Prolonged Benign Episodic Unilateral Mydriasis in Hemiplegic Migraine

Clinical Correspondence Section Editors: Robert Avery, DO Karl C. Golnik, MD Caroline Froment, MD, PhD An-Guor Wang, MD Prolonged Benign Episodic Unilateral Mydriasis in Hemiplegic Migraine Stephen J. X. Murphy, MRCPI, MRCPUK, PhD, Irene Francis, MRCPUK, BSc, Vivek Nadarajan, BSc (Hons), MBBS, FRCPUK B enign Episodic Unilateral Mydriasis (BEUM) represents a rare migraine aura variant that has not previously been reported in association with hemiplegic migraine. A 52-year-old man with a history of hemiplegic migraine presented to the stroke service as a candidate for thrombolysis. In addition to left-sided hemiparesis and headache, he had notable anisocoria (Fig. 1). The left pupil was dilated, had no direct or consensual light response and did not react to accommodation. Visual acuity for near and far objects was normal as were ocular movements. The hemiplegic migraines had started at the age of 20, varying in frequency from 3 to 10 episodes per year. They could affect either side of his body. He had been reviewed by a Neurologist and trialed on a number of prophylactic migraine treatments that were ineffective and stopped 2 years before presentation. Collateral from the patient’s partner established that the episodes were always accompanied by mydriasis, ipsilateral to the side of the weakness. He had no other medical history and was not taking any medications. He had a family history of epilepsy with his brother and son affected, but had never had a seizure himself. The hemiparesis and headache resolved within an hour, whereas the mydriasis lasted for 24 hours. Neuroimaging with MRI Brain and CT angiography found no evidence of stroke or aneurysm. BEUM is a rare migraine aura variant that can be associated with blurred vision, orbital pain, or photosensitivity. Although its exact pathophysiology is unknown, it is believed to relate to parasympathetic exhaustion or sympathetic hyper-reactivity (1). The episodes may occur during a migraine or independent of a headache (2). In acute cases, it may be mistaken for an ipsilateral oculomotor palsy or a contralateral Horner’s syndrome. It typically affects young females and lasts less than 3 hours although cases have been reported lasting up to a week (3). Department of Neurology (SJXM, IF) and Stroke Service (SJXM, IF, VN), University College London Hospitals NHS Foundation Trust, National Hospital for Neurology and Neurosurgery, London, United Kingdom; Department of Neurology (SJXM), Chelsea and Westminster NHS Foundation Trust, London, United Kingdom. Department of Geriatric Medicine (VN), Royal Free Hospital, London, United Kingdom. The authors report no conflicts of interest. Address correspondence to Stephen J. X. Murphy Department of Neurology, Chelsea and Westminster Hospital, London, United Kingdom; E-mail: [e-mail] e140 FIG. 1. The left pupil is dilated with no direct or consensual response to light and does not react to accommodation consistent with BEUM. This case is unusual in that it occurred in a man, was associated with hemiplegic migraine (including previous episodes), and was longer than typical attacks. Although the patient declined genetic testing, his family history of epilepsy and hemiplegic migraine is suggestive of a channelopathy such as CACNA1A (4). This case demonstrates that BEUM may occur as part of hemiplegic migraine and should be added to the list of clinical features of this condition (5). STATEMENT OF AUTHORSHIP Conception and design: S. J. X. Murphy; Acquisition of data: S. J. X. Murphy, I. Francis, V. Nadarajan; Analysis and interpretation of data: S. J. X. Murphy, I. Francis, V. Nadarajan; Drafting the manuscript: S. J. X. Murphy, I. Francis; Revising the manuscript for intellectual content: V. Nadarajan; Final approval of the completed manuscript: S. J. X. Murphy, I. Francis, V. Nadarajan. REFERENCES 1. Maggioni F, Mainardi F, Malvindi ML, Zanchin G. The borderland of migraine with aura: episodic unilateral mydriasis. J Headache Pain. 2011;12:105–107. 2. Jacobson DM. Benign episodic unilateral mydriasis. Clinical characteristics. Ophthalmology. 1995;102:1623–1627. 3. Woods D, O’Connor PS, Fleming R. Episodic unilateral mydriasis and migraine. Am J Ophthalmol. 1984;98:229–234. 4. Huang Y, Xiao H, Qin X, Yuan N, Zou D, Wu Y. The genetic relationship between epilepsy and hemiplegic migraine. Neuropsychiatr Dis Treat. 2017;13:1175–1179. 5. Jen JC. Familial Hemiplegic Migraine [Internet]. Seattle (WA): University of Washington, Seattle; In: Adam MP, Ardinger HH, Pagon RA, et al., editors. GeneReviewsÒ. 1993–2022. 2001 Updated 2021 Apr 29. Murphy et al: J Neuro-Ophthalmol 2024; 44: e140 Copyright © North American Neuro-Ophthalmology Society. Unauthorized reproduction of this article is prohibited.