We report the case of a patient with concomitant
Lyme borreliosis and acute paraplegia. The paraplegia was complete, flaccid and of upper motor neurone type. The diagnosis of borreliosis was based on the detection of large amounts of IgM and IgG borrelia antibodies in the acute phase serum and on the complete disappearance of IgM antibody during the review period. IgG borrelia antibodies were also detected in the CSF, but leakage of antibodies from the blood to the intrathecal space could not be ruled out. Lymphocytosis and increased total protein concentration in the CSF were signs compatible with neuroborreliosis. Ceftriaxone therapy effected dramatic recovery of the patient. This case suggests that borreliosis should be considered a possible cause of acute flaccid paraplegia.