Coats' disease

In Coats' disease (syn. retinitis exudative and retinal telangiectasia) is a rare congenital eye disease of the retinal vessels, which usually occurs only on one side and to the deterioration of eyesight, often leads to blindness. The blood vessels are dilated here and leaking, so blood and lipid-containing liquid secretions ( exudates ) can penetrate into and under the retina and its deeper layers. This results in retinal edema, which when viewed from the outside by a whitish- gray pupil staining ( leukocoria ) is noticeable. If left untreated, it comes as a result of the exudate to a progressive inflammatory retinal detachment and irreversible damage.

So far, the cause of the causative vascular changes are not known. The Coats' disease occurs predominantly in boys and young men. The treatment consists in the obliteration of the vessels by cold treatment ( cryotherapy) or in the segregation of retinal detachment boundaries by laser therapy, which is a complete blindness in many cases, prevent or at least seriously delay. In exceptional cases, the removal of the affected eye may be necessary.

Dissemination

The Coats' disease is a rare congenital eye disease with visible enhancements and changes ( telangiectasia) of the retinal vessels. 100,000 people get about 1-9 cases of disease. They occur in 90 % of cases on one side and mostly in boys and young men in the first or second decade of life. The peak incidence is between six and eight years, the disease can affect any person but generally between one month and 79 years of age. The frequency of some 69 % is distributed to male and 31% females.

Causes and development

The reason is a Endotheldefekt of retinal blood vessels, which leads to Aussackungen and aneurysms of these vessels. As a result, occur both sunsets in the capillaries as well as a disruption of the blood - retinal barrier, so that large amounts of liquid can leak out ( exudate) in the retina. There are deposited in this way present in the blood lipid- laden macrophages and cholesterol crystals from. Over time, these substances accumulate and lead only to retinal thickening and then ultimately in - by the exudate -related - detachment, which goes hand in hand with an increasing loss of vision.

The reason for the causal defect of the retinal vessels is unknown. In some individuals, there were elevated levels of a specific signaling molecule, the Vascular Endothelial Growth Factor ( VEGF). Individual case descriptions ( case reports ) on the occurrence of the disease together with different other genetic defects are, however, considered as an indication of a genetic involvement. Thus, in one case the X-chromosome locus P11.4 was affected. This is also known as NDP gene ( see also Norrie disease ) because he is responsible for the formation of Norrin. The latter is a protein, which is believed that it is a growth factor has an influence on the development of the retinal vessels. An association with the fazioskapulohumeralen muscular dystrophy is also described. This change affects the chromosome 4, locus q35.

Clinical manifestations

Typical initial symptoms are a secondary squint (strabismus ) and the whitish illuminated pupil ( leukocoria ). In the case of the latter, the reflex of the fundus at made ​​with flash photography is not the usual red, but whitish- gray dar. Patients often see on the affected eye blurry, which is also affected their spatial vision. In young children the loss of vision in one eye can also go completely unnoticed. The Coats' disease runs usually painless. If the exudate but results in an increase of intraocular pressure, it may be a " Glaucoma " ( glaucoma) result. Also a different eye color is typical. The Coats' disease runs in just under ten percent of the cases initially completely asymptomatic.

Although Coats' disease generally long term leads to blindness in the affected eye, its course is not same in all cases. Its progression can spontaneously come to a temporary or permanent and stationary. There are described some few cases in which the disease even regressed. However, when it comes to a complete retinal detachment, then it must be of a permanent loss of vision. In children under five years, the disease runs much fulminant than in persons over ten years in most cases.

The vast majority of cases developed a distinct subretinal exudation and retinal detachment. Characteristic effects are vascular neoplasms on the iris ( rubeosis iridis ), Green and Cataracts ( cataracts), as well as inflammation of the middle eyeball ( uveitis ) and a shrinkage of the eyeball ( phthisis bulbi). Statistically, the lower outer portion of the retina is very often affected, which can lead to a medial upper quadrant of the visual field loss. The blindness rate is particularly high in those patients in whom the subretinal fluid accumulation is not resolved after treatment or the retina has large cysts or telangiectasia. The removal of the eye ( enucleation ) is most often necessary iridis in patients with glaucoma or rubeosis. The disease can clinically impress as a retinoblastoma.

Staging systems

So far, two slightly different staging systems have been published. The first is from Gomez Morales ( 1964) and divides the history into five stages a. In only very limited exudates (stage I ) followed by massive intraretinal (II ), the first small -scale (III ) and then the complete detachment of the retina ( IV). Stage V stands for complications such as glaucoma.

