Atrophy of an optic nerve
Atrophy of an optic nerve (optical neuropathy) – partial or full destruction of the nervous fibers transferring visual irritations from a retina to a brain. The atrophy of an optic nerve leads to decrease or full loss of sight, narrowing of fields of vision, violation of color sight, DZN pobledneniye. The diagnosis of an atrophy of an optic nerve is made at identification of characteristic symptoms of a disease by means of an oftalmoskopiya, perimetry, color testing, definition of visual acuity, a kraniografiya, KT and MRT of the brain V-scanning ultrasonography of an eye, an angiography of vessels of a retina, a research of visual VP, etc. At an atrophy of an optic nerve treatment is directed to elimination of the pathology which caused this complication.
Atrophy of an optic nerve
Various diseases of an optic nerve in ophthalmology meet in 1-1,5% of cases; from them from 19 to 26% lead to a full atrophy of an optic nerve and an incurable blindness. Patomorfologichesky changes at an atrophy of an optic nerve are characterized by destruction of axons of gangliozny cells of a retina with their glial transformation, an obliteration of capillary network of an optic nerve and its thinning. The atrophy of an optic nerve can be a consequence of a large number of the diseases proceeding with an inflammation, a sdavleniye, hypostasis, damage of nervous fibers or damage of vessels of an eye.
Reasons of an atrophy of an optic nerve
As the factors leading to an atrophy of an optic nerve diseases of an eye, defeat of TsNS, mechanical damages, intoxications, the general, infectious, autoimmune diseases, etc. can act.
As the reasons of defeat and the subsequent atrophy of an optic nerve various oftalmopatologiya quite often acts: glaucoma, pigmentary dystrophy of a retina, occlusion of the central artery of a retina, a miopiya, uveit, retinit, neuritis of an optic nerve and so forth. Danger of injury of an optic nerve can be connected with tumors and diseases of an orbit: meningiomy and glioma of an optic nerve, nevrinomy, neurofibroma, primary cancer of an orbit, osteosarcoma, local orbital vaskulita, sarkoidozy, etc.
Among TsNS diseases the leading role is played by tumors of a hypophysis and a back cranial pole, sdavleny areas of an optic chiasm (hiazma), pyoinflammatory diseases (brain abscess, encephalitis, meningitis, arakhnoidit), the multiple sclerosis, craniocereberal injuries and injuries of a facial skeleton which are followed by wound of an optic nerve.
Quite often the atrophy of an optic nerve is preceded by the course of a hypertension, atherosclerosis, starvation, avitaminosis, intoxications (poisonings with alcohol substitutes, nicotine, hlorofosy, medicinal substances), big one-stage blood loss (is more often at uterine and gastrointestinal bleedings), diabetes, anemias. Degenerate processes in an optic nerve can develop at an anti-phospholipidic syndrome, system red a wolf cub, Wegener's granulematoza, Bekhchet's disease, Horton's disease, Takayasu's disease.
In some cases the atrophy of an optic nerve develops as a complication heavy bacterial (syphilis, tuberculosis), virus (flu, measles, a clumsy rubella, a SARS, the surrounding herpes) or parasitic (toxoplasmosis, a toksokaroz) infections.
Congenital atrophies of an optic nerve meet at an akrotsefaliya (a tower-shaped skull), micro and a makrotsefaliya, a craniofacial dizostoz (Kruzon's disease), hereditary syndromes. In 20% of observations the etiology of an atrophy of an optic nerve remains obscure.
Classification of an atrophy of an optic nerve
The atrophy of an optic nerve can carry the hereditary and not hereditary (acquired) character. Carry to hereditary forms of an atrophy of an optic nerve autosomno-diminantny, autosomno-recessive and mitochondrial. Autosomno-dominantnaya the form can have a heavy and easy current, is sometimes combined with congenital deafness. Autosomno-retsessivnaya the form of an atrophy of an optic nerve occurs at patients with syndromes Vera, Tungsten, Burnevilli, Janszen, Rosenberg-Chattoriana, Kenny-Coffi. The mitochondrial form is observed at a mutation of mitochondrial DNA and accompanies Leber's disease.
The acquired atrophies of an optic nerve, depending on etiologichesky factors, can have primary, secondary and glaukomatozny character. The mechanism of development of primary atrophy is connected with a sdavleniye of peripheral neurons of a visual way; DZN at the same time is not changed, its borders remain accurate. In pathogenesis of a secondary atrophy DZN hypostasis caused by pathological process in a retina or the most optic nerve takes place. Replacement of nervous fibers with a neuroglia has more expressed character; DZN increases in the diameter and loses the clearness of borders. Development of a glaukomatozny atrophy of an optic nerve is caused by a collapse of a trellised plate skler against the background of the increased intraocular pressure.
On extent of change of coloring of a disk of an optic nerve distinguish an initial, partial (incomplete) and full atrophy. Initial degree of an atrophy is characterized by an easy pobledneniye of DZN at preservation of normal coloring of an optic nerve. At a partial atrophy the disk pobledneniye in one of segments is noted. The full atrophy is shown by a uniform pobledneniye and thinning of all disk of an optic nerve, narrowing of vessels of an eye bottom.
On localization allocate ascending (at damage of cells of a retina) and descending (at damage of fibers of an optic nerve) an atrophy; on localization - unilateral and bilateral; on extent of progressing - stationary and progressing (is defined during dynamic observation of the ophthalmologist).
