Acute transient large-angle exotropia caused by traumatic orbital contusion

Abstract

We report an unusual case of acute large-angle left exotropia associated with blunt orbital trauma in a healthy 8-year-old boy. Examination revealed a large-angle left exotropia with limitation in adduction of the left eye. Microhyphema and commotio retinae of the left eye were also present. High-resolution orbital magnetic resonance imaging (MRI) demonstrated perimuscular and intramuscular edema mostly involving the left medial rectus muscle but also involving the left lateral rectus muscle. The extraocular muscle insertions were intact. Complete resolution of the strabismus and adduction limitation occurred within 24 hours of starting systemic steroid therapy. This case highlights the utility of high-resolution imaging to assess for injury to the extraocular muscles. If disinsertion, transection, or rupture of the muscle is not present on imaging, resolution may occur with systemic steroid therapy and surgical intervention is not needed.

Keywords: Contusion; exotropia; trauma.