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This is a clinician-written, evidence-based summary aligned to the 2026 MLA Content Map. It is intended for medical students and junior doctors preparing for the UKMLA. Always cross-reference with NICE guidance, local protocols, and clinical judgement.
The Bottom Line
- Severe paroxysmal electric shock-like or stabbing pain lasting seconds-minutes in trigeminal nerve distribution (V2 and V3 most common)
- Triggered by light touch: eating, talking, brushing teeth, cold wind — the hallmark
- Most common cause: neurovascular compression of trigeminal nerve root (usually by superior cerebellar artery)
- First-line treatment: carbamazepine 100–200 mg BD, titrated to response. Monitor FBC and LFTs
- MRI brain to exclude secondary causes: MS plaque, CPA tumour, vascular malformation
Overview
Trigeminal neuralgia (TN, tic douloureux) is a facial pain syndrome characterised by recurrent paroxysms of severe, electric shock-like pain in the distribution of one or more branches of the trigeminal nerve. The maxillary (V2) and mandibular (V3) divisions are most commonly affected. Classical TN is caused by neurovascular compression of the trigeminal nerve root entry zone, usually by the superior cerebellar artery, causing focal demyelination and ectopic nerve firing. Secondary TN occurs due to MS, cerebellopontine angle tumour (vestibular schwannoma), or other structural lesion.
Epidemiology
Incidence is approximately 12 per 100,000 per year. It is more common in women and increases with age (peak onset 50–70 years). Young-onset TN (<40 years) should raise suspicion of MS. Right-sided pain is more common than left (3:2).
Clinical Features
Symptoms
Intense paroxysmal stabbing or electric shock-like pain lasting seconds to 2 minutes
Pain in V2 (maxillary) and/or V3 (mandibular) distribution — V1 alone is uncommon and should raise suspicion of secondary cause
Triggered by light touch: eating, talking, brushing teeth, shaving, cold wind, touch to face
Trigger zones: nasolabial fold, upper lip, lateral nose, chin
Pain-free intervals between paroxysms
Refractory periods after attacks (cannot retrigger immediately)
Continuous background pain between attacks (suggests secondary cause or progression)
Signs
Normal neurological examination in classical TN
Sensory loss in trigeminal distribution = red flag for secondary cause (MS, tumour)
Patient may avoid touching face, refuse to eat, appear distressed
Investigations
First-line
MRI brainNICE CG150 recommends MRI for all new trigeminal neuralgia. To exclude secondary causes: MS plaque (brainstem), CPA tumour, vascular malformation. May show neurovascular contact
Second-line
MRI with CISS/FIESTA sequencesHigh-resolution MRI of posterior fossa — delineates vascular contact with trigeminal nerve root for surgical planning
Specialist
Trigeminal reflexes / neurophysiologyMay help distinguish classical from secondary TN if clinical doubt
1
Pharmacological (first-line)
- Carbamazepine 100–200 mg BD, titrated gradually (max 1,600 mg/day) — effective in ~70%
- Monitor FBC, LFTs, U&Es (risk of hyponatraemia, agranulocytosis, Stevens-Johnson syndrome, hepatotoxicity)
- HLA-B*15:02 testing before starting in patients of Han Chinese, Thai, or South-East Asian descent (risk of SJS/TEN)
- Oxcarbazepine: alternative to carbamazepine — may be better tolerated
2
If carbamazepine fails or not tolerated
- Refer to specialist pain service or neurology
- Consider: lamotrigine, baclofen, gabapentin, phenytoin as add-on or alternative
3
Surgical options (specialist)
- Microvascular decompression (MVD): definitive treatment for classical TN with neurovascular compression. ~80% pain-free long-term. Carries surgical risk (hearing loss, stroke)
- Percutaneous procedures: radiofrequency thermocoagulation, balloon compression, glycerol injection — for those unfit for MVD
- Stereotactic radiosurgery (gamma knife): non-invasive alternative — slower onset of relief
Complications
- Refractory pain: Some patients become resistant to medical therapy — surgical referral
- Carbamazepine side effects: Drowsiness, dizziness, hyponatraemia, rash, agranulocytosis, hepatotoxicity, SJS/TEN
- Depression and suicide risk: Chronic severe pain — screen and support
- Weight loss: Pain triggered by eating can lead to avoidance of food
UKMLA Exam Tips
- 1Electric shock-like facial pain triggered by light touch = trigeminal neuralgia
- 2Carbamazepine is first-line — effective in ~70%. Monitor FBC and LFTs
- 3Sensory loss in trigeminal distribution = secondary TN — investigate for MS or tumour
- 4V1 involvement or bilateral TN = think MS or structural lesion
- 5MRI brain for ALL new trigeminal neuralgia (NICE CG150)
- 6Microvascular decompression is the definitive surgical treatment
- 7Young patient with TN: must exclude MS (check for other demyelinating features, MRI brain)
practicetest your knowledge on trigeminal neuralgiaApply what you've learnt with UKMLA-style questions from the iatroX Q-Bank — neurology and beyond.
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Trigeminal Neuralgia: guidance by region
Recommendations, thresholds and pathways can differ. Open the page written for the jurisdiction you need.