OPTIC NEURITIS ASSOCIATED WITH CAT SCRATCH DISEASE IN AN IMMUNOCOMPETENT PATIENT: CASE REPORT

Abstract

Introduction: Cat scratch disease (CSD), caused by Bartonella henselae, is a zoonosis with variable clinical manifestations. Among its atypical forms is optic neuritis, usually described in immunosuppressed patients but also possible in immunocompetent individuals. Diagnosis can be challenging, especially in the absence of systemic signs and in contexts of normal imaging tests. Case report: A 33-year-old female physician, previously healthy, presented with sudden onset of left retro-ocular pain, visual deficit and limitation of ocular motility. She sought care at emergency services and later ophthalmology, with initial hypothesis of demyelinating disease. MRI of brain, orbits and neuraxis were normal, as was CSF analysis. She was admitted for investigation, without diagnostic clarification. Due to persistent pain, she received pulse therapy with methylprednisolone 1 g/day for 5 days, with significant improvement in pain. As blurred vision persisted, repeat ophthalmologic evaluation with optical coherence tomography (OCT) showed a lesion in the left optic nerve. Late serology revealed Bartonella henselae and Bartonella quintana with reactive IgM and IgG (IgM 1:100). Treatment with doxycycline 100 mg every 12 hours and rifampicin 300 mg every 12 hours for 4 weeks was initiated, with complete resolution of the condition. Comments: Optic neuritis related to CSD is rare, especially in immunocompetent patients, and may mimic inflammatory or demyelinating neurological diseases. Diagnosis requires a high index of suspicion, particularly in the absence of lymphadenopathy or fever. Specific antibiotic treatment, with or without corticosteroids, can lead to full recovery. This case reinforces the importance of considering CSD in the differential diagnosis of optic neuritis, even in patients without apparent immunosuppression, and highlights the role of detailed clinical history and serologic investigation for diagnostic and therapeutic definition.