Nejm 1986;315:174

Cause:Idiopathic

Pathophys:Unknown

Most age >50 yr old

Sx:Paroxysms of neuralgic, unilateral pain in trigeminal nerve distribution; many patients may identify specific actions that trigger the sx; maxillary and mandibular branches more frequently involved than ophthalmic; precipitated by touch. Occasional painless sensory neuropathy precedes (Nejm 1969;281:873)

Si:

Pain on rotation of tongue blade inside cheek with teeth lightly clenched is diagnostic of syndrome; absence is diagnostic of remission (Trans Am Neurol Assoc 1966;91:163)

Corneal reflex preserved

ENT consult to look at posterior nasal space?

Recheck si's q 2 mo since frequent remissions

Frequent spontaneous remissions in 50%

R/o cluster headache, postherpetic neuralgia, 5th cranial nerve pressure by tumor, arteritis, syphilis

Lab:

Hem:ESR to r/o arteritis

Serol: VDRL

Xray: MRI

Rx:

(Nejm 1996;334:1123)

• Meds:
• 1st, carbamazepine (Tegretol) 100 mg po bid × 24 h, increase by 100 mg q 12 h until pain controlled up to 1200 mg/d; 70% effective long term; adverse effects: agranulocytosis and aplastic anemia, thus get CBC weekly × 6 then q 6 mo; nausea and vomiting; vertigo; urinary retention; sedation
• 2nd, phenytoin (Dilantin)
• OTHERS:
• Baclofen (Lioresal) 10-20 mg po tid-qid; a muscle relaxant, effective in 70%, less toxic, used alone or with above, don't stop abruptly (seizures), taper by 5-10 mg qd q 1 wk (Ann Neurol 1984;15:240)
• Gabapentin (Neurontin) 300-1200 mg po tid

Surgical microvascular decompression helps >75% immediately and long term (Nejm 1996;334:1077). Radiofrequency probe destruction of nerve results in 90% success (3% have anesthesia, 10% recur—Nejm 1973;288:680). Other surgical procedures sometimes include nerve section, or alcohol or phenol injection; both cause permanent numbness.