Trigeminal neuralgia has an incidence of 4-5 per 100,000 of the population. It is characterized by shooting, severe lancinating pain. It is located in the V-2 distribution of the trigeminal nerve, most commonly. Typical symptoms include a shock or jab of pain, lasting 20-30 seconds. Triggers - cold air, motion, eating, sensitive "trigger zones". Often a history of dental procedure -- may be chicken or egg. Sometimes also occurs post-sinus surgery. Possibly related to herpes infection in ganglion. Usually normal examination. Peak incidence is 50-69 y/o. About 1% of persons with MS have trigeminal neuralgia, and 2% of persons with trigeminal neuralgia have MS.
Treatment: Pain relievers -- rarely effective, even narcotics. Carbamazepine (200 BID-TID, check levels at 1 week, get CBC if it works, repeat 2 months and 6 months) and Oxcarbazepine (Trileptal) are effective. One can add baclofen (5 TID, then increase). Phenytoin (Dilantin)less effective, used if allergic to carbamazepine/oxcarbazepine. Also a host of new anticonvulsants are available, such as Gabapentin (Neurontin) and topiramate (Topamax). Response to oxcarbazepine/dilantin may make diagnosis. Some use Depakote/Clonopin. If medical treatment is unsuccessful, can treat with radiofrequency ganglioneurectomy, percutaneous microcompression of trigeminal ganglion, or gamma knife.
Corneal neuralgia -- this is a subtype of trigeminal neuralgia, thought to be due to damage done to the cornea by surgery.
Geniculate neuralgia - neuralgia of sensory portion of 7th nerve. Causes ear pain. Can be a part of the Ramsey-Hunt syndrome. May respond to same agents as trigeminal neuralgia. Surgical approach - cut nervous intermedius.
Glossopharyngeal neuralgia - neuralgia of 9/10. Ear, tonsil, larynx, posterior tongue location. Triggered by swallowing, foods. May have syncope due to the involvement of the glossopharyngeal nerve in blood pressure control. Incidence is about 1/100 of Trigeminal neuralgia. Brain tumor is found in 15-25%. May be a complication of ear surgery. Similar approach to treatment as trigeminal neuralgia.
Eagle syndrome. This is a facial pain, ear pain, dysphagia, voice changes and trouble swallowing that occurs due to elongation of the styloid process. The symptoms are similar to glossopharyngeal neuralgia (see above). The styloid process is a bone below the ear that is used to anchor several muscles (stylohyoid, styloglossus, and stylopharyngeus). Pain is thought to occur from compression of several cranial nerves (V, VII, IV or X), as well as pain may arise from arthritis and tendonitis (Kim et al, 2008). Eagle syndrome is diagnosed through symptoms and 3D CT reconstruction, and treated via surgical excision or shortening of the process.
Occipital neuralgia - characterized by jabbing pain in the distribution of the greater or lesser occipital nerves or of the third occipital nerves. The nerve may be tender and pain is temporarily relieved by injection of local anesthetic. The location is suboccipital pain that radiates to the back of the head. It can be caused by injury, inflammation or compression of the greater occipital nerve. C1 to C2 arthritis can also mimic occipital neuralgia. Can be difficult to separate from migraine headache. Treatment often involves blocks administered by anesthesiology.
Sphenopalatine/vidian neuralgia -- same symptoms as cluster headache and most authors don't think this entity is separate from cluster headache.
Atypical facial pain. Wastebasket syndrome, commonly considered when thinking about neuralgia. Not paroxysmal or triggered, and not in the distribution of any cranial nerve. Does not respond to carbamazepine or close relatives (if it did, it would be classified as neuralgia instead). May respond to antidepressants. Surgery is contraindicated.