Bartonella henselae neuroretinitis misdiagnosed as multiple sclerosis

INTRODUCTION Bartonellosis, known as cat-scratch disease, is caused by Bartonella gram negative bacilli, including Bartonella henselae. Human infection occurs mainly after cat scratch or contact with cat saliva, but other animals may be involved in the transmission. Neuroretinitis presents with optic disc edema and retinal exsudates in a macular star configuration. METHODS We describe a 48-old woman, previously heathy with neuroretinitis on the left eye, B. henselae positive serology, with no history of cat contact and diagnosed with as multiple sclerosis. RESULTS Neurological examination was normal and ophthalmic examination revealed visual acuity 20/20 on the right eye (RE) and 20/100 on the left eye (LE). Pupils were simetric with relative afferent pupillary defect on the LE. Ishihara test results were 10/10 on RE and 5/10 on LE. Binocular indirect ophthalmoscopy showed no abnormalities on RE and diffuse moderated optic disc edema with incomplete macular star on LE. Patient received corticosteroids for ocular allergy, but vision remained low on LE. Orbital MRI revealed abnormal signal intensity on the anterior portion of the left optic nerve and the patient was erroneously diagnosed with multiple sclerosis. New brain and orbital MRI showed no brain abnormalities. B. henselae blood serology was positive. CONCLUSION Infectious and inflammatory diseases should be considered in the differential diagnosis of neuroretinitis, although demyelinating diseases are exceptional. Abnormal signal intensity on the anterior portion of the optic nerve can be present at MRI scan. History of contact with cats may suggest infectious causes for neurorretinitis but it’s not always typical.