Inaugural Sixth Nerve Palsy in a Patient with Neuroborreliosis: A Case Report

We report an uncommon presentation of Lyme disease and highlight the importance of a detailed history in a patient with new-onset sixth nerve palsy. A 46-year-old man presented to the ophthalmology emergency department with horizontal binocular diplopia and holocranial headaches. Ophthalmologic examination revealed a left sixth cranial nerve palsy. The workup showed positive Borrelia serum IgG antibodies. At the follow-up appointment, the patient reported left-sided peripheral facial palsy, associated with worsening headache and diplopia. Further history-taking revealed a tick bite four months earlier. Cerebrospinal fluid (CSF) Lyme antibodies were also positive. Neuroborreliosis, defined as neurologic involvement secondary to systemic infection by the spirochete Borrelia burgdorferi, was diagnosed. The patient was treated with oral doxycycline 100 mg twice daily for 28 days. At the end of treatment, the patient was symptom-free. This case illustrates the importance of a detailed history and follow-up in atypical cases with red flags. Lyme disease can present with various ocular manifestations, underscoring the crucial role of ophthalmologists in its diagnosis.