Acute retinal necrosis (ARN) is an ocular inflammatory syndrome caused by the herpes group of viruses.1 We describe a case of bilateral ARN in an immuno-competent child who presented with inflammatory hemorrhagic retinopathy resembling a retinal vascular occlusion.
A 14-year-old boy had painful decrease in vision in his left eye of five days' duration. The best corrected visual acuity (BCVA) in the right eye was 20/20 and in the left eye was perception of light with inaccurate projection of rays. The right eye was normal on detailed evaluation. The left eye had fine keratic precipilates (KPs), 2+ aqueous cells and flare, 3+ vitreous haze, edematous optic disc and engorged and tortuous venules with numerous flame-shaped retinal hemorrhages extending from the posterior pole to the peripheral retina. The macula and peripheral retina was pale and opacified. No areas of occlusive vasculitis were seen. A hemorrhagic retinopathy resembling a combined central retinal vein and retinal artery obstruction of inflammatory etiology was suspected.
Systems' review and investigations by an internist were negative. These included complete hemogram, autoimmune profile, serology for HIV and syphilis, renal and hepatic parameters and X-ray of chest. Inflammation was treated with oral prednisolone 1 mg/kg body weight and topical 1% prednisolone acetate eye drops six times a day.
Five days later, his vision had reduced to no perception of light. Examination showed reduced media haze. There were multiple large retinal breaks temporally with retinal detachment. The widespread, pale, opacified areas of retina [Fig. 1] that were initially thought to be due to retinal arterial obstruction, were re-interpreted as areas of widespread retinal necrosis. The diagnosis was revised to possible ARN. Aqueous tap of the left eye for detection of any viral DNA by multiplex polymerase chain reaction (PCR) was positive for HSV 1/2 DNA [Fig. 2] and negative for varicella zoster and cytomegalovirus DNA. Subsequently it was independently tested and found negative for HSV 2 DNA leading to the conclusion of HSV 1 DNA positivity.
Ten days after the initial presentation he developed painful decrease in vision in the right eye. The BCVA was 20/25 and intraocular pressure was 27 mmHg. Examination showed fine KPs, 1+ aqueous cells and flare, 2+ vitreous haze and dilated and tortuous veins with no disc edema. There was an arcuate white patch of necrosis in the posterior pole and multiple areas of peripheral retinal necrosis. He was diagnosed to have bilateral ARN due to HSV 1. Treatment included intravenous Acyclovir 500 mg every eight hours for seven days followed by tablet acyclovir 200 mg five times a day for 12 weeks; intravenous dexamethasone 4 mg once a day for seven days followed by oral prednisolone 1 mgm/Kg bodyweight tapered over eight weeks. Topical medication included prednisolone acetate 1% every two hours, cyclopentolate hydrochloride 1% three times a day and timolol maleate 0.5% twice daily. Barrage laser photocoagulation posterior to the area of resolving necrosis was done two days later [Fig. 3]. Retinal detachment two months later [Fig. 4] was managed successfully with vitreoretinal surgery using silicone oil as internal tamponade. Silicone oil was removed after six months and ten months later the final visual acuity was 20/40 in the right eye.
Acute retinal necrosis is characterized by progressive circumferential, peripheral retinal necrosis, occlusive retinal vasculitis and vitritis. Extensive hemorrhagic retinopathy with venous engorgement as seen in our case, is not a common presentation, especially in children. The right eye also had congestion of retinal veins at the time of involvement with ARN. Literature search (Medline) revealed a single case of ARN with central retinal vascular obstruction and optic neuropathy in an adult by Kang et al.2 and none in children. Interestingly, our immuno-competent patient had simultaneous retinal necrosis in the periphery and at the posterior pole in both eyes. The arcuate posterior pole lesion [Figs 2 and 3] along the nerve fiber layer in the right eye possibly signified the retrograde invasion of the virus through the optic chiasma, from the left eye.3 Unlike previous reports of ARN in children,4 there were no preexisting chorioretinal scars in our patient. Due to this variant clinical presentation, there was an initial misdiagnosis. This was however correctly diagnosed at the very next visit five days later once the media had cleared and details of peripheral retinal breaks and retinal necrosis were visualized in the left eye.
The PCR analysis of aqueous can identify causal virus with very high sensitivity and specificity.5 The HSV 1 DNA detected in our case was unusual because HSV 2 is reported as a more common etiology in the young.1 Whether systemic antiviral therapy at that stage could have prevented the spread of disease to the contralateral eye in our patient, is debatable. As there was no light perception and in the absence of clear guidelines about duration and efficacy of prophylactic treatment and the expenses involved, we did not start such therapy.
In conclusion, we describe a unique case of bilateral ARN caused by HSV 1 in a child who initially presented with extensive hemorrhagic retinopathy in one eye. The other eye also had associated retinal venous engorgement. Both eyes did not have occlusive vasculitis as is described for ARN. In a young patient, viral etiology should be considered in eyes with inflammatory hemorrhagic retinopathy.
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