Patient's question:
BR>What is a cat"s eye disease? Medical history: 4 Current general condition: Visual acuity 0.03 Auxiliary examinations: Previous diagnosis and treatment history and effectiveness:Doctor's answer:
Coats disease (outer retinal exudative retinopathy) is an idiopathic disorder characterized by abnormal dilatation of retinal capillaries, progressive inner and subretinal exudation, and extensive retinal detachment. The etiology is not yet fully understood. This condition primarily affects adolescent males, with the vast majority presenting with unilateral disease. It was first reported by Coats in 1908, hence its alternative name. It is more common in male adolescents than in females and rarely occurs in adults or the elderly. The ratio of juvenile to adult patients is approximately 4:1 (Woods, 1963). When seen in adults, it is referred to as adult-onset Coats disease, also known as the multiple millet-seed-like microaneurysms reported by Leber in 1912. Coats disease typically affects one eye, though it can occasionally be bilateral. The course is slow and progressive, often going unnoticed in the early stages (especially in pediatric patients) until vision significantly declines, a leukocoria appears, or esotropia develops.[Pathogenesis] The etiology of this disease remains unclear. Its pathogenesis is associated with structural abnormalities of retinal vessels, including the loss of the endothelial barrier function, leading to substantial plasma leakage and accumulation beneath the retinal neuroepithelium. This results in widespread, multi-layered damage to retinal neural tissue and vascular structures, causing a series of clinical manifestations. However, whether this retinal vascular abnormality is congenital or acquired, primary or secondary, remains undetermined.
[Clinical Manifestations] Physical examination of the patient reveals no other systemic abnormalities. Before the macula is affected, vision is unaffected, and no other discomfort is reported. Anterior segment examination shows no positive findings, with clear refractive media and a normal or slightly congested optic disc. Large retinal exudative plaques are commonly found in the posterior pole of the fundus but can occur in any location. The size varies, ranging from single to multiple plaques with irregular shapes, appearing white or yellowish-white and elevated below retinal vessels. Occasionally, they may obscure part of the vessels. The elevation varies significantly, from barely noticeable to over 10 diopters. Dark red hemorrhages are often observed around the plaques, accompanied by scattered or ring-shaped deep white spots. The surface of the plaques may show glistening small dots (cholesterol crystals) or pigmentation. Both retinal arteries and veins are significantly damaged,、，，，，。These vascular abnormalities are the underlying cause of large retinal exudates and hemorrhages. Microcirculatory disturbances lead to regional or generalized grayish-white edema in the retina, with a starburst appearance in the macula. Over a slow and prolonged course, these changes alternate between new and old, with the disease fluctuating in severity until retinal detachment develops. The detached area appears grayish-brown or bluish-gray. In some cases with extensive subretinal hemorrhage, blood may enter the vitreous humor, forming a proliferative vitreoretinal membrane after organization. Some cases may also be complicated by cataracts, anterior uveitis, secondary glaucoma, or hypotony.
Fluorescein angiography (FA) reveals dilated and tortuous larger arterial and venous branches in the affected areas, occluded capillary beds, and microaneurysms on surrounding capillaries or small vessels. Arteriovenous shunts may also be observed. In the early phase of FA, the background fluorescence is obscured at hemorrhagic sites, while large exudative plaques show pseudofluorescence. In the late phase, leakage and tissue staining are seen.
[Diagnostic Differential] This condition should be differentiated from other childhood eye diseases that present with leukocoria, such as retinoblastoma, retinopathy of prematurity, and metastatic intraocular inflammation. The differentiation from retinoblastoma is particularly important, as misdiagnosing retinoblastoma as Coats disease can delay treatment and endanger the child's life. Additionally, conditions like central retinal vein occlusion and diabetic retinopathy may sometimes show extremely similar findings under ophthalmoscopy (large yellowish-white exudates, microaneurysms, cholesterol crystals), referred to as Coats-like reaction.
[Treatment] Due to the unclear etiology, effective medical treatments are currently unavailable. Corticosteroids can promote edema and exudation absorption, providing temporary relief but failing to halt disease progression. Laser photocoagulation is used in early, localized disease when subretinal fluid accumulation is minimal. Argon-green laser is typically selected to close abnormal vessels (microaneurysms, fusiform arterioles, and capillary) to control exudation and promote absorption, with some efficacy. For lesions in the peripheral fundus that are difficult to treat with laser, cryopexy may be adjunctive. If subretinal fluid is abundant and exudation is widespread, affecting laser efficacy, cryopexy or electrocoagulation may be necessary. Laser photocoagulation may also be performed after cryopexy. In late-stage cases with severe proliferative vitreoretinal membrane and extensive subretinal exudates, vitrectomy with retinal surgery may be considered.