Idiopathic orbital myositis.

PURPOSE: There is a paucity of reliable data and limited experience on the clinical features and therapeutic outcomes of orbital myositis. The purpose of this study was to collate data on the clinical features, imaging, diagnosis, and therapeutic effects of case reports from patients with myositis of idiopathic orbital inflammation pseudotumor in a tertiary eye hospital in China.

METHODS: A retrospective study was performed on the records of 44 Chinese patients with orbital myositis. Data were obtained from the period of January 1, 2000, to August 31, 2010, from patients treated at the Eye Hospital of the Zhongshan Ophthalmic Center at Sun Yat-sen University, Guangzhou, China.

RESULTS: Twenty-five patients were women and 19 men. The mean age was 39.1 years (range, 11-77 years). Right eyes were involved in 18 cases, left in 17 cases, and both eyes in 9 cases. Dysfunctions of the affected muscles included pure paretic (20.5%), pure restrictive (45.5%), or mixed paretic-restrictive (34.1%). The ratio of acute to subacute stage was 1:3. The rank order of affected muscles was as follows: superior rectus (29.1%), lateral rectus (25.6%), medial rectus (24.4%), inferior rectus (19.8%), and superior oblique (1.16%). The proportion of single muscle involvement was 37.5%, and tendon involvement was seen in 40.9% of the muscles. All patients were treated with systemic corticosteroids (prednisone or dexamethasone). Full recovery was achieved in 38.6% of patients, whereas 59.1% achieved partial recovery with an average of 6.4 recurrences (range, 2.0-8.0 recurrences). Recurrences occurred in 81.8% of the patients.

CONCLUSIONS: Orbital myositis occurs in multiple clinical manifestations and may be recurrent. Imaging is an important technique for use in diagnosis. Systemic corticosteroid represents an effective approach for treatment.