Facial Pain
Neuropathic Pain and Trigeminal Neuralgia
Facial Pain (Neuropathic Pain and Trigeminal Neuralgia)
Neuropathic pain (Neuralgia) is a disorder of the nervous system and the nerve tissues, rather than the actual structures that they innervate. According to the International Association for the Study of Pain (IASP), neuropathic pain originates due to lesions in, or damage to, nerve tissues in the central nervous system (CNS), or the peripheral nervous system (PNS). There are many causes of neuropathic pain, some of those include: infections (Viral and Bacterial), trauma, metabolic abnormalities, nerve compression, chemotherapy, surgery, dental procedures, tumor infiltration, neurotoxins, and radiation treatment. According to the National Institute of Health (NIH), it is estimated that 7-10% of the U.S. population will experience neuropathic pain. Neuropathic pain can be very challenging for clinicians to diagnose as many patients present with chronic pain, rather than neuropathic pain. Neuropathic pain has very distinct pain characteristics; they include electrical shock, burning, tingling, cold, prickling, and itching.
Types of Neuralgias
Trigeminal Neuralgia (Tic Douloureux)
TN typically affects women more than men, in the age range of 50-70
years of age. It is an extremely painful condition that usually occurs
on one side of the face, more often on the “right” side. It is described
as an extreme, sharp, stabbing, lancinating pain that can last for a few
seconds to several minutes. In the United States it affects less than
200,000 people at any one time. Although it is considered a rare
condition, life with TN is so excruciating and debilitating, that
unfortunately, some patients have even contemplated suicide! It
originates in the “trigeminal ganglion” where it then branches into
three divisions: V1 Ophthalmic Nerve division, V2 Maxillary Nerve
division and V3 Mandibular Nerve division. The most common branch
affected is V3, the mandibular branch, which affects the lower jaw.
The most common causes of trigeminal neuralgia include nerve
compression by blood vessels in the base of the skull, Tumors
compressing the nerve, Multiple sclerosis, and injury to the nerve
itself (trauma, infections, dental procedures). One of the methods
used to diagnose TN is to block the nerve with topical and/or local
anesthetic blocks and see if the pain resolves. Treating Trigeminal
Neuralgia includes:
– Medications (anticonvulsants, antidepressants, and muscle
relaxants)
– Opioid medications are usually not helpful
– Percutaneous Rhizotomy Surgery (Chemical or Radiofrequency)
– Balloon Rhizotomy Surgery
– Microvascular Decompression Surgery (Neurosurgery)
Atypical Odontalgia
This is one of the most common and frustrating conditions presented
to dentists. This is basically a toothache of unknown origin or
“phantom tooth pain” Patients usually present with a chief complaint
that their “tooth hurts” and naturally, dentists start focusing on a
“dental problem” rather than a neuropathic pain problem.
Unfortunately, this can lead to unnecessary dental procedures
because the pain is not a “tooth problem”, but rather a peripheral or
central nerve problem. Consequently, dental procedures like root
canals and extractions are performed, then sadly the pain persists.
