[Clinical and neuroradiological studies on orbital myositis and Tolosa-Hunt syndrome].

Tolosa-Hunt syndrome and orbital myositis have common features such as ocular pain, ophthalmoplegia and exophthalmos. Both syndromes are thought to be caused by a granulomatous inflammation involving the cavernous sinus area in the former and the orbital cavity in the latter. The question whether these two conditions represent different presentations of a single disease, or they belong to different entities has not been settled. To address this question, we reviewed our cases having clinical diagnosis of either Tolosa-Hunt syndrome or orbital myositis. Six cases were diagnosed as Tolosa-Hunt syndrome, and 7 orbital myositis. In the thin-slice enlarged orbital CT, hypertrophic and high-density changes of at least one of the extraocular muscles were found in all cases with orbital myositis, but in none of the patients with Tolosa-Hunt syndrome. The age of onset was younger and the duration of the disease before admission was shorter in Tolosa-Hunt syndrome. They responded to steroid therapy better than those with orbital myositis. These findings lead us to conclude that Tolosa-Hunt syndrome and orbital myositis belong to different syndromes, although clinical manifestations have many similarities. Then we studied the relationship between the hypertrophic change of the extraocular muscle and the direction of the oculomotor restriction. For this purpose four additional cases with dysthyroid ophthalmopathy were also studied. We found that the presence of hypertrophic change was frequently associated with the restriction of ocular movement to the direction not only of the hypertrophic muscle but also of the opposite muscle.(ABSTRACT TRUNCATED AT 250 WORDS)