A second classification by Shields et al also describes five but partly under differentiated stages, beginning with stage I, the mere occurrence of retinal telangiectasia, without demonstrably leaked exudate. Stage II describes its exit outside (II A) and within the fovea centralis (II B). Stage III describes the detachment of the retina, starting with a partial detachment outside (III A 1), or within the fovea centralis (III A 2) and the entire retina ( III B). Stage IV refers to the complete detachment with glaucoma and stage V komplizierendem an advanced stage disease.

Clinical examination

Classic symptom is leukocoria. Due to the unilateral loss of vision and a resulting disturbance of binocular vision ( binocular vision ) may develop a secondary strabismus. On examination of the fundus by ophthalmoscopy the Kapillarmuster is coarsened, and the vessels of the retina provide expanded (dilated ) and tortuous dar. This finding is most particularly in the temporal side and the peripheral region can be clearly seen. If the disease has broken out, to retinal detachments find large, lipidhaltig exudates and bleeding from the altered vessels. These vascular changes are - if necessary for a diagnosis - by fluorescence angiography particularly crystal clear.

Technical examination findings

Imaging techniques such as ultrasonography, computed tomography (CT) and magnetic resonance imaging (MRI ) may contribute to the diagnosis. Ultrasound impressed the Coats' disease as echogenicity in the rear area of the vitreous without acoustic shadowing; Hemorrhages in the vitreous body and the retina are typical.

In CT, the eyeball is due to the protein-rich exudate dense ( hyperdense ) compared to healthy Represents the exudate can affect the entire vitreous body in an advanced stage. The front edge of subretinal exudation is confronted by a contrast enhancement dar. Since the retina is fixed to the papilla of the optic nerve around, advanced detachments are V-shaped.

In NMR, the retina detaching exudate in both the T1 - and T2 - weighted images in a high signal intensity. In the presence of hemorrhagic fibrosis may represent irregular ( heterogeneous). The space behind the retina does not expand the use of gadolinium-based contrast agents. However, a slight widening may show between exudate and the remaining vitreous itself. Exudate has a broad peak at 1-1.6 ppm in the nuclear magnetic resonance spectroscopy.

Differential Diagnosis

Differential diagnosis of prematurity especially retinoblastoma, but also retinopathy, a persistent hyperplastic, primary vitreous ( PHPV - the primary vitreous body is formed in the early embryonic stage ) and toxocariasis -associated chorioretinitis, idiopathic juxtafoveolare telangiectasia and the damage to the retina ( retinopathy ) to take into account due to Leber's Miliaraneurysmen (irregular ectasia of the retinal vessels ). It should be noted in addition that the liver 's Miliaraneurysmen and Coats' disease very similar symptoms and are therefore equated by some authors.

Pathology

• Pathological specimens in Crohn's Coats

Complete detachment of the retina by the exudate.

A pronounced retinal detachment and a yellowish exudate under the retina that contains cholesterol crystals are characteristic of the pathological findings.

Under the microscope, the wall of the vessels of the retina, in some cases, thickened, thinned appear in others. In addition, an irregular enlargement of the affected vessels. A characteristic feature is an exudate which consists of both cholesterol crystals, laden with cholesterol and pigment macrophages, as well as from red blood cells and hemosiderin. A granulomatous reaction caused by the exudate and also find a triggered by the violation of gliosis in some cases on the retina.

Prevention, treatment and cure views

Preventive measures are not known. Particularly in the early stages of the disease cold treatments ( cryotherapy) and focal laser can be used to prevent destroying the altered vessels ( deserted ) and so predictable there blood or liquid spills. If the illness is more advanced and it has come to the retinal detachment, treatment attempts may be made in the form of a partial removal of the vitreous ( vitrectomy ) or a Netzhautkoagulation ( connection with the choroid by photocoagulation ). Is the blindness already occurred, the removal ( enucleation ) of the affected eye may be necessary - especially when it comes to pain and other complications or retinoblastoma can not be excluded with absolute certainty. In particular in the early stage of at least a part of the vision can often be obtained through the use of appropriate prompt therapeutic interventions. Although a curative treatment is not possible in individual cases, however, a spontaneous regression of the disease is described. Under the notion that the vascular endothelial growth factor has a significant importance for the course of the disease, an experimental treatment using bevacizumab or pegaptanib was described in the recent past in individual cases. However, this approach is critically evaluated.

History

The disease was after its discoverer, the Scottish ophthalmologist George Coats, named. He described it in 1908 to six children. In 1912, the German ophthalmologist Theodor Carl Gustav of liver described a disease that was characterized by retinal degeneration due to multiple retinal aneurysms and primarily occurred in young men. 1955 showed Reese on similarities between the two diseases ( Coats' disease and Leber's miliary aneurysms ) and assumed that both merely different manifestations of the same underlying disorder were. The concept of Coats' disease, he used it for the combination of telangiectasia and exudative retinitis.