This leads to wondering why treatment failed, then more procedures
are done thinking that “another tooth” is the problem and the cycle
continues. Orofacial Pain specialists can help diagnose these
conditions and determine whether it is a “tooth” related problem, or
a “neuropathic” Pain condition. Treatment includes:
– Topical Anesthetics
– Medications (antidepressants, anticonvulsants)
– Capsaicin ointments
Glossopharyngeal Neuralgia
Glossopharyngeal Pain is pain that is localized to the ear and tonsillar
area in the back of the throat and is exacerbated by yawning and
swallowing food. As a result of this pain, patients tend to refrain from
eating which leads to undernourishment. To diagnose this type of
pain, a clinician will see if topical anesthetic on the back of the throat
alleviates the pain. Treatment includes:
– Medications (Carbamazepine, Oxcarbazepine, Topiramate,
Gabapentin)
– Rhizotomy
– Gamma Knife Procedures
– Microvascular Decompression
Nervus Intermedius Neuralgia
This type of neuralgia affects the inner ear, the outer ear, and the
pinna of the ear. It is typically triggered by touching the ear. The pain
can also radiate to the back of the throat and the palate. Treatment
includes:
– Medications
– Rhizotomy
– Microvascular Decompression
Complex Regional Pain Syndrome (CRPS)
CRPS is a type of neuralgia that can present in the head and neck
region but is most common in the limbs and extremities. There are
two types of CRPS; Type I which is associated with tissue damage and
Type II which is associated with nerve damage. Patients describe this
type of neuralgia as a constant burning, tingling, cold pain, with
redness, swelling and stiffness of the tissues. Treatment Includes:
– A concerted effort by neurologists, anesthesiologists, and
orthopedists, to treat the myriad of complications that exist with
this syndrome. Medications, surgical procedures and infusion
therapy with Ketamine seem very promising for CRPS.
More Common Neuralgias seen in the Dental Office
- Occlusal Dysesthesia
A condition where patients describe a feeling in the gums and teeth as a “fullness, tingling, pins and needles, electrical shock, burning, or itching” sensation in a tooth or the surrounding gum tissues. Unfortunately, as with atypical odontalgia, this condition can lead to unnecessary dental procedures trying to resolve the problem. Recognizing that this is possibly a neuropathic pain problem is the key in this situation. Topical anesthetics in bleaching trays and anticonvulsant drugs are commonly used to treat this problem. - Burning Mouth/Tongue Syndrome
With this condition, patients will have a chief complaint of a “Burning tongue, lips, and/or gums”. There are so many etiologies that can cause burning mouth syndrome that it is often difficult to manage. Fungal infections, dry mouth, as well as neuropathic disorders can all be reasons why this condition occurs. Depending on the etiology, antifungal drugs, topical anesthetics, anticonvulsants, benzodiazepines and saliva stimulants can be used to treat burning mouth syndrome. - Post Herpetic Neuralgia
This condition occurs “after” an acute herpes zoster (shingles) infection and rarely occurs before the age of 40. The incidence of PHN is about 10% in individuals age 40 and increases to about 75% by age 90. It is a chronic, superficial burning pain in the area where the shingles infection occurred. If this pain persists for more than a year, it most likely won’t respond to most therapies. Management of PHN pain can be very challenging. It is commonly treated with anticonvulsants (like Gabapentin and Pregabalin), narcotics, capsaicin creams, and most recently, Botox injections. The best way to avoid shingles is to get the “shingles Vaccine” around the age of 60 years old. - Mandibular Paresthesia (Lower Lip Numbness)
Occasionally following a dental procedure, the area where the dental work was performed, stays numb after the dental anesthetic has worn off. This condition is known as “Paresthesia” and occurs most often in the lower jaw or mandible. Most patients are alarmed by this phenomenon as they have a continuing sensation of numbness, tingling, pins and needles, and sometimes pain. This condition can be the result of an iatrogenic dental procedure where the main nerve of the jaw is damaged either by the dental injection, the procedure itself, or both. Paresthesia can also be the result invading tumors (benign or malignant), infections, and various neurologic disorders. When it is the result of a dental procedure, the good news is that it is usually temporary. It can last for a few days, up to several months. It is important to notify your treating dentist or an orofacial pain specialist, to determine what type of procedure caused the paresthesia-was it a root canal procedure, is gutta percha pushing on the nerve? Was it due to an extraction and the nerve was damaged during the procedure? Was it caused during the dental injection? Once it is determined how the paresthesia occurred, treatment should be initiated to calm the nerve down. Case studies have shown favorable results when paresthesia is treated with corticosteroids and pregabalin (Lyrica). If this course of treatment does not work, referral to a neurologist, a neurosurgeon, and/or an oral and maxillofacial surgeon is in order, where surgical intervention to repair the nerve might be attempted.