Unilateral optic disc drusen mis-diagnosed as optic neuritis: Diagnostic and therapeutic implications.

To present a case of unilateral optic disc drusen, initially mis-diagnosed as optic neuritis, which led to chronic systemic administration of steroids and the development of hypercortisolism. A 22-year-old female was referred because of the lack of improvement of the manifestations of optic neuritis despite the chronic use of systemic steroids. Presence of unilateral optic disc edema was initially observed, associated with ipsilateral scotomata and increased ipsilateral latency time in visually evoked potentials (VEP). A CT scan, A and B ultrasonography and autofluorescence of the optic disc confirmed the diagnosis of optic disc drusen. In cases of optic disc edema, the possibility of drusen should always be examined even if functional disturbances, such as scotomas in visual fields or electrophysiological findings, are present, to avoid potential toxicity from unnecessary medications.