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A disorder characterized by idiopathic progressive,
retinal telangiectasia with intraretinal and/or subretinal exudation.
Possible association with renal dysfunction and cranial malformations.
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Congenital Retinal Telangiectasia; Leber Miliary Aneurysm
Disease; Exudative Retinitis.
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A progressive congenital retinopathy first described by
the Scottish ophthalmologist George Coats in 1908.
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Coats disease is a sporadic, nonhereditary
condition. Males are affected three times more often than females. No racial
or ethnic predilection has been reported.
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The retinal capillary endothelium is abnormally
permeable. Affected vessels show a marked thickening of the basement
membrane and widespread loss of endothelial cells and pericytes with
subsequent disintegration of the blood-retinal barrier. The retinal protein
norrin may be deficient or abnormal. There are retinal telangiectasias and
aneurysms of the capillaries, venules, and arterioles. Lipoproteinaceous
exudations are found in intraretinal and subretinal areas.
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The age at onset has two peaks, one before 20 years of age
and the second afterward. Most often, however, it is diagnosed at 7 to
10 years of age by the onset of retinal telangiectasias with intraretinal and/or
subretinal exudation.
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Coats disease is unilateral in more than 90%
of cases and most frequently occurs in otherwise healthy patients. Bilateral
occurrence is so rare that some researchers recommend questioning the
diagnosis in these patients. The disease manifests as a deterioration in
either central or peripheral vision. Rarely, Coats disease is associated
with pathologic findings of the head and neck (microcephaly, intracranial
calcifications, ataxia, depressed premaxillary region), the skin (absent
scalp hair, syndactyly of fingers, dysplastic, grooved nails), and other
ocular manifestations (paresis of ocular muscles, glaucoma). Renal
impairment has been reported in some patients.
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In cases of isolated Coats disease,
no specific anesthetic precautions are required. However, if there is an
association with extraocular manifestations, anesthetic care is influenced
by the nature and severity of these features. Renal function may need to be assessed
(electrolytes, serum creatinine, blood urea nitrogen). Check for difficult
airway management.
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Tracheal intubation can be difficult.
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Renal dysfunction may affect
elimination of drugs with predominantly renal excretion. Perioperative fluid
regimen must be adapted to renal function. Avoid drugs that may increase
intraocular pressure in the presence of glaucoma (e.g., atropine,
succinylcholine).
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Similar ocular features may be seen in retinitis pigmentosa, Alport
Syndrome, Brachmann-de Lange Syndrome, Epidermal Nevus Syndrome,
Hallermann-Streiff Syndrome, Landouzy-Dejerine Dystrophy,
Loken Senior Syndrome,
Ullrich-Turner Syndrome, aplastic anemia, and in renal transplant patients.
However, the most important differential diagnosis in pediatric patients is
Retinoblastoma, and failure to distinguish these two conditions will
have serious consequences. Retinoblastoma usually is diagnosed at a younger
age and does not have a sexual predilection. Retinoblastoma has a positive
family history in approximately 10% and is bilateral in approximately
40% of patients, whereas Coats disease is unilateral in more than 90% ...