Ch. 18 - Facial pain and hemifacial spasm

Question 1

What is trigeminal neuralgia?

Answer 1

Excruciating paroxysmal pain in CN5 distribution; AKA ‘tic douloureux’

Question 2

Etiology of trigeminal neuralgia

Answer 2

Microvascular compression theory (vascular loop at brainstem junction); associated with MS; less likely from tumor compression or AVM in posterior fossa

Question 3

Clinical features of trigeminal neuralgia

Answer 3

Sudden, severe pain lasting for seconds; can be triggered by anything (e.g. moving one specific hair in moustache); limited to one branch of CN5

Question 4

What CN5 branches are most commonly affected in trigeminal neuralgia?

Answer 4

V2 +/- V3

Question 5

How does trigeminal neuralgia in patients with MS differ?

Answer 5

Often occurs bilaterally

Question 6

What is the nerve function abnormality in trigeminal neuralgia?

Answer 6

NO detectable abnormality of nerve function

Question 7

Why get an MRI in trigeminal neuralgia?

Answer 7

Exclude mass in cerebellopontine angle in posterior fossa or intrinsic brainstem lesion (e.g. demyelination)

Question 8

DDx of trigeminal neuralgia

Answer 8

Atypical facial pain, dental pain, TMJ, postherpetic neuralgia, migrainous neuralgia (i.e. cluster HA)

Question 9

Medical tx options for trigeminal neuralgia

Answer 9

Carbamazepine is 1st line but often causes intolerable side effects (e.g. dizziness, n/v)

Question 10

Surgical tx of choice for elderly, frail patient with trigeminal neuralgia

Answer 10

Infraorbital or supraorbital nerve section if pain localized to these distributions

Question 11

Describe percutaneous thermocoagulation (i.e. rhizotomy) for tx of trigeminal neuralgia. Complications?

Answer 11

Needle passed percutaneously through foramen ovale into ganglion and nerve roots (behind Meckle’s cave) then heated or bathed in glycerol; complications include facial numbness and frequent recurrence

Question 12

Describe the posterior fossa craniotomy procedures available for tx of trigeminal neuralgia. Complications?

Answer 12

Trigeminal nerve section - causes facial numbness and possibly ‘anesthesia dolorosa’

Microvascular decompression (superior cerebellar artery dissected away) - best results but some relapse occurs

Question 13

What is the preferred surgical tx for trigeminal neuralgia?

Answer 13

Microvascular decompression - greatest chance of producing permanent relief with no facial numbness

Question 14

What is glossopharyngeal neuralgia?

Answer 14

Intense attacks of pain in distribution of glossopharyngeal and auricular + pharyngeal branches of trigeminal nerve (throat, tongue, ear)

Question 15

Tx for glossopharyngeal neuralgia

Answer 15

Carbamazepine (less success than for trigeminal neuralgia); surgery is very effective (section of CN9 and upper part of CN10)

Question 16

What is postherpetic neuralgia?

Answer 16

Burning pain after herpes zoster in distribution of trigeminal nerve (V1 most common)

Question 17

Tx of postherpetic neuralgia

Answer 17

No surgical tx; early use of steroids and acyclovir in patients with herpes zoster may reduce risk

Question 18

What is atypical facial pain?

Answer 18

Facial pain without pathologic basis, most frequently affects middle-aged females

Question 19

What is hemifacial spasm?

Answer 19

Unilateral spasm of facial muscles supplied by CN7; proposed etiology is similar to trigeminal neuralgia (nerve compression) with same tx (microvascular decompression)

Question 20

What is ‘tic convulsif’?

Answer 20

Coexisting hemifacial spasm and trigeminal neuralgia