The trigeminal neuralgia ( NT ) is a painful and unilateral facial pathology described as a brief episode of electric shock or burning sensation (Boto, 2010).
Specifically, the pathologies that cause facial pain or facial cranium, constitute a series of diseases among which are a large number of medical conditions: facial neuralgia, symptomatic facial pain, neurological signs, trigeminal autonomic headaches and facial pains without symptoms or signs neurological diseases (Tenhamm and Kahn, 2014).
Thus, trigeminal neuralgia is considered one of the most severe and intense facial pain symptoms (Montero and Carnerero, 2016). Although its annual incidence varies, it usually occurs in people older than 50 years (Lezcano et al., 2015) and, in addition, substantially alters the quality of life of those affected (Alcántara Montero and Sánchez Carnerero, 2016).
Trigeminal Neuralgia Symptoms
Regarding the etiological cause of trigeminal neuralgia, it is usually associated with an understanding or mechanical tension of the trigeminal nerve product of vascular factors: anomalies in blood vessels, arterial hypertension or dyslipidemia, among others (International Association for Study of Pain, 2011 ; Lezcano et al, 2015).
The diagnostic evaluation of this pathology is usually carried out based on the detailed study of the characteristics of pain and various imaging studies , which allow detecting the presence of neurological alterations (Tenhamm and Kahn, 2014).
With regard to the treatment of trigeminal neuralgia, the initial interventions focus on pharmacological prescription. However, in severe cases , surgical interventions or percutaneous techniques can be chosen (Alcántara Montero and Sánchez Carnerero, 2016).
Characteristics of trigeminal neuralgia
Trigeminal neuralgia, also known as “painful tic,” is a condition that causes neuropathic pain, that is, pain associated with various anomalies or nerve injuries (National Institute of Neurological Disorders and Stroke, 2015).
The clinical definition of this pathology dates back to the seventeenth century. Since ancient times it has been referenced as ” the most intense pain that man can suffer ” (Seijo, 1998). In addition, in the most recent clinical reports, trigeminal neuralgia continues to be classified as ” one of the worst causes of suffering due to pain ” (Lezcano et al., 2015).
The pain derived from this pathology is characterized by different episodes of stabbing pain, burning, or cramping sensation and electric shock in the cranial facial areas innervated by the trigeminal nerve (Alexander, 2008).
In addition, it usually appears when eating, brushing teeth, touching one’s face, etc. (Boto, 2010), so it is mentally and physically disabling (National Insititute of Neurological Disorders and Stroke, 2015).
The trigeminal nerve or cranial nerve V, is a nervous structure that has a mixed function: motor and sensitive. Thus, its essential function is to control the musculature and facial sensitivity (Alcántara Montero and Sánchez Carnerero, 2016):
The sensitive branches of the trigeminal nerve are responsible for driving the nerve impulses related to tactile sensations (external stimulation, proprioception and pain) of the anterior areas of the tongue, the teeth, the dura mater (outermost meningeal layer), the oral mucosa and the paranasal sinuses (cavities located in the maxillary, ethmoid, sphenoid and frontal bone areas).
The motor branches of the trigeminal nerve fundamentally innervate the mandibular areas: chewing muscles (temporal, pterygoid mast) and, in addition, the tympanic, mylohyoid, and dysgastric tensor muscle.
This nervous structure, in turn, is divided into 3 main branches (Alcántara Montero and Sánchez Carnerero, 2016):
- Ophthalmic nerve ( V1 ): is responsible for the conduct of sensitive information through the areas of the scalp, forehead, upper eyelid, nose, frontal sinuses, cornea and most of the meninges. Specifically, it is distributed through
the upper facial areas.
- Maxillary nerve ( V2 ): is responsible for the conduct of sensitive information of the skin areas of the cheek, the lower eyelid, the tip of the nose, the nasal mucosa, the teeth and the upper lip, the palate, the part superior of the pharynx and the maxillary ethyroid and sphenoid sinuses. It is distributed through the middle facial skull areas.
- Mandibular nerve ( V3 ): it is in charge of the conduction of the sensitive information of the teeth and the lower lip , the chin, the nasal wings and, in addition, the one related to the pain and temperature of the mouth. Specifically, it is distributed through the lower facial areas .
Due to these characteristics, when the trigeminal nerve presents damage or injury to one or several of its branches, this pathology is associated with a significant decrease in quality of life and work capacity. It is also common for many affected people to develop depressive syndromes (Alcántara Montero and Sánchez Carnerero, 2016).
Trigeminal neuralgia is a medical condition that usually occurs chronically.
Although there are few statistical data on this pathology, it has been identified that it has an approximate incidence of 12 cases per 100,000 people per year (National Institute of Neurological Disorders and Stroke, 2014).
It is estimated that 140,000 people with this condition can live in the United States (International Radio Surgery Association, 2016).
It has been observed that, depending on sex, it affects women in a majority way and that, moreover, it is more prevalent in the population over 50 years of age (Mayo Clinic, 2015).
However, trigeminal neuralgia is a pathological condition that can develop any person, male or female, at any stage of maturation (National Institute of Neurological Disorders and Stroke, 2014).
