Purpose: Orbital myositis is described as exquisitely sensitive to therapy with systemic corticosteroids. However, it may turn into a recurrent or chronic disease, requiring repeated courses or maintenance of corticotherapy that often is complicated with serious side effects. The authors conducted this study to evaluate their experience and the current status in the literature as to treatment of orbital myositis with corticosteroids and corticosteroid-sparing alternatives.
Methods: The clinical records and computed tomography scans of patients with orbital myositis who presented at the Orbital Center Amsterdam between 1977 and 1991 were studied for the clinical course and therapeutic outcome. Recurrences were defined as a new attack of the same or another extraocular muscle as the primary affected, in the same or the other orbit.
Results: The study group comprised 16 patients. All patients responded to initial treatment with oral corticosteroids (14/16) or nonsteroidal anti-inflammatory drugs (NSAID) (2/16). Of these 16 patients, 9 (56%) had 1 or more recurrences. Recurrences responded to repeated courses of corticosteroids, NSAID, or 20 Gy irradiation. Despite radiotherapy in six patients, recurrences continued to occur within a mean period of 2.7 years (range, 0.5 month-8.8 years). The mean follow-up after initial therapy in general was 9.7 years (range, 2.6-16.9 years), and after radiotherapy, in particular, was 7.4 years (range, 4.1-10.5 years).
Conclusions: Orbital myositis responds well to oral corticosteroids, but recurs in 50% of the cases. Based on a long-term follow-up of six patients who received irradiation of 20 Gy, radiotherapy appears ineffective in stopping recurrent orbital myositis.