[Intra-optic nerve and chiasmal abscess caused by methicillin-resistant Staphylococcus aureus (a case report and literature review)].

A 27-year-old immunocompetent male with headache, transient polydipsia, and polyuria suddenly developed visual impairment (predominantly in the left eye) and, 2 days later, left-sided amaurosis. MRI in T1, T2, DWI, and FLAIR modes revealed a space-occupying lesion of the left intracranial optic nerve and chiasm. According to the clinical X-ray picture, malignant chiasmal glioma was suspected; another and less likely variant was lymphoma. An open biopsy of the space-occupying lesion of the chiasmal-sellar region revealed purulent-necrotic masses. Material from the operative wound was positive for a Staphylococcus aureus strain. The polymerase chain reaction of a cerebrospinal fluid sample revealed methicillin-resistant Staphylococcus aureus. The patient underwent systemic and intrathecal antibiotic therapy with linezolid and vancomycin, respectively, with a good clinical effect: there was an improvement in the vision in a right single sighted eye and normalization of the cerebrospinal fluid composition.