on the trigeminal nerve

Evidence suggests that in 80-90% of cases, the cause of trigeminal neuralgia is pressure on the trigeminal nerve close to where it enters the brain stem (the lowest part of the brain that merges with the spinal cord).

One study found that in 64% of cases, the cause of the pressure on the trigeminal nerve was an artery, and in 36% of cases it was caused by a vein.

It is thought pressure on the trigeminal nerve causes uncontrollable pain signals to travel along the nerve to your face, resulting in the sudden stabbing pains.

Other underlying causes

Other underlying causes that can affect the trigeminal nerve include:

• a tumour (a growth or lump)
• a cyst
• multiple sclerosis
  , a long-term condition that affects the central nervous system (the brain and spinal cord)

In multiple sclerosis, nerve fibres of your central nervous system become damaged by the immune system (the body’s defence system). This damage can affect the trigeminal nerve.

Triggers

Neuralgia can sometimes be triggered or made worse by a number of different things. You may be able to ease the pain of neuralgia by avoiding these triggers as much as possible.

For example, your pain may be triggered by wind or even a draught in a room. If this is the case, avoid sitting near open windows or the source of air conditioning, and wear a scarf wrapped around your face in windy weather.

Hot or cold food, or drink may trigger your pain, so try to avoid anything very hot or icy cold. Using a straw to drink warm or cold drinks may help prevent the liquid coming in contact with the painful areas of your mouth.

Diagnosis of trigeminal neuralgia

See your doctor if you think you have trigeminal neuralgia. Your doctor will first ask about your symptoms and then may request some tests to rule out other conditions.

As the pain caused by trigeminal neuralgia is often felt in the jaw, teeth or gums, it is common for people to visit their dentist rather than their doctor. If you visit your dentist, they will investigate your facial pain using a dental

.

This can sometimes delay a diagnosis of trigeminal neuralgia because other more common causes are normally considered first.

If you have already seen your dentist and they have not been able to diagnose trigeminal neuralgia or another cause of your pain, visit your doctor.

Seeing your doctor

If your symptoms suggest you have trigeminal neuralgia, your doctor will examine your face to find exactly which parts are painful. They will first perform a careful examination on the following areas:

• head and neck
• ears
• mouth
• teeth
• joint of the lower jaw (temporomandibular joint)

Ruling out other conditions

Other conditions that can cause facial pain will need to be ruled out before a diagnosis of trigeminal neuralgia.

It is important to determine whether or not you have the classic form of trigeminal neuralgia or neuralgia caused by another condition (symptomatic trigeminal neuralgia). If this is the case then treatment should focus on the underlying condition.

Other conditions that should be ruled out are:

• dental infection or cracked tooth
• migraine
• joint pain in the lower jaw
• temporal arteritis, a serious condition that causes blood vessels in the temple to become inflamed, which can lead to blindness or
  stroke
• traumatic injury to the nerve in the face (post-traumatic neuralgia)
• ongoing facial pain with no known cause (idiopathic)

If you are under 40 years old, a different diagnosis will be investigated by your doctor. This is because trigeminal neuralgia is uncommon in people under 40.

MRI scan

A

(MRI) scan can reliably show whether the trigeminal nerve is compressed. An MRI scan uses a strong magnetic field and radio waves to create detailed images of the inside of your brain and the trigeminal nerve.

An MRI scan can also rule out other causes of facial pain, such as a tumour found in the base of the skull. These other causes account for 5-10% of trigeminal neuralgia cases.

Multiple sclerosis

Around 1-5% of people with

(a long-term condition that affects the brain and spinal cord) develop trigeminal neuralgia, so this condition will need to be investigated.

You will be asked a number of questions relating to the symptoms of multiple sclerosis to rule out this condition. Symptoms relating to multiple sclerosis include:

• dizziness
• unsteady, shaky limb movements and muscle co-ordination
• weakness in the eye
• changes in vision affecting just one side

If necessary, an MRI scan can also be used to diagnose or rule out multiple sclerosis.

Trigeminal neuralgia treatment

Medication can provide temporary relief from the pain of trigeminal neuralgia. Surgery may be considered for people who experience severe pain despite medication, worsening pain or adverse effects from the medication.

Your doctor will first prescribe a type of medicine called an anticonvulsant (usually used to treat seizures in

), which can help relieve pain in your face. These drugs work by slowing down electrical impulses in the nerve and reducing its ability to transmit pain. Normal painkillers such as are not effective in treating trigeminal neuralgia.

The anticonvulsant medicine called carbamazepine (see below) is usually the first medication recommended. However, if carbamazepine is not effective, a different anticonvulsant called gabapentin may be used.

Carbamazepine

Although carbamazepine is usually used to treat epilepsy, it can sometimes be effective in treating trigeminal neuralgia because it lessens the uncontrollable pain signals.

You will usually need to take this medicine one to two times a day to begin with, although some people may need a higher dose.

Carbamazepine can cause side effects which may make it difficult for some people, such as the elderly, to use. Possible side effects are outlined below.

