Koats's disease is the hereditary pathology which is characterized by polymorphic changes of vessels of a retina in combination with a massive intra-and a subretinalny ekssudation. The clinical symptomatology is presented by a leykokoriya, decrease in visual acuity, emergence of "fog", "bright flashes" or specific patterns before eyes. Diagnostics is based on carrying out an oftalmoskopiya, ultrasonography of an eye, OCT, a patomorfologichesky research, KT of the head, an angiography, perimetry, a vizometriya. Therapeutic tactics includes application of laser coagulation, cryotherapy, ekstraskleralny sealing. At the IV stage the enukleation is shown.
Koats's disease (the retina teleangiektaziya, ekssudativny retinit) is among orphan diseases. The first pathology was diagnosed by V. A. Braly in 1876. The English scientist G. Koats in 1908 described morphological forms of a disease. The general prevalence of a teleangiektaziya of an internal cover in structure of eye pathologies makes 1:100 000. According to statistical data, ekssudativny retinit more often meets among males. In most cases the disease is diagnosed at achievement of seven years by the child, however cases when clinical manifestations were debuted in old age are described. The probability of development of a recurrence at adequate treatment makes 40%.
The disease etiology is up to the end not studied. Detection of pathology at close relatives allows to assume the hereditary nature of a disease of Koats. In view of low prevalence of a retinit it was not succeeded to establish type of the struck gene and the nature of inheritance. Teleangiektaziya of a retina can arise separately or against the background of genetic anomalies: Alport's disease, a syndrome of Cornelia de Lange, the progressing front gemiatrofiya, a craniofacial dismorfiya. Development of pathology is promoted by influence of teratogenny factors (ionizing radiation, consumption of alcoholic beverages and drugs), viruses of a rubella, the surrounding herpes, toxoplasma during pregnancy.
In the mechanism of development of a disease the leading role is assigned to defeat of endoteliotsit of a gemato-retinalny barrier. Because of pathology of a structure of a vascular wall there are periodic hemorrhages. In the thickness of a mesh cover and subretinalny space crystals of cholesterol and lipidosoderzhashchy macrophages accumulate. The organization of exudate and (to a large extent) blood clots becomes the cover thickening reason in the beginning, and further provokes a massive ekssudativny otsloyka. The genetic mutations leading to developing of pathology are not established. Scientists study a pathogenetic role of increase of a caption of a factor of growth of fibroblast in blood in development of a teleangiektaziya of a retina.
In a basis of the classification offered by G. Koats the nature of change of vessels (without vascular changes, with anomalies of vessels, with extensive arteriovenozny malformation) and features of an ekssudation laid down. From the clinical point of view in domestic ophthalmology allocate the following stages of a disease:
- I – initial. On І stages come to light vascular malformation and the small scattered centers of the increased density on the periphery or a back pole. At Іb of a stage of a malformation and exudates are defined both on peripheries, and in a makulyarny zone.
- II – developed. ІІ and the stage is characterized by the raised ekssudation in a back pole, signs of an ekssudativny otsloyka whose size makes no more than 2 quadrants. On ІІ b of a stage are visualized opukholeobrazny deposits, a subtotal otsloyka 2-3 quadrants long.
- III – far come. ІІІ and a stage – the total form of an otsloyka is formed, formation of subretinalny membranes is noted. On ІІІ b of a stage are observed objective signs of defeat of a uvealny path, a cataract, an iris neovaskulyarization.
- IV – terminal. IVA the stage differs in development of secondary neovascular glaucoma. The eyeball subatrophy is characteristic of IVb of a stage ().
Symptoms of a disease of Koats
Ekssudativny retinit is characterized by unilateral damage of an organ of vision. The symptomatology of a disease develops within the first 10 years of life. The peak of clinical manifestations comes in 6-8 years. Seldom the first signs come to light in the neonatal period. Specific display of a disease – an abnormal reflex of a mesh cover of white color (leykokoriya). Decrease in visual acuity a long time can remain unnoticed for patients because of slow progressing of pathology. The first symptoms are presented by emergence of "fog" or "veil" before eyes. The clinic is most expressed when closing a healthy eye.
At a long current of a retinit of Koats violation of deep and spatial perception of an object is noted. Patients note emergence of bright flashes of light or roundish pomutneniye before eyes. Visual dysfunction begins with the top departments of a field of vision that is caused by a blood congestion in the lower part. Blood clots, exudate, sites of peeling of a retina mechanically interact with the receptor device of a cover. It leads to emergence of specific "color patterns" which patients can take for visual hallucinations. At early age of the child parents note that one eye on the photo made with flash has yellow color. The pain syndrome appears at massive hemorrhages which exponentiate increase in intraocular pressure.
Abnormal growth of vessels in back departments of an internal cover of an eyeball – a common cause of development of secondary glaucoma and cataract. Damage of a retina becomes the reason of its thinning, an otsloyka, formation of multiple gaps. Because of pathological change of vessels quite often there are subretinalny hemorrhages, a gifema and . Frequent carrying out coagulation at Koats's disease provokes formation of makulyarny tractions and folds. Excess of power of laser influence is the cornerstone of development of a glioz of a makula. The high risk of postoperative bleedings is caused by necrotic changes of a vascular wall.
