Diagnosis

Pain is defined as an unpleasant sensation related to actual or potential tissue damage.  There is a lot of room for variation in that statement.  Unpleasant?  Actual or potential?  It is difficult to diagnose pain and certainly difficult to diagnose a specific type of pain.  It is a physical sensation combined with an emotional reaction.  Basically, pain is whatever the person who is experiencing it says it is.  Trigeminal neuralgic pain is no different.  It is diagnosed based on history and current description of the symptoms by the patient.

Trigeminal neural  is often diagnosed by ruling out other diseases.  For example, shingles, TMJ and multiple sclerosis are all able to cause facial pain but specific testing can be done to determine whether or not one of these three diseases is the cause.

Sometimes, a differential diagnosis is used.  This is done by aligning specific symptoms of the current disease and determining which category they fall into.  Below is a table showing differential diagnoses between trigeminal neuralgia and atypical facial pain.

Feature Trigeminal Neuralgia  Atypical Facial Pain Prevalence Rare  Common Main location Trigeminal area  Face, neck, ear Pain duration Seconds to 2 minutes  Hours to days Character Electric jerks, stabbing  Throbbing, dull Pain intensity Severe  Mild to moderate Provoking factors Light touch, washing, shaving, eating, talking  Stress, cold Associated symptoms        None  Sensory abnormalities

It is difficult to diagnose trigeminal neuralgia.  It is a relatively rare disorder with similar symptoms to several other disorders.  The most important thing in the process of diagnosing is to remember that this person in front of us is in great pain and offering some comfort and compassion while we determine how we can help.



References:

http://www.ninds.nih.gov/disorders/trigeminal_neuralgia/detail_trigeminal_neuralgia.htm#280103236

http://emedicine.medscape.com/article/1145144-differential

WHY has this happened and WHY does it hurt?

Imagine a typical daily task such as brushing your teeth or putting on sunscreen.  Pretty uneventful, right?  Get it done, move on.  Well, now imagine having to do that task knowing that it was going to cause you excruciating pain that could last for minutes, hours, etc.  That is what those who have trigeminal neuralgia suffer from daily.  The most minimal of contact with the trigeminal nerve will change the course of their near future due to the pain that it is sure to cause them.  Here is how it works...

The trigeminal nerve is the fifth cranial nerve.  It is one pair of 12 different pairs of nerves that are attached directly to the brain.  Here is a list of the cranial nerves.  The cranial nerves are sensory only, which means that they relay information regarding the senses (smell, sight, touch, etc.) or both sensory and motor, which means that they relay sensation but also assist with movement.  The numbers are placed into the photo based on what information they carry.

1. Olfactory - smell
2. Optic - vision
3. Oculomotor - the muscles of the eye
4. Trochlear - the superior, oblique muscles of the eye
5. Trigeminal (sensory and motor) - sends sensory information from the face and mouth and motor information to the chewing muscles of the mouth (Notice how large the corresponding number is on the image!  If this nerve is the cause of pain, it unfortunately has a lot of reach.)
6. Abducens - the lacteral rectus muscles of the eye
7. Facial - muscles of facial expression, lacrimal glands (tear ducts!) and salivary glands
8. Vestibulocochlear (Acoustic) - equilibrium and hearing
9. Glossopharyngeal - throat for swallowing, posterior part of tongue, salivary glands
10. Vagus - internal organs
11. Spinal Accessory - the muscles that move head, neck and shoulders
12. Hypoglossal - muscles of the tongue

The trigeminal nerve splits into three different branches which carry information from three different areas of the face and mouth.  Here is an image of these three areas -

In a trigeminal neuralgic attack, pressure is applied directly to a part of the nerve that has lost its protective covering called its myelin sheath.  Nerves are composed of nerve cells called neurons which relay information by sending an electrical impulse up an axon, a long, thin cablelike projection.  Because the axon is sending electrical information, it is covered with a protective covering called the myelin sheath.  Myelin is only found in our nervous system and is basically insulation for the nerve cells to give protection and to allow information to travel quickly, like the protective covering of an electrical wire.

Something has damaged this protective covering in a case of trigeminal neuralgia and the nerve is exposed.  This can be caused by a number of different things.  The different causes of damage to the myelin sheath define the type of trigeminal neuralgia.  The different types of this disease are:

• TN1 (classic or tic douloureux) - This pain is caused by loss or damage to the myelin typically from pressure on the sheath from a surrounding blood vessel.  The pain occurs spontaneously and is temporary.

