Trigeminal neuralgia
Trigeminal neuralgia causes brief, unilateral, electric shock-like facial pain in the maxillary or mandibular trigeminal distribution, often triggered by light touch, most commonly from neurovascular compression of the nerve; contrast-enhanced brain MRI evaluates for a structural or demyelinating cause, and first-line treatment is carbamazepine, with microvascular decompression or ablative procedures for medically refractory disease.
- Topic reviewThe full article, organized the way the exam asks it.
- ABIM-format MCQsVignettes with an explanation for every wrong answer.
- Key factsThe numbers and thresholds worth memorizing, up front.
- AI tutorMedBrain answers the question you're stuck on.
What this article covers
- Overview
Definition: trigeminal neuralgia is the most common and most intense cranial neuralgia, characterized by brief, severe, electric shock-like or stabbing facial pain confined to one or more divisions of the trigeminal nerve (cranial nerve V).
- Epidemiology
Age distribution: incidence increases with advancing age, with most cases occurring after age 50; onset before age 50, or bilateral symptoms, should raise suspicion for a secondary cause, particularly multiple sclerosis.
- Risk factors
Advancing age: the dominant risk factor, likely reflecting age-related vascular tortuosity and greater likelihood of neurovascular contact.
- Pathophysiology
Neurovascular compression: in most patients, a vessel, classically a loop of the superior cerebellar artery, pulsates against the trigeminal root as it exits the brainstem, producing focal demyelination at the contact point.
- Clinical features
Pain quality: sudden, brief, unilateral episodes of severe, electric shock-like or stabbing pain, lasting seconds to at most a couple of minutes per paroxysm.
- Differential diagnosis
Dental or temporomandibular joint pain: more constant and related to jaw movement or a visible dental source on examination, lacking the brief shock-like, trigger-refractory pattern of trigeminal neuralgia.
- Diagnosis
Establishing basis: the diagnosis is made clinically from the characteristic history of brief, unilateral, electric shock-like facial pain in a trigeminal distribution, often trigger-evoked, together…
- Management
First step: begin carbamazepine 100 mg PO twice daily, increasing by 200 mg per day as needed and tolerated to 400–800 mg per day in divided doses, maximum 1200 mg per day, as first-line…
- Complications
Chronic disabling pain and reduced quality of life: severe, recurrent, unpredictable pain can lead to anxiety around eating, speaking, and grooming (due to fear of triggering an attack), sometimes…
- Prognosis
Response to first-line medical therapy: most patients achieve meaningful pain relief with carbamazepine, particularly early in the disease course.
- Prevention
No established primary prevention: because the dominant mechanism is anatomic neurovascular contact or an unpredictable demyelinating event, there is no proven strategy to prevent a first episode.
Read the whole article
Subscribing to Internal Medicine opens every article, the full question bank and MedBrain, on the web, iPhone and Android.
Related articles
- Multiple sclerosis
Multiple sclerosis is an autoimmune, demyelinating CNS disorder causing optic neuritis, myelitis, and brainstem/cerebellar syndromes separated in space and time. Diagnosis uses the McDonald MRI-based criteria; acute relapses are treated with high-dose glucocorticoids, and disease-modifying therapy (interferon beta, glatiramer, or a higher-efficacy agent such as ocrelizumab or natalizumab) is started early to prevent relapse and disability accumulation.
- Migraine headache
Migraine is a primary episodic headache disorder diagnosed by ICHD-3 clinical criteria (recurrent attacks, 4-72 hours, pulsatile/unilateral pain with nausea or photophobia/phonophobia). First-line acute treatment is an NSAID or oral triptan started early in the attack; prevention with a beta-blocker, topiramate, or CGRP-targeted therapy is added once attacks are frequent or disabling.
- Cluster headache
Cluster headache is a trigeminal autonomic cephalalgia causing severe unilateral orbital or temporal pain lasting 15 to 180 minutes, up to eight times daily, with ipsilateral autonomic features. First-line acute treatment is 100% oxygen inhalation or subcutaneous sumatriptan; verapamil is first-line prevention.
- Facial palsy
Facial palsy is weakness of the muscles innervated by the facial nerve (cranial nerve VII); most cases are idiopathic (Bell palsy), producing unilateral weakness of both upper and lower facial muscles, distinguishing it from the upper-face-sparing pattern of a central (stroke) lesion. Classic Bell palsy needs no imaging and is treated with a 10-day course of oral prednisone started within 72 hours of onset.