Trigeminal Neuralgia

THE CLINICAL SYNDROME

Trigeminal neuralgia occurs in many patients because of tortuous blood vessels that compress the trigeminal root as it exits the brain stem. Acoustic neuromas, cholesteatomas, aneurysms, angionmas, and bony abnormalities may also lead to the compression of nerve. The severity of pain produced by trigeminal neuralgia can be rivaled only by that of cluster headache. Uncontrolled pain has been associated with suicide and therefore should be treated as an emergency. Attacks can be triggered by daily activities involving contact with the face such as brushing the teeth, shaving and washing. Pain can be controlled with medication in most patients. About 2% to 3% of patients experiencing trigeminal neuralgia also have multiple sclerosis. Trigeminal neuralgia is also called tic douloureux.

SIGNS AND SYMPTOMS

Trigeminal neuralgia is an episodic pain afflicting the areas of the face supplied by the trigeminal nerve. The pain is unilateral in 97% of cases reported. When it does occur bilaterally, it is in the same division of the nerve. The second or third division of the nerve is affected in the majority of patients, with the first division affected less than 5% of the time. The pain develops on the right side of the face in unilateral disease 57% of the time. The pain is characterized by paroxysms of electric shocklike pain lasting from several seconds to less than 2 minutes. The progression from onset to peak is essentially instantaneous.

Paroxysms of pain triggered by brushing of teeth.

Cystic and solid schwannoma of the right trigemial nerve and ganglion. A, Axial enhanced image showing a dumbbell-shaped tumor extending across the incisura from the posterior fossa into the medial portion of the right middle fossa. Note the heterogeneous enhancement of the tumor, suggesting areas of decreased cellularity and cystic change and a more solid component. B. Axial magnetic resonance angiogram performed after the magnetic resonance examination showing near-homogeneous enhancement of the tumor because of the delay in imaging. Note the exquisite demonstration of the tumor in the skull base, including the displaced right petrous carotid artery. (From Stark DD, Bradley WG Jr. Magnetic Resonance Imaging, Vol. III, 3rd ed. St. Lousis, Mosby, 1999, p 1218.)

The patient with trigeminal neuralgia will go to great lengths to avoid any contact with trigger areas. Persons with other types of facial pain, such as temporomandibular joint dysfunction, tend to constantly rub the affected area or apply heat or cold to it. Patients with uncontrolled trigeminal neuralgia frequently require hospitalization for rapid control of pain. Between attacks, the patient is relatively pain free. A dull ache remaining after the intense pain subsides may indicate persistent compression of the nerve by a structural lesion. This disease is almost never seen in persons under 30 unless it is associated with multiple sclerosis.

The patient with trigeminal neuralgia will often have severe and, at time, even suicidal depression with high levels of superimposed anxiety during acute attacks. Both of these problems may by exacerbated by the sleep deprivation that often occurs during episodes of pain. Patients with coexisting multiple sclerosis may exhibit the euphoric dementia characteristic of that disease. Physicians should reassure persons with trigeminal neuralgia that the pain can almost always be controlled.

TREATMENT

Drug Therapy
Carbamazepine

This drug is considered first-line treatment for trigeminal neuralgia. In fact, rapid response to this drug essentially confirms a clinical diagnosis of trigeminal neuralgia. Despite the safety and efficacy of carbamazepine compared with other treatments for trigeminal neuralgia, much confusion and unfounded anxiety surround its use. This medication, which may be the patient’s best chance for pain control, is sometimes discontinued because of laboratory abnormalities erroneously attributed to it. Therefore, baseline screening laboratory measures, consisting of a complete blood count, urinalysis, and automated chemistry profile, should be obtained before starting the drug.

Carbamazepine should be started slowly if the pain is not out of control, with a starting dose of 100 to 200mg at bedtime for two nights. The patient should be cautioned regarding side effects, including dizziness, sedation, confusion, and rash. The drug is increased in 100- to 200-mg increments, given in equally divided doses over 2 days, as side effects allow until pain relief is obtained or a total dose of 1200 mg daily is reached. Careful monitoring of laboratory parameters is mandatory to avoid the rare possibility of life-threatening blood dyscrasia. At the first sign of blood count abnormality or rash, this drug should be discontinued. Failure to monitor patients started on carbamazepine can be disastrous because aplastic anemia can occur. When pain relief is obtained, the patient should be kept at that dosage of carbamazepine for at least 6 months before tapering of this medication is considered. The patient should be informed that under no circumstances should the dosage of drug be changed or the drug refilled or discontinued without the physician’s knowledge.

