Neuropathic pain
Neuropathic pain

Neuropathic pain refers to pain emanating from the nerves. Neuropathic pain disorders are a set of conditions which result either from a disorder or an injury to the nervous system.  The human nervous system is composed of two parts. The first is the central nervous system which consists of the brain and spinal cord.  The second is the peripheral nervous system which conveys nerves to the trunk, limbs, face and the outlying areas of the body. Injury to the nerves of the central or peripheral nervous system can cause pain signals to be sent to the brain, which can result in a chronic pain condition referred to as neuropathic pain.

Neuropathic pain may manifest itself as continuous or episodic. Neuropathic orofacial pain refers to those symptoms that primarily affect a patient’s mouth and facial area.

Episodic neuropathic pain is described as a very intense, quick, sharp, electric-like debilitating pain. The pain follows the distribution of the affected nerve. One of the most diagnosed and well known episodic neuropathic pains is trigeminal neuralgia (TN).  TN is characterized by sudden, usually unilateral, severe electrical like stabbing episodes of pain, followed by total remission of symptoms.  Attacks usually last from a fraction of a second to two minutes. Causes of TN include:  nerve compression, tumors, multiple sclerosis and physical injury.  TN is commonly brought on by non-noxious stimuli (i.e., washing or touching the face, wind on the face, talking, brushing teeth, etc.) and can also occur spontaneously. There are other episodic neuropathic conditions that are much less common such as: glossopharyngeal neuralgia, geniculate neuralgia, superior laryngeal neuralgia, nervous intermedius neuralgia and occipital neuralgia.

Continuous neuropathic pain is described often, as a dull, yet burning type pain. The pain is usually ongoing and unremitting, yet the intensity can show patterns of fluctuation. It is also usually accompanied by other neurological signs (i.e., an increase or decrease in pain perception, etc.). One of the most common and well known continuous forms of neuropathic pain is atypical odontalgia (AO).  AO is a poorly understood chronic pain disorder that is best defined as a persistent pain in apparently normal teeth and adjacent oral tissues (i.e., bone and gum tissue), in the absence of any signs of pathology. It can also occur in a site from which a tooth has been extracted (phantom teeth). AO disorders are characterized by constant pain without any periods of remission. The pains are of variable intensity, ranging from mild to severe, but are not as excruciating as the pain of trigeminal neuralgia. The quality of pain is usually described as dull and aching, and is often accompanied by burning or throbbing components. A high proportion of the patients precipitating factors include traumatic injury and various routine dental procedures.  Suspected causes are: psychological, neurovascular, or interruption or destruction (i.e., being cut or compressed) of the nerves.  Other occurring but maybe not as common continuous neuropathic conditions are: Bell’s palsy, herpes zoster, burning mouth syndrome, postherpetic neuralgia, complex regional pain syndrome, etc.

Diagnosis

Various orofacial neuropathies derive from a number of causes. Therefore, depending on the symptoms experienced, the diagnostic process often varies.  As with any diagnostic process, it is most important for a doctor to take a complete medical history and description of the symptoms, perform a thorough physical exam, and order any necessary tests or scans (i.e., magnetic resonance imaging (MRI), magnetic resonance angiography (MRA), dental x-rays, nerve blocks, electromyogram (EMG), etc).  Some neuralgias are often diagnosed by eliminating other serious medical problems, and ruling out other possible causes.

Treatment

Fortunately, for those suffering from facial neuropathies, while much is unknown about these conditions and their causes, a number of treatments have been found to be effective. A combination of treatments and therapies is often found most effective in managing orofacial neuropathic pain symptoms, such as: palliative treatment, physical therapy, a variety of medications and their delivery systems, injections again using a variety of medicaments, and different types of surgical procedures, etc.