Trigeminal Neuralgia
Trigeminal neuralgia is a facial pain disorder characterised by recurrent, severe, electric shock-like pain in the distribution of one or more branches of the trigeminal nerve (CN V).
This updated UKMLA guide to trigeminal neuralgia is based primarily on NICE CKS, which covers causes, risk factors, symptoms, diagnosis, and management.
Causes and Risk Factors
There are 2 main types of trigeminal neuralgia:
| Classical trigeminal neuralgia | Occurs due to neurovascular compression of the trigeminal nerve root, typically by an artery / vein near the pons |
| Secondary trigeminal neuralgia | Key causes include:
|
Risk factors:
- Females
- Peak incidence: 50-60 y/o
- Family history
Clinical Features
| Disease course | Recurrent and episodic – the patient may go into remission for weeks or months before returning
Pain-free periods may gradually shorten between episodes |
| Provoking factors | Episodes may be triggered by mild stimulation of the face, such as:
|
| Features of a painful episode | Almost always unilateral (only ~3% cases are bilateral)
Some patients may experience continued aching after the acute pain has resolved Patients may experience multiple attacks a day, with a refractory period between each attack |
Mild ipsilateral autonomic symptoms, such as tearing or eye redness, may occur during painful attacks of trigeminal neuralgia.
However, prominent autonomic symptoms such as marked lacrimation, conjunctival injection, rhinorrhoea, nasal congestion, ptosis, eyelid swelling, or facial sweating are more suggestive of a trigeminal autonomic cephalalgia, such as cluster headache
Investigation and Diagnosis
Trigeminal neuralgia is primarily a clinical diagnosis, if there is an absence of red flags
Investigations are usually only needed if red flags or features of a secondary cause are present.
It is important to examine the face and oral cavity to exclude dental causes that might be contributing to the pain.
Red flags:
- Sensory changes
- Deafness or other ear problems
- History of skin / oral lesions that could spread perineurally
- Pain only in the ophthalmic division of CN V
- Optic neuritis
- Family history of multiple sclerosis
- Onset <40 y/o
Management
Referral Criteria
If any of the following, admit or refer urgently for specialist assessment:
| Red flag | Rationale |
|---|---|
| Sensory changes | Suggests nerve compression or demyelination (e.g. multiple sclerosis or tumour) |
| Deafness or other ear problems | Possible vestibular schwannoma or other cerebellopontine angle lesion (compresses both CN V and VIII) |
| Pain only in the ophthalmic division of CN | Possible sinonasal / orbital / intracranial pathology |
| Bilateral symptoms | Bilateral trigeminal neuralgia is unusual and should raise suspicion for secondary causes, esp. multiple sclerosis |
| Optic neuritis | Suggest multiple sclerosis |
| Family history of multiple sclerosis | |
| Onset <40 y/o | Suggest secondary causes (e.g. multiple sclerosis, genetic syndromes) |
| History of skin or oral lesions that could spread perineurally | Possible cancer / perineural tumour spread |
Pharmacological Management
1st line: carbamazepine
- Start at 100 mg up to twice daily, then titrate upwards until pain is controlled
- Maximum dose: 1600 mg daily
If carbamazepine is not appropriate or not effective: seek advice from secondary care (do not offer any other drug treatment unless advised by a specialist).
References