Clinical Study of the Idiopathic Orbital Myositis

ABSTRACT

The purpose of this study is to evaluate the clinical features and efficacy of therapeutic method of 14 pseudotumor patients with radiologically suspected orbital myositis. Retrospective analysis was performed to elucidate correlation with clinical finding, ocular symptom and sign, involved muscles, therapeutic response, and combined ocular diseases. Patients enrolled in this study were 5 men(35.7%) and 9 women(64.3%) (mean age 38.9 years). Two(14.3%) of 14 patients had bilateral disease, 9(64.3%) in the left eye, and 3(21.4%) in the right. The characteristic signs and symptoms included proptosis(35.7%), eyelid swelling(28.6%), periocular pain(28.6%), diplopia(14.3%), and blepharoptosis(7.1%). Radiologically, the medial and superior rectus muscles were affected in equal frequency(64.3%) as were the lateral and inferior rectus muscles(42.9%). Therefore, 11(71.4%) of 14 patients had enlargement of at least 2 muscles. Drug therapy such as ibuprofen, indomethacin, and prednisolone or radiation therapy of pseudotumor with the orbital myositis was less effective in case of patients with the longer duration of myositis than 1 year or involved all the rectus muscles. These patients usually accompany optic neuropathy(35.8%), paranasal sinusitis(28.6%), ocular hypertension(28.6%), scleritis(14.3%), keratitis(14.3%), dry eye(14.3%), and dacryoadenitis(7.1%). In view of the results of this study, when a case presents clinically suspected pesudotumor with the inflammatory reaction or enlargement of extraocular muscle on CT or MRI, it is suggested that the early differential diagnosis, such as orbitoathy of Graves` disease, neoplastic disorder, ateriovenous malformation be made, and that proper treatment of the orbital myositis be institued for good prognosis of disease.