The exact etiology of Coats’ disease is not known. However, mutations in retinal proteins encoded by Crumbs cell polarity complex component (CRB1) and Norrie disease pseudoglioma (NDP) genes is believed to be the possible pathogenesis . There are two evident pathological processes in the vasculature of Coats’ disease . The first change consists of the breakdown of the blood–retinal barrier at the level of endothelium, which results in plasma leakage and thickening of portions of the vessel wall. These necrotic changes in the vessel wall lead to its disorganization, which is also termed as sausage-like configuration . Second is the degeneration of abnormal pericytes and endothelial cells, causing aneurysms and the closure of vessels leading to ischemia . This process generates lipid-rich exudation into the retina, which can lead to changes in the retina, including thickening, cyst formation, or retinal detachment . These changes are comparable to the changes occurring in diabetic retinopathy .
The diagnosis of our case was reached on the basis of clinical examination alone and meticulous exclusion of other probable differentials . The limited resources in our setup precludes us from further genetic testing for confirmation. Ancillary tests such as magnetic resonance imaging and computed axial tomography can be useful diagnostic aids, however, the priority shifted to surgical management in our case. Upon review of the literature, all the features of our case matches those defined for Coats’ disease, which supports our clinical diagnosis. Nonetheless Coats’ disease is believed to have no appreciable retinal or vitreal traction . The rhegmatogenous retinal detachment encountered in Coats’ disease available in the literature has been reported to be of iatrogenic origin following vitrectomy surgery , and even after photocoagulation due to traction from preretinal membrane.
There is a paucity of similar reports on rhegmatogenous retinal detachment in Coats’ disease, and we believe this could be the first from this region. A similar report from 1979 was identified . Other than complications of therapeutic modality, retinal break can be the natural course of the disease. There may be a number of factors that might contribute to the formation of retinal break in retinal vascular disorders, including  retinal ischemia, retinal exudation, vitreous detachment, vitreous contraction, retinal neovascularization, and underlying choroidal changes. Accelerated senescent vitreous changes at a relatively early age leading to vitreous condensation and vitreous traction might have led to retinal break . Though vitreoretinal traction and fibrosis are rare , this could be only attributed to the rhegmatogenous retinal detachment in our case.
The modality of management for Coats’ disease essentially depends upon the stage of the disease. Milder disease with telangiectasia and exudation but not threatening the vision can be observed alone. Laser photocoagulation and cryotherapy are effective options for management . Nonetheless, treatment modalities in Coats’ disease should be tailored individually due to the low incidence of the disease and the great variation in severity upon presentation . Surgery is reserved for advanced cases of detachment. Vitrectomy is advocated for refractory detachment . External drainage of subretinal fluid is generally performed , similarly internal drainage is combined with vitrectomy procedure . There does not exist a common consensus for the choice of treatment, surgeon’s discretion based on stage and severity of the disease can influence the management option. We managed the case with encircling band buckle combined with vitrectomy and silicon oil tamponade. The posterior location of the break prompted us for the preference of lens sparing vitrectomy and encircling band to support the vitreous base. Following the subsequent cataractous lens exchange with posterior chamber intraocular lens implantation and silicon oil removal, the useful vision was restored in this patient with good anatomical result. The rapid and complete resolution of subretinal fluid further supported our belief of rhegmatogenous retinal detachment in Coats’ disease .
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