Atypical Cogan's syndrome mimicking encephalitis.

Cogan's syndrome is a rare autoimmune multisystem disease. The main clinical features of typical Cogan's syndrome are vestibuloauditory dysfunction and interstitial keratitis. The authors present a case of atypical Cogan's syndrome with headache, fever, deafness, trigeminal neuralgia and electroencephalographic abnormality which mimicked viral encephalitis.