TRIGEMINAL NEURALGIA

TRIGEMINAL NEURALGIA

• DEFINITION
  

Imagine having a jab of lightning-like pain shoot through your face when you brush your teeth or put on makeup. Sound excruciating? If you have trigeminal neuralgia, attacks of such pain may occur frequently.

You may initially experience short, mild attacks, but trigeminal neuralgia can progress, causing longer, more frequent bouts of searing pain. These attacks can be spontaneous or provoked by even mild stimulation of your face. Trigeminal neuralgia affects women more often than men, and it's more likely to occur in people who are older than 50.

Because of the variety of treatment options available, having trigeminal neuralgia doesn't necessarily mean you're doomed to a life of pain. Doctors usually can effectively manage trigeminal neuralgia with medications, injections or surgery.

• SYMPTOMS
  

symptom patterns with trigeminal neuralgia:

• Occasional twinges of mild pain
• Episodes of severe, shooting or jabbing pain that may feel like an electric shock
• Spontaneous attacks of pain or attacks triggered by things like touching the face, chewing, speaking, and brushing teeth
• Bouts of pain lasting from a few seconds to several seconds
• Episodes of several attacks lasting days, weeks, months or longer — some people have periods when they experience no pain
• Pain in areas supplied by the trigeminal nerve (nerve branches), including the cheek, jaw, teeth, gums, lips, or less often the eye and forehead
• Pain affecting one side of your face at a time
• Pain focused in one spot or spread in a wider pattern
• Attacks becoming more frequent and intense over time.

• CAUSES
  

The trigeminal nerve carries sensation from your face to your brain. In trigeminal neuralgia, also called tic douloureux, the nerve's function is disrupted. Usually, the problem is contact between a normal artery or vein and the trigeminal nerve, at the base of your brain. This contact puts pressure on the nerve and causes it to malfunction.

Trigeminal neuralgia can occur as a result of aging, or it can be related to multiple sclerosis or a similar disorder that damages the myelin sheath protecting certain nerves. Less commonly, trigeminal neuralgia can be caused by a tumor compressing the trigeminal nerve. In other cases, a cause cannot be found.

A variety of triggers may set off the pain of trigeminal neuralgia, including:

• Shaving
• Stroking your face
• Eating
• Drinking
• Brushing your teeth
• Talking
• Putting on makeup
• Encountering a breeze
• Smiling

• TESTS & DIAGNOSIS

Your doctor will review your medical history and ask you to describe your pain — how severe it is, what part of your face it affects, how long it lasts and what seems to trigger it. You'll also undergo a neurological examination, during which your doctor examines and touches parts of your face to try to determine exactly where the pain is occurring and — if you appear to have trigeminal neuralgia — which branches of the trigeminal nerve may be affected.

You may need to have a magnetic resonance imaging (MRI) scan of your head, which can show if multiple sclerosis is causing trigeminal neuralgia.

Facial pain can be caused by many different disorders, so an accurate diagnosis is important. Your doctor may order additional tests to rule out other conditions.

• TREATMENT & DRUGS
  

• Medications

Medications to lessen or block the pain signals sent to your brain are the most common initial treatment for trigeminal neuralgia.

• Anticonvulsants. Carbamazepine (Tegretol, Carbatrol), phenytoin (Dilantin, Phenytek) and oxcarbazepine (Trileptal) are the most common anticonvulsant medications used to treat trigeminal neuralgia. Other anticonvulsants include lamotrigine (Lamictal) or gabapentin (Neurontin). If the anticonvulsant you're using begins to lose effectiveness, your doctor may increase the dose or switch to another type. Side effects of anticonvulsants may include dizziness, confusion, drowsiness, double vision and nausea. Anticonvulsants have been linked to an increased risk of suicidal thoughts and behavior, so be sure to monitor your mood closely if you're taking an anticonvulsant for the first time. Also, carbamazepine can trigger a serious drug reaction in some people, mainly those of Asian descent, so genetic testing may be recommended before you start carbamazepine.
• Antispasticity agents. Muscle-relaxing agents such as baclofen may be used alone or in combination with carbamazepine or phenytoin. Side effects may include confusion, nausea and drowsiness.

