Anisocoria secondary to inadvertent contact with scopolamine patch

A unilaterally fixed mydriasis, also known as a ‘blown pupil,’ is considered an ominous sign concerning for intracranial pathology. Causes of anisocoria can range from benign to immediately life-threatening. When a patient presents with anisocoria, the concern for a fatal diagnosis leads the clinician to obtain numerous tests, many of which may be unnecessary. The authors present a case of a healthy woman in her 30s who presented with an acute unilateral mydriasis likely secondary to inadvertent contact with a scopolamine patch. On examination, she had no other neurological deficits. Further investigation did not reveal any abnormality. In the event of a patient with an isolated mydriasis in an otherwise healthy and conversant patient with no other neurological deficits, it is essential to rule out other causes before pursuing aggressive and unnecessary testing and treatment.