What is trigeminal neuralgia?
Excruciating paroxysmal pain in CN5 distribution; AKA 'tic douloureux'
Etiology of trigeminal neuralgia
Microvascular compression theory (vascular loop at brainstem junction); associated with MS; less likely from tumor compression or AVM in posterior fossa
Clinical features of trigeminal neuralgia
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
What CN5 branches are most commonly affected in trigeminal neuralgia?
V2 +/- V3
How does trigeminal neuralgia in patients with MS differ?
Often occurs bilaterally
What is the nerve function abnormality in trigeminal neuralgia?
NO detectable abnormality of nerve function
Why get an MRI in trigeminal neuralgia?
Exclude mass in cerebellopontine angle in posterior fossa or intrinsic brainstem lesion (e.g. demyelination)
DDx of trigeminal neuralgia
Atypical facial pain, dental pain, TMJ, postherpetic neuralgia, migrainous neuralgia (i.e. cluster HA)
Medical tx options for trigeminal neuralgia
Carbamazepine is 1st line but often causes intolerable side effects (e.g. dizziness, n/v)
Surgical tx of choice for elderly, frail patient with trigeminal neuralgia
Infraorbital or supraorbital nerve section if pain localized to these distributions
Describe percutaneous thermocoagulation (i.e. rhizotomy) for tx of trigeminal neuralgia. Complications?
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
Describe the posterior fossa craniotomy procedures available for tx of trigeminal neuralgia. Complications?
Trigeminal nerve section - causes facial numbness and possibly 'anesthesia dolorosa'
Microvascular decompression (superior cerebellar artery dissected away) - best results but some relapse occurs
What is the preferred surgical tx for trigeminal neuralgia?
Microvascular decompression - greatest chance of producing permanent relief with no facial numbness
What is glossopharyngeal neuralgia?
Intense attacks of pain in distribution of glossopharyngeal and auricular + pharyngeal branches of trigeminal nerve (throat, tongue, ear)
Tx for glossopharyngeal neuralgia
Carbamazepine (less success than for trigeminal neuralgia); surgery is very effective (section of CN9 and upper part of CN10)
What is postherpetic neuralgia?
Burning pain after herpes zoster in distribution of trigeminal nerve (V1 most common)
Tx of postherpetic neuralgia
No surgical tx; early use of steroids and acyclovir in patients with herpes zoster may reduce risk
What is atypical facial pain?
Facial pain without pathologic basis, most frequently affects middle-aged females
What is hemifacial spasm?
Unilateral spasm of facial muscles supplied by CN7; proposed etiology is similar to trigeminal neuralgia (nerve compression) with same tx (microvascular decompression)
What is 'tic convulsif'?
Coexisting hemifacial spasm and trigeminal neuralgia