Very common side effects

These side effects have affected more than one in 10 people and include:

• nausea (feeling sick) and vomiting
• dizziness
• tiredness
• finding it difficult to control movements
• a reduced number of infection-fighting white blood cells (leukopenia)
• changes in liver enzyme levels (enzymes are proteins that speed up any reaction happening in the body)

Less common side effects

These side effects have affected up to one in 10 people and include:

• increased risk of bruising or bleeding
• fluid retention (being unable to pass urine)
• weight gain
• confusion
• headache
• blurred or double vision
• dry mouth

Uncommon side effects

Uncommon side effects of carbamazepine can include:

• uncontrollable (involuntary) movements such as tremors
• abnormal eye movements
• diarrhoea
• constipation

If you are of Chinese or Thai ethnicity, you may need a

before you can take carbamazepine. This is because people of these ethnicities are more vulnerable to developing a severe rash from the medication.

Anticonvulsants have been linked to thoughts of self-harm or suicide. Therefore, if you are prescribed them, you should immediately report any suicidal feelings to your doctor. For more information about potential side effects of carbamazepine, ask your doctor or read the information leaflet found inside your medicine.

Referral to a specialist

Anticonvulsants for trigeminal neuralgia may stop working over time. This is because they are only effective in numbing the pain and not at stopping the cause of it. If this occurs, you may be referred for specialist treatment.

You may also be referred for specialist treatment for trigeminal neuralgia if:

• you have pain in your face between spasms of trigeminal neuralgia
• any of your senses are affected
• anticonvulsants are not effective in controlling your pain
• anticonvulsants cause you to experience severe side effects
• you are under 40 years old
• you don't want to take medication for the indefinite future

Specialist treatment may be provided by a number of different healthcare specialists including:

• a neurologist – a specialist in conditions of the central nervous system who will test to rule out multiple sclerosis, and advise on medication
• a pain specialist in treating trigeminal neuralgia who can prescribe medication
• a neurosurgeon – an expert in surgery of the brain and nervous system who may advise whether surgery is likely to be beneficial

If carbamazepine or gabapentin have not been effective in controlling your pain, your specialist may recommend other medications. For example, oxcarbazepine and phenytoin may be recommended for treating trigeminal neuralgia, although they may currently be unlicensed for treating this condition in the UK.

Unlicensed medications

Unlicensed medications do not have a license to be used to treat certain conditions. In other words, the medication has not undergone

(a type of research that tests one treatment against another) to determine whether it is effective and safe to treat the condition.

However, some experts will use an unlicensed medication if they think it is likely to be effective and the benefits of treatment outweigh any associated risk.

If your specialist is considering prescribing an unlicensed medication to treat trigeminal neuralgia, they should inform you that it is unlicensed and discuss possible risks and benefits with you.

Possible procedures

Some procedures that you may wish to consider are outlined briefly below, although they each carry risks.

• glycerol injection – this is injected into the central part of the trigeminal nerve to provide temporary pain relief for around 6-12 months
• peripheral radiofrequency thermocoagulation – electrical stimulation is used to damage the nerve endings but carries a risk of permanent untreatable pain (anaesthesia dolorosa)
• balloon compression – a tiny balloon is inflated over the trigeminal nerve to relieve pressure. This may be used in rare cases if surgery has been unsuccessful
• electric current – this is used to numb the trigeminal nerve and can be very effective

Research has shown 90% of people will gain immediate pain relief from radiofrequency thermocoagulation, glycerol injection or balloon compression. However, 50% of patients will lose sensation in their face after the procedure.

Patients having peripheral radiofrequency thermocoagulation may find their pain returns after one year.

Surgery

Surgery may be recommended. The aim of surgery is to either stop your blood vessels from putting pressure on the trigeminal nerve, or to damage the nerve just enough to stop the uncontrollable pain signals.

The two surgical procedures used are:

• microvascular decompression
• ablative treatments

These are described below.

Microvascular decompression

Microvascular decompression is an operation to release the pressure of blood vessels pressing on the trigeminal nerve.

During microvascular decompression surgery, the surgeon will either remove or relocate the blood vessels, separating them from the trigeminal nerve.

For most people, this type of surgery is effective in easing the pain of trigeminal neuralgia and appears to provide the longest lasting relief. In over 70% of people, pain relief was still felt 10 years after surgery.

However, the operation can cause hearing loss which is estimated to occur in less than 3% of people. Also, it is possible for pain to return after surgery and for surgery to cause a loss of sensation in the face, but this is unusual and often temporary. Very rarely, this type of surgery can result in stroke, meningitis or even death.

Stereotactic radiosurgery

Stereotactic radiosurgery is a fairly new treatment that uses a concentrated beam of radiation to try and reduce pain signals travelling along the trigeminal nerve. Stereotactic radiosurgery does not require

(painkilling medication) and no incisions (cuts) are made in your skin.

Your surgeon will discuss with you exactly what is involved before your operation. So far, this treatment has been found to be quite effective for trigeminal neuralgia: 33-90% of patients experience an immediate end to facial pain, although 14% of patients can expect to have pain returning after 18 months. The treatment can take up to two months to achieve its maximum effect.

Stereotactic radiosurgery can cause facial numbness in 8% of cases. Uncommon complications include:

• loss of taste
• numbness in the eyes
• deafness

This procedure, although safe, is generally not recommended unless there are exceptional reasons not to use other techniques.