Acute Optic Neuritis Diagnosed by Bedside Ultrasound in an Emergency Department

Transorbital ultrasound was used to diagnose acute optic neuritis (AON) at bedside in an emergency department (ED).

A 59-year-old female patient presented to an ED after 7 days of progressive unilateral visual loss while she was receiving outpatient treatment for relapsing-remitting multiple sclerosis. Transorbital ultrasound revealed a disparity between the optic nerve sheath diameters of the affected and nonaffected eyes and striking optic nerve edema in the affected eye. These findings led to a diagnosis of AON and early definitive treatment. WHY SHOULD AN EMERGENCY PHYSICIAN BE AWARE OF THIS?: Given an absence of reliable diagnostic criteria for AON, comorbidity with multiple sclerosis, and limitations inherent to magnetic resonance imaging, transorbital sonography may facilitate diagnosis of this condition in emergent presentations.