This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Retina, Subject name: Ophthalmology
[{'content': '"Cattle truck" appearance on fundoscopy \nSelect and explain. \nA. Central serous retinopathy, B. Coat\'s disease, C. Central retinal artery occlusion (CRAO), D. Retinopathy of prematurity (ROP)', 'role': 'user'}, {'content': 'Answer: C \nExplanation: Ans. c (Central retinal artery occlusion (Ref: Parson\'s 20lh/302, A K Khurana 2nd/26, 253)CENTRAL RETINAL ARTERY OCCLUSION (CRAO)# Etiology/pathogenesis- There is usually an embolus or thrombus.- A yellow cholesterol embolus (Hollenhorst plaque) on the head of the optic nerve or in a branch of retinal artery confirms the diagnosis.- The most important causes of emboli are atherosclerotic plaques of the carotid arteries, arterial hypertension, and cardiac valve lesions.# Epidemiology- The prevalence of CRAO is 0.85 per 100,000 population in one year.- It is a disease of adulthood (in the sixth decade of life on average).- More common in males than in females. Involvement is bilateral in 1-2%, with the exception of temporal arteritis and other systemic vasculitides.# Clinical features- Patients present with sudden painless loss of vision.- Usually unilateral.- Direct pupillary light reflex is absent.- Retinal arteries are markedly narrowed.- Central part of mascular area shows \'cherry-red\' spot due to vascular choroid shining through thin retina.- Segmented blood column within retinal veins (\'cattle- track\' appearance) is pathognomonic of central retinal artery occlusion.- The arteries are thin and the segmented blood flow in the retinal arteries can be observed in acute stages of the disease.# Diagnosis- Diagnosis is made clinically.- The diagnosis can be confirmed by fluorescence angiography.# Differential diagnosis- Differentiation between arteritic (Horton disease) and nonarteritic CRAO is very important because in Horton disease the fellow eye can become involved within a few days without appropriate treatment.# Treatment- There is no consensus currently about the efficacy of different forms of treatment.- Conservative treatment: globe massage, anterior chamber paracentesis, infusion treatment with pentoxifylline, hyperbaric oxygen, intravenous rTPA, or corticosteroid injection.- Invasive treatment: selective catheterization of the ophthalmic artery with administration of fibrinolytic drugs.# Prognosis.- The visual acuity on first presentation generally decides the prognosis.- Spontaneous improvements are observed in up to 15%.Various fundoscopic appearance Appearance on FundoscopyDiagnosis1Pinkish with central area of pallorNormal disc2HyperemiaPapilledema, papillitis3Pale discPartial optic atrophy4\'Chalky white\' discPrimary optic atrophy5\'Yellow waxy\' discConsecutive optic atroph6\'Shot-silk\' fundusPseudopapilitis7\'Champagne pale cork\'fundusChronic papilledema8Pale waxy disc with \'bone corpuscles\' like pigmentary changesRetinitis pigmentosa9\'Cattle truck\' appearance (of retinal veins)CRAO10\'Ink-blot/ Enlarging dot\' pattern/ \'Smoke stake\' patternCentral serous retinopathy11\'Flower petal\' appearanceCystoid macular edema12\'Cotton wool\'spotsMost common abnormality in AIDS13\'Tomato sauce and cheese\' OR \'Crumbled cheese and Ketchup\' OR \'Brush-fire\' OR \'Pizza pie\' appearanceCMV retinitis14.Angioid streaks# Pseudoxanthoma elasticum# Pagets disease of bone,# Ehler Danlos disease# Sickle cell disease.15.Bull\'s eye maculopathyChloroquine16.Severe retinal telangiectesiaCoat\'s disease17.\'Salt and pepper\' fundus# Congenital rubella, syphilis, HSV, Varicella, mumps# Leber\'s amaurosis# Mayous-Batten disease# Thioridazine toxicity# Cancer associated retinopathy# Carriers of Choroideremia, albinism, Retininitis Pigmentosa.18."Sea Fan" RetinaSickle cell disease19.\'Candle wax\'appearanceSarcoid retinopathy20.Cherry Red spots(Mnemonic: Pick My QT Bags)# Niemann-Pick\'s disease# Multiple sulfatase deficiency# Quinine amblyopia# TaySachs disease# Berlin\'s edema (Commontio retinae) due to blunt trauma# CRAO# Gaucher\'s disease# Sandhoff disease# Sialidosis type 1 and 221.Cherry red spotsNOT seen in CRVOIn CRVO, Rubeosis iridis develops in about 50% of eyes, usually in 3 months (100-day glaucoma), and there is a high risk of neovascular glaucoma.', 'role': 'assistant'}]