Optic neuritis
Optic neuritis is an acute inflammation of the optic nerve, which provokes an inevitable decrease in visual functions. The disease is accompanied by such manifestations as decreased vision and pain in the eyes. Treatment of pathology involves a combination of anti-inflammatory, decongestant, metabolic, antibacterial, desensitizing and detoxification therapy.
The content of the article:
Etiology and pathogenesis of optic neuritis
Classification of optic neuritis
Symptoms of intrabulbar neuritis
Symptoms of retrobulbar neuritis
Diagnosis of optic neuritis
Treatment and prognosis of optic neuritis
Optic neuritis
This disease is considered common. It is most often diagnosed in patients over the age of 30, mainly women (77% of all cases). In many patients, optic neuritis is the first sign of the onset of multiple sclerosis.
Almost always, after the elimination of the disease, vision is restored completely. This rule is so proven that otherwise doctors can judge the wrong diagnosis initially. However, if the inflammatory process leads to atrophy of the optic nerve, vision can greatly decrease up to blindness. Therefore, the treatment of the disease can not be delayed, it is fraught with serious complications.
Etiology and pathogenesis of optic neuritis
The disease is provoked by inflammatory processes of the eyeball (retinitis, keratitis, iridocyclitis, panophthalmitis), orbit (periostitis, phlegmon) and brain (meningitis, arachnoiditis, encephalitis). Infectious lesions of the nasopharynx can also provoke the disease: frontitis, sinusitis, angina, chronic tonsillitis, pharyngitis). Patients with malaria, tuberculosis, acute respiratory viral infections, gonorrhea, diphtheria are at risk of developing facial neuritis.
Common causes of the disease are blood diseases, traumatic brain injuries, alcoholism, diabetes mellitus, gout, autoimmune disorders. Optic neuritis often occurs in multiple sclerosis. At the heart of the disease in this case is the process of destruction of the myelonic membrane of nerve fibers. This process is called demyelination. It is not inflammatory, but it is still classified as retrobulbar neuritis due to the similarity of symptoms.
The inflammatory process in neuritis covers both the membranes of the optic nerve and its trunk. Edema caused by inflammation and infiltration cause compression of the visual fibers and their subsequent degeneration, which leads to deterioration of vision. After removing the inflammation, some of the nerve fibers can restore their functions, so vision will improve. In severe pathology, the breakdown of nerve fibers occurs in patients. As a result, optic nerve atrophy occurs, which leads to irreversible consequences for the patient’s vision.
Classification of optic neuritis
In neurology, it is customary to subdivide optic neuritis into several varieties, depending on the localization of inflammation and its etiology. According to the etiological classification, optic neuritis can be demyelinating, parainfectious (a consequence of vaccination or viral infection), autoimmune (caused by autoimmune diseases), infectious (provoked by Lyme disease, syphilis, cryptococcal meningitis), toxic (a consequence of methyl alcohol poisoning).
Ophthalmoscopic classification:
Retrobulbar. This type of neuritis is characterized by inflammation of the optic nerve after it leaves the orbit. It occurs mainly in multiple sclerosis. During ophthalmoscopy, no changes are observed on the part of the visual disc. Usually, pathological changes appear in the late period of the disease, when inflammation covers the intraocular part of the nerve.
Intrabulbar (papillitis) is a pathological process characterized by damage to the optic disc. Pathology is manifested by disc edema and hyperemia of varying degrees, which are accompanied by parapillary hemorrhages. Often this type of neuritis occurs in children.
Neuroretinitis is papillitis, which is combined with inflammation of the nerve fibers of the retina. This pathology is characterized by the appearance of a “star figure” in the macular region, which is a solid exudate. Sometimes there is serous edema of the macula and parapapillary edema of the retina. Neuroretinitis is one of the rarest types of optic neuritis, which usually occurs due to viral infection, syphilis, cat scratch disease.
Symptoms of intrabulbar neuritis
Intrabulbar optic neuritis has an acute onset. The inflammatory process can be triggered by pathogens such as Staphylococcus, streptococcus, influenza and herpes viruses. The infection penetrates into the optic nerve through the vitreous and perivascular spaces. Inflammation of the nerve can be total or partial. Total inflammation is characterized by a sharp decrease in normal vision. With partial nerve damage, vision may remain normal, however, paracentral and central scotomas of oval, rounded and arc-like shape are noted. Patients also have reduced color perception.
All pathological changes are usually concentrated in the area of the optic disc. The disc itself is hyperemic, its hue merges with the background of the retina, its tissue is edematous, and the edema has a pronounced exudative character. The boundaries of the disk are blurred, there is no excessive prominence. The fundus of the optic nerve with this neuritis is poorly and indistinctly visible. Hemorrhages can be seen on the disc, the veins are slightly dilated.