• TN2 - This is similar to TN1, however the pain is more chronic.

• STN (secondary symptomatic TN) - The loss of myelin sheath in this type of trigeminal neuralgia is caused by multiple sclerosis.

• PHN (post-herpetic neuralgia) - This pain is caused by a shingles outbreak on the trigeminal nerve.

• TNP (trigeminal neuropathic pain) - Neuropathic pain differs from neuralgic pain in that it is caused by damage to the nerve itself...not just the myelin sheath.  The injured nerve will send random painful signals to the brain.  It could be a result of facial trauma, ear, nose or throat surgery, a stroke, etc.

• TDP (trigeminal deafferentation pain) - This type of trigeminal pain results from a loss of the nerve, but continued pain signals...sort of like phantom limb pain.

The bottom line is that damage to the myelin sheath and exposure of the trigeminal nerve can result in an excruciating pain whenever pressure is applied to that nerve.  The pain and suffering that this disease causes to the person can be debilitating.

References:

http://www.brainfacts.org/brain-basics/neuroanatomy/articles/2012/the-neuron/

http://fpa-support.org/trigeminal-neuralgia/

How often does this disorder occur?

Trigeminal neuralgia is a rare chronic pain disorder, but one that needs to be taken seriously.  It can severely decrease the quality of life for those who are diagnosed with it.  And who are these people who are diagnosed with the disorder?  Below is an infograph outlining the incidence and prevalence of the disease in the world. 

To summarize:

• Trigeminal neuralgia is most commonly diagnosed in those over the age of 50, although it can be diagnosed as early as teenage years and there has even been a case of trigeminal neuralgia found in infancy.  
• Women are diagnosed more often than men.
• There will be a rise in number of cases that are both diagnosed and prevalent by the year 2022.  (This forecast is likely due to the changes in population as opposed to the changes in the disease itself.)

The most common cause of trigeminal neuralgia is pressure on the trigeminal nerve from a surrounding blood vessel.  It can be an outcome of multiple sclerosis, as well, if the body attacks the covering of the trigeminal nerve (the myelin sheath.)  One final and more rare cause is pressure on the trigeminal nerve from a tumor.

References:

www.ninds.nih.gov/disorders/trigeminal_neuralgia/detail_trigeminal_neuralgia.htm#280093236 

http://dana.org/Publications/GuideDetails.aspx?id=50054

http://www.prnewswire.com/news-releases/epicast-report-trigeminal-neuralgia---epidemiology-forecast-to-2022-246134431.html

What is it?

Stabbing, burning, aching, electric shock-like...these are all descriptions that have been used to refer to the pain caused by trigeminal neuralgia.  This chronic pain disorder, also known as tic douloureux, has been said to cause the most excruciating pain known to humanity.  Trigeminal neuralgia is sometimes called 'the suicide disease' because of a number of people who have taken their own lives as an alternate to living with this pain.  A person diagnosed with this disorder is often made physically and mentally incapacitated for the duration of these bouts of pain.

In the picture below, you can see that this nerve splits into three separate branches.  The nerve endings from branch 1, the uppermost branch, end in the forehead and eye area.  Branch 2 nerve endings end in the nose and upper mouth and branch 3 nerves end in the lower mouth and jaw.  These areas are where trigeminal neuralgic pain is felt.

Trigeminal neuralgia is caused by pressure on the trigeminal nerve, which innervates the face.  This pressure is often due to a blood vessel pressing on the nerve and wearing down the myelin sheath, or the insulating cover that surround nerve cells.  In some rare cases the pressure is caused by a tumor. Symptoms of trigeminal neuralgia may also appear in multiple sclerosis, which is a disease in which the body attacks the myelin sheath.

Regardless of the cause of the pressure, the pain that comes with the disorder can be unbearable and must be closely managed in order to allow those diagnosed with trigeminal neuralgia to function.

References:

http://www.ninds.nih.gov/disorders/trigeminal_neuralgia/detail_trigeminal_neuralgia.htm

http://www.mayoclinic.org/diseases-conditions/trigeminal-neuralgia/basics/definition/con-20043802

http://www.aans.org/patient%20information/conditions%20and%20treatments/trigeminal%20neuralgia.aspx