TRIGEMINAL NEURALGIA

DISCLAIMER

| DESCRIPTION | CAUSES | SYMPTOMS | DIAGNOSIS | TREATMENTS |  REFERENCES
| ONLINE RESOURCES |

DESCRIPTION
Trigeminal Neuralgia (TN), also known as Tic Douloureux, is considered by many to be the "most terrible pain known to man."  The electric shock-like pain generally is on one side of the face and is spasmodic, coming in short bursts lasting a few seconds.   Several attacks can follow each other within minutes.  There are often trigger points, places on the face which, if touched,  trigger an attack.. Eating, shaving, applying makeup and talking can be triggers.  There can be periods of remission when pain is completely absent. These periods of remission, which  can last days, weeks, months, even years, are unpredictable and without medical treatment, the pain usually returns.

TN is a very rare condition. Statistics vary, but TN occurs in approximately 150 per million people per year. Medical literature notes  this condition is rare for anyone under age 50 but in reality, TN is known to exist in many younger individuals including children.

Trigeminal Neuralgia was described as early as the  first century A.D. in the writings of Aretaeus.. Early treatments included bloodletting and bandages containing poisons such as arsenic, mercury, hemlock, cobra and bee venom. An 18th century French surgeon, Nicolaus Andre coined the condition "Tic Douloureux," which means "painful spasm."

Several syndromes are closely related to  TN, but have specific unique features as well. These include post-herpetic neuralgia,  atypical facial pain  (ATFP), and TN resulting from multiple sclerosis (MS). Although the distinctions tend to be fluid, these are discussed separately.

There are some relatively effective treatments for TN. Unfortunately, although some of the treatments are becoming standard, there is no single treatment that is effective for all victims.

A SHORT ANATOMY LESSON
Trigeminal Neuralgia is a disorder of the  trigeminal nerve, one of twelve pairs of cranial nerves on each side of the head. 

The cranial nerves control movement and sense pressure, touch, pain and temperature in the head and neck. These twelve cranial nerves are numbered from 1 to 12 using Roman numerals -  e.g. I II III IV V VI VII etc..

You have two trigeminal nerves, one on the right side of your head and one on the left. The trigeminal nerve, the largest cranial nerve can be seen here. 

Since the trigeminal nerve is the fifth cranial nerve, it is referred to as "V" in medical literature.   The word "trigeminal" derives from the Latin word "tria" which means "three" and from "geminus" which means "twin" and refers to the fact that the trigeminal nerve has three distinct branches on each side of the head. These branches are referred to as V1, V2, and V3. The following table lists these branches and describes what areas each branch affects.

For a more in depth discussion of the trigeminal nerve, see 

You've Got Some Nerve (12 of Them): The Trigeminal Nerve

 by Richard Schuerger, Ph.D., Neurosciences Guide at about.com 

For an exceptional, detailed anatomy tour of all aspects of the Trigeminal Nerve, see

Trigeminal Nerve Anatomy

written by Jeremy S. Melker, a medical student at the University of
Florida. With complex interactive graphics, this is a site not to be missed to gain insight into the complexity of the trigeminal nerve.

CAUSES
There are a number of causes of Trigeminal Neuralgia:

• Pressure of a blood vessel on the root of the trigeminal nerve.
• Demyelinization of the nerve. In rare instances (less than 3%), TN is a symptom of Multiple Sclerosis which destroys the myelin sheaths protecting nerve fibers. Trigeminal Neuralgia is rarely the first symptom of Multiple Sclerosis and typically appears in advanced stages of MS.
• Pressure of  a tumor on the trigeminal nerve (rare)
• Physical damage to the nerve caused by dental  or surgical procedures,  injury to the face or infections.
• Unknown. Not all cases seem to have a clear cause.
• There is some speculation that some cases of  trigeminal neuralgia may be inherited.  See references and more information at:  OMIM™ Online Mendelian Inheritance in Man

SYMPTOMS
TN pain is usually described as a sudden sharp electrical, shocking, stinging, stabbing pain that lasts for several seconds and may repeat many times over the course of the day. Usually only one side of the face is affected with pain, but TN on both sides (bilateral TN) is known to exist.   TN pain is often triggered by certain stimuli, such as touching the face, eating, talking, shaving, etc. These triggers vary from person to person. The pain may last for days, weeks, or months and then may disappear for months, even years.

Area of Pain
The area of facial pain is reflected by which of the three branches of the trigeminal nerve is affected. From the brief "anatomy lesson" above, we see that

V1 (Opthalmic) the first branch affects the eye, forehead and nose.

V2 (Maxillary) the second branch affects upper teeth, gum and lip, the cheek, lower eyelid and the side of the nose.

V3 ((Mandibular) the third branch affects lower teeth, gum, lower lip and jaw.

Here is an excellent picture of the three areas.

TN pain can involve one or more branches of the trigeminal nerve. 

"Classic" TN Pain
In classic TN described in medical literature, the pain is extremely sharp, throbbing, and shock-like. There is no facial numbness or weakness.  With classic TN pain, there are distinct periods of remission, when there is no pain at all. Classic TN generally responds well to Tegretol, an anti-convulsive drug used to treat seizure disorders.

