In our clinical experience we happen to come across frequently with patients with normal cerebrospinal fluid (CSF) findings (pleocytosis, protein and sugar content) but with clinical and serological confirmation of Lyme neuroborreliosis (LN) that were also successfully treated with appropriate antibiotic therapy. Among 10 consecutively admitted patients with diagnosis LN, five had normal CSF findings, three in early disseminated disease (second stage) (enecephalomyelitis acuta, polyradiculitis and polyneuritis) and two in chronic disease (third stage) (encephalomyelitis progressiva and encephalopahty). Two patients remembered the tick bite (one in second and one in third stage) and three did not (two in second and one in third stage). None of them had erythema migrans.

All patients were successfully treated with ceftriaxone by intravenous route(one gram BID). They all started to improve during the first five days and continued to be better during the whole treatment period. LN in any stage of the disease can manifest itself clinically and serologically without concurrent pleocytosis and/or elevated protein content in CSF. If other diagnostic criteria have been fulfilled we should treat such patients with appropriate antibiotic schedule.