Background/purpose: To evaluate the clinical manifestations, prognosis, recurrence rate and development of multiple sclerosis between papillitis group and retrobulbar group in Taiwanese patients with isolated acute optic neuritis (AON) after treatment with intravenous methylprednisolone pulse therapy.
Methods: We retrospectively reviewed patients with AON who had received intravenous methylprednisolone pulse therapy. These patients were classified into retrobulbar or papillitis groups. Demographic characteristics, responsiveness to pulse therapy, recurrence rate and incidence of multiple sclerosis were compared between these two groups.
Results: Of the 43 patients enrolled in this study, 19 patients (44%) were in the retrobulbar group and 24 patients (56%) were in the papillitis group. Seven cases (16%) showed periventricular plaque on magnetic resonance imaging (MRI). Among these seven patients, five developed definite or probable multiple sclerosis. The incidence of multiple sclerosis in patients with positive brain MRI findings was significantly higher than in patients with negative MRI findings (p = 0.002). There was no statistical difference in final visual acuity between the two group (p = 0.353). Sixteen patients suffered from recurrence of AON (21% in the papillitis group and 58% in the retrobulbar group, p = 0.029). Two patients (8%) in the papillitis group and six patients (32%) in the retrobulbar group developed multiple sclerosis (p = 0.061) with a mean interval of 21.6 +/- 11.2 months.
Conclusion: AON in Taiwan has a relatively lower percentage of development of multiple sclerosis than in Western countries. The presence of periventricular plaque on MRI is significantly associated with the later development of multiple sclerosis. The retrobulbar group had a stronger association with recurrence and development of multiple sclerosis.