Idiopathic Macular Telangiectasia Type 1 with Ruptured Retinal Arterial Macroaneurysm Post Intravitreal Bevacizumab.

A 50-year-old Indian male presented with defective vision in the right eye for 6 months. He was diagnosed to have idiopathic macular telangiectasia (IMT) type 1 associated with diffuse macular edema and multiple retinal arterial macroaneurysms (RAM). Intravitreal bevacizumab was administered for the treatment of macular edema, following which there was a rupture of a preexisting RAM with multilevel retinal hemorrhages. The hemorrhage gradually resolved over time with foveal thinning noted at last visit. We report this case for the rare occurrence of IMT type 1 and also the possibly associated rupture of RAM post intravitreal bevacizumab injection.

INTRODUCTION

Idiopathic juxtafoveolar retinal telangiectasia is an uncommon retinal vascular malformation with characteristic features. The clinical and angiographic features and classification were first described by Gass and Oyakawa in 1982 and further reclassified by Gass and Blodi in 1993.1 Yannuzzi et al., added the optical coherence tomography (OCT) features to a modification of the original classification by Gass and called the lesions idiopathic macular telangiectasia (IMT).2 Type 1 IMT or aneurysmal telangiectasia is characterized by predominantly unilateral capillary, venular and arteriolar aneurysms, and telangiectatic abnormalities in the juxtafoveal region, seen more commonly in males. They may be associated with fluid and/or lipid leakage into the macula. Retinal arterial macroaneurysms (RAM) are also seen in cases of type 1 IMT. Considering their unilateral involvement and male predominance, Gass suggested that these vascular telangiectasis are developmental in origin and represent one end of the spectrum of Coats syndrome.1

CASE REPORT

A 50-year-old, nondiabetic, nonhypertensive Indian male reported with incidentally noted defective vision of 6 months duration in the right eye. His best-corrected visual acuity was 20/200 in the right eye and 20/20 in the left eye. The anterior segment examination was unremarkable. Retinal examination in his right eye revealed multiple telangiectatic vessels in the perifoveal region with associated cystoid macular edema (CME). The first order retinal arterioles showed multiple RAMs, with evidence of a small retinal hemorrhage surrounding the RAM along the inferotemporal vessel. Fundus fluorescein angiography (FFA) revealed distorted perifoveal capillary network with multiple dilated telangiectatic outpouchings [Figure 1], with associated late leakage. The left eye retina and FFA were within normal limits. OCT of the right eye showed CME, for which he received intravitreal bevacizumab (Avastin, Genentech, Inc., South San Francisco, CA; 1.25 mg/0.05 cc). The gentleman had been seen by another ophthalmologist 6 months prior and a previous fundus angiogram showed similar findings as noted by us. He underwent a thorough systemic workup including a complete blood count, blood sugars, serum lipid profile, coagulation profile, and all parameters were within normal limits. A cardiologist opinion including a carotid doppler examination did not reveal any significant structural changes in the vascular network of the head and neck. His blood pressure was checked previously and at all visits and was within normal limits for his age.

Figure 1

(a) Color fundus photo of the right eye showing idiopathic macular telangiectasia type 1 with retinal arterial macroaneurysms (RAM) along superior and inferior arcade, with cystoid macular edema. (b) Early phase fundus fluorescein angiography (FFA) showing macular telangiectasia with RAM (solid white arrow). (c) Late phase FFA showing leak from macular telangiectasia

However, on review, the patient reported seeing “a central black spot” in the field of vision, which was noticed almost immediately following the injection. His retinal examination revealed a ruptured RAM along the inferotemporal arcade with resultant sub-internal limiting membrane, subretinal, and intraretinal bleed, corroborated on OCT [Figure 2]. His CME was persistent and hence intravitreal bevacizumab was repeated. Pneumatic displacement of the subretinal blood was not contemplated as the hemorrhage was old.