Atypical TN Pain
One typical feature of TN is that it is rarely typical. For many TN patients, the condition does not conform to the symptoms of "classic" TN.  In addition to the stabbing shock-like pain, many victims experience various kinds of pain that they may describe as throbbing, burning, crushing, pulsating, etc.  For some, there are no remissions from the pain.  These "atypical" forms of TN are often very difficult to treat.

DIAGNOSIS
A thorough medical exam and history of symptoms should be done along with medical tests  to rule out any serious medical problems. These tests  can include a CAT scan or MRI.  In some cases, high-definition MRI angiography (MRTA) of the trigeminal nerve and the brain stem can identify where the nerve is compressed by a vein or artery but more often than not, no cause is found for the pain. If the pain is diminished with carbamazepine (Tegretol)  treatment, this is a positive indicator for a diagnosis of TN. A special MRI technique, 3-D volume acquisition, performed with contrast injection, can detect 80% of the time whether a blood vessel pressing on the trigeminal nerve is causing TN pain.

However, up to now, no medical test exists that clearly diagnoses all cases of TN.  TN diagnosis should not be difficult, especially in cases of classic TN where  the symptoms are clear and distinct.   Yet time and again, TN patients  have seen numerous medical professionals and have had multiple dental procedures performed before a diagnosis is made.  Sometimes years, even decades pass before the patient is diagnosed.  In some instances, the diagnosis is missed  because the patient does not display "classic" TN symptoms but this does not explain entirely why so many TN patients are misdiagnosed.

TREATMENT
Initial treatment for TN is usually medication with cabamazepine (Tegretol®) being the first drug of choice. Other drugs such as baclofen (Lioresal®) , clonazepam (Klonopin ®) and gabapentin  (Neurontin®) are often used alone or in combination. Trileptal, a drug which was recently approved for use in the US, appears to have fewer side-effects than Tegretol and is often effective in controlling TN pain. When medication fails, surgery may be considered. For an overview and in depth description of treatments for TN see the FNR Treatment section.

REFERENCES
1.  Dorweiler, Bryce D.,  Trigeminal Neuralgia,

ONLINE RESOURCES

Professional TN Websites

Centre for Cranial Nerve Disorders
New (11/01) website from this neurosurgery clinic features:

• Interactive animated Trigeminal Neuralgia Tutorial
• Guide to Trigeminal Neuralgia

and detailed discussions of several cranial nerve disorders, their characteristics, and surgical and non-surgical treatment options. Dr. Anthony M. Kaufmann, neurosurgeon and Director of the Centre for Cranial Nerve Disorders has   authored the information presented on the web-site.

Trigeminal Neuralgia 
Excellent and extensive discussion of trigeminal neuralgia from emedicine.com.

Trigeminal Neuralgia Workshop: Opportunities for Research and Treatment, September 14, 1999
Summary of a workshop focusing on understanding the current status of TN research and to identify new avenues of research and collaborations that might have an impact on treatments, diagnosis, etc.

Slide Show on Surgical Treatments for Trigeminal Neuralgia
Excellent presentation on TN and its treatments by Dr. Kenneth Ott.

Trigeminal Neuralgia
Good discussion of using MRI imaging to identify  vascular loops  to help  deciding  whether MVD procedure is appropriate. Also presents an interesting method of deciding on surgical procedures based on a patient's age.

Surgical Treatment Trigeminal Neuralgia and Hemifacial Spasm
Albert L. Rhoton, Jr., MD,  Chairman of the Department of Neurological Surgery at the College of Medicine University of Florida writes an excellent description of TN and Hemifacial Spasm along with some of the best illustrations depicting TN pain and surgical procedures we've seen.

A Description of TN.
A simple-to-read description written specifically for the FNR site by Dr R. Wayne Hurt, M.D. The focus is on treatments

Trigeminal Neuralgia.
Another short but comprehensive introduction, written by Dr Roger Melvill (neurosurgeon). Has somewhat a focus on surgical treatments.

Trigeminal Pain.
A translation of an article written by Jakke Makela in Finnish for his local MS Foundation magazine. Provides a short description of TN and also its more atypical forms. However, please note that the article is not written by a medical professional.

NEJM: Treatment of TN.

Personal TN Websites

Trigeminal Neuralgia - You Are Not Alone
A user-friendly site by Debby Creps with excellent information on TN, treatments, support resources and other information of use to people searching for information on trigeminal neuralgia..

Julie's Trigeminal Neuralgia Resources
A Co-editor of Facial Neuralgia Resources tells the story of her encounter with Trigeminal Neuralgia, her successful Microvascular Decompression surgery and also provides pointers to other TN resources.

Trigeminal Neuralgia - A Personal Narrative
Follow a 60 year old woman's experience with Trigeminal Neuralgia and how she found relief for her pain.

Trigeminal Neuralgia: A Personal Perspective
A good description of one woman's experience with microvascular decompression and the complications she experienced.