eMedicine Specialties > Neurology > Headache and Pain

Trigeminal Neuralgia

Author: Gordon H Campbell, MSN, Senior Nurse Practitioner, Department of Mental Health and Neuroscience, Portland Veterans Affairs Medical Center
Coauthor(s): Helmi L Lutsep, MD, Professor, Department of Neurology, Oregon Health and Science University; Associate Director, Oregon Stroke Center
Contributor Information and Disclosures

Updated: Jun 8, 2006

Introduction

Background

Trigeminal neuralgia (TN) is a common and potentially disabling pain syndrome, the precise pathophysiology of which remains obscure. Although neurologic examination findings are normal in patients with the idiopathic variety, the clinical history is distinctive. The initial response to carbamazepine therapy typically is diagnostic and successful. Despite obtaining this satisfying early relief with medication, patients may experience breakthrough pain that requires additional drugs and, in some patients, one or more of a variety of surgical interventions.

Historical note

In 1900, in a landmark article, Cushing reported a method of total ablation of the gasserian ganglion to treat TN.

In 1912 Osler described TN as follows:

• In patients with advanced TN, the paroxysms follow one another rapidly without any assignable cause, and in the intervals the patient may never be quite free from pain.
• They are initiated by almost any form of external stimulus, for example by a draught of air; movement of the facial muscles or tongue while speaking; touching the skin, particularly over those points from which the pain seems to take its origin; and the act of swallowing, especially when the pain involves the mucous membrane field of distribution of the nerve.
• It is not a self-limited disease. In some instances, the neuralgia reaches such a frightful intensity that it renders the patient's life unbearable. In earlier times, suicide was not an uncommon consequence.

Pathophysiology

Usually no structural lesion is present, although many investigators agree that vascular compression, typically venous or arterial loops at the trigeminal nerve entry into the pons, is critical to the pathogenesis of the idiopathic variety. This compression results in focal trigeminal nerve demyelination.

Since the exact pathophysiology remains controversial, TN may have either a central and/or peripheral etiology.

Frequency

United States

According to Penman in 1968, the prevalence of TN is approximately 107 men and 200 women per 1 million people. Mauskop states that approximately 40,000 patients in the US suffer from this condition at any particular time. The incidence is 4-5 cases per 100,000.

Rushton and Olafson found that approximately 1% of patients with multiple sclerosis (MS) develop TN, whereas Jensen et al stated that 2% of patients with TN have MS.

Mortality/Morbidity

• TN is not associated with a shortened life. However, the morbidity associated with the chronic and recurrent facial pain can be considerable if the condition is not controlled adequately.
• Individuals may choose to limit activities that precipitate pain, such as chewing, possibly losing weight in extreme circumstances.
• TN may evolve into a chronic pain syndrome, and patients may suffer from depression and related loss of daily functioning.

Race

No racial risk factors have been identified.

Sex

The male-to-female ratio is 2:3.

Age

• Age of onset typically is 60-70 years; thus, advanced age is a major risk factor.
• Patients who present with the disease when aged 20-40 years are more likely to suffer from a demyelinating lesion in the pons secondary to MS.
• MS and hypertension are the 2 risk factors found in epidemiologic studies.

Clinical

History

• Clinical presentation
  • TN presents as a stabbing unilateral facial pain that is triggered by chewing or similar activities or by touching affected areas on the face.
  • Patients can localize their pain precisely. The pain is not confined exclusively to one of the 3 divisions of the nerve but more commonly runs along the line dividing either the mandibular and maxillary nerves or the mandibular and ophthalmic portions of the nerve.
    • Of patients, 60% complain of lancinating pain shooting from the corner of the mouth to the angle of the jaw.
    • Jolts of pain from the upper lip or canine teeth to the eye and eyebrow, sparing the orbit itself, are experienced by 30% of patients. This distribution falls between the division of the first and second portions of the nerve.
    • According to Patten, less than 5% of patients experience ophthalmic branch involvement.
  • Strictly unilateral, the disorder affects the right side of the face 5 times more frequently than the left.
  • Pain quality is characteristically severe, paroxysmal, and lancinating.
    • It commences with a sensation of electrical shocks in an affected area, then quickly crescendos in less than 20 seconds to an excruciating discomfort felt deep in the face, often contorting the patient's expression.
    • The pain then begins to fade within seconds, only to give way to a burning ache lasting seconds to minutes.
  • During attacks, patients may grimace; hence the term "tic douloureux."
  • The number of attacks may vary from less than one per day, to a dozen or more per hour, up to hundreds per day. Outbursts fully abate between attacks, even when they are severe and frequent.
  • TN is an exception to the rule that nerve injuries typically produce symptoms of constant pain and allodynia. If the pain is particularly frequent, patients may be difficult to examine during the height of an attack.
  • A valuable clue to the diagnosis is the triggering of the pain with certain activities. Patients carefully avoid rubbing the face or shaving a trigger area, in contrast to other facial pain syndromes, in which they massage the face or apply heat or ice.
    • According to Sands, trigger zones, or areas of increased sensitivity, are present in one half of patients and often lie near the nose or mouth.
    • Chewing, talking, smiling, or drinking cold or hot fluids may initiate TN pain. Touching, shaving, brushing teeth, blowing the nose, or encountering cold air from an open automobile window also may elicit pain.
  • In contrast to migrainous pain, persons with TN rarely suffer attacks during sleep, which is a key point in the history.
  • Patients with MS and TN have similar complaints to those with the idiopathic variety, except that they present at a much younger age (often <40 y).
    • Some present with atypical facial pain, without trigger zones, and without the lancinating brief paroxysms of discomfort.
    • As previously noted, TN is not unusual in MS, but it is rarely the first manifestation. Typically, it occurs in the advanced stages of MS.
• Natural history and prognosis
  • After an initial attack, the disorder may remit for months or even years. Thereafter the attacks may become more frequent, more easily triggered, more disabling, and may require long-term medication.
  • Patients may find immediate and satisfying relief with one medication, typically carbamazepine. However, over the years, they may require a second or third drug to control breakthrough episodes and finally may need surgical intervention.
  • Simpler, less invasive procedures are well tolerated but usually provide only short-term relief.
    • At this point, further and perhaps more invasive operations may be required, and with these procedures the risk of the disabling adverse effect of anesthesia dolorosa increases.
    • The long-term prognosis of this disorder varies.
  • According to Fromm et al, some patients may present with pretrigeminal neuralgia syndrome for a period of weeks or even years before developing the customary symptoms of TN. They complain of an unrelenting sinus pain or toothache lasting for hours, triggered by moving the jaw or drinking fluids. Not surprisingly, they first seek dental care. Some find benefit from baclofen or carbamazepine.

