Leber's miliary aneurysms.

Leber's disease is a form of primary retinal telangiectasia characterized by the presence of abnormalities in the retinal vasculature. It is an idiopathic, unilateral condition with male predilection. It is not associated with any other systemic or ocular disease. The disease has a very slow progression and can be complicated by vascular dilatations, neovascularizations, thromboses, retrovitreal hemorrhages, and macular changes. We present a case of Leber's miliary aneurysms in an asymptomatic 22-year-old male patient. His fundus examination showed aneurysmal dilatations with lipid exudation. Intravenous fluorescein angiography showed early and late leakage as well as capillary dropout with late hypofluorescence. In this case, the patient was treated with laser photocoagulation of the retina.

Introduction

In 1908 Coat described an ophthalmologic disease, characterized by unilateral retinal vascular abnormalities and retinal exudation.[1] In 1912, Leber described a retinal disorder which he called “retinal degeneration with multiple miliary aneurysms”. He wrote two more articles in 1915 and concluded that the disease he had described in 1912 was a variant of Coats’ disease.[23] This conclusion was later reinforced by Reese in 1956 who suggested that Coats's disease and Leber's miliary aneurysms were the same condition but in different stages of evolution. Both together he called telangiectasia.[4]

Leber's miliary aneurysm is a form of primary retinal telangiectasia characterized by presence of multiple miliary aneurysms associated with intraretinal lipid exudates. It is an idiopathic, unilateral condition with male predilection. It is not associated with any other systemic or ocular disease.[23]

Case Report

A 22-year-old male patient presented to the Ophthalmology clinic with a chief complaint of right eye floater. His past medical and ocular history were unremarkable. He gave no history of any systemic illness.

On examination, his visual acuity was 20/20 in the right eye (OD) and 20/25 in the left eye (OS). Intra ocular pressure was 19 and 13 mmHg. Anterior segment exam was normal in both eyes. Dilated fundus exam of the right eye was unremarkable. The left eye demonstrated a physiologic appearing optic nerve. However, the presence of multiple hard exudates in the inferior temporal retinal of the left eye was noticed. There were also multiple aneurysms in the temporal retina with vascular dilations, neovascularisation and very mild macular edema [Figure 1].

Figure 1

Color fundus photograph (a) Normal right eye and (b) Left eye hard exudate deposition in the inferior temporal macula

Intravenous fluorescein angiography showed early and late leakage as well as capillary dropout with late hypofluorescence in the temporal macula based on that picture we decided to treat him with laser photocoagulation although he was asymptomatic [Figure 2].

Figure 2

Fluorescein angiogram. (a) Early venous laminar phase with areas of hyperfluorescence in the inferior temporal retina. (b) Late venous phase: Aneurysmal dilatation, leakage, and hypofluorescence consistent with ischemia in the inferior temporal retina

Optical coherence tomography (OCT) showed mild retinal thickening in the inferior macular region.

The patient was instructed to regularly follow up and to return to the clinic if he noticed any changes.

Discussion

Reese defined primary retinal telangiectasia in 1956 as multiple abnormalities within the retinal vasculature, including vascular ectasia and aneurysms of the capillaries, arteries, and veins.[4] He recognized that vascular endothelial decomposition within the telangiectasia resulted in retinal fluid accumulation, exudates, and hemorrhages.[5] Juxtafoveal telangiectasiae, Leber's miliary aneurysm, and Coats disease are considered to be part of the clinical spectrum of a single process known as primary retinal telangiectasia.[67]

Primary retinal telangiectasia may be regarded as a congenital malformation.[8] It has been said that Coat's disease and Leber's disease are variants of the same pathological phenomenon. There have been a lot of discussions on this correlation. Coat (1908) believed that his cases were due to organization of hemorrhage from diseased capillaries and veins. Leber insisted that his disease was primarily a toxic or embolic arterial disease in which hemorrhage was of secondary importance.[9]

The patient with Leber's miliary aneurysms is typically a young male and frequently is asymptomatic.[2] The condition is usually unilateral, only rarely bilateral.[10] Clinically, it is characterized by being localized to a relatively small area, usually in the periphery of the retina, and by consisting of slightly elevated white intraretinal exudates over saccular and fusiform dilatations maybe found in the blood vessels, which itself often slightly dilated. The aneurysmal changes, which vary in width, are often grouped in small clusters lying superficially in the retina, usually in the equator region or peripheral to it.[3] These telangiectatic vessels may remain stable or progress slowly but only associated with mild intraretinal leakage.[5] Leber's miliary aneurysms are not typically associated with visual impairment. However, leakage can extend into the macular area, resulting in decreased vision.[511]

Circinate lesions were observed in Leber's miliary aneurysms. Usually, these consisted of large and heavy exudative rings surrounding areas of less exudation containing aneurysms. It has been stressed that cases with circinate retinopathy (with or without aneurysms) often progress to Coats’ disease.[12]

Leber's miliary aneurysms is diagnosed by fundoscopy and fluoscein angiography that highlights the vascular anomalies. It shows multiple aneurysms with chronic and focalized extravasation which give rise to hard exudates. In the early stage of fluorescein angiography, there is hyperfluorescence of vascular dilatations, and at the later stage a diffusion of contrast from the telangiectasiae.[11]

The treatment consists of ablation of the aneurysms by argon laser photocoagulation if the exudate may compromise the macula. Laser scars should not be very intense to avoid damage of Bruch's membrane and development of neovascularizations and proliferations. Cryotherapy is indicated when the aneurysms are in the periphery.[10] In some cases, triamcinolone or intravitreous antiangiogenics could be associated, as well as vitreo-retinal surgery in the presence of macular traction or epiretinal membrane.[13] If the area of telangiectasis is isolated to 1 quadrant without significant lipid accumulation, observation of the lesions on a 3- to 6-month basis is recommended.[5] Prognosis of Leber's miliary aneurysms is generally good and the progression is typically slow.[10] The prognosis depends on the presence of foveal compromise by the exudates, macular edema, vitero-macular traction, or epi-retinal membrane. Other complications are possible such as thrombosis of the aneurysms, neovascularization, hemorrhage in the vitreous, and progression to Coat's disease.[10] Usually, these patients need to follow up regularly to determine if there is leakage and exudation.[11]

Important differential diagnosis includes other causes of primary retinal telangiectasia like Coat's disease and Juxtafoveal telangiectasiae and secondary retinal aneurysms such as retinal arterial macroaneurysm and diabetic retinopathy. Other vascular diseases such as venous occlusion, retinal capillary and cavernous hemangioma should be excluded as well as excluding past radiation as a cause of retinopathy with micro-aneurysms.[711]

Even though the patient was asymptomatic in this case, the disease was complicated by the development of vascular dilation, neovascularizations, and mild macular changes. Laser photocoagulation was applied to the aneurysms to avoid subsequent complications.