Trigeminal neuralgia -Atypical facial pain

The International Association for Study of Pain (IASP) has defined Trigeminal neuralgia as “sudden, usually unilateral, severe, brief, stabbing, recurrent episodes of pain in the distribution of one or more branches of the trigeminal nerve.”

1. Trigeminal neuralgia Fact sheet

2. Definition The International Association for Study of Pain (IASP) has defined Trigeminal neuralgia as “sudden, usually unilateral, severe, brief, stabbing, recurrent episodes of pain in the distribution of one or more branches of the trigeminal nerve.”

3. Etiology of Trigeminal neuralgia The exact etiology of Trigeminal neuralgia is unknown.

4. Neurovascular compression Most common origin =Superior cerebellar artery involving about 50% of the cases . In 25% of the cases, the origin seems to be exclusively venous, while in a few cases, the involvement is considered mixed. (Hardy, D. G.; Rhoton , A. L. Microsurgical relationships of the superior cerebellar artery and the trigeminal nerve. J. Neurosurg . 1978, 49 (5), 669-678) Jannetta et al concluded that microvascular decompression is a safe and effective treatment for trigeminal neuralgia, with a high rate of long-term success. (N Engl J Med 1996;334: 1077-83.)

5. Multiple sclerosis(MS ) Trigeminal neuralgia is reported to occur in 0.9% to 4.5% of patients with multiple sclerosis . Hooge J.P., and Redekop W.K.: Trigeminal neuralgia in multiple sclerosis. Neurology 45: 1294—1296, 1995. P atients with multiple sclerosis to be twenty times more likely to develop Trigeminal neuralgia than the general population. Foley, P.L.; Vesterinen , H.M.; Laird, B.J.; Sena , E.S.; Colvin, L.A.; Chandran , S.; MacLeod, M.R.; Fallon, M.T. Prevalence and natural history of pain in adults with multiple sclerosis: Systematic review and meta-analysis. Pain 2013, 154, 632–642.

6. Tumor The reported range for patients with Trigeminal neuralgia due to tumors is from 0.8% to 11.6%. Bullitt E., Tew J.M., and Boyd J.: Intracranial tumors in patients with facial pain. J Neuro surg 64:865—871,1986.

7. Diabetes mellitus An electrophysiological study indicated that diabetes often affects trigeminal nerve function. . Urban P.P., Forst T., Lenfers M., Koehler J., Connemann B.J.,and Beyer J.: Incidence of subclinical trigeminal and facial nerve involvement in diabetes mellitus. Electro- myogr Clin Neurophysiol39: 267—272, 1999

8. Herpes simplex virus(HSV ) Ecker et al. have suggested that HSV is a causative agent for Trigeminal neuralgia. HSV reactivation occurred in 10% of patients after MVD including 1% of herpes zoster. A previous history of herpes labialis and reoperation is identified as risk factors for reactivation.

9. Allergy Hanes advanced a theory that the lack of sufficient gastric acid caused improper protein digestion with resultant release of histamine or a histamine-like substance into the general circulation. HanesW.J .: Tic douloureux : A new allergic approach to the etiology and treatment . A report of seventy six cases. Ann Allergy 20: 635—448, 1962

10. Theories Described for Trigeminal Neuralgia Trigeminal Convergence Projection Theory Bioresonance Hypothesis Ignition Hypothesis

11. Demograpy Trigeminal neuralgia is considered a rare condition, and epidemiological studies are scarce . .

12. Incidence and prevalence The first report on Trigeminal neuralgia incidence was published in the US by Penman in approximately 107 men and 200 women per 1 million people. Penman, J. Trigeminal neuralgia. In: Vinken , P. J.; Bruyn , G. W.;Klawans , H. L. Harold L. Handbook of Clinical Neurology; Amsterdam:North -Holland, 1968. In the general population, an analysis of prevalence studies indicates that the range of Trigeminal neuralgia prevalence is 0.03% to 0.3%. De Toledo, I. P.; Conti Réus, J.; Fernandes, M.; Porporatti, A. L.; Peres, M. A.; Takaschima, A.; Linhares, M. N.; Guerra, E.; De Luca Canto, G. Prevalence of trigeminal neuralgia. J. Am. Dent. assoc. 2016, 147 (7), 570-576.

13. Incidence and prevalence Female predominance (m: f = 1:2 ~2:3) Rozen , T. D. Trigeminal neuralgia and glossopharyngeal neuralgia. Neurol . Clin., 2004, 22 (1), 185-206. Katusic , S.; Beard, C. M.; Bergstralth , E.; Kurland, L. T. Incidence and clinical features of trigeminal neuralgia, Rochester, Minnesota, 1945-1984. Ann. Neurol., 1990, 27 (1), 89-95.

14. Age Mean age: 50 yrs . TN is uncommon in young adults and rare in children. Pediatric Trigeminal neuralgia is more likely to be bilateral (42%) compared with adult Trigeminal neuralgia . In 90% of the cases, symptoms begin after age 40, and incidence progressively increases with age. De Toledo, I. P.; Conti Réus, J.; Fernandes, M.; Porporatti, A. L.; Peres, M. A.; Takaschima, A.; Linhares, M. N.; Guerra, E.; De Luca Canto, G. Prevalence of trigeminal neuralgia. J. Am. Dent. assoc. 2016, 147 (7), 570-576. Mason, W. E.; Kollros, P.; Jannetta, P. J. Trigeminal neuralgia and its treatment in a 13-month-old child: A review and case report. J. Craniomandib. Disord., 1991, 5 (3), 213-216.

15. Racial or geographic differences There are no reports of racial or geographic differences accounting for Trigeminal neuralgia incidence. Erika Ivanna Araya etal . Trigeminal Neuralgia: Basic and Clinical Aspects. Current Neuropharmacology , 2020, 18, 109-119

16. F amily history The occurrence of trigeminal neuralgia in families has been uncommon and the subject of controversy. Katusic et al. found that 5.3% of the patients is family history of Trigeminal neuralgia .

17. Hypertension and Trigeminal neuralgia The relationship between hypertension and Trigeminal neuralgia has also been investigated by some groups, but the results are still inconclusive. Hypertension may be a predisposing factor for the development of Trigeminal neuralgia . Teruel , A.; Ram, S.; Kumar, S. K. S.; Hariri, S.; Clark, G. T. Prevalence of hypertension in patients with trigeminal neuralgia. J. Headache Pain, 2009, 10 (3), 199-201

18. Site of facial region The right side of the face is affected more commonly (ratio of 1.5:1) Neto, H. S.; Camilli, J. A.; Marques, M. J. Trigeminal neuralgia is caused by maxillary and mandibular nerve entrapment: Greater incidence of right-sided facial symptoms is due to the foramen rotundum and foramen ovale being narrower on the right side of the cranium. Med. Hypotheses, 2005, 65 (6), 1179-1182 .

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