Aaruran Nadarajasundaram
Introduction
Migraines are a common presentation to the emergency department. They are noted to be the most common primary headache disorder and ranked the 2nd most disabling disease globally by the Global Burden of Disease study 2016 (1). Data from the National Health Service (NHS) in the United Kingdom further support this, with admission rates for headaches having risen by 14% over a 5-year period in 2018/19 (2).
More importantly, migraine with auras manifesting as visual disturbance symptoms is the commonest subtype, occurring in 98% of all such cases (3). This poses a significant challenge for doctors due to the various etiologies at play; in particular ophthalmologists who are increasingly being referred headache presentations rule out potential sinister ophthalmic causes (4).
The Challenges
Ophthalmologists are increasingly encountering patients in emergency departments presenting with migraines accompanied by visual auras. These visual disturbances, including scintillating scotomas and transient visual field defects, often mimic serious ocular conditions including retinal artery occlusion and amaurosis fugax.
Differentiating between benign migraine-induced visual symptoms and severe pathologies is crucial to avoid misdiagnosis and ensure timely and appropriate care. The transient nature of visual auras, typically if evolving over several minutes and lasting less than an hour, contrasts with the abrupt onset often associated with ischemic events, providing a key diagnostic distinction (5).
Comprehensive patient history and clinical examination remain crucial, while advanced imaging, such as MRI, is sometimes required to rule out other etiologies. As the prevalence of such presentations increases, ophthalmologists must maintain a high level of diagnostic vigilance and collaborate effectively with neurologists and other specialties to enhance patient outcomes.
Retinal Artery Occlusion
Retinal artery occlusion (RAO) is a sudden blockage of blood flow to the retina, typically causing painless, severe vision loss in one eye. It presents as an ophthalmic emergency, often described as the ocular equivalent of a cerebral stroke. The hallmark symptom is abrupt, unilateral vision loss, which can be complete or partial depending on whether the central retinal artery or a branch is affected (6).
Differentiating RAO from migraine with visual aura can be challenging, as both conditions can cause sudden visual disturbances. However, migraine aura typically presents with bilateral, transient visual phenomena like scintillating scotomas or fortification spectra, lasting 5-60 minutes, whereas RAO causes persistent, unilateral vision loss (7). Whilst this is the usual case, a challenge arises when a patient is not able to confirm if the visual symptoms are unilateral or bilateral due to various factors such as anxiety and stress during the episode. As a result, examination plays a vital role. Fundoscopic examination in RAO
reveals characteristic findings such as retinal pallor and cherry-red spot at the fovea, which are absent in migraine aura. The key to accurate diagnosis lies in careful history-taking, thorough ophthalmologic examination, and appropriate neuroimaging when necessary.
Amaurosis fugax
Amaurosis fugax is a temporary, painless loss of vision in one eye, typically lasting seconds to minutes. It often presents as a sudden “curtain” or “shade” descending over the visual field, although patients may also experience monocular blindness, dimming, fogging, or blurring (8). Unlike migraine with visual aura, which affects both eyes and often includes positive phenomena like flashing lights or zigzag patterns, amaurosis fugax is usually monocular and characterized by negative symptoms.
The key diagnostic challenge lies in distinguishing amaurosis fugax from migraine with visual aura, as both can cause transient visual impairment. However, amaurosis fugax is more commonly associated with vascular risk factors and requires urgent evaluation to rule out serious underlying causes such as carotid artery disease or embolic events (9). This is achieved through CT, MRI or vascular US investigations to look for any underlying vascular pathology to explain the symptoms. Therefore, given its potential to indicate more severe conditions, amaurosis fugax warrants immediate medical attention, unlike typical migraine auras.
In the emergency department
The points above highlight the importance of the need for close integration of expertise between ophthalmology and other specialties such as emergency medicine and neurology, to ensure timely and accurate diagnosis. Emergency medicine doctors, upon initial assessments, would often be able to safely determine whether the patient’s symptoms are consistent with a typical migraine aura or whether further investigation is warranted and refer appropriately.
At the same time, this also stresses the importance for ophthalmologists to be aware of common headache disorders and their potential association with ophthalmic disease to provide appropriate advice, safely and appropriately discharge or refer patients to a more appropriate team (10).
Conclusion
Migraine with aura is a condition commonly encountered in the emergency department, but its ophthalmic and neurological symptoms can overlap with serious and potentially vision threatening conditions. Ophthalmologists being aware of the ways in which these conditions manifest and potentially mimic benign conditions such as migraine is key. Additionally, a multi-disciplinary approach, involving emergency medicine physicians and other specialists such as ophthalmologists and neurologists are essential for accurate diagnosis and management. Such a collaborative approach ensures that patients receive the correct diagnosis, appropriate imaging when necessary, and timely treatment.
References
- Feigin VL, Nichols E, Alam T, et al.: Global, regional, and national burden of neurological disorders, 1990-2016: a systematic analysis for the Global Burden of Disease Study 2016. Lancet Neurol. 2019;18:459-480. 10.1016/S1474-4422(18)30499-X
- NHS England: Improved NHS migraine care to save thousands of hospital stays. (2020). Accessed: December 15, 2024: https://www.england.nhs.uk/2020/01/improved-nhs- migraine-care/2020
- Viana M, Sances G, Linde M, et al.: Clinical features of migraine aura: Results from a prospective diary-aided study. Cephalalgia. 2017;37:979-989. 10.1177/0333102416657147
- Mollan SP, Spitzer D, Nicholl DJ. Raised intracranial pressure in those presenting with headache. BMJ. 2018;363:k3252. 10.1136/bmj.k3252
- Shams PN, Plant GT. Migraine-like visual aura due to focal cerebral lesions: case series and review. Surv Ophthalmol. 2011;56:135-161. 10.1016/j.survophthal.2010.07.005
- Hayreh SS. Acute retinal arterial occlusive disorders. Prog Retin Eye Res. 2011;30(5):359-394
- Al-Moujahed A, et al. Migraine and risk of retinal artery occlusion: A retrospective cohort study. Am J Ophthalmol. 2021;225:108-119
- Hill DL, Daroff RB, Ducros A, et al. Most cases labeled as “retinal migraine” are not migraine. J Neuroophthalmol. 2007;27(1):3-8
- Grosberg BM, Solomon S, Lipton RB. Retinal migraine. Curr Pain Headache Rep. 2005;9(4):268-71
- Mollan SP, Virdee JS, Bilton EJ, Thaller M, Krishan A, Sinclair AJ. Headache for ophthalmologists: current advances in headache understanding and management. Eye (Lond). 2021, 35:1574-1586. 10.1038/s41433-021-01421-4