RESUMEN
INTRODUCTION: The most frequent neurological expression of Lyme disease (borreliosis) during its secondary phase is meningoradiculitis, but atypical presentations occur. Lyme disease must be considered especially in endemic areas and during the summer (May-October). CASES: We report cases of two patients with unusual clinical presentations of neuroborreliosis. Both had acute inflammatory back pain, resistant to the usual analgesic treatment. Both patients responded negatively to questions about tick bites and erythema migrans. Laboratory tests revealed an inflammatory process in only one patient. Lyme disease was confirmed by lymphocytic meningitis and serological tests positive for Borrelia in blood (both cases) and cerebrospinal fluid (one case). Antibiotic treatment led to the disappearance of pain and the normalization of laboratory tests. DISCUSSION: Inflammatory back pain, even without radiculitis, may be related to Lyme disease in endemic areas.