The acute period of pathology lasts about 3-5 weeks, after which the swelling begins to gradually subside, the boundaries of the disc become clearer, all hemorrhages resolve. As a result, it is possible to recover and fully restore normal vision, even if the forecasts were initially unfavorable. However, if the disease is severe, the death of nerve fibers, their decay and gradual replacement with glial tissue is possible. The prognosis for the patient is unfavorable, since atrophy of the optic nerve occurs. The degree of atrophy varies from minimal to complete, which leads to a sharp deterioration of vision.
Symptoms of retrobulbar neuritis
Retrobulbar neuritis refers to inflammation of the optic nerve, which occupies the area from the eyeball to the chiasm. There are three forms of this pathology: peripheral, transversal, axial. Each form of neuritis has its own symptoms. Most often there is an axial form of retrobulbar neuritis, which is characterized by localization of inflammation in the axial bundle. The patient has the appearance of central cattle in the field of vision and a decrease in vision.
The most severe form of the disease is considered to be transversal, since it is characterized by the spread of inflammation to the entire tissue of the optic nerve. The patient’s vision gradually decreases, blindness may occur. Inflammation usually begins in the axial bundle or on the periphery, after which it passes through the septa to the rest of the tissue. The peripheral form of neuritis begins to develop with inflammation of the membranes of the optic nerve, which then passes to its tissue. The inflammatory process is characterized by the accumulation of exudative effusion in the subarachnoid and subdural space of the optic nerve. Patients note strong painful sensations in the orbit area, which begin to intensify with the movement of the eyeball. Central vision remains normal. All types of neuritis are characterized by the absence of changes in the optic disc.
Retrobulbar neuritis can occur in acute and chronic form. In the acute course of the disease, a decrease in visual acuity occurs a couple of days after the onset of inflammation. With a chronic course of pathology, vision decreases gradually. Usually, the chronic course of the disease occurs in the case of diabetes mellitus. This form of the disease occurs mainly in men. Almost always, the lesion is bilateral in nature, and visual acuity decreases very slowly. At the beginning of the disease, the discs of the optic nerves are normal, but gradually their temporal paleness appears.
Diagnosis of optic neuritis
The diagnosis of optic neuritis is carried out by a neurologist and an ophthalmologist. The disease is accompanied by pronounced symptoms, so an ophthalmologist will be able to diagnose it after a clinical examination of the patient. During the ophthalmological examination, the doctor compares the patient’s complaints, the results of ophthalmoscopy and visual acuity tests.
It is more difficult to correctly diagnose neuritis, which is not characterized by visual impairment or edema. Differential diagnosis is indicated for the diagnosis. Optic neuritis should be distinguished from pseudoneuritis and congestive disc. A patient with pseudoneuritis retains normal visual functions. As for the stagnant disc, this pathology differs from neuritis by the presence of edema of the optic disc and the preservation of normal vision. Fluorescence angiography of the fundus is considered to be the most accurate diagnostic method that allows differentiating other pathologies from neuritis.
It is possible to distinguish retrobulbar neuritis from ordinary neuritis due to the discrepancy between visual acuity and the intensity of disc changes. Retrobulbar neuritis is indicated by a sudden decrease in vision with minimal changes in the optic disc. A neurologist may additionally prescribe consultations with a rheumatologist, an infectious disease specialist, an immunologist, as well as conducting studies such as blood culture for sterility, PCR studies, brain MRI, RPR test, ELISA.
Treatment and prognosis of optic neuritis
Urgent hospitalization is indicated for patients. Treatment of the disease is aimed at suppressing the inflammatory reaction and infection, desensitization, immunocorrection, dehydration, activation of metabolism in the tissues of the central nervous system. In the first week of treatment, antibiotics, intravenous glucose infusions, diacarb with potassium preparations (panangin), corticosteroids, magnesium sulfate injections, B vitamins, nootropil, actovegin are prescribed.
In parallel with drug therapy, doctors find out the causes of the disease. After determining the causes of optic neuritis, specific treatment is prescribed to eliminate them. This can be immunocorrective or antiviral therapy of herpes, specific treatment of tuberculosis, surgical treatment of sinusitis.
The patient may require emergency therapy, which includes detoxification measures. Oral administration of a 30% solution of ethyl alcohol in a dose of 100 ml, gastric lavage with a 4% solution of baking soda and other measures that are usually used in acute poisoning are prescribed. If the patient has symptoms of optic nerve atrophy, he is additionally prescribed antispasmodic drugs and medications that improve microcirculation (trental, nicotinamide, sermion, nicotinic acid).
The prognosis for the patient depends on the type of disease and severity. If you start treating pathology on time and choose the most optimal tactics, you can achieve a complete recovery of the patient. However, often after the end of treatment, partial (in rare cases complete) atrophy of the optic nerve occurs.