Physical

• In idiopathic TN, neurologic examination findings are normal.
  • Facial sensation, masseter bulk and strength, and corneal reflexes should be intact.
  • No sensory loss is found unless checked immediately after a burst of pain. Any permanent area of numbness excludes the diagnosis.
  • The corneal reflex also should be intact. Loss of this reflex also excludes the diagnosis of idiopathic TN, unless a previous trigeminal nerve section procedure has been performed.
  • The diagnosis of idiopathic TN is tenable only if no physical findings of fifth nerve dysfunction are present.
  • Any jaw or facial weakness or swallowing difficulties suggests another etiology.
  • In patients with MS or a structural lesion and TN, sensory loss often is found on examination.
• Any objective abnormalities in the neurologic examination exclude the diagnosis of idiopathic TN.

Causes

Other diagnostic considerations are relevant with TN.

• Other syndromes with paroxysmal lancinating head pain include the less common glossopharyngeal neuralgia (GN) and occipital neuralgia (ON) syndromes.
• GN causes pain in the tonsillar fossa, posterior pharynx, and ear and may be initiated by coughing, yawning, or swallowing cold liquids.
• During acute attacks of this disease, which frequently is associated with an underlying pathology, the patient may be unable to speak and tries to avoid moving the lips or tongue.
• An involuntary startle during an attempt to touch the affected side of the face is diagnostic.
• ON causes pain in the posterior head region.
  • Thus, the distribution easily distinguishes it from TN.
  • Confusion arises only if the patient cannot provide a clear history.
• According to Goadsby and Lipton, paroxysmal hemicrania syndromes typically last only seconds, similar to TN, but occur in and around one eye.
• Intense unilateral conjunctival injection and lacrimation signal an autonomic component, which further distinguishes this condition.
• This condition does not respond to carbamazepine.
• Migraine and cluster headaches may produce severe unilateral pain but are not triggered by movement or contact with the face; nor do they respond promptly to carbamazepine.
• According to Turp and Gobetti, atypical face pain usually extends beyond the distribution of the fifth cranial nerve, rarely is triggered, and presents with a steady unrelenting discomfort lasting hours to days.
• Secondary TN is a consideration.
• When pain is associated with hyperesthesia along the course of the fifth nerve or is observed with other cranial neuropathies, symptomatic or secondary TN is much more likely than the idiopathic form.
• Further investigation may reveal MS, a tumor in the posterior fossa, or a tumor on thetrigeminal nerve.
• Acoustic neuromas, cerebral aneurysms, trigeminal neuromas, and meningiomas can produce syndromes similar to idiopathic TN. Consider these conditions in patients with onset of pain when younger than 40 years, those with predominant forehead and/or orbit pain (ie, first division of the trigeminal nerve), or those with bilateral facial pain.
• Further, consider secondary TN in patients with bilateral sensory loss or weakness of the facial muscles or jaw.
• Patients with prominent hemifacial spasm, especially if it is continuous, may have tic convulsif, a condition associated with a dilated and ectatic basilar artery or other vascular malformation compressing the trigeminal nerve.
• Brain MRI with and without contrast is critical in diagnosing the secondary causes of TN.
• Trigeminal neuropathy also is a consideration.
• As noted, idiopathic TN presents as episodic, unilateral, lancinating, triggerable, often shocklike facial pain with pain-free intervals.
• Trigeminal neuropathic pain, by contrast, presents as a constant, unilateral, often mild facial pain with prominent sensory loss. It is nontriggerable and unremitting. It may be either symptomatic or idiopathic.
• To further complicate diagnostic matters, the clinician may encounter atypical TN, a syndrome that overlaps TN and trigeminal neuropathy.
• This syndrome consists of constant pain that episodically intensifies.
• According to Burcheil, these patients experience both lancinating triggered pain and a baseline, constant, dull and throbbing discomfort.
• The atypical form may occur in up to 5% of people after facial surgery or significant trauma and in 1-5% after the removal of impacted teeth.
• In the experience of many neurosurgeons, atypical trigeminal neuralgic pain results from lesions or injuries of the trigeminal nerve root distal to the route entry zone but with even greater compression than found in the idiopathic form of TN.
• In contrast to trigeminal neuropathy, whether typical or atypical, atypical facial pain is distinguished by the extension of discomfort beyond the distribution of the fifth cranial nerve and by the frequent lack of triggers.

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