TN triggers, symptoms & diagnosis

Trigeminal imageBackground

A number of causes can be attributed to facial pain, which makes a trigeminal neuralgia diagnosis an often challenging experience. Patient distress, as well as the clinical overlap with general dentistry, can lead to different kind of outcomes before the diagnosis is made. Because of this, close attention needs to be paid to avoid misdiagnosis, especially as one of the symptoms of a neurodegenerative illness.

In those without MS, compression of the trigeminal nerve is a common cause of TN. It is believed to be the pressing of a blood vessel on the trigeminal nerve as it leaves the brainstem, causing the wearing away of the protective coating around the myelin sheath around the nerve. When the nerve fibres short-circuit, electric shock-like pain happens.

People with MS are 20 times more likely to develop TN, of which approx. 20% can experience it on both sides of the face (although rarely at the same time). Compression is unlikely to be the reason in those living with MS, where the cause most likely is a demyelinating scar or plaque.

More rarely, symptoms of TN may be caused by nerve compression from a tumour. Injury to the trigeminal nerve (perhaps the result of sinus surgery, oral surgery, stroke, or facial trauma) may also produce neuropathic facial pain.

Red flags

  • Progressive pain, disability, and distress
  • Focal neurological deficit
  • Weight loss
  • Facial swelling or rash
  • Vision disturbance
  • Hearing loss/tinnitus/vertigo
  • Unilateral nasal obstruction/discharge


A variety of triggers may set off the pain of trigeminal neuralgia, including:

  • Shaving
  • Touching your face
  • Eating
  • Drinking
  • Brushing your teeth
  • Talking
  • Putting on makeup
  • Encountering a breeze
  • Smiling
  • Washing your face


  • Spontaneous attacks of pain or attacks triggered by things such as touching the face, chewing, speaking and brushing teeth
  • Episodes of shooting or jabbing pain that may feel like an electric shock
  • A constant, aching, burning sensation
  • Bouts of pain lasting from a few seconds to several minutes
  • Episodes of several attacks lasting days, weeks, months or longer — some people have periods when they experience no pain
  • Pain in areas supplied by the trigeminal nerve, including the cheek, jaw, teeth, gums, lips, or less often the eye and forehead
  • Attacks that become more frequent and intense over time
  • TN is typified by attacks that stop for a period of time and then return, but the condition can be progressive
  • The attacks often worsen over time, with fewer and shorter pain-free periods before they recur
  • Eventually, the pain-free intervals disappear and medication to control the pain becomes less effective
  • The disorder is not fatal but can be extremely debilitating
  • Due to the intensity of the pain, some individuals may avoid daily activities or social contacts because they fear an impending attack. 


When you see your GP or neurologist, describe your pain as detailed as possible; write down your symptoms if need be. Your medical consultant might use the SOCRATES history-taking in the form of Site, Onset, Character, Radiation, Associated factors, Timing, Exacerbating/relieving factors, Severity score to have a detailed overview of your pain.

Other questions might be:

  • Headache/previous migraine?
  • Pain related to eating?
  • Malaise, vision disturbance or scalp tenderness?
  • Facial rash or blisters?
  • Hearing loss/tinnitus?
  • Nasal obstruction/epistaxis?
  • Exacerbation by wind or touch?
  • Bruxism (jaw clenching/teeth grinding), jaw clicking?
  • Bleeding gums/tooth hygiene issues?
  • Altered mood and impact on quality of life such as sleep?


Based primarily on the person’s history and description of symptoms, along with results from physical and neurological examinations.

Other disorders that cause facial pain should be ruled out before trigeminal neuralgia is diagnosed. Some disorders that cause facial pain include postherpetic neuralgia (nerve pain following an outbreak of shingles), cluster headaches, and temporomandibular joint disorder (TMJ, which causes pain and dysfunction in the jaw joint and muscles that control jaw movement).

Most people with TN eventually will undergo a magnetic resonance imaging (MRI) scan to rule out a tumour or multiple sclerosis as the cause of their pain. This scan may or may not clearly show a blood vessel compressing the nerve. Special MRI imaging procedures can reveal the presence and severity of compression of the nerve by a blood vessel.

A diagnosis of classic trigeminal neuralgia may be supported by an individual’s positive response to a short course of an antiseizure medication.

Diagnosis of TN2 is more complex and difficult but tends to be supported by a positive response to low doses of tricyclic antidepressant medications (such as amitriptyline and nortriptyline), similar to other neuropathic pain diagnoses.

The International Headache Society has established criteria for making the diagnosis and includes the following:

  1. Paroxysmal attacks of pain lasting from a fraction of a second to 2 minutes, affecting 1 or more divisions of the trigeminal nerve and fulfilling criteria B and C.
  2. Pain has at least one of the following characteristics: (1) intense, sharp, superficial or stabbing; or (2) precipitated from trigger areas or by trigger factors
  3. Attacks stereotyped in the individual patient
  4. No clinically evident neurologic deficit
  5. Not attributed to another disorder


Idiopathic trigeminal neuralgia is a clinical diagnosis and often no testing is required after the health care professional takes a history of the situation and performs a physical examination which should be normal.

There are two specific areas to test. There can be no muscle weakness; V3 is responsible for chewing and there can be no jaw or facial weakness found. The corneal reflex controlled by V1must be present. When the cornea or covering of the eye is touched, the eye blinks in response. If these two findings are not normal, the search should begin for an inflammatory or compression cause of the trigeminal nerve. Some clinicians may order an MRI to help diagnose other conditions that may cause trigeminal neuralgia.

Other investigations may include

  • Blood tests – including FBC, ESR, CRP
  • Dental x-rays – for tooth misalignment, bone destruction, cysts, solid growths and sinus opacification.
  • Temporal artery biopsy.
  • Sialography or ultrasound for salivary gland pathology such as duct stones.

When to seek help

  • If you are showing increasing disability or neurological signs. A dentist can exclude an odontogenic cause and can refer onward to secondary care.
  • Clicking jaws or recurrent jaw dislocation warrants an examination by a doctor of dental surgery to exclude facial trauma.
  • Referral to ENT is required for any nasal (obstruction, epistaxis) or ear (hearing loss, tinnitus, discharge) symptoms.

New post with treatment options will appear here soon.



  1. National Institute of Neurological Disorders and Stroke:

© Willeke Van Eeckhoutte and Ireland, Multiple Sclerosis & Me, 2011-2017. Unauthorised use and/or duplication of this material without express and written permission from this blog’s author and/or owner is strictly prohibited. Excerpts and links may be used, provided that full and clear credit is given to Willeke Van Eeckhoutte and Ireland, Multiple Sclerosis & Me with appropriate and specific direction to the original content.

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