Coats' Disease: Symptoms and Treatment

• Here are the study notes as requested based on the provided text

Coats' Disease

• This is a condition with retinal telangiectasia, abnormal vessel growth, peripheral dilated capillaries, and small aneurysms. These lead to fluid accumulation and exudation, potentially resulting in exudative retinal detachment.
• It is idiopathic (cause unknown).
• There is no identified hereditary pattern.
• It is typically unilateral, affecting one eye in 95% of cases.
• Primarily affects males (75%) in the first decade of life.
• Symptoms can include decreased vision, leukocoria (white pupil), and strabismus (misaligned eyes).
• Periphery is affected rather than the macula
• Treatment options include observation for Stage 1, laser therapy for Stage 2, and retinal detachment cryotherapy for Stage 3.
• Overaggressive treatment for Stage 3 may worsen retinal detachment.
• Repeat treatments after 3 months will allow for subretinal fluid reabsorption.
• Extensive retinal detachment may require scleral buckle, vitrectomy, or both.

Coats' Disease Classification Progression

• Stage 1 involves telangiectasia, with worse than 20/200 vision being rare.

• Stage 2 involves both telangiectasia and exudation, with 20/200 vision or worse in 50% of cases.

• Stage 3 features retinal detachment, with 20/200 vision or worse in 75% of cases, even with treatment.

• Stage 4 involves total retinal detachment and secondary glaucoma, resulting in poor visual prognosis.

• Stage 5 is the end stage, approaching phthisis bulbi (shrunken, non-functional eye).

Posterior Segment Involvement

• Telangiectasias occur at the equator and periphery, rarely affecting the macula.

• Posterior segment findings include clusters of microaneurysms (grape-like), fusiform dilation of retinal arterioles ("light bulb aneurysms"), sheathing of vessels, and venous beading.

• Exudates are massive and migrate toward the macula.

• Exudative retinal detachment can occur.

Retinal Arterial Macroaneurysm (RAM)

• RAM is an acquired focal aneurysmal dilation of an arteriole, typically within the first 3 orders of the retinal arterial system.
• It is uncommon, affecting approximately 1 in 4,500 people.
• Typically unilateral, bilateral cases reported account for less than 10% of cases.
• There is a predilection for elderly, hypertensive women aged 64-74.
• 75% of presenting patients have hypertension.
• It occurs along the temporal branches, at points of bifurcation or arteriovenous crossing.
• Occurs within the first three bifurcations of the central retinal artery.
• The thickening of the arteriolar vessel wall is similar to arteriosclerotic changes, resulting in focal ischemia, remodeling of the greater intimal collagen, and dilation of the vessel diameter.
• Breaks within the arteriolar wall result in a fusiform dilation of the wall, increasing the risk of exudation and rupture.

RAM Signs and Presentation

• Blood can be found in multiple layers, including subretinal, intraretinal, preretinal, and vitreal layers. High flow vessels (arteries).
• The macroaneurysm is visible as a rounded dilation within an artery.
• Exudation may be present, usually in a circinate pattern surrounding the aneurysm, but may also be found in the macular region.
• Quiescent RAMs occur where hemorrhage or exudation exists, but the macula is spared, and there is no effect on visual acuity.
• Can be exudative or hemorrhagic.

RAM Diagnosis and Imaging

• Symptoms include acute or insidious loss of vision when hemorrhage or edema involves the macula or when vitreous hemorrhage is present.
• FA: Self sealed may show no leakage, while others may exhibit late leakage.
• ICG if blood is obscuring.
• OCT shows the RAM elevating the internal limiting membrane and ganglion cell layers, producing a shadowing effect on deeper retinal layers.
• SUB-ILM Hemorrhage can occur between the ILM and posterior vitreous cortex.

RAM Clinical Course and Treatment

• In most patients, RAMs resolve spontaneously without significant sequelae.
• Macular edema is the most common complication
• Better visual acuity with eyes with vitreous and pre-retinal hemorrhage compared to eyes with macular edema and deeper retinal hemorrhaging.
• Submacular hemorrhage yields the poorest visual outcome, damaging photoreceptors.
• Differentials to consider include Coat's Disease (young), Valsalva retinopathy, posterior vitreous detachment with secondary preretinal hemorrhage, proliferative diabetic retinopathy, Exudative ARMD, Leber's miliary aneurysms (younger), or angiomatosis retinae (younger patients, >peripherally)
• Asymptomatic cases of RAM can be monitored
• If pre-retinal, intra-retinal, and vitreous hemorrhage, spontaneous resolution of the hemorrhage can occur but should still be closely monitored within the first 3 months
• For direct macular involvement, argon laser is an option
• Pars plana vitrectomy for visually significant vitreous hemorrhage
• Anti-VEGF can reduce vascular permeability by vasoconstriction, which in turn helps to balance out coagulation and fibrinolysis to promote faster hemorrhage clearance and reduce surrounding edema.