Introduction
Background
Trigeminal neuralgia (TN), also known as tic douloureux, is a pain syndrome recognizable by the patient's history alone. The condition is characterized by pain often accompanied by a brief facial spasm or tic. Pain distribution is unilateral and follows the sensory distribution of cranial nerve V, typically radiating to the maxillary (V2) or mandibular (V3) area. At times, both distributions are affected. Physical examination will usually eliminate alternative diagnoses. Signs of cranial nerve dysfunction or other neurologic abnormality exclude the diagnosis of idiopathic trigeminal neuralgia and suggest that pain may be secondary to a structural lesion.
Microscopic demonstration of demyelination in primary trigeminal neuralgia. A tortuous axon is surrounded by abnormally discontinuous myelin. Electron microscope, 3, 300 X.
MRI with high resolution on the pons demonstrating the trigeminal nerve root. In this case, the patient with trigeminal neuralgia has undergone gamma-knife therapy, and the left-sided treated nerve (arrow) is enhanced by gadolinium.
Pathophysiology
The mechanism of pain production remains controversial. One theory suggests that peripheral injury or disease of the trigeminal nerve increases afferent firing in the nerve; failure of central inhibitory mechanisms may be involved as well. Pain is perceived when nociceptive neurons in a trigeminal nucleus involve thalamic relay neurons. In about 85% of cases, no lesion is identified even after extensive investigations, and the etiology is labeled idiopathic by default and is then categorized as classic trigeminal neuralgia.Aneurysms, tumors, chronic meningeal inflammation, or other lesions may irritate trigeminal nerve roots along the pons causing symptomatic trigeminal neuralgia. An abnormal vascular course of the superior cerebellar artery is often cited as the cause. Uncommonly, an area of demyelination from multiple sclerosis may be the precipitant. Lesions of the entry zone of the trigeminal roots within the pons may cause a similar pain syndrome.
Infrequently, adjacent dental fillings composed of dissimilar metals may trigger attacks, and an atypical case has been reported following tongue piercing.
Frequency
International
Trigeminal neuralgia (TN) is uncommon, with an estimated prevalence of 155 cases per million persons.
Mortality/Morbidity
- No mortality is associated with idiopathic trigeminal neuralgia (TN), although secondary depression is common if a chronic pain syndrome evolves. In rare cases, pain may be so frequent that oral nutrition is impaired.
- In symptomatic or secondary trigeminal neuralgia, morbidity or mortality relates to the underlying cause of the pain syndrome.
Sex
The male-to-female ratio is 2:3.
Age
Development of trigeminal neuralgia in a young person suggests the possibility of multiple sclerosis.
- Idiopathic trigeminal neuralgia typically occurs in patients in the sixth decade of life, but it may occur at any age.
- Symptomatic or secondary trigeminal neuralgia tends to occur in younger patients.
Clinical
History
History is the most important factor in the diagnosis of trigeminal neuralgia (TN).
- Nature of pain
- Pain is brief and paroxysmal, but it may occur in volleys of multiple attacks.
- Pain is stabbing or shocklike and is typically severe.
- Distribution of pain
- One or more branches of the trigeminal nerve (usually maxillary or mandibular) are involved.
- Pain is unilateral (rarely bilateral).
- Duration of pain is typically from a few seconds to 1-2 minutes.
- Pain may occur several times a day; patients typically experience no pain between episodes.
- Trigger points
- Various triggers may commonly precipitate a pain attack.
- Light touch or vibration is the most provocative.
- Activities such as shaving, face washing, or chewing often trigger an episode.
- Stimuli as mild as a light breeze may provoke pain in some patients.
- Pain provokes brief muscle spasm of the facial muscles, thus producing the tic.
Physical
Physical examination findings are normal; in fact, a normal neurologic examination is part of the definition of classic trigeminal neuralgia (TN). Perform a careful examination of the cranial nerves, including the corneal reflex.
- Be alert to the presence of any abnormality on physical examination. Abnormality suggests that the pain syndrome is secondary to another process.
- Remember that patients report pain following stimulation of a trigger point; thus, some patients may limit their examination for fear of stimulating these points.
Causes
Most patients' conditions are idiopathic, but compression of the trigeminal roots by tumors or vascular anomalies may cause similar pain (see Pathophysiology).
More on Trigeminal Neuralgia |
 Overview: Trigeminal Neuralgia |
| Differential Diagnoses & Workup: Trigeminal Neuralgia |
| Treatment & Medication: Trigeminal Neuralgia |
| Follow-up: Trigeminal Neuralgia |
| Multimedia: Trigeminal Neuralgia |
| References |
| Further Reading |
| Next Page » |
References
Gronseth G, Cruccu G, Alksne J, Argoff C, Brainin M, Burchiel K, et al. Practice parameter: the diagnostic evaluation and treatment of trigeminal neuralgia (an evidence-based review): report of the Quality Standards Subcommittee of the American Academy of Neurology and the European Federation of Neurological Societies. Neurology. Oct 7 2008;71(15):1183-90. [Medline].
Bennetto L, Patel NK, Fuller G. Trigeminal neuralgia and its management. BMJ. Jan 27 2007;334(7586):201-5. [Medline].
Cheshire WP Jr. The shocking tooth about trigeminal neuralgia. N Engl J Med. Jun 29 2000;342(26):2003. [Medline].
Chole R, Patil R, Degwekar SS, Bhowate RR. Drug treatment of trigeminal neuralgia: a systematic review of the literature. J Oral Maxillofac Surg. Jan 2007;65(1):40-5. [Medline].
Kubitz PK, Wijdicks EF, Bolton CF. Tic douloureux or "tic dentaire". Neurology. Jan 27 2004;62(2):333. [Medline].
Liu JK, Apfelbaum RI. Treatment of trigeminal neuralgia. Neurosurg Clin N Am. Jul 2004;15(3):319-34. [Medline].
Rasche D, Kress B, Schwark C, Wirtz CR, Unterberg A, Tronnier VM. Treatment of trigeminal neuralgia associated with multiple sclerosis: case report. Neurology. Nov 9 2004;63(9):1714-5. [Medline].
Zvartau-Hind M, Din MU, Gilani A, Lisak RP, Khan OA. Topiramate relieves refractory trigeminal neuralgia in MS patients. Neurology. Nov 28 2000;55(10):1587-8. [Medline].
Further Reading
Clinical guidelines
Practice parameter: the diagnostic evaluation and treatment of trigeminal neuralgia (an evidence-based review). Report of the Quality Standards Subcommittee of the American Academy of Neurology and the European Federation of Neurological Societies. Gronseth G, Cruccu G, Alksne J, Argoff C, Brainin M, Burchiel K, Nurmikko T, Zakrzewska JM. Practice Parameter: The diagnostic evaluation and treatment of trigeminal neuralgia (an evidence-based review). Report of the Quality Standards Subcommittee of the American Academy of Neurology and the European Federation of Neurological Societies. Neurology 2008 Oct 7;71(15):1183-90.
Keywords
trigeminal neuralgia, symptoms, treatment, causes, TN, tic douloureux, pain syndrome, idiopathic TN, idiopathic trigeminal neuralgia, secondary trigeminal neuralgia, secondary TN, facial spasm, tic, abnormal vessels, aneurysms, tumors, chronic meningeal inflammation, multiple sclerosis, vascular anomalies