Figure 2

(a) Color fundus after bevacizumab injection showing ruptured retinal arterial macroaneurysms along inferotemporal arcade with multilevel hemorrhage. (b) Optical coherence tomography showing subretinal hemorrhage (solid white arrow) with persistent cystoid macular edema

Fundus fluorescein angiography was repeated 3 months after the second injection and it showed considerable, though not complete reduction in leakage from the perifoveal telangiectasis. There was persistent CME as documented by OCT. Further injections were withheld as there was no significant improvement in his clinical picture. On final follow-up, 10 months after the rupture of the RAM, his best-corrected visual acuity was maintained at 20/200 and the retinal and subretinal hemorrhages were resolving. There were hard exudates in the macular area and foveal thinning documented by OCT [Figure 3].

Figure 3

(a) Optical coherence tomography at 10 months showing foveal thinning and a detached internal limiting membrane. (b) Color fundus at final visit showing macular hard exudates with sclerosed retinal arterial macroaneurysms

DISCUSSION

Type 1 IMT is a rare vascular disease, which makes it difficult to decide an optimal treatment as various modalities cannot be evaluated in a controlled randomized protocol and hence guidelines on treatment are not well defined. Gass described a good visual outcome after focal laser to the leaking telangiectatic capillaries. This prevented further leakage and helped preserve the visual function.1 Subsequently in the era of anti-vascular endothelial growth factor (VEGF) pharmacotherapy, bevacizumab has also been used the treatment of leaking telangiectasia in this group.3

The telangiectatic vessels in IMT type 1 are congenital in origin. This can explain the poor response to bevacizumab in terms of persistent leakages and cystoid spaces. It also prompts reconsideration for the use of intravitreal anti-VEGF pharmacotherapy in this condition whose pathology is poorly understood.

The treatment strategies for RAM are also not well defined. General guidelines state that unruptured RAMs should be observed, subhyaloid or vitreal hemorrhage should be treated with laser disruption of the posterior hyaloid or vitrectomy as applicable. RAMs with exudation into the macular area can be treated by gentle laser photocoagulation either directly to the RAM or to the surrounding retinal capillary bed. Intraretinal and subretinal hemorrhages are generally observed.4 Pneumatic displacement of large submacular hemorrhages with adjunctive intravitreal tissue plasminogen activator has been described and is best effective within less than 10 days from occurrence of symptoms.5

Two types of RAMs, saccular or blowout and fusiform or cuffed have been described. The saccular type, as seen in our case are more prone for rupture.6 This is more evident in hypertensive patients due to increased hydrostatic pressure.7 Our patient was normotensive. His blood parameters and a detailed physician evaluation were not suggestive of any associated underlying systemic disorder. The RAM in this case is part of the spectrum of IMT type 1 and not age-related or secondary to hypertension.

The macular edema in our patient was due to diffuse leakage from the telangiectasia of the perifoveal vasculature. We deferred laser and went ahead with intravitreal pharmacotherapy as the leak was diffuse and there was slight enlargement of his foveal avascular zone. In our case, the preexisting RAM had shown evidence of intraretinal hemorrhage in a small area surrounding the lesion prior to treatment. The hemorrhage increased significantly following the intravitreal injection of bevacizumab. We postulate that fibrous changes in the already weak vessel wall could have been precipitated by bevacizumab. The resulting contraction of the vessel wall could have led to the rupture of the RAM. Another possibility is the increase in intravitreal volume during injections, which can increase shearing forces on the weak vessel wall of the aneurysm leading to its rupture. A similar hypothesis concerning the action of intravitreal ranibizumab was postulated by Cornish and Harvey as a cause of retinal pigment epithelial tear following intravitreal ranibizumab.8

To the best of our knowledge and a detailed literature search, we could not find any reported cases of ruptured RAM post intravitreal injections. Rupture of a RAM with submacular hemorrhage can have adverse outcomes on the final visual acuity. It is possible that the rupture of the RAM might be coincidental and due to the natural history of the condition. However, even though a causal association between intravitreal injection and macroaneurysm rupture cannot be made with certainty in our case, the fact that the patient had these vascular abnormalities, presumably for many years without spontaneous rupture, warrants consideration.