Diagnostic challenges in an atypical presentation of Lyme neuroborreliosis.

A man in his early 70s presented with back pain, sleep disturbances, ataxia and confusion, which was initially diagnosed as radicular back pain. On re-presentation, a lumbar puncture on admission revealed lymphocytic pleocytosis, elevated protein levels and low glucose levels; an electroencephalogram indicated encephalopathy. The primary concern was malignancy with an associated paraneoplastic encephalitis, but MRI of the brain and spine and positron emission tomography-CT revealed no specific abnormalities of consequence. Following a period of diagnostic uncertainty, Lyme neuroborreliosis (LNB) encephalitis was confirmed by positive Lyme serology and Lyme antibodies in cerebrospinal fluid. He was treated with 21 days of intravenous antibiotic therapy with complete resolution of neurological symptoms. This case highlights the variable presentation of LNB and the limitations in understanding and in the availability of diagnostic testing, which can delay diagnosis and treatment.