Cat scratch neuroretinitis: the role of acute and convalescent titers for diagnosis.

Cat scratch neuroretinitis (CSN) is a clinical diagnosis supported by serological testing. We present 2 cases of CSN in which initial acute titers were negative or equivocal for Bartonella henselae while convalescent titers were shown to be positive. We report these cases to emphasize that a single acute negative titer is insufficient to exclude the diagnosis of CSN and that convalescent titers should be obtained in patients for whom there is a high clinical suspicion of the disease.