Teaching NeuroImages: Painful diplopia and Crohn disease: Think about orbital myositis.

A 34-year-old man with Crohn disease (CD) treated with infliximab was seen for a 2-month history of painful binocular horizontal diplopia. Pain initially appeared in the right eye, then switched to the left eye 1 month later. Neuro-ophthalmologic testing revealed a painful limitation of the left eye during adduction and periorbital edema. Thyroid tests were normal. Orbital MRI showed features of orbital myositis (figure).