Have you ever experienced facial pain that seemed sudden and probably brought on by a daily activity such as brushing your teeth or eating? If the pain didn’t last very long but came back frequently and is or was sever enough to cause you distress you might have visited a dentist in hopes of alleviating it. However, if you or someone you know has had dental procedures such as root canals and still find the pain returning you should consider that it could be something else. Perhaps you know the pain and have not yet visited your dentist. Either way, consider that when it comes to facial pain there might be more to it than you might think. Trigeminal Neuralgia
Trigeminal Neuralgia or “tic douloureux” is one of the most severe types of facial pain. It is pain so severe that it renders a patient’s life unbearable and in some instances suicide is not an uncommon occurrence. Unfortunately many patients go undiagnosed for months because their physician is not familiar with this painful syndrome.
Patients with this disorder have similar and unique type of symptoms. A diagnosis can be made on the history itself because of the uniqueness of the symptoms. Patients can present with intense facial pain that can last up to two minutes. In fact, the pain attacks can last only a few seconds but can recur within short periods. Some patients may have multiple episodes per day while others can have only a few episodes per year and the intensities can vary between the attacks.
An attack can occur by stimulating a trigger zone which can be located within the distribution of the trigeminal nerve. Stimuli like brushing teeth, eating, drinking, talking, laughing, light touch, can cause an attack to occur. The attacks can occur over a few weeks to months and there can be episodes of remission lasting a few months or longer.
The criteria for diagnosis of Trigeminal Neuralgia as per the International Headache Society is: facial pain lasting less than two minutes; pain that has at least four characteristics such as: a distribution along one or more divisions of the trigeminal nerve; sudden, intense, sharp, stabbing, or burning pain; lancinating pain; initiation of pain from trigger areas or by daily activities such as brushing teeth, eating, talking; no symptom between attacks; no neurological deficit; attacks are stereotyped in individual patients, exclusion of other causes of facial pain.
The trigeminal nerve is the largest and most complex of cranial nerves. It contains sensory and motor nerve fibers. The trigeminal nerve consists of three sensory divisions, the ophthalmic (V1), maxillary (V2), and mandibular (V3). Somatic afferent impulses carried by the trigeminal nerve can transmit pain, light touch, and temperature sensation. Information is transmitted to the central nervous system via the trigeminal nerve from the skin of the face, the mucosal lining of the nose and mouth, the teeth, and the anterior two thirds of the tongue. In addition to sensory innervation, the trigeminal nerve innervates a variety of muscles of facial expression, tensor tympani and some muscles of mastication.
Trigeminal neuralgia is caused by demyelination of the sensory fibers within the trigeminal nerve root. This could be in part from compression by an overlying artery or vein. Other causes where demyelination is involved include multiple sclerosis and compressive space occupying tumors. Ectopic generation of spontaneous nerve impulses and their conduction to adjacent fibers is likely increased by the buckling associated with pulsatile vascular indentation. Decompression of the nerve root from the vessel rapidly relieves symptoms. Other compressive type lesions can cause trigeminal neuralgia such as vestibular schwannomas, epidermoid cysts, and tumors.
Patients with multiple sclerosis have a higher incidence of trigeminal neuralgia. Since multiple sclerosis has plaques of demyelination, one of these plaques can affect the trigeminal dorsal root entry zone. Patients with peripheral nerve demyelination due to Charcot-Marie-Tooth disease also are prone to develop trigeminal neuralgia. Infiltrative disorders of the trigeminal nerve root such as carcinomatous deposit can occur causing the neuralgia.
When the symptoms develop at the onset of trigeminal neuralgia, many patients think it is due to dental problems. They usually seek dental treatment first. Sometimes these patients may undergo procedures such as root canals and extractions in trying to obtain pain relief. Unfortunately patients arrive at pain clinics after several failed attempts at fixing a dental problem that does not exist.
Patients undergoing medical management of trigeminal neuralgia should have baseline blood studies and biochemical studies to determine if side effects are related to treatment. Imaging studies can include x-rays of upper/lower jaws if patient is suspect of having dental pain. More importantly, an MRI scan can be used to detect benign or malignant lesions or multiple sclerosis plaques. Also the presence or absence of vessels in contact with the trigeminal nerve can be seen.
Treatment for trigeminal neuralgia consists of pharmacotherapy and/or surgical intervention. The anti convulsant drug such as carbamezapine has shown to decrease pain in this disorder. Baclofen and lamotrigine have helped in decreasing pain. Uncontrolled observations with other drugs such as phenytoin, clonazepam, sodium valproate, gabapentin, and lidocaine can decrease pain in trigeminal neuralgia. In some instances, multi drug use has been utilized with some beneficial results. Carbamezapine should be considered the mainstay of pharmacotherapy for trigeminal neuralgia. Baclofen, lamotrigine, oxcarbazepine, and gabapentin should be used as secondary drug choices.
Neurosurgical interventions include retrogasserian percutaneous radio frequency thermocoagulation, glycerol rhizolysis, balloon compression of the gasserion ganglion, and sterotactic radiosurgery. No randomized controlled trials have been found but are needed to see which procedure(s) have significant positive outcomes.
A typical patient with trigeminal neuralgia is often misdiagnosed and mistreated, with many undergoing unnecessary dental or medical procedures that bring no relief. It is important that doctors, dentists, and other health care professionals be familiar with trigeminal neuralgia, its diagnosis and treatment options. This in turn will bring proper treatment to patients sooner and minimize suffering.
Raul G. Martinez, MD is a diplomat of the American Board of Anesthesiology with a subspecialty certification in Pain Management. He completed his post-doctorate Fellowship in Pain Medicine from the University of Texas Health Science Center and has been in private practice since 1999. With offices in the Quarry Area, Medical Center, Stone Oak and Southeast he can be reached for an appointment at (210) 447-6333 or for more information about our practice visit us at http://www.cipm.com/. You can also follow us on twitter @sapaindocs or read our other blog Got Pain at MySA.com
