Dysthyroid Optic Neuropathy: Treatment with Additional Intravenous Methylprednisolone Pulses after the Basic Schedule Is Associated with Stabilization or Further Improvement of Clinical Outcome

Background: Dysthyroid optic neuropathy (DON) is a sight-threatening complication of Graves' orbitopathy (GO). Treatment of DON consists of the urgent administration of intravenous methylprednisolone (ivMP) in very high doses followed by orbital decompression if the response is poor or absent. It is advised to continue the therapy with pulses of ivMP in a weekly schedule. The purpose of this study was to evaluate the impact of the additional treatment with ivMP in a 12-week protocol on visual acuity (VA), color vision, clinical activity score (CAS) and proptosis in patients with DON. Methods: This study was performed on 19 patients with DON (26 eyes) treated with ivMP in very high doses, with further orbital decompression in 11 individuals (15 eyes). VA, color vision, CAS and proptosis were evaluated prior to the DON treatment, before and after the 12-week ivMP (first and last pulse). Additionally follow up was performed (22 eyes). Results: VA and color vision improved between the first and last pulse of the additional ivMP treatment (p = 0.04 and p = 0.003, respectively). CAS and proptosis were reduced at the end of the 12-week ivMP therapy compared to observations at the beginning (p < 0.001 and p = 0.04, respectively). Follow up confirmed stabilization of this achievement. Conclusions: The results of this study suggest that additional treatment with 12 pulses of ivMP improves or stabilizes the outcome of basic therapy in patients with DON.