A 17-year-old girl with 12-year history of systemic lupus erythematosus (SLE) was presented with one month history of diplopia and headache. She had experienced acute cerebral infarction due to multiple cerebral arterial stenosis one year before, and fully recovered except right-side central facial nerve palsy. When she visited pediatric emergency room, ophthalmologic examination showed ophthalmoplegia of the left eye ball; limitation of medial gaze, supra-adduction and infra-adduction. Neurologic examination didn't show any newly developed neurologic defect. There was no newly developed intra-cranial lesion on the brain MRI. But, the brain MRI revealed irregularly enhanced thickened left medial rectus muscle, and that was compatible with orbital myositis. There was no definite evidence of infection or other autoimmune disease. Her condition responded to high dose intravenous methylprednisone therapy (1 g/day for 3 days) and continued oral prednisolone.

Keywords: Orbital myositis, Ophthalmoplegia, Systemic lupus erythematosus, Diplopia