Neuralgia of a trigeminal nerve
Neuralgia of a trigeminal nerve — the recidivous damage of a trigeminalny cranial nerve which is characterized by the shooting paroksizmalny prozopalgiya. The clinical picture is made by repeated paroxysms of unilateral intensive front pain. Alternation of phases of an aggravation and remission is typical. Diagnostics is based on clinical yielded, results of neurologic inspection, additional researches (KT, MPT). The basis of conservative therapy is made by anticonvulsive pharmaceuticals. According to indications surgical treatment is carried out: back decompression, destruction of a trunk and separate branches.
Neuralgia of a trigeminal nerve
The first description of trigeminal neuralgia is dated 1671. In 1756 the disease was allocated in a separate nosology. In 1773 the British physician J. Fozergill gave the detailed report on a pain syndrome, characteristic of a disease. In honor of the author of the report neuralgia received the name Fozergill's disease. In modern neurology the term "trigeminalny (trigeminal) neuralgia" is more often used. According to World Health Organization, incidence makes 2-4 persons on 10 thousand population. Pathologies are more subject persons 50 years are more senior. Women are ill more often than men.
For the entire period of researches of an etiology of this disease of various authors about 50 causal factors were mentioned. It is established that in 95% of cases the sdavleniye of a trunk and branches of a trigeminal nerve acts as an etiofaktor. Distinguish the following from the main reasons for a compression:
- Pathology of vessels. Expansion, an izvitost, aneurism of the vessel lying near a nervous trunk leads to irritation and a sdavleniye of the last. The pain syndrome is result. Cerebral atherosclerosis, arterial hypertension become the contributing factors.
- Volume educations. Cerebral tumors, new growths of bones of a skull localized in a zone of an exit of a trigeminal nerve from a cerebral trunk or on the course of its branches in process of growth begin to squeeze nervous fibers. The compression provokes development of neuralgia.
- Changes of structures of a skull. Etiologichesky value has the narrowing of bone channels and openings arising owing to injuries of the head, chronic antritises, otitises. Change of a relative positioning of cranial structures is possible at pathology of a bite, deformation of a tooth alignment.
In certain cases defeat of a nervous cover and fibers is caused by a herpetic infection, chronic infectious process of zubochelyustny system (periodontitis, stomatitis, gingivity). At certain patients trigeminal neuralgia is formed against the background of a demiyeliniziruyushchy disease. Overcooling, dental manipulations, the raised chewing loading, in case of infectious genesis — decrease in immunity belong to the factors provoking developing of pathology.
The etiofaktor stated above exponentiate morphological changes in a cover of a trigeminal nerve. Researches showed that structural changes of a myelin cover and axial cylinders develop 3-6 months later from an onset of the illness. Local microstructural violations provoke formation of the peripheral generator of pathologically strengthened excitement. The excess impulsation which is constantly arriving from the periphery causes formation of the central center of hyper excitement. There are several theories explaining communication of a local demiyelinization and emergence of focus of hyper excitement. One authors point to a possibility of emergence of cross mezhaksonalny momentum transfer. According to other theory the pathological afferent impulsation becomes the reason of damage of trigeminal kernels of a cerebral trunk. According to the third theory in the place of defeat regeneration of axons goes in an opposite direction.
Systematization of a disease according to an etiology has practical value. This principle is the cornerstone of definition of the most expedient medical tactics (conservative or surgical). According to etiologichesky aspect neuralgia of a trigeminal nerve is subdivided into two main forms:
- Idiopathic (primary). It is caused by a vascular compression of a trigeminalny back, is more often in the field of a brain trunk. In connection with difficulties of diagnostics of pathological relationship the vessel nerve, idiopathic neuralgia is supposed after an exception of other reasons of a trigeminalny pain syndrome.
- Secondary (symptomatic). Becomes result of new growths, infections, demiyeliniziruyushchy pathology, bone changes. It is diagnosed according to neurovisualization, a skull tomography.
The clinical picture consists of prozopalgiya paroxysms (front pain) which is characterized by a series of the intensive painful impulses going from the side surface of a face to the center. Patients describe a pain syndrome as "current rush", "lumbago" "electric discharge". The attack proceeds up to two minutes, repeatedly repeats. Localization of pain depends on the place of defeat. At pathology of separate branches the painful impulsation occurs in supraorbitalny area, on the course of a malar arch, the lower jaw. Defeat of a trunk leads to spread of pain on all half of the face. The behavior of patients at the time of a paroxysm is characteristic: they fade on the place, are afraid to move, speak. Despite high intensity of pain, patients do not shout.
