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Chikungunya virus iridocyclitis in Fuchs′ heterochromic iridocyclitis

2011; Medknow; Volume: 60; Issue: 1 Linguagem: Inglês

10.4103/0301-4738.90495

1998-3689

Kalpana Babu, GowriJaydev Murthy,

Retinal Diseases and Treatments

Dear Editor, We read with interest the article titled "Chikungunya virus iridocyclitis in Fuchs' heterochromic iridocyclitis" by Mahendradas et al.[1] We would like to raise some important points through a similar case. A 37-year-old male with a six-month history of recurrent non-granulomatous anterior uveitis with secondary glaucoma was referred for a second opinion. He had a history of chikungunya fever a month back. His best corrected visual acuity (BCVA) was 20/60 and 20/30 in the right and left eye respectively. Slit-lamp examination of the right eye showed fine, pigmented keratic precipitates inferiorly [Fig. 1] and an anterior chamber (AC) reaction of 1+.[2] Fundus showed a cup-disc ratio of 0.7 with a pale neuroretinal rim. Intraocular pressures (IOP) were 38 mm of Hg. Left eye examination was normal. Gonioscopy showed open angles with increased pigmentation inferiorly in the right eye. Laboratory investigations including erythrocyte sedimentation rate (ESR), Mantoux test, serum angiotensin converting enzyme, venereal disease research laboratory test, computed tomography (CT) scan thorax, rheumatoid factor, Human leukocyte antigen B27 and antinuclear antibody tests were normal. Polymerase chain reaction (PCR) on the aqueous tap was negative for Herpes simplex, Varicella zoster, cytomegalovirus, rubella, toxoplasma, Mycobacterium tuberculosis, and positive for chikungunya virus. Topical steroids were added along with anti-glaucoma medications. At one-month follow-up, his IOP was 16 mm of Hg. He came back to us after three months with a reactivation of anterior uveitis and an IOP recording of 34 mm of Hg. He underwent trabeculectomy with mitomycin C in the right eye. PCR on the aqueous was negative for all organisms tested above including the chikungunya virus. He was once again seen after six months with an IOP of 48 mm of Hg. He had a failed bleb and an AC inflammation (1+). He underwent an Ahmed valve implant in the right eye [Fig. 2] and since then his IOP is 10 mm of Hg. PCR on the aqueous was again negative for all organisms tested above including the chikungunya virus.Figure 1: Slit-lamp photograph of the right eye in slit illumination showing the keratic precipitates inferiorlyFigure 2: Slit-lamp photograph of the right eye in diffuse illumination showing the Ahmed valve implantIn the above case, the patient had a well-documented history of recurrent anterior uveitis with increased IOP prior to the development of chikungunya fever. Although the clinical history favored a viral etiology, the finding of the chikungunya virus in the aqueous tap raised a lot of questions. The aqueous tap was done within one month of the chikungunya fever while this patient had a history of recurrent anterior uveitis six months prior to the development of the chikungunya fever. Also, what is interesting is that the aqueous tap repeated three and six months after the viral fever was negative for the chikungunya virus by the PCR. We speculate that the finding of chikungunya virus in the aqueous tap is casual and could probably be due to the high viraemia which usually occurs at the time of the chikungunya fever. This may result in a spillover of the viral antigen in body fluids like the cerebrospinal fluid (CSF), aqueous, pericardial fluid, etc., and hence the demonstration of the viral antigen. In the case described by Mahendradas et al.,[1] the same mechanism may be speculated as the duration of the aqueous tap following the chikungunya fever was only two weeks. As we do not know the duration the viral antigen persists in the aqueous,[3] it is difficult to speculate a causal role of the virus in the uveitis in the two cases. Acknowledgment We would like to acknowledge the help of Professor Ravi Kumar and Dr. Latha, Microbiologists, for their assistance in interpreting the polymerase chain reactions.