trigeminal neuralgia

Question 1

def trigeminal neuralgia

Answer 1

Trigeminal neuralgia (TN) is a facial pain syndrome in the distribution of ≥1 divisions of the trigeminal nerve.

Question 2

aetiology trigeminal neuralgia

Answer 2

RF: - increased age, MS

trigeminal nerve compression by anomolous or aneurysmal intracranial vessels or tumour, chronic meningeal inflammation, MS, zoster, skull base malformation (Chiari)

many patients have similar compression on the asymptomatic, contra-lateral side, and asymptomatic patients without trigeminal neuralgia (TN) may demonstrate vascular compression

80% to 90% of patients have demonstrable focal compression of the trigeminal nerve root at the root entry zone by an aberrant vascular loop (typically the superior cerebellar artery), rarely compression by aneurysms or arteriovenous malformations

demyelinating disease - demyelinating plaques in the pons that encompass the root entry zone of the trigeminal nerve.

rare - brainstem infarcts and amyloid or calcium deposition along the trigeminal sensory pathway

Question 3

pathophysiology trigeminal neuralgia

Answer 3

focal demyelination and resultant conduction aberrations (ephatic transmission)

chronic myelin loss at the root entry zone in close proximity to the region of vascular compression.

Question 4

epi trigeminal neuralgia

Answer 4

>50yrs

male

in Asian - female more

Question 5

sx trigeminal neuralgia

Answer 5

Paroxysms of intense, stabbing pain, lasting seconds, in the trigeminal nerve distribution

unilateral

typically affecting maxillary and mandibular divisions

face screws up with pain - hence tic douloureux

triggers: washing affected area, shaving, eating, talking, dental prostheses

Question 6

ix trigeminal neuralgia

Answer 6

MRI necessary to exclude secondary causes - 14% cases

Question 7

mx of trigeminal neuralgia

Answer 7

carbamazepine 1st line