[Idiopathic orbital myositis]

Orbital myositis is a subtype of nonspecific orbital inflammation confined to one or more of the extraocular muscles.

Three female patients presented presumed orbital myositis, in each of whom the diagnosis was suspected clinically and confirmed by the computed tomography (CT) scan appearances. All presented with orbital pain, diplopia and periorbital edema. All patients responded to systemic corticosteroid with prompt resolution of symptoms and signs, but one patient had recurrent episodes of myositis, leading to the prescription of azathioprine. The clinical and radiological constellation of findings allowing a definitive diagnosis of the nonspecific orbital inflammatory syndrome in most cases is discussed.

The nonspecific orbital inflammatory syndromes are a heterogenous group of conditions and the CT scan is a valuable tool in differentiating these conditions. Most cases of idiopathic orbital myositis require corticosteroids, but therapeutic alternatives to corticosteroids in refractory diseases are warranted.