WHEN ALL TESTS ARE NORMAL: STEROID RESPONSIVENESS AS A KEY DIAGNOSTIC ARGUMENT FOR MULTIPLE SCLEROSIS IN PEDIATRIC OPTIC NEURITIS

Background: Pediatric optic neuritis (ON) represents a diagnostic challenge, particularly when extensive investigations fail to identify a clear etiology. While imaging and laboratory findings are central to diagnosis, clinical reasoning and therapeutic response may play a decisive role. Case presentation: We report a 14-year-old girl presenting with acute unilateral visual loss of the right eye associated with headache and pain on eye movement. Clinical examination revealed anterior optic neuropathy with stage II optic disc edema.A comprehensive ophthalmologic, neurological, infectious, and immunological workup was performed. Brain and orbital MRI showed inflammatory involvement of the right optic nerve without evidence of disseminated lesions. Cerebrospinal fluid analysis and extensive autoimmune and infectious testing were unremarkable.