Apply fizikalny and special methods of diagnostics to detailed inspection of the patient. At visual survey diffusion hyperaemia of a conjunctiva, turbidity and a smoothness of the drawing of an iris comes to light. Enters a complex of ophthalmologic inspection:
- Oftalmoskopiya. The wavy and expanded vessels of an internal cover which are most expressed in peripheral departments are defined. Sites of hemorrhages, zones of an otsloyka of an internal cover are visible. Puffiness of DZN is characteristic, signs of its partial atrophy are less often observed.
- Perimetry. The research is conducted periodically for control of changes of the visual field. Expansion of a zone of defeat leads to asymmetric narrowing of a field of vision, emergence of scotomas that speaks about the progressing course of pathology.
- Vizometriya. Allows to diagnose degree of visual dysfunction. The result of test from midriatika is negative.
- Retina angiography. At additional use of flyuorestseinovy dye malformation of vessels, zones of occlusion of links of the microcirculator course, neogenic arteriovenozny shunts are visualized. The fluorescent angiography is carried out on the eve of surgery for definition of the sites which are subject to coagulation.
- Optical coherent tomography. The technique gives the chance to reveal a thickening of a mesh cover, an exudate layer behind an internal cover, to measure parameters of a disk of an optic nerve.
- Ultrasonography of an eye. At ultrasonography giperekhogenny congestions behind a vitreous body are visible. The back acoustic shadow is absent or is poorly expressed. Signs of a gemoftalm and subretinalny hemorrhages are defined. The research is appointed for the purpose of differentiation with malignant new growths.
- Head KT. When carrying out a computer tomography in an axial projection behind a vitreous body the consolidation formed by a congestion of exudate of the proteinaceous nature comes to light.
- Patomorfologichesky research. At macroscopic diagnostics the otsloyka of a retina, exudate availability is found. The thickening of a vascular wall which alternates with thinning is microscopically visible. The gleam of vessels is expanded unevenly. Cholesterol crystals, macrophages, pigmentotsita, erythrocytes, are a part of exudate.
Differential diagnostics is performed with a retinoblastoma, malignant medulloepiteliomy, Ilz's disease. Tool methods do not allow to find visible differences between retinity and such oncopathologies as a retinoblastoma and a medulloepitelioma. Existence of a malignant new growth is demonstrated by increase in level of a neyronspetsifichesky enolaza in blood and laktatdegidrogenaza in liquid of the forward camera. Unlike a retina teleangiektaziya at Ilz's disease preretinalny fibrosis and recurrent hemorrhages in a vitreous body is defined, there are no solid exudates.
Treatment of a disease of Koats
Tactics of treatment is defined by a clinical stage, age of the patient at the time of the disease demonstration. Efficiency of therapy is highest at its early application. The main methods of treatment include:
- Laser coagulation of a retina. It is shown on Ia-IIa disease stages provided that the zone of defeat does not exceed 240 °. Treatment is carried out by courses. Average quantity of courses – 2-6 with intervals on 3-4 months. In the beginning appoint barrier coagulation around zones of malformation. Further coagulate a zone of an otsloyka, putting at the same time 2-3 I am glad coagulates. If in 5-7 days additional anomalies of vessels are visualized, still the procedure session is shown.
- To Kriopeksy of a retina. It is applied in addition to laser coagulation at localization of defects on the periphery of an internal cover at Ia-IIa of degree. At diagnostics of IIb-IIIa of degree the technique is used separately.
- Ekstraskleralny sealing. Expediency of purpose of a technique at development of a diffusion ekssudativny otsloyka of a retina on IIb-IIIa of a stage is proved.
- Conservative therapy. Use of medicines from group of vasoprotectives, antiagregant is shown.
At preservation of visual acuity pleoptichesky treatment of the affected eye by means of laser stimulation, tsvetoimpulsny therapy, reflexotherapy is carried out. The complicated course of pathology often demands a vitrektomiya, excision of subretinalny membranes. Exudate needs to be drained by means of transretinalny access. Tamponada is carried out with use of special silicone oil or perfluorocarbon. The endodiathermy, coagulation of the bleeding vessels is in parallel carried out. Enukleation is applied only at a terminal stage of a disease of Koats in case of a total blindness.
Forecast and prevention
The forecast at Koats's disease in many respects depends on tactics of maintaining the patient. Early carrying out laser coagulation of a retina in 88% of cases allows to keep visual functions, and in 70% – to reach their full stabilization. At passive observation of the patient the blindness develops in 94% of cases. Prevention of a deep visual deprivation comes down to purpose of the dosed occlusion better than the seeing eye. To patients with the established diagnosis of a pigmentary retinit it is necessary to undergo 1 time in half a year inspection at the ophthalmologist. Regular drawing coagulates in the field of pathologically changed vessels allows to reach remission.