Synopsis
Identify the distinctive paroxysmal facial-pain syndrome, detect secondary causes and dangerous mimics, and use carbamazepine and neurosurgical referral safely within current specialist pathways.
- Trigeminal neuralgia causes recurrent unilateral electric-shock, stabbing or shooting pain in one or more trigeminal divisions, most often maxillary or mandibular, lasting a fraction of a second to about two minutes.
- Innocuous triggers such as light touch, talking, chewing, tooth brushing, shaving or a breeze are characteristic; patients may identify a small trigger zone and pause during attacks.
- Classical disease is associated with neurovascular compression that produces morphological change of the trigeminal root; secondary disease arises from multiple sclerosis, tumour or another structural lesion.
- A normal examination is usual in classical disease. Objective sensory loss, bilateral symptoms, prominent hearing change or another cranial-nerve sign increases concern for a secondary cause.
- Persistent aching can coexist between paroxysms, but continuous pain without brief triggered shocks should prompt reconsideration of dental, temporomandibular, neuropathic or trigeminal-autonomic diagnoses.
- MRI of the brain and trigeminal pathways is indicated through specialist pathways, especially in younger people, atypical presentations, sensory signs or when an intervention is being considered.
- Carbamazepine is the standard initial medicine in UK guidance; introduce and titrate it deliberately, checking interactions, pregnancy potential, baseline blood count, liver tests, sodium and relevant ancestry-related genetic risk.
- Oxcarbazepine is commonly used by specialists when carbamazepine is ineffective or poorly tolerated, but hyponatraemia and off-label or local formulary status require explicit review.
- Opioids and ordinary analgesics rarely control the momentary discharges and can add harm; early expert help is preferable during severe flares that prevent oral intake.
- Microvascular decompression offers durable relief when neurovascular compression is suitable and the person accepts craniotomy; ablative procedures and stereotactic radiosurgery trade different onset, recurrence and sensory-loss risks.
Key red flags
Repeated triggers can make swallowing, drinking and oral hygiene impossible, causing dehydration, weight loss and psychological crisis despite a normal examination.
Investigation priorities
Test the syndrome against recognised diagnostic features and common mimics.
Management branches
A patient reports recurrent unilateral episodes of severe facial pain.
- Characterise each attack's quality, duration, distribution and triggers, then ask about rash, vision, dental symptoms, jaw pain, temporal tenderness and cranial autonomic features.
- Examine oral structures, temporomandibular joints, trigeminal sensation and the remaining cranial nerves, escalating infection, ocular disease, vasculitis or neurological deficit appropriately.
- Make a working clinical diagnosis when brief shock-like triggered attacks fit, but arrange imaging or specialist review rather than using medicine response as proof.
Adequately titrated first-line therapy fails, toxicity occurs or nutrition is threatened.
- Check diagnosis, adherence, interactions and whether a continuous pain syndrome or dental pathology has been misclassified before simply increasing the dose.
- Seek neurology or specialist facial-pain advice about oxcarbazepine or other add-on options, making off-label status and laboratory monitoring clear.
- Use urgent hospital or specialist pathways when attacks prevent fluids, oral medicines or sleep, avoiding reflex opioid escalation that does not target the mechanism.
Key medicines
CarbamazepineA common oral introduction is 100 mg once or twice daily with gradual increments; use the current BNF regimen, lowest effective dose and individualised maximum rather than a fixed template.Check interactions, blood count, liver function and sodium; counsel about dizziness, ataxia, teratogenicity, reduced hormonal-contraceptive effectiveness, blood dyscrasia and serious cutaneous reactions including ancestry-related HLA-B*1502 risk.
OxcarbazepineSpecialists often begin a low divided oral dose and titrate against attacks; exact use follows the local formulary because trigeminal-neuralgia prescribing may be off label.Hyponatraemia can be prominent and cross-sensitivity with carbamazepine rash is possible; review sodium, renal context, interactions, pregnancy considerations and shared-care responsibility.