Alcohol injection
Alcohol injections provide temporary pain relief by numbing the affected areas of your face. Your doctor will inject alcohol into the part of your face corresponding to the trigeminal nerve branch causing pain. The pain relief isn't permanent, so you may need repeated injections or a different procedure in the future.

• Surgery

The goal of surgery for trigeminal neuralgia is either to stop the blood vessel from compressing the trigeminal nerve, or to damage the trigeminal nerve to keep it from malfunctioning. Damaging the nerve often causes temporary or permanent facial numbness, and with any of the surgical procedures, the pain can return months or years later. Surgical options include:

• Microvascular decompression (MVD). Instead of damaging the trigeminal nerve, MVD involves relocating or removing blood vessels that are in contact with the trigeminal root, and separating the nerve root and blood vessels.

  During MVD, your doctor makes an incision behind the ear on the side of your pain. Then, through a small hole in your skull, part of your brain is lifted to expose the trigeminal nerve. Any artery in contact with the nerve root is directed away from the nerve, and the surgeon places a pad between the nerve and the artery. If a vein is compressing the nerve, the surgeon typically will remove it. If no artery or vein appears to be compressing the nerve, your surgeon may sever the nerve instead.

  MVD can successfully eliminate or reduce pain most of the time, but pain can recur in some people. While MVD has a high success rate, it also carries risks. There are small chances of decreased hearing, facial weakness, facial numbness, double vision, and even a stroke or death. Since MVD doesn't damage the trigeminal nerve, most people who have this procedure have no facial numbness afterwards.

• Glycerol injection. During this procedure, called percutaneous glycerol rhizotomy (PGR), your doctor inserts a needle through your face and into an opening in the base of your skull. The needle is guided into the trigeminal cistern, a small sac of spinal fluid that surrounds the trigeminal nerve ganglion — where the trigeminal nerve divides into three branches — and part of its root. Images are made to confirm that the needle is in the proper location, and then a small amount of sterile glycerol is injected. After three or four hours, the glycerol damages the trigeminal nerve and blocks pain signals. Initially, PGR relieves pain in most people. However, some people have a later recurrence of pain, and many experience facial numbness or tingling.
• Balloon compression. In percutaneous balloon compression of the trigeminal nerve (PBCTN), your doctor inserts a hollow needle through your face and into an opening in the base of your skull. Then, a thin, flexible tube (catheter) with a balloon on the end is threaded through the needle. The balloon is inflated with enough pressure to damage the nerve and block pain signals. PBCTN successfully controls pain in most people, at least for a while. Most people undergoing PBCTN experience some facial numbness, and more than half experience temporary or permanent weakness of the muscles used to chew.
• Electric current. Percutaneous stereotactic radiofrequency thermal rhizotomy (PSRTR) selectively destroys nerve fibers associated with pain. While you're sedated, your doctor places a hollow needle through your face and into an opening in your skull. Once the needle is positioned, an electrode is threaded through it to the nerve root. You're then awakened from sedation so that you can indicate when and where you feel tingling from the mild current pulsed through the tip of the electrode. When the neurosurgeon locates the part of the nerve involved in your pain, you are returned to sedation. Then the electrode is heated until it damages the nerve fibers, creating an area of injury (lesion). If your pain isn't eliminated, your doctor may create additional lesions. Almost everyone who undergoes PSRTR has some facial numbness after the procedure.
• Severing the nerve. A procedure called partial sensory rhizotomy (PSR) involves cutting part of the trigeminal nerve at the base of your brain. Through an incision behind your ear, your doctor makes a quarter-sized hole in your skull to access the nerve. Because it cuts the nerve at its source, your face will be numb permanently. In some cases, instead of cutting the nerve the surgeon will choose to traumatize the nerve by rubbing it.
• Radiation. Gamma-knife radiosurgery (GKR) involves delivering a focused, high dose of radiation to the root of the trigeminal nerve. The radiation damages the trigeminal nerve and reduces or eliminates the pain. Relief occurs gradually and can take several weeks to begin. GKR is successful in eliminating pain for the majority of people, but sometimes the pain may recur. The procedure is painless and typically is done without anesthesia. Because this procedure is relatively new, the long-term risks are not yet known.