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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.
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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:
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Paroxysmal attacks of facial or frontal pain, lasting a few seconds to less than
2 minutes.
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Pain has at least 4 of the following characteristics:
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Distribution along one or more divisions of the trigeminal nerve
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Sudden, intense, sharp, superficial, stabbing, or burning in quality
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Severe pain intensity
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Precipitation from trigger areas or by certain daily activities (e.g., eating,
talking, washing the face, cleaning the teeth)
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No symptoms between paroxysms
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No neurologic deficit is present.
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Attacks are stereotyped in the individual patient.
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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:
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Tumor (glioma, lymphoma, neuroma, metastatic)
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Infarct
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AVM
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Compression by the adjacent superior cerebellar or anterior inferior cerebellar
artery
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Multiple sclerosis (MS)
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Sarcoidosis
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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.
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Treatment
Treatment of trigeminal neuralgia is divided into pharmacological and surgical.
Patients are generally referred for surgical procedures if medical therapy is
unsuccessful.
Pharmacological
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Carbamazepine (first drug of choice)
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Baclofen
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Neurotin
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Oxcarbazepine
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Lamotrigine
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Surgical
• Nerve block
with alcohol or glycerol
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Percutaneous radio frequency, thermo-coagulation
is frequently the procedure of choice in most centers.
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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%.
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Above: Microvascular
decompression - placing a teflon pad between the trigeminal nerve and adjacent
artery
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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). |
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Above: Gamma-knife |
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