CLINICAL AND ECHOGRAPHIC FINDINGS IN IDIOPATHIC ORBITAL MYOSITIS

We performed a retrospective chart review of 100 patients with idiopat hic orbital myositis, who were of ages 9 to 84 years. Data from 75 pat ients gave the following results. Females were affected more than twic e as often as males. Fifty-one patients (68%) had single muscle involv ement, with the lateral and medial recti affected most frequently (38 cases [33%] and 33 cases [29%] of muscles, respectively). In 34 patien ts (45%), affected muscles functioned normally; the remaining 55% (63 muscles) were fairly equally distributed between paretic (20%), restri ctive (20%), or combined paretic and restrictive (15%) myopathies. Ana lysis of muscle function, echographic findings, and duration of sympto ms indicates that Within days of onset of symptomsl the affected muscl e is initially enlarged but retains normal function. Within thefirst t wo weeks, continued enlargement results in muscle paresis. The muscle may then enter a partially or completely restrictive phase, virhich ma y become permanent. Fifty-one patients (68%) responded well to systemi c corticosteroids, although 11 patients (15%) had further recurrences of the disease. Seven patients (9%) later developed thyroid eye diseas e after initially having unimuscular orbital myositis. We advocate ear ly institution of corticosteroids in order to avoid permanent restrict ive myopathies.