The Trigeminalny paroxysm is exponentiated by various external influences: wind, cold air and water, shaving. As load of mimic and chewing muscles can act as a provocative factor, patients avoid widely to open a mouth, to talk, laugh, eat rigid food. Trigeminal neuralgia differs in a recidivous current. During remission paroxysms are absent. In the subsequent symptoms of loss of function of a trigeminal nerve – decrease in sensitivity of face skin appear. The symptomatic form proceeds with a combination of typical painful attacks and other neurologic symptomatology. It is possible , symptoms of damage of other cranial nerves, a vestibular syndrome, a cerebellar ataxy.
The fear to provoke a neuralgic paroxysm forces patients to chew only a healthy half of a mouth that it leads to formation of consolidations in muscles of a counterlateral part of the face. Frequent paroxysms reduce quality of life of patients, negatively are reflected in their emotional background, worsen working capacity. Intensive painful pains, constant fear of emergence of the next paroxysm are capable to cause development of neurotic frustration: neurosis, depression, morbid depression. The progressing morphological changes (a demiyelinization, degenerate processes) cause deterioration in functioning of a nerve that is clinically shown by touch deficiency, some atrophy of chewing muscles.
In typical cases neuralgia of a trigeminal nerve is without effort diagnosed by the neurologist. The diagnosis is established on the basis of clinical yielded and results of neurologic survey. Existence of the trigger points corresponding to an exit of branchings of a nerve to the front area acts as the main diagnostic criterion. Presence of neurologic deficiency testifies in favor of the symptomatic nature of pathology. The next tool researches are applied to specification of an etiology of defeat:
- Skull KT. Allows to reveal change of the sizes and a relative positioning of bone structures. Helps to diagnose narrowing of openings and channels through which there passes the trigeminal nerve.
- Brain MRT. It is made for an exception of volume education as the reasons of a compression of a nervous trunk. Visualizes tumors, brain cysts, the demiyelinization centers.
- MR-angiography. It is used for aim verification of vascular genesis of a compression. It is informative at rather big size of a vascular loop or aneurism.
Neuralgia of a trigeminal nerve is differentiated with prozopalgiya of vascular, miogenny, psychogenic character. Presence of the expressed vegetative component (dacryagogue, puffiness, reddening) speaks about the vascular character of a paroxysm typical for a puchkovy headache, a paroksizmalny hemicrany. Psychogenic front pain differs in variability of duration and a pattern of a painful paroxysm. The exception of oftalmogenny, odontogenny and rinogenny pain syndromes requires consultation of the ophthalmologist, stomatologist, otorhinolaryngologist.
Treatment of neuralgia of a trigeminal nerve
Basic therapy is directed to knocking over of peripheral and central focal hyper excitement. Means of the first line are antikonvulsant (carbamazepine). Treatment begins with gradual building of a dose before achievement of optimum clinical effect. The supporting therapy is carried out is long within several months with the subsequent gradual decrease in dosages. In the absence of paroxysms pharmaceutical cancellation is possible. Anticonvulsive medicines apply additional medicines to increase in efficiency of treatment. Treat auxiliary methods of therapy:
- The means exponentiating effect of antikonvulsant. Antihistaminic medicines allow to reduce puffiness. Spazmolitiki promote knocking over of a painful paroxysm. Proofreaders of microcirculation (nicotinic acid, ) provide the increased oxygenation and food of a nervous trunk.
- Medical blockade. Introduction of local anesthetics, glucocorticoid hormones is carried out in trigger points. The medical procedure gives good analgesic effect.
- Physical therapy. Effective use of galvanization with novocaine, an ultrafonoforeza with a hydrocortisone, diadynamic currents. Procedures provide reduction of expressiveness of an inflammation, possess the anesthetizing action.
Existence of intra cranial education, insufficient efficiency of pharmacotherapy are indications to surgical intervention. Expediency of operation is defined by the neurosurgeon. As basic technicians of neurosurgical treatment are considered:
- Microsurgical decompression. It is carried out in the field of a nerve exit from a brain trunk. It is necessary to remember big risk of application of a technique for patients of advanced age, patients with the burdened premorbidny background.
- Chreskozhny radio-frequency destruction. A modern alternative to open interventions with crossing of trigeminalny branches. An essential lack of a method is rather high percent of a recurrence.
- Stereotaksichesky radio surgery. Operation consists in destruction of a touch back the directed local gamma radiation. Loss of sensitivity in a zone of an innervation of the destroyed back belongs to side effects.
Forecast and prevention
Neuralgia of a trigeminal nerve does not pose hazard to life, but attacks of a disease have the painful exhausting character. The outcome is defined by an etiology, a premorbidny background, duration of existence of a disease. For the first time the arisen trigeminalny neuralgia at young patients at adequate treatment has the favorable forecast. A recurrence after surgical intervention makes 3-15%. Primary prevention consists in timely therapy of inflammatory pathologies of zubochelyustny system, an ear, okolonosovy bosoms. Measures of secondary prevention are regular observation at the neurologist, the exception of influence of trigger factors, preventive reception of antikonvulsant at catarrhal diseases.