Acute Retinal Necrosis Associated With Central Retinal Artery Occlusion Followed After its Resolution by Keratouveitis

Acute retinal necrosis (ARN) is rare sight-threatening condition, typically affecting immunocompetent individuals. It is defined by the combination of clinical features, including areas of retinal necrosis usually located in peripheral retina with circumferential extension, occlusive vasculopathy, as well as vitritis and/or anterior chamber inflammatory reaction.1 Varicella zoster virus (VZV) and herpes simplex virus (HSV) are the most frequent causes of ARN.2,3 Central retinal artery occlusion (CRAO) has been rarely reported in the setting of ARN, worsening the visual prognosis of the condition.4 Although fellow eye involvement is quite common,2,3 recurrence of ARN in the same eye has been rarely seen.5 Furthermore, occurrence of anterior uveitis without posterior segment involvement has been described after healed ARN.6

We describe herein a patient with ARN associated with CRAO who developed after complete recovery of ARN ipsilateral keratouveitis.

A 53-year-old female complaining of loss of vision in the right eye for 3 weeks was referred to our institution for panuveitis. The patient had a history of arterial hypertension and atrial fibrillation, which was being treated with amiodarone. No previous episode of eye redness was reported.

Visual acuity was hand motions in the right eye (RE) and 20/20 in the left eye (LE). Slit-lamp examination of the RE showed granulomatous anterior uveitis without associated iris atrophy, active keratitis, or corneal scar. There were 2+ vitreous cells and haze in the RE. Dilated fundus examination showed areas of necrotizing retinitis in the posterior pole and temporal periphery over approximately 5 clock hours, and an area of ischemic retinal whitening in the posterior pole along with diffuse narrowing of retinal vessels and segmental fuzzy vascular sheathing in the RE (Figure 1A). Results of examination of the LE were unremarkable. Fluorescein angiography revealed a marked delay of retinal artery filling consistent with CRAO in the RE (Figure 1B, C).

Figure 1. (A) Fundus photograph of the right eye shows 2+ vitreous haze, central and peripheral necrotizing retinitis (arrows), retinal opacification in the posterior pole (arrowheads) as well as narrowing and sheathing of retinal vessels. (B) Early phase fluorescein angiography image of the right eye reveals delay in arterial filling (C) Late phase fluorescein angiography image of the right eye reveals impaired arterial and venous filling, as well as late diffuse leakage from the optic disc. (D) Anterior segment photograph of the same eye five months after the resolution of acute retinal necrosis, shows disciform keratitis, granulomatous precipitates and sectorial iris atrophy.

A diagnosis of ARN was made. Workup for toxoplasmosis, syphilis, tuberculosis, and human immunodeficiency syndrome was negative. Polymerase chain reaction (PCR) on aqueous humor sample was positive for HSV type 1. The patient was treated with intravenous acyclovir (10 mg/kg, 3 times a day) for only 3 days, because of the increase of serum creatinine levels. Oral valacyclovir (1 g, 3 times a day) was then given for 12 weeks, and was associated with oral prednisolone started with a dose of 1 mg/kg/day and gradually tapered over 6 weeks. Necrotic lesions completely healed within 2 months. Visual acuity was then 20/400 in the RE.

A cardiovascular workup was conducted to rule out other possible causes of CRAO. Blood pressure values and serum lipid profile were within normal levels. Electrocardiogram showed a regular sinus rhythm. A transoesophageal echocardiography revealed no atrial thrombi. Carotid ultrasonography found some plaques but no significant stenosis.

Five months after the resolution of ARN episode, the patient presented with red and painful RE. Slit-lamp examination showed disciform keratitis, mutton-fat keratic precipitates, 2+ cells and 1+ flare in anterior chamber, and sectoral iris atrophy (Figure 1D). Corneal sensitivity was found to be decreased. The intraocular pressure was normal. The vitreous cavity was clear, without any obvious cells. Dilated fundus examination showed optic disc atrophy, diffuse arterial narrowing, mild pigmentary changes in the temporal periphery, and no active retinal lesion. The patient was treated with topical corticosteroids and oral valacyclovir 500 mg, 3 times daily for 10 weeks. She has been maintained on a preventive dose of valacyclovir 500 mg, once a day for 3 additional months. Visual acuity of the RE at last follow-up was 20/400.

This patient had ARN syndrome with unique clinical presentation and course. There was associated CRAO at presentation, and the patient developed ipsilateral, isolated keratouveitis 5 months after complete resolution of retinal lesions.

Occlusive retinal vasculitis, usually involving retinal arteries, is a common finding in ARN syndrome.1–3 However, its presentation in the form of CRAO has been already described in only five cases that were associated with VZV or HSV.4,7,8 In our patient, HSV type 1 could be detected by PCR. CRAO probably contributed to the poor visual outcome, and this is consistent with previous data. The mechanism of CRAO in eyes with ARN is still undetermined, but seems to be immune-mediated rather than infectious in nature.4,9

On the other hand, a history of previous herpetic anterior uveitis may be found in some patients with ARN.6 The occurrence of isolated anterior uveitis without associated recurrent retinitis after healed ARN has been rarely described.6 There was no history of previous keratitis or anterior uveitis before the development of ARN syndrome in our patient, and a unique disciform keratitis developed in association with anterior uveitis. The isolated anterior segment involvement might result from an immunological reaction related to the involved virus rather than an active viral replication.6

In summary, CRAO should be considered as a potential, severe manifestation of occlusive vasculitis associated with ARN. Patients with ARN also should be closely monitored after healing of retinal lesions for the development of isolated keratouveitis or anterior uveitis.

Declaration of interest

The authors report no conflicts of interest. The authors alone are responsible for the content and writing of the paper.

This work has been supported by the Ministry of Higher Education and Research of Tunisia.