# Benign Episodic Unilateral Mydriasis in a 52-Year-Old Female

## TL;DR

A 52-year-old woman with migraines experienced rare, harmless episodes of one-sided pupil dilation that mimicked more serious conditions.

## Contribution

This case report highlights the diagnostic challenges of benign episodic unilateral mydriasis in the context of migraines.

## Key findings

- The patient had recurrent left-sided mydriasis with ipsilateral headaches.
- BEUM was considered after ruling out more serious neurological or ophthalmological conditions.
- The case emphasizes the importance of recognizing BEUM as part of a migraine process.

## Abstract

Benign episodic unilateral mydriasis (BEUM) is a very rare, under-recognized condition characterized by transient, self-limited episodes of unilateral pupil dilation. It may frequently be part of a migraine process and may present as a diagnostic challenge due to its potential to mimic more serious neurological or ophthalmological conditions. In this case report, we describe the case of a 52-year-old female with a medical history significant for hypertension, anxiety, prior right retinal detachment, and longstanding migraines, who presented with a new onset of recurrent, episodic left-sided mydriasis accompanied by ipsilateral headaches. This paper will outline the findings, medical thought processes, and different diagnoses considered when the patient was assessed in the emergency department and during her hospital stay.