Symptoms of an atrophy of an optic nerve
The decrease in visual acuity which is not giving in to correction by means of points and lenses is the main sign of an atrophy of an optic nerve. At the progressing atrophy decrease in visual function develops in terms from several days to several months and can end with a total blindness. In case of an incomplete atrophy of an optic nerve pathological changes reach a certain point and further do not develop in this connection sight is lost partially.
At an atrophy of an optic nerve of violation of visual function can be shown by concentric narrowing of fields of vision (disappearance of side sight), development of "tunnel" sight, disorder of color sight (mainly green-red, is more rare – a blue-yellow part of a range), emergence of dark stains (scotomas) on sites of a field of vision. Identification on the party of defeat of afferent pupillary defect - decrease in reaction of a pupil to light at preservation of sodruzhestvenny pupillary reaction is typical. Such changes can be noted both in one, and in both eyes.
Objective signs of an atrophy of an optic nerve come to light in the course of ophthalmologic inspection.
Diagnostics of an atrophy of an optic nerve
At inspection of patients with an atrophy of an optic nerve it is necessary to find out existence of associated diseases, the fact of reception of medicines and contact with chemicals, existence of addictions, and also the complaints confirming possible intrakranialny defeats.
At fizikalny inspection the ophthalmologist defines absence or existence of an ekzoftalm, investigates mobility of eyeballs, checks reaction of pupils to light, a corneal reflex. A visual acuity inspection, perimetry, a color sensation research is surely carried out.
The main information on existence and degree of an atrophy of an optic nerve are received by means of an oftalmoskopiya. Depending on the reasons and a form of optical neuropathy the oftalmoskopichesky picture will differ, however there are typical characteristics which are found at different types of an atrophy of an optic nerve. Treat them: pobledneny DZN of various degree and prevalence, change of its contours and color (from grayish to a wax shade), excavation of a surface of a disk, reduction on a disk of number of small vessels (Kestenbaum's symptom), narrowing of caliber of arteries of a retina, change of veins, etc. The condition of DZN is specified by means of a tomography (optical coherent, laser scanning).
The electrophysiological research (ZVP) reveals decrease in lability and increase in threshold sensitivity of an optic nerve. At a glaukomatozny form of an atrophy of an optic nerve by means of a tonometriya increase in intraocular pressure is defined. Pathology of an eye-socket comes to light by means of a survey X-ray analysis of an orbit. Examination of vessels of a retina is conducted by means of a fluorescent angiography. The blood-groove research in orbital and nadblokovy arteries, the intrakranialny site of an internal carotid is made by means of ultrasonic doppler sonography.
If necessary ophthalmologic inspection is supplemented with the research of the neurologic status including consultation of the neurologist, carrying out a X-ray analysis of a skull and the Turkish saddle, brain KT or MPT. At identification at the patient of volume formation of a brain or intra cranial hypertensia consultation of the neurosurgeon is necessary. In case of pathogenetic communication of an atrophy of an optic nerve with system vaskulita, consultation of the rheumatologist is shown. Existence of tumors of an orbit dictates need of survey of the patient oftalmoonkology. Medical tactics at okklyuziruyushchy damages of arteries (orbital, internal sleepy) is defined by the surgeon-ophthalmologist or the vascular surgeon.
At the atrophy of an optic nerve caused by infectious pathology laboratory tests are informative: IFA and PTsR-diagnostics.
The differential diagnosis of an atrophy of an optic nerve should be carried out with a peripheral cataract and an ambliopiya.
Treatment of an atrophy of an optic nerve
As the atrophy of an optic nerve in most cases is not an independent disease, and serves as a consequence of other pathological processes, its treatment needs to be begun with elimination of the reason. Etc. neurosurgical operation is shown to patients with intrakranialny tumors, intra cranial hypertensia, aneurism of vessels of a brain.
Nonspecific conservative treatment of an atrophy of an optic nerve is directed to the greatest possible preservation of visual function. For the purpose of reduction of inflammatory infiltration and hypostasis of an optic nerve are carried out couple - retrobulbarny injections of solution of dexamethasone, intravenous injections of solution of glucose and calcium of chloride, intramuscular introduction of diuretic medicines (furosemide).
For improvement of blood circulation and traffic of an optic nerve are shown to an injection of a pentoksifillin, a ksantinol of a nikotinat, atropine (parabulbarno and retrobulbarno); intravenous administration of nicotinic acid, eufillin; vitamin therapy (B2, B6, B12), injections of extract of an aloe or vitreous body; reception of cinnarizine, piracetam, inosine, ATP, etc. For maintenance of low level of intraocular pressure pilocarpine instillations are carried out, diuretics are appointed.
In case of lack of contraindications at an atrophy of an optic nerve acupuncture, physical therapy is appointed (an electrophoresis, ultrasound, lazero-or electrostimulation of an optic nerve, magnetotherapy, an endonasal electrophoresis, etc.). At decrease in visual acuity lower than 0,01 any the carried-out treatment is not effective.
Forecast and prevention of an atrophy of an optic nerve
In case an atrophy of an optic nerve it was succeeded to diagnose and begin to treat at an early stage, preservation and even some increase in sight is possible, however the complete recovery of visual function does not occur. At the progressing atrophy of an optic nerve and lack of treatment the total blindness can develop.
Prevention of an atrophy of an optic nerve requires timely treatment of eye, neurologic, rheumatologic, endocrine, infectious diseases; the prevention of intoxications, timely blood transfusion at profuzny bleedings. At the first signs of violation of sight consultation of the oculist is necessary.