Spotlight: Trigeminal neuralgia in MS

Spotlight: Trigeminal neuralgia in MS

28/07/2023
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Spotlight: Trigeminal neuralgia in MS

Trigeminal neuralgia (TN) refers to a type of neuropathic pain caused by damage to the trigeminal nerve, which is responsible for transmitting signals from the face to the brain. It is defined as sudden paroxysmal electric shock-like pain in the face that is brief in onset and cessation, and usually unilateral. It occurs in recurrent episodes and is limited to the distribution of one or more of the trigeminal nerve branches responsible for sensations in the head1:

  • Ophthalmic division: This nerve is responsible for sensations in the forehead, eyeball, lacrimal glands or tear ducts, upper eyelids, frontal sinuses, and side of the nose.
  • Maxillary division: This nerve is responsible for the middle third of the face.
  • Mandibular division: This nerve is responsible for the lower jaw, including the attached teeth, the temporomandibular or jaw joint, the mucous membrane of the mouth, and the front two-thirds of the tongue.

These painful paroxysms may occur many times a day and can last from a fraction of a second to 2 minutes, with refractory periods of no pain in between in about 50% of patients. The other half of TN patients will experience continued pain of lower intensity in the same distribution2.

TN can be triggered by things as simple as light touch of the affected area, talking or chewing, and brushing teeth. Stimulus-dependence is considered one of the most striking characteristics of TN and a criterion of clinically established TN.3 It can be classified into the following three categories3,4:

  • Idiopathic TN (primary): no apparent cause
  • Classical TN (primary): caused by vascular compression of one or more of the trigeminal roots
  • Secondary TN: caused by neurological disease such as MS plaque that damage the nervous system

TN is one of the most common neuropathic pain syndromes in people with MS and can greatly affect their quality of life, increasing the prevalence of anxiety, depression and sleep disorders in affected patients5. People with MS have an approximately 20 times greater risk of TN relative to the general population, with an estimated 3–5% experiencing the painful symptom, without differences between relapsing-remitting, secondary and progressive forms6-8. Although the underlying mechanisms have not been completely explained, damage to the myelin sheath that protects the trigeminal nerve is thought to be at the root of the pain sensations in people with MS9. Sometimes, a blood vessel pressing on the nerve can cause trigeminal neuralgia.

TN secondary to MS is more common in women than in men, and affects the right side more frequently than the left side10. Although the characteristics of TN secondary to MS are similar to those observed in classical TN, the pain is more frequently bilateral in people with MS, with an estimated 18% of patients reported to have bilateral TN.

Classical or idiopathic TN can be treated with medications, usually starting with carbamazepine or other sodium-channel blockers. Another commonly used medication is baclofen. It relaxes the muscles to help ease the pain. If pharmacologically derived treatments fail, patients are generally referred to neurosurgery to discuss gamma knife, rhizotomy or vascular decompression11.

Guidelines for treating MS-associated TN have not been well established. According to international guidelines, there is insufficient evidence to support or refute the effectiveness of any medication in treating pain in TN secondary to MS12. It is generally agreed that the first line therapy is pharmacological and based on the use of sodium-channel blockers and oxcarbazepine. Gabapentinoids and antidepressants might be more effective in persistent than in paroxysmal pain and are often tried as an add-on to oxcarbapezine or carbamazepine in people with the atypical form of TN with concomitant persistent pain13.

Available data indicate that medications are poorly tolerated in people with MS, and can possibly exacerbate existing symptoms of the neurodegenerative disorder14. It is also becoming increasingly recognised that people with MS and TN can become medically refractory to treatment and increasingly require surgical intervention for pain management15.

A multidisciplinary care pathway for these patients has been proposed which is the same as for classical TN16. This pathway has been shown to result in significant improvement in global impression of change and includes support from clinical nurse specialists and psychology support to help patients live well with pain and uncertainly17,18.

In summary, people with MS experiencing TN face many challenges in achieving pain control in relation to their condition. Enabling the person to be well informed regarding pharmacological and surgical options available via joint discussions with physicians and neurosurgeons ensures they are empowered to make the right decision for their individual care.

Sources | Further reading

  1. Racke M, Frohman E, Frohman T.  Pain in MS: Understanding pathophysiology, diagnosis and management through clinical vignettes. Front Neurol. 2022;12;799698.
  2. Maarberg S, Di Stefano G, Bendsten L, Cruccu G. Trigeminal neuralgia-diagnosis and treatment. Cephalgia. 2017;37:648–57.
  3. Cruccu G, Finnerup NB, Jensen TS, et al. Trigeminal neuralgia: new classification and diagnostic grading for practice and research. Neurology 2016;87:220–22.
  4. Bendsten L, Zakrzewska J, Abbott J, et al. European Academy of Neurology guideline on trigeminal neuralgia. Eur J Neurol. 2019;26:831-49.
  5. Wu TH, Hu LY, Lu T, et al. Risk of psychiatric disorders following trigeminal neuralgia: a nationwide population-based retrospective cohort study. J Headache Pain. 2015;16:64.
  6.  Jensen T, Rasmusssen P, Reske-Nielsen E. Association of trigeminal neuralgia with multiple sclerosis; clinical and pathological features. Acta Neurologica Scandanavia. 1982;66:182–189.
  7. Hooge JP, Redekop WK. Trigeminal neuralgia in multiple sclerosis. Neurology 1995;45:1294–1296.
  8. Solaro C, Cella M, Signori A, et al. Identifying neuropathic pain in patients with multiple sclerosis: a cross-sectional multicenter study using highly specific criteria. J Neurol. 2018;265:828–835.
  9. Laakso SM, Hekali O, Kurdo G, et al. Trigeminal neuralgia in multiple sclerosis: prevalence and association with demyelination. Acta Neurol Scand. 2020;142:139–144.
  10. Truini A, Prosperini L, Calistri V, et al. A dual concurrent mechanism explains trigeminal neuralgia in patients with multiple sclerosis. Neurology 2016;31:2094–2099.
  11. Reder A, Arnason B. Trigeminal neuralgia in multiple sclerosis relieved by a prostaglandin E analogue. Neurology 1995;45:1097–98.
  12. Cruccu G, Gronseth G, Alksne J, et al. AAN-EFNS guidelines on trigeminal neuralgia management. Eur J Neurol. 2008;15:1013–1028.
  13. Di Stefano G, Truini A. Pharmacological treatment of trigeminal neuralgia. Expert Rev Neurother. 2017;17:1003–1011.
  14. Ramsaransing G, Zwanikken C, De Keyser J. Worsening of symptoms of multiple sclerosis associated with carbamazepine. BMJ 2000; 22:320–1113.
  15. Krishnan S, Bigder M, Kaufmann AM. Long-term follow-up of multimodality treatment for multiple sclerosis-related trigeminal neuralgia. Acta Neurochir (Wien). 2018;160:135–144.
  16. Zakrzewska JM. Trigeminal neuralgia. Dent Update. 2019;46:730–737.
  17. O'Callaghan L, Floden L, Vinikoor-Imler L, et al. Burden of illness of trigeminal neuralgia among patients managed in a specialist center in England. J Headache Pain 2020;21:130.
  18. Ghiai A, Mohamed TY, Hussain M, Hayes E, Zakrzewska JM. The role of a clinical nurse specialist in managing patients with trigeminal neuralgia. Br J Pain. 2020;14:180–187.
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