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SYMPTOMS
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Nyctalopia, Vision loss, Visual field defects, Color vision defects
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SIGNS
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Bilateral
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Small areas of chorioretinal atrophy with scalloped borders that start in the mid-peripheral retina and will eventually coalesce into larger areas of chorioretinal atrophy and spread to the far periphery and posterior pole (the macula is affected last), RPE clumping, Loss of choroidal vasculature which exposes the sclera, Posterior subcapsular cataracts, Cystoid macular edema
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WORK-UP
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Pupils, Color vision (abnormal), Full eye exam with dilation, Visual field, OCT of the macula, OCT-Angiography (presence of choriocapillaris loss), Fundus Autofluorescence, Fluorescein Angiography (presence of choriocapillaris loss), Indocyanine Green Angiography (presence of choriocapillaris loss), Fundus photos, Infrared photos, Electrodiagnostic testing (ERG: Abnormal / EOG: Abnormal), Dark adaptation (abnormal), Watzke-Allen test, Macular photostress test, Amsler grid
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TREATMENT
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Give take home Amsler grid in order to monitor for macula involvement
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Gyrate atrophy without cystoid macular edema: Monitor
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Refer to PCP to monitor levels of ornithine
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Recommend a low protein diet (especially low arginine). Patient should follow-up with their PCP
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Recommend Vitamin B6 supplementation. Patient should follow-up with their PCP
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Recommend genetic counseling for other family members
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If the patient develops poor vision, refer to low vision
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Gyrate atrophy with cystoid macular edema: Refer to a retinal specialist ASAP for further evaluation and treatment
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If the patient presents with a visual significant posterior subcapsular cataract, refer for cataract surgery
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FOLLOW-UP
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If monitoring, the patient should be seen back in 6-12 months
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After patient is evaluated and treated by a retinal specialist and the retina/macula is stable, the patient should be seen back every 6 months
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ADDITIONAL LAB | TESTS
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Genetic testing, Serum levels of ornithine
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ETIOLOGY
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Autosomal recessive progressive retinal dystrophy that occurs due to a mutation in ornithine amino transferase which leads to increased levels of ornithine (10-20 times more than normal) which causes damage to the photoreceptors, RPE, and choroid
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DIFFERENTIAL DX
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Retinitis pigmentosa, Choroideremia, “Salt and pepper" fundus, Ocular albinism
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NOTES
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Symptoms are typically first noted during the first decade of life. Central vision loss typically occurs during the fourth or fifth decade of life
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Gyrate atrophy is associated with myopia 80% of the time
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Gyrate atrophy can be associated with delayed development and reduced cognitive ability. Thin, sparse hair and muscular atrophy can also be associated with gyrate atrophy
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