Trigeminal neuralgia

Question 1

What is trigeminal neuralgia?

Answer 1

Neuropathic disorder with paroxysms of intense pain in the face

Question 2

Describe trigeminal neuralgia (pathophysiology)

Answer 2

Pain syndrome causes paroxysms of intense unilateral stabbing pain in the trigeminal nerve distribution (typically the mandibular and maxillary distributions). The face will often screw/ scrunch up with the pain (hence why it is also called tic douloureux).

Question 3

What are the triggers for pain?

Answer 3

Touching/ moving tongue, lips, face; chewing, shaving, brushing teeth, blowing nose, hot and cold drinks, smoking, washing the area, dental prostheses.

Question 4

What are the risk factors for trigeminal neuralgia?

Answer 4

• Male
• Age >50
• Demyelinating disorders (MS)
• Varicella zoster
• Acoustic neuroma
• Saccular aneurysm
• In Asians, more common in females 2:1

Question 5

What are the causes of trigeminal neuralgia?

Answer 5

Most common- compression CN V root causing pain.

Compression caused by anomalous or aneurysmal intracranial vessels/ tumour, chronic meningeal tumour.

Question 6

What are the symptoms of trigeminal neuralgia?

Answer 6

1. Intense pain paroxysms; unilateral shock-like pains, abrupt onset and termination. Can be in one or more than one divisions of the trigeminal nerve
2. Dull pain between paroxysms
3. Autonomic symptoms- lacrimation, diffuse conjunctival injection, rhinorrhea

Question 7

What are the signs O/E?

Answer 7

• Classical trigeminal neuralgia- no other real neurological deficit but diagnosis based on 3 or more attacks of unilateral facial pain. Pain must not radiate beyond the trigeminal regions, attacks should be less than 2 mins, shooting/ stabbing like pains
• Electromyographyrigeminal reflex testing- measures muscles’/ controlling nerves’ electrical activity.

Question 8

What investigations would you do?

Answer 8

Do a CT/ MRI in order to visualise lesion/ vascular compression and exclude those causes.

Question 9

What medication management could you give to people with trigeminal neuralgia?

Answer 9

Mainly for pain management

• Carbamazepine (100mg/12h PO but can escalate to 400mg/6h)- anti-convulsant [VGSC blocker] to reduce depolarisation
• Lamotrigine
• Phenytoin 200-400mg/24h PO

Question 10

What surgical options do you have with trigeminal neuralgia?

Answer 10

• Microvascular decompression- anomalous vessels are separated from the trigeminal root
• Neuroablation- radiofrequency thermocoagulation/ mechanical balloon compression
• Stereotactic gamma knife surgery (radiosurgery)- use radiation to fix vascular malformations.