Characteristic signs and symptoms
The essential clinical feature of trigeminal neuralgia is the presence of episodes of facial pain that is characterized by (Mayo Clinic, 2015):
- Acute episodes of burning, stinging sensations. Many patients report feeling “shock” or “electric shocks”.
- Pain episodes occur spontaneously and usually occur when you start talking, chewing, talking or brushing your teeth.
- The episodes of pain are usually temporary, lasting a few seconds or several minutes.
- These episodes frequently occur recurrently in active periods, for days, weeks or months.
- The annoying and painful sensations usually present unilaterally, that is, they affect only one side of the face.
- The episode of pain can appear focused on a specific area and progressively, it extends to other areas, generating a larger pattern.
- It is possible that with the development of the pathology, pain crises become more intense and frequent.
Despite the fact that the presentation of these episodes can be variable among the people affected, the intensity of pain is often defined as unbearable, reaching to keep the individual immobile (Seijo, 1998).
As for the most affected areas, the pain typically appears on the cheek or jaw and occasionally in the areas surrounding the nose and eyes, although this situation will depend mainly on the nerves that are affected ( Alexander, 2008).
In addition, this pathology can also be classified into two different types, depending on their clinical use (National Institute of Neurological Disorders and Stroke, 2014):
- Type 1 ( NT1 ): is the classic or typical presentation of trigeminal neuralgia, usually associated with the development of episodes of extreme pain, similar to a shock that lasts from minutes to hours. In addition, these attacks often happen to each other quickly.
- Type 2 ( NT2 ): it is the atypical form of this pathology, it is characterized by a sharp and constant pain, but of less intensity than in type 1.
This pathology is classified into two differential forms depending on its cause (Boto, 2010):
- Primary trigeminal neuralgia : the etiological cause that explains the clinical picture of the pathology can not be discovered. It is the most frequent form of trigeminal neuralgia.
- Secondary trigeminal neuralgia : the underlying cause of this pathology is associated with an identified medical event or condition .
Although the factors that can lead to the development of this pathology are diverse, they will all affect the trigeminal nerve, causing injuries and / or mechanical understanding.
Among the most common causes of trigeminal neuralgia are:
- Mechanical compression by a blood vessel or arteriovenous malformation.
- Demyelination of nerve branches resulting from other pathologies, such as multiple sclerosis
- Mechanical compression due to the development and growth of tumor masses.
- Nerve injury or mechanical compression resulting from facial or head trauma.
- Nerve injury or mechanical compression product of cerebrovascular attacks.
- Secondary lesions and neurosurgical interventions.
The diagnostic evaluation that is usually used in pathologies related to facial pain is mainly focused on clinical analysis, paying special attention to details (Tenhamm and Kahn, 2014).
The essential objective is, therefore, to carry out an anamnesis for the recognition of the clinical and evolutionary profile of pain (Tenhamm and Kahn, 2014).
- Temporary period of evolution.
- Duration of each episode or crisis.
- Location or areas most affected.
- Intensity of pain
- Factors that trigger or worsen the event.
- Factors that reduce or alleviate the intensity of the event.
- Other secondary symptomatology
In addition, this is usually accompanied by a physical examination that confirms some data such as anatomical distribution or triggers.
On the other hand, it is also frequent the use of complementary laboratory tests, such as magnetic resonance imaging. This test allows us to identify the presence or absence of nerve involvement in the trigeminal nerve branches (Alcántara Montero and Sánchez Carnero, 2016).
In the same way, the identification of the possible etiological medical cause is another essential point, since it will allow the design of an effective and individualized therapy (Seijo, 1998).
In the medical literature and in professional practice, various therapeutic interventions have been described that are effective both in the treatment of the signs and symptoms of trigeminal neuralgia and in the control of etiological medical conditions. Some of these have been described by authors such as DM Alexander (2008):
The initial treatment of facial pain, usually includes various drugs: analgesics, anticonvulsants or muscle relaxants. In some patients, the pain can be treated through opiates such as methadone or antidepressants, used in the treatment of other types of neuropathic pain.
Despite the fact that this approach is usually effective in the initial episodes, many patients present adverse reactions such as myelosuppression, somnolence, ataxia or fatigue.
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In the most serious cases, there are other options such as surgery. However, its use will depend mainly on the characteristics of the patient and the identification of the cause of trigeminal neuralgia.
Some interventions include:
- Stereotactic radiosurgery : through this procedure, a high dose of radiation is applied to a particular area of the trigeminal nerve . It is used to produce a lesion in the brain that interrupts the transmission of pain signals to the brain.
- Percutaneous Rizaotomy : Through the insertion of a needle into areas that allow reaching the trigeminal nerve, especially through the foramen ovale in the cheek, the fibers are damaged or destroyed to prevent the conduction of pain.
- Myovascular decompression: through a craniotomy and the placement of a pad between the blood vessels that compress the trigeminal nerve, it is possible to relieve the neurovascular pressure and consequently, the symptoms of pain. Although it is the most effective, they present important risks: facial weakness, paresthesia, diplopia, loss of hearing ability, cerebrovascular accident, among others.