Irvan Syndrome (idiopathic retinal vasculitis, aneurysms, and neuro-retinitis) is a disease that was initially described as "bilateral retinal vasculitis with multiple aneurysmal dilatations" in 1983. It is an inflammatory disease of the retina and retinal blood vessels. It corresponds to the combination of inflammation of the retinal arteries, arterial aneurysms (especially in the bifurcations where the angles are widened) and retinal edema. The vision can be threatened by neovascular proliferation and by the accumulation of lipid exudates in the macula. The lesions are bilateral and can spread across the entire fundus of the eye. No systemic damage occurs in most cases.Definition
The exact frequency of Irvan Syndrome is not known. Patients are usually young women and of geographical origin centered on the Mediterranean Basin has been noted.
Irvan Syndrome seems to be of acquired origin.
The patient usually consults for a loss of vision. The diagnosis is based on the examination of the fundus and on fluorescein angiography.
An examination of the fundus reveals multiple aneurismal dilatations of the arteries. These dilatations can affect all the retinal arteries including those at the head of the optic nerve. They are usually located at the arterial bifurcations, causing them to stretch. Lipid exudates build up around the vascular walls or converge on the macular area. Papillary edema is sometimes observed.
Fluorescein angiography shows the aneurysms more clearly. They are visible from the early stage (arterial periods). During the sequence, the dye is taken up by the retinal arteries and aneurysms. This uptake suggests that the vascular damage is the result of inflammation. The examination also shows capillary uptake during later periods.
The exam of the retinal periphery show extensive areas devoid of capillary perfusion. Optical coherence tomography can be used to quantify the macular edema.
Irvan Syndrome usually develops in a succession of eruptions. No triggering factors have been identified. There are two types of complication: exudative and neovascular. Intraretinal exudations can lead to the formation of lipid exudates in the macula and poor long-term visual prognosis. The occurrence of preretinal or prepapilla neovessels is secondary to peripheral retinal ischemia which can be complicated by vitreous bleeds tractions with retinal detachments. In very severe cases, rubeosis can develop in the iris followed by neovascular glaucoma.
The prevention and treatment of neovascular complications are based on laser photocoagulation of the areas of peripheral retinal ischemia. Vitreous bleeds may result in the need for vitrectomy. The treatment of exudation requires control of the abnormalities in the arterial wall. Systemic steroid treatment does not appear to be very effective, whereas intravitreal injections of steroid an effective option.