Gabapentin

In the uncommon event that carbamazepine does not adequately control a patient’s pain, gabapentin may be considered. As with carbamazepine, baseline blood tests should be obtained before starting therapy. Start with 300 mg of gabapentin at bedtime for two nights, and caution the patient about potential side effects, including dizziness, sedation, confusion, and rash. The drug is then increased in 300-mg increments, given in equally divided doses over 2 days, as side effects allow until pain relief is obtained or a total dose of 2400 mg daily is reached. At this point, if the patient has experienced partial relief of pain, blood values are measured and the drug is carefully titrated upward using 100-mg tablets. Rarely will more than 3600 mg daily be required.

Baclofen

This drug has been reported to be of value in some patients who fail to obtain relief from the aforementioned medications. Baseline laboratory tests should also be obtained before starting baclofen. Start with a 10-mg dose at bedtime for two nights, and caution the patient about potential adverse effects, which are the same as those of carbamazepine and gabapentin. The drug is increased in 10-mg increments, given in equally divided doses over 7 days as side effects allow, until pain relief is obtained or a total dose of 80 mg daily is reached. This drug has significant hepatic and central nervous system side effects, including weakness, and sedation. As with carbamazepine, careful monitoring of laboratory values is indicated during the initial use of this drug. In treating individuals with any of these drugs, the physician should make the patient aware that premature tapering or discontinuation of the medication may lead to the recurrence of pain and that it will be more difficult to control pain thereafter.

Invasive Therapy
Trigeminal Nerve Block

The use of trigeminal nerve block with local anesthetic and steroid serves as an excellent adjunct to drug treatment of trigeminal neuralgia. This technique rapidly relieves pain while medications are being titrated to effective levels. The initial block is carried out with preservative-free bupivacaine combined with methylprednisolone. Subsequent daily nerve blocks are carried out in a similar manner, substituting a lower dose of methylprednisolone. This approach may also be used to obtain control of break through pain.

Retrogasserian Injection or Glycerol

The injection of small quantities of glycerol into the area of the gasserian ganglion has been shown to provide long-term relief for patients suffering from trigeminal neuralgia who have not responded to optimal trials of therapy. This procedure should be performed only by a physician well versed in the problems and pitfalls associated with neurodestructive procedures.

Radiofrequency Destruction of the Gasserian Ganglion

The destruction of the gasserian ganglion can be carried out by creating a radiofrequency lesion under biplanar fluoroscopic guidance. This procedure is reserved for patients who have failed all the treatments previously discussed for intractable trigeminal neuralgia and are not candidates for microvascular decompression of the trigeminal root.

Microvascular Decompression of the Tigeminal Root

This technique, which is also called Janetta’s procedure, is the major neurosurgical procedure of choice for intractable trigeminal neuralgia. It is based on the theory that trigeminal neuralgia is in fact a compressive mononeuropathy. The operation consists of identifying the trigeminal root close to the brain stem and isolating the offending compressing blood vessel. A sponge is then interposed between the vessel and nerve, relieving the compression and thus the pain.

Low intensity laser therapy as well as a coordinated wellness program is also effective in treating this disorder.

Low Intensity Laser Therapy (LILT)

The low intensity Laser (LILT) sends photons (light) into the injured tissues and can penetrate two to three inches to treat affected areas. It uses a natural enhancement of the cellular machinery that can and has been dynamically measured in published studies to promote healing without burning affected tissue .Once the photons find the injured tissues, they stimulate and energize the cells to repair and strengthen at a remarkable rate. The treatment does not hurt, takes about 30 minutes and is very cost advantageous.

Wellness Program

A wellness program whichindividualizes treatment for age, performance and function has been shown in pilot studies to improve the overall health and well being of the individuals evaluated. A well conceived dietary and supplementary regimen based on scientific age –related decline in certain necessary compounds can improve quality of life, correct the ravages of hormone imbalance, balance critical neurotransmitter function without resorting to powerful drugs for depression that often have unfavorable side-effect profiles and restore vitality and youth in daily exercise routines. Furthermore, when wellness products are utilized with success, individuals often seek less costly interventions including unnecessary surgeries and narcotic options to treat pain. For more information go to www.drpwellness.com.