THE LABORATORY DIAGNOSIS OF GRANULOMATOUS ANTERIOR UVEITIS AND KERATOUVEITIS OF SUSPECTED VIRAL ORIGIN

Background In epithelial viral keratitis as in viral retinitis, the di agnosis is made on the basis of typical clinical findings. A laborator y confirmation is achieved in over 80% using routine laboratory method s. In contrast, it is almost impossible to confirm the diagnosis of st romal herpetic keratitis in vivo using the currently available laborat ory methods. Nothing is known about the situation in cases of viral an terior uveitis. Methods Of 52 patients with granulomatous anterior uve itis, 31 were diagnosed on the basis of clinical findings as active he rpetic uveitis (group 1), 14 as active granulomatous uveitis of unknow n origin (group 2), and 7 had inactive disease after quietening down o f herpetic uveitis (group 3). From all patients, aqueous humor was col lected at the time of diagnosis and processed for viral culture, Herpe s antigen ELISA, and amplification of viral DNA of HSV-1 and VZV. Resu lts Viral growth in culture was found in only one case in group 3. In this group, viral antigen or viral DNA were detected in no case. Herpe s antigen was found in 5/31 cases (16%) in group 1 and in 1/11 cases ( 9%) in group 2, and viral DNA was found in 8/31 cases from group 1 (5x HSV-1 and 3x VZV) and in 5/14 cases (31%) from group 2. After combina tion of antigen detection and DNA amplification, the presence of virus was confirmed in 14/45 cases (29%). Conclusion Virus culture has not proven useful in the diagnosis of viral anterior segment disease. Desp ite their high overall sensitivity, neither antigen ELISA nor the ampl ification of viral DNA prooved sensitive enough to establish a viral e tiology. Nevertheless, a laboratory confirmation should be attempted i n granulomatous uveitis of unknown origin after preclusion of an under lying systemic disease because of the consequences of a diagnosis of v iral anterior segment disease for treatment and prognosis.