Trigeminal neuralgia (TN) used to also be called ‘tic douloureux’ or ‘tic convulsif’. In French, tic means “muscle twitch” or “spasm”; douloureux means “painful”. TN is an example of neuropathic pain, arising from the trigeminal nerve (the fifth cranial nerve). New cases of trigeminal neuralgia affect 4 to 5 of every 100,000 people in the United States each year. TN affects women slightly more often than men; however, there is a much higher incidence for males over 80. Peak incidence begins as 50-60 years of age and increases with age. In 60-69 year-olds, it is 17.5/100,000; in >80 year-olds, it is 25.9/100,000.

TN is a unilateral facial pain syndrome (on one side); however bilateral cases (on both sides) have been reported in 2%-5% of cases. For those with bilateral pain, one side usually precedes the onset of pain on the second side- sometimes by years.

There are three branches of the trigeminal (facial) nerve: from top to bottom, they are ophthalmic, maxillary, and mandibular. Pain in one branch is reported by 36%-42% of patients: in 17%-19%, it occurs in the maxillary or mandibular branch, and 2% solely in the ophthalmic branch. When more than one branch is involved, it is most commonly in the maxillary and mandibular branches jointly (35%), and pain in all three branches in 14% of patients. This means that pain in the lower two branches accounts for 69% of patients. This helps to explain why pain in the jaw area is confused with dental pain many times.

What does TN pain feel like?

TN episodes may start as short, mild attacks and progress and cause longer, more-frequent bouts of searing pain. TN pain is described as sudden and  intense, with  patient ratings of 9 out of 10, or more, although less severe attacks can occur. TN pain is often describes as stabbing, shooting, sharp, piercing or electrical in nature. Pain can occur almost anywhere between the jaw and forehead, including inside the mouth. This pain can include facial twitching (hence, the term ‘tic’).

A large proportion of people have a constant aching pain between attacks; attacks might last for longer that two minutes. Some people have eye tearing on the same side of the face. Mild sensory changes are also reported. Many people report that their TN attacks become more intense and frequent over time, sometimes with pain-free periods in between. 

What are the types of TN?

The names used to differentiate types of TN may vary from doctor to doctor. In order to provide one internationally accepted naming standard, below is the International Classification of Headache Disorders 3rd Edition. The following classifications are based on a consensus between the International Headache Society (IHS) and the International Association for the Study of Pain (IASP).

Classical trigeminal neuralgia (also called TN1/Typical TN)

Description: Classical trigeminal neuralgia without persistent background facial pain.

An artery or vein compressing the trigeminal nerve causes the intense pain of TN. This type of TN is sometimes referred to as TN1, Type 1, or Classic TN. Classical TN is characterized by sharp, stabbing, paroxysms of severe pain, typically lasting a fraction of a second to two minutes. The paroxysms are very severe in intensity, usually having a trigger zone or an action that will trigger or activate the shock-like jolt. The pain is almost always unilateral (on one side) and located in the second (midface) or third (jaw) trigeminal nerve branches. Pain rarely is seen in the first division (forehead).

The cause of Classical TN is typically nerve compression by a vessel, usually the superior cerebellar artery on the trigeminal nerve root as it leaves the brain stem or pons. Classical trigeminal neuralgia with purely paroxysmal pain is also marked by periods of complete pain-free remissions.

Classical TN with concomitant continuous pain (also called Atypical TN/ATN/TN 2)

Description: Classical trigeminal neuralgia with persistent background facial pain. People with atypical TN experience a persistent dull ache or burning sensation in one part of the face. However, episodes of sharp pain can complicate atypical TN. There is often not a specific trigger point for the pain;the pain may grow worse over time.

Secondary trigeminal neuralgia

Description: Trigeminal neuralgia caused by an underlying disease.

Idiopathic trigeminal neuralgia

Description: Trigeminal neuralgia with neither electrophysiological tests nor MRI showing significant abnormalities.

Painful trigeminal neuropathy

Description: Facial pain in the distribution(s) of one or more branches of the trigeminal nerve caused by another disorder and indicative of neural damage (including herpes zoster, postherpetic neuralgia, and post-traumatic neuropathy).

Medication for trigeminal neuralgia

The medicines doctors typically prescribe to treat trigeminal neuralgia were originally developed to treat epilepsy. However, this class of medications, called anticonvulsants, has been found to be quite effective in treating nerve pain, including trigeminal neuralgia. A positive response to these drugs might signal to your doctor that classical TN is an accurate diagnosis. Carbamazepine and oxcarbazepine are frequency-dependent sodium channel blockers that reduce pain in approximately 90% of people with TN. These drugs are not always well tolerated and need to be titrated (increasing or lowering doses) carefully.

Where there is a continuous or longer lasting dull, burning, aching background pain, the addition of a tricyclic antidepressant such as nortriptyline, in doses around 50-100 mg, at bedtime, may be helpful. Other anticonvulsants such as levetiracetam and zonisamide may be useful but have not been studied in placebo-controlled trials. Baclofen is a muscle relaxant that is very effective in trigeminal neuralgia in doses between 5 and 80 mg daily. Sedation is the most significant side effect. Phenytoin may be used as an alternative in doses of 100 – 300 mg per day.

Pain triggers

Stimulus-provoked pain is typical of TN. Triggered pain is one of the signs to your doctor to indicate a diagnosis of TN. In most people, TN pain is triggered by ‘innocuous mechanical stimuli’- that would not hurt someone without TN. Subtle stimuli can be a breeze or light touch of the face. Touch plus facial movements can also trigger pain. Movement alone can also be enough to provoke TN pain. The location of your pain may be different from the location that was stimulated. You may also experience a refractory period of several seconds or minutes after a pain attack when a new attack cannot be provoked.

Attacks of TN may be triggered by:

• Touching the skin lightly (reported in 65%)
• Washing
• Shaving
• Brushing teeth
• Blowing the nose
• Drinking hot or cold beverages
• Encountering a light breeze
• Applying makeup
• Smiling
• Talking (reported in 76%)
• Chewing (reported in 74%)
• Cold (reported in 48%)

There are also reports of pain triggered by sweet, salty, or spicy foods, which also might indicate a dental issue. Your trigger may not be listed here, but that does not mean that you do not have TN.

Diagnosing TN

TN can be very difficult to diagnose, because there are no specific diagnostic tests and symptoms are very similar to other facial pain disorders. Trigeminal neuropathic pain is almost always diagnosed by your description of your symptoms. The Burchiel Questionnaire or the McGill Pain Questionnaire may help your doctors determine how to treat you for your pain.

Your doctor will likely order an MRI scan when TN is suspected in order to rule out multiple sclerosis or a tumor and to look for an offending blood vessel that is causing the pain. High-resolution, thin-slice or three-dimensional MRIs have the ability to show fine trigeminal nerve compression.

Commercial names for high-resolution images are:

• SSFP: Steady-State Free Precession
• GE FIESTA: Fast Imaging Employing Steady-state Acquisition
• Siemens FISP: Fast Imaging with Steady-state Precession
• Philips FFE: Fast Field Echo, b-FEE: Balanced Fast Field Echo

Does TN go away on its own?

It is not likely that your pain will resolve on its own. TN pain usually occurs in cycles, sometimes with periods of remission for weeks, months or even years. Over time, attacks of pain may come more frequently and be increasingly severe