Not the usual frosted branch angiitis!

A 19-year-old girl presented with acute onset diminution of vision in her left eye for the past one week. Visual acuity at the presentation was 20/40. Anterior segment examination showed 2+ cells and granulomatous keratic precipitates. Fundus examination revealed frosted branch appearance of both arteries and veins. [Fig. 1] (A) Fluorescein angiography showed active vasculitis [Fig. 1] (B-C). She gave history of chickenpox 2 months back.Figure 1: Fundus photograph (Optos California ultra-widefield imaging 200 DTx icg, Scotland, United Kingdom) of left eye shows perivascular sheathing of retinal vessels giving appearance of frost on tree branches (a). Fluorescein Angiography shows active vasculitis (b-c)What is your next step? Clinical diagnosis of CMV retinitis and treatment with ganciclovir Evaluate for hematological malignancy AC paracentesis for viral polymerase chain reaction (PCR) Systemic work-up to rule out rheumatological disorder. Findings PCR done from aqueous fluid was positive for varicella-zoster virus (VZV). The patient was treated with intravenous acyclovir 750 mg TDS, given for 14 days followed by oral valacyclovir 1 gm TDS. Oral steroids (1 mg/kg/d) were added 48 hrs after initiating antiviral treatment. Diagnosis Retinal perivasculitis secondary to VZV infection. Correct answer C, AC paracentesis for viral polymerase chain reaction (PCR). Discussion Frosted branch angiitis (FBA) is a rare form of retinal vasculitis characterized by prominent perivascular sheathing of retinal vessels. The term is derived from the resemblance to frost on tree branches in icy winter. Etiological causes of FBA include autoimmune diseases (Systemic lupus erythematosus, Behcet’s disease), hematological malignancies (leukemia, lymphoma) and infective causes such as cytomegalovirus (CMV), ocular toxoplasmosis, and tuberculosis (TB).[1] In the absence of any obvious etiology, the diagnosis is labeled as idiopathic FBA. Talebo-Taher et al.[2] reported FBA caused by VZV in an immunocompetent patient. PCR from aqueous fluid helped in the diagnosis and the patient was managed with intravitreal ganciclovir. FBA secondary to viral infections can progress to acute retinal necrosis (ARN) and lead to permanent loss of vision.[3] Accurate diagnosis is therefore crucial for prompt treatment with antiviral drugs and prevent ocular morbidity. PCR from ocular fluid (aqueous/vitreous) sample plays an important role in identifying the etiological cause like HSV, VZV, or CMV and institute appropriate antiviral therapy. Declaration of patient consent The authors certify that they have obtained all appropriate patient consent forms. In the form, the patient(s) has/have given his/her/their consent for his/her/their images and other clinical information to be reported in the journal. The patients understand that their names and initials will not be published and due efforts will be made to conceal their identity, but anonymity cannot be guaranteed. Financial support and sponsorship: Nil. Conflicts of interest: There are no conflicts of interest.