DNP 637 Module 1 Case Study Discussion Board 1: Neurological System (Trigeminal Neuralgia) Example

Case Study Discussion Board 1: Shocks in the Cheek When She Chews

Two Seconds of Lightning: Diagnosing and Treating Trigeminal Neuralgia in a 58-Year-Old Woman in Primary Care

The Case and My Assigned Question

M.R. is a 58-year-old woman who reports three weeks of sudden, stabbing, electric pains in her right cheek and lower jaw. Each attack lasts one to two seconds, she has dozens a day, and they are set off by chewing, brushing her teeth and cold wind on her face. Between attacks she is pain-free. Her dentist found no dental cause. Her neurological examination, including facial sensation, corneal reflexes and the other cranial nerves, is normal. My assigned question: What is the most likely diagnosis, what workup is needed and what is the first-line treatment?

Initial Post

Diagnosis

M.R.'s history fits trigeminal neuralgia. Under ICHD-3, the diagnosis needs repeated attacks of one-sided facial pain confined to trigeminal territory, each lasting between a split second and two minutes, severe, with an electric, shooting or stabbing character, and brought on by harmless touches or movements in that area (Headache Classification Committee of the International Headache Society, 2018). Her pain follows the maxillary and mandibular divisions, is brief and severe and has clear triggers.

Workup

The key task is to separate classical trigeminal neuralgia, usually caused by a blood vessel compressing the nerve root, from secondary trigeminal neuralgia caused by multiple sclerosis or a tumor (Cruccu et al., 2016). Red flags for a secondary cause include onset before age 40, bilateral pain, sensory loss in the face, hearing loss or other cranial nerve findings. M.R. has none of these, but the European Academy of Neurology recommends MRI for all patients, using sequences that show the nerve root and any neurovascular contact, because a secondary cause cannot be excluded by examination alone (Bendtsen et al., 2019). I would order an MRI of the brain with trigeminal nerve sequences and baseline labs for medication safety: complete blood count, sodium and liver function.

First-Line Treatment

Carbamazepine is first-line therapy, with oxcarbazepine an equally effective and often better tolerated alternative (Bendtsen et al., 2019). I would start carbamazepine at 100 to 200 mg twice daily and increase gradually until the attacks stop or side effects limit the dose. Before starting either drug, patients of Asian ancestry should be tested for HLA-B*15:02, because carriers face a sharply higher risk of the severe skin reactions SJS and TEN (Phillips et al., 2018). Monitoring includes sodium, since both drugs cause hyponatremia, blood counts and liver tests, and a review of interactions, since carbamazepine induces CYP3A4. Opioids have no role. If medications fail or cannot be tolerated, or if the MRI shows neurovascular compression and she prefers a definitive option, I would refer her to neurosurgery to discuss microvascular decompression.

Reply to a Classmate (On Giant Cell Arteritis)

Priya, you raised giant cell arteritis because M.R. is over 50 and has jaw pain with chewing. That is a smart can't-miss diagnosis to name. Jaw claudication in giant cell arteritis is usually an aching or cramping pain that builds during sustained chewing and eases with rest, rather than a two-second electric shock, and it often comes with new headache, scalp tenderness or visual symptoms. Even so, at her age a quick ESR and CRP would be a low-cost way to close the question. Would you add them to the first visit or only if the MRI is normal?

Reply to a Classmate (On Patient Teaching)

Marcus, your point about teaching is important, because M.R. may stop eating or brushing to avoid attacks. I would add two things to your plan: tell her that carbamazepine works best when taken on schedule rather than at the first sign of pain, and warn her to report any rash in the first two months, along with dizziness or unsteadiness, which can raise her fall risk.

References

Bendtsen, L., Zakrzewska, J. M., Abbott, J., Braschinsky, M., Di Stefano, G., Donnet, A., Eide, P. K., Leal, P. R. L., Maarbjerg, S., May, A., Nurmikko, T., Obermann, M., Jensen, T. S., & Cruccu, G. (2019). European Academy of Neurology guideline on trigeminal neuralgia. European Journal of Neurology, 26(6), 831-849. https://doi.org/10.1111/ene.13950

Cruccu, G., Finnerup, N. B., Jensen, T. S., Scholz, J., Sindou, M., Svensson, P., Treede, R.-D., Zakrzewska, J. M., & Nurmikko, T. (2016). Trigeminal neuralgia: New classification and diagnostic grading for practice and research. Neurology, 87(2), 220-228. https://doi.org/10.1212/WNL.0000000000002840

Headache Classification Committee of the International Headache Society. (2018). The International Classification of Headache Disorders, 3rd edition. Cephalalgia, 38(1), 1-211. https://doi.org/10.1177/0333102417738202

Phillips, E. J., Sukasem, C., Whirl-Carrillo, M., Muller, D. J., Dunnenberger, H. M., Chantratita, W., Goldspiel, B., Chen, Y.-T., Carleton, B. C., George, A. L., Mushiroda, T., Klein, T., Gammal, R. S., & Pirmohamed, M. (2018). Clinical Pharmacogenetics Implementation Consortium guideline for HLA genotype and use of carbamazepine and oxcarbazepine: 2017 update. Clinical Pharmacology & Therapeutics, 103(4), 574-581. https://doi.org/10.1002/cpt.1004