Accidental Unilateral Mydriasis from Hyoscine Patch in a Care Provider

The hyoscine patch is effective and is frequently used in motion sickness treatment. Not uncommonly, it is used to control excessive respiratory secretions in palliative patients. Patients, healthcare workers, and caregivers who administer these may experience a benign, although worrying, mydriasis should they inadvertently rub their eye after handling the patch. A 46-year-old staff nurse working in a stroke ward presented with sudden-onset unilateral enlarged pupil. To rule out any intracranial pathology, the stroke team requested an urgent head computed tomography (CT) scan, which showed no abnormality. Upon ophthalmology review, nonreactive dilated left pupil was noted. Examination was otherwise unremarkable with no focal neurology findings. Following further history, she recalled applying a hyoscine patch to a patient in the morning. Two days later, her left pupil returned to normal size. This unique presentation of pharmacological mydriasis reinforces the importance of a detailed targeted history to avoid unnecessary investigations and anxiety, as well as the importance of informing patients, healthcare workers, and caregivers of this peculiar side-effect.