Cat-scratch disease neuroretinitis diagnosed by a polymerase chain reaction approach.

To assess the value of polymerase chain reaction in the diagnosis of cat-scratch disease neuroretinitis without conclusive serology. Interventional case report. A 13-year-old girl developed a right neuroretinitis 2 months after a cat scratch. Despite the lack of accompanying features, an infection by Bartonella henselae was suspected and a systemic check-up was performed. Serologic results excluded other proposed origins but were insufficient in making the diagnosis because of low B. henselae specific IgG level in serum. A polymerase chain reaction analysis for B. henselae DNA in a small axillary lymphadenopathy aspirate enabled us to achieve a definitive diagnosis of cat-scratch disease. Polymerase chain reaction is a valuable method of diagnosing cat-scratch disease when serology is considered negative or borderline.