Most migraine patients know their symptoms like they know their reflection in the mirror. But many of these symptoms—disturbances in vision and language, for example—can also be indicators of stroke.
Although the absolute risk is small, recent studies show that people who suffer from migraine with aura have double, or even triple, the risk of stroke compared with people who don’t get migraines at all. The exact connection between the two diseases is still unclear, but there are things you can do to lower your risk.
José Biller, MD, FACP, FAAN, FAHA, professor and chair of the department of neurology at the Stritch School of Medicine at Loyola University Chicago, has been a practicing neurologist for more than 30 years with subspecialty expertise in stroke and headache medicine. He recently sat down with Head Wise to discuss the migraine-stroke connection.
Head Wise (HW): How can people learn to recognize a stroke?
Dr. Biller: The symptoms of stroke depend on the area of the brain that is affected. The most common manifestations are characterized by the sudden onset of a focal neurological deficit. That can be visual loss in one or both eyes, or in half of the visual field; speech or language impairment; weakness or paralysis in one part of the body—that can be in the face, the arm or the leg; numbness or tingling in one part of the body; unexplained headaches; unexplained dizziness or vertigo; or a combination of these symptoms.
HW: Recent research has solidified the connection between migraine and stroke. So how are the two diseases related?
Dr. Biller: First of all, true migraine-induced stroke, or migrainous infarction, is very rare. Migraine is associated with a low absolute risk of stroke or mini-stroke, also known as transient ischemic attacks. The risk of stroke, though, is largely associated to the subtype of migraines with aura and most commonly occurs in women under the age of 45. That is magnified by other associated risks, particularly the consumption of tobacco and the use of oral contraceptives. The incidence of migrainous infarction varies if you have associated risk factors or not.
HW: What makes people who have migraine with aura more susceptible?
Dr. Biller: One possibility is that during migraine, there is a component that is known as “spreading depression” that may cause changes in [blood] flow. There is an inflammatory component associated with that as well as a vasodilatation that can lead to reduced, or slowed, flow in the arteries. Combined with the possibility of other risk factors—particularly dehydration, vasospasm, increased viscosity (or stickiness of the blood), clustering or the adhesion of blood elements like platelets—this may cause a coagulation within the blood vessel that can impair delivery of nutrients and subsequently cause a stroke.
HW: How can someone with a lifelong history of head pain learn to recognize the distinct symptoms of stroke?
Dr. Biller: As recommended by the International Headache Society, migrainous infarction has a strict definition. Number one, that one or more aura symptoms— the symptoms that antedate the headache phase—last more than an hour and are associated with a neuroimaging study confirming the presence of an ischemic stroke. In somebody who has a history of migraine with aura, the attack will be typical of previous attacks, except for the longer duration of the neurological deficit. And finally—and this is very important to highlight—that other causes of stroke have been ruled out. So in essence, we are talking about a diagnosis of exclusion.
HW: What should migraineurs do if they start noticing stroke symptoms?
Dr. Biller: Stroke is a very serious disease that is highly treatable, and the treatment should be done immediately. Therefore, my advice would be for the patient to call 911, and hopefully be transported to the nearest emergency room where he or she can be evaluated by an individual with expertise in the diagnosis and management of stroke.
HW: What are some of the other risk factors for stroke?
Dr. Biller: The modifiable risk factors include mainly high blood pressure or arterial hypertension, high cholesterol, diabetes and heart disease (particularly atrial fibrillation, carotid artery disease or carotid stenosis). Prior stroke will increase your risk of having another stroke. And certainly some lifestyle behaviors increase risk—particularly the consumption of cigarettes, excessive consumption of alcohol, obesity, sleep apnea and a sedentary lifestyle.
HW: What can migraineurs do to reduce the risk of stroke?
Dr. Biller: First, they should be properly diagnosed to determine whether they have migraine with or without aura. Many patients with migraine have co-morbidities that need to be taken into consideration, and these co-morbidities dictate the best treatment approach, particularly when we are addressing preventive strategies. We want to know whether the migraineur has high blood pressure, diabetes, high cholesterol or heart disease. The patient should be encouraged to maintain adequate lifestyle, particularly as far as the consumption of tobacco products. They should maintain good sleep habits and good nutrition, and recognize their triggering factors. And obviously patients who have risk factors, for, let’s say, coronary artery disease, should have a proper cardiovascular evaluation before receiving medications, such as triptans, commonly used for migraines.