Coats Disease

Coats disease is a rare congenital, nonfamilial, idiopathic disease of the vessels of the retina that is characterized by leakage of fluid into and around vessel walls, leading to progressive intraretinal and subretinal leakage and exudative retinal detachment. Weak vessel walls also predispose them to development of telangiectases and aneurysms.

The disease is unilateral in the majority of cases (80%–90%) and has a male predisposition. Diagnosis is usually in childhood, and about 50% of untreated patients will eventually have total retinal detachment, blindness, and painful neovascular glaucoma.

The ophthalmologists handle the diagnosis in the majority of cases. Radiology becomes important in differentiating advanced Coats disease from retinoblastoma because both diseases may present as a non-rhegmatogenous (see below) retinal detachment associated with telangiectases and subretinal collections.

CT and MRI may show partial or total retinal detachment without evidence of an intraocular mass or intraocular calcifications. There is homogeneously increased intraocular attenuation compared to the unaffected eye. The subretinal fluid collection may be seen as hyperintense on all pulse sequences and there may be enhancement along the leaves of the detached sensory retina and at the sites where retina inserts. In contrast, retinoblastoma may show an intraocular mass with calcifications. An additional finding that may help differentiate the two is the observation that the affected globe is smaller than the unaffected globe in Coats disease.

Rhegmatogenous: Comes from the greek rhegma = discontinuity or break. Rhegmatogenous retinal detachment is more common, and occurs when a tear in the retina causes fluid accumulation between the neurosensory retina and retinal pigment epithelium. Non-rhegmatogenous detachments can occur via traction from a contracting vitreous (tractional retinal detachment) or via fluid accumulation due to damage to the retinal pigment epithelium (exudative detachment). Coats disease falls into the latter type of non-rhegmatogenous detachment.

References

Galluzzi P, Venturi C, Cerase A, Vallone IM, Bracco S, Bardelli AM, Hadjistilianou T, Gennari P, Monti L, Filosomi G. Coats disease: smaller volume of the affected globe. Radiology. 2001 Oct;221(1):64-9.