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TRIGEMINAL NEURALGIA


Trigeminal neuralgia (a.k.a., tic douloureux) is a classic headache syndrome of the fifth cranial (trigeminal) nerve. The syndrome results in episodes of intense, stabbing, electric shock-like pain in the distribution of the trigeminal nerve, most often the maxillary (V2) or mandibular (V3) divisions. The attacks of pain, which generally last several seconds and may be repeated one after the other, may be triggered by talking, brushing teeth, touching the face, chewing, or swallowing. The pain is so severe that it has been known to result in “suicide” if not treated. Trigeminal neuralgia may come and go, and lasts for weeks or months. It may then disappear for months or years as well. The disorder is more common in women than in men. Most commonly, it affects individuals older than age 50.


Clinical

Trigeminal neuralgia is a diagnosis made by patient history alone. In idiopathic trigeminal neuralgia, the neurologic exam and brain imaging are normal. Diagnostic criteria for idiopathic trigeminal neuralgia by the International Headache Society are as follows:

Paroxysmal attacks of facial or frontal pain, lasting a few seconds to less than 2 minutes.

Pain has at least 4 of the following characteristics:

Distribution along one or more divisions of the trigeminal nerve

Sudden, intense, sharp, superficial, stabbing, or burning in quality

Severe pain intensity

Precipitation from trigger areas or by certain daily activities (e.g., eating, talking, washing the face, cleaning the teeth)

No symptoms between paroxysms

No neurologic deficit is present.

Attacks are stereotyped in the individual patient.


Etiology


For the vast majority of cases, trigeminal neuralgia is idiopathic. However, structural lesions of the trigeminal nerve may result in a similar syndrome. Any fixed abnormality on neurologic exam and a younger age should alert the physician to the possibility of a secondary condition. Although rare, bilateral trigeminal neuralgia is classically seen in multiple sclerosis. Secondary conditions include:

Tumor (glioma, lymphoma, neuroma, metastatic)

Infarct

AVM

Compression by the adjacent superior cerebellar or anterior inferior cerebellar artery

Multiple sclerosis (MS)

Sarcoidosis


Evaluation

Because of the possibility of a secondary cause, imaging studies are indicated in all patients. It may not be possible clinically to distinguish between idiopathic and secondary forms of trigeminal neuralgia. MRI is the imaging modality of choice as it is able to well visualize the posterior fossa (much better than CT). MRI also has the ability to detect demyelinating plaques of multiple sclerosis.


Treatment


Treatment of trigeminal neuralgia is divided into pharmacological and surgical. Patients are generally referred for surgical procedures if medical therapy is unsuccessful.

Pharmacological

Carbamazepine (first drug of choice)

Baclofen

Neurotin

Oxcarbazepine

Lamotrigine
 

Surgical


Nerve block with alcohol or glycerol

Percutaneous radio frequency, thermo-coagulation is frequently the procedure of choice in most centers.

Microvascular decompression is a procedure where an opening is created in the mastoid area and the trigeminal nerve is released from nearby arteries. A piece of Teflon is placed the nerve and vascular structures. Large series have been published, and the efficacy is reported as > 80%.

 

Above: Microvascular decompression - placing a teflon pad between the trigeminal nerve and adjacent artery
 

Gamma knife is one of the newest techniques with a varying degree of success. Gamma-knife treatment consists of high-energy photons concentrated on a target (i.e., trigeminal nerve root).

Above: Gamma-knife