Addressing Migraine That Mimics Stroke

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Differentiating migraine with aura from stroke has several challenges, although there are some early features that help direct the diagnosis.
Differentiating migraine with aura from stroke has several challenges, although there are some early features that help direct the diagnosis.

Migraine with aura (MA) is one of the 3 most common conditions (along with seizures and psychiatric/conversion disorders) that mimic stroke, often leading to inappropriate and unnecessary thrombolytic treatment.1,2

A 2018 review by Terrin et al2 reported that 1% of emergency stroke unit evaluations are performed on patients who actually have MA, largely as a result of increased efforts in recent years to reduce door to needle times for intravenous tissue plasminogen activator (IV-tPA) for stroke treatment.

Among patients likely to receive IV-tPA for stroke-mimicking symptoms, the prevalence of MA is quite high, resulting in an estimated 18% of patients receiving improper treatment.2

Overall, according to Peter McAllister, MD, Chief Medical Officer of the New England Institute for Clinical Research in Stamford, Connecticut, “about 7% of IV-tPA is administered for nonstroke events, and migraine makes up about 18% of that.”

Differentiating Signs of MA From Stroke

Differentiating MA from stroke has several challenges, although there are some early features that help direct the diagnosis. “Stroke is sudden, while migraine develops over many minutes to hours,” Dr McAllister told Neurology Advisor. At his institution, they see approximately 1200 people with MA and 300 people with stroke per year. “Migraine stroke symptoms are positive (shimmering, moving sparkles in your visual field), whereas stroke symptoms are negative (a fixed black field cut of vision). Numbness in migraine often moves (up the leg to arm to face over 20-30 minutes), and in stroke, it does not,” he said.

“Stroke usually does not present with headache, and when it does it is not a prominent feature,” Dr McAllister further explained, “whereas in migraine it is, and it is associated with features such as light and sound sensitivity and nausea. The exception to this is an intracranial bleed from an aneurysm rupture — here the headache is catastrophic and immediately at maximal intensity, where migraine gets more severe over time.” 

The most important clues to separating the conditions come from taking a complete patient and family history of migraine. Stroke-like symptoms presenting for the first time require rapid stroke evaluation, preferably in the emergency department or stroke unit. In patients with a history of MA, the approach to ruling out stroke may be different, Dr McAllister pointed out. “The stereotype of stroke is that it is often a 1-time event, whereas stroke-like migraines recur,” he said. “The first one may prompt a workup, while subsequent ones do not.” Stroke evaluation in these cases includes neuroimaging using noncontrast computed tomography in the emergency department. Additional functional magnetic resonance imaging studies and single-photon emission computed tomography imaging may help confirm stroke vs mimic, although they are considered too slow for initial stroke evaluation.1 Dr McAllister added that “diffusion weighted image magnetic resonance imaging can show an acute ischemic infarct but is often not readily available in the emergency department setting, particularly during the short time window for consideration of IV-tPA administration.”

Demographic statistics may also be of value in separating stroke from mimicking migraine. “All things being equal, a 24-year-old female is much more likely to have a migraine, and a 65-year-old male who has diabetes and is a smoker is much more likely to have stroke,” he noted.

Possible Mechanisms of Overlapping Presentations

There are multiple theories about the confluence of symptoms between MA and acute ischemic stroke.3 A common concept is that cortical spreading depression believed to cause vasodilation of the blood vessels in MA may instead produce vasoconstriction — or stroke. “Migraine with aura is a stroke risk factor, but the magnitude of the risk is rather small,” Dr McAllister said.

At the same time, migraine and stroke share several common comorbidities, and some conditions are also known to produce manifestations of both migraine-like headache and cerebrovascular disease. “Migraine is a paroxysmal brain disorder, so subtle stroke-like symptoms like visual obscurations, word-finding problems, and tingling are not uncommon and represent a brain cell energy uncoupling rather than a vascular phenomenon. The rare condition hemiplegic migraine looks much more like a true stroke,” Dr McAllister observed, “which is due to known gene mutations.”4

Considering Risks

The time constraints for effective stroke treatment often necessitate making decisions before confirming the diagnosis, and the consensus is to initiate IV-tPA in cases of doubt. According to a 2018 commentary by Purdy and Diener,5 “Despite the absence of strong supporting data, thrombolysis in migraine with aura seems to be a procedure with an extremely low risk for adverse events such as major bleeding,” and they therefore advocate proceeding with treatment. Dr McAllister agrees. “Adverse events are very low, so it's worth administering IV-tPA even if you're not 100% sure,” he said.

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References 

  1. Ridolfi M, Granato A, Polverino P, et al. Migrainous aura as stroke-mimic: the role of perfusion-computed tomography. Clin Neurol Neurosurg. 2018;166:131-135.
  2. Terrin A, Toldo G, Ermani M, Mainardi F, Maggioni F. When migraine mimics stroke: a systematic review [published online January 1, 2018]. Cephalalgia. doi: 10.1177/0333102418767999
  3. Lee MJ, Lee C, Chung CS. The migraine-stroke connection. J Stroke. 2016;18:146-156.
  4. Malik R, Freilinger T, Winsvold BS, et al. Shared genetic basis for migraine and ischemic stroke: a genome-wide analysis of common variants. Neurology. 2015;84:2132-2145.
  5. Purdy RA, Diener HC. Migraine mimicking stroke: What to do? [published online January 1, 2018]. Cephalalgia. doi:10.1177/0333102418768087
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