There is considerable interest in the relationship between a migraine and a stroke. It is very important that you have your migraines diagnosed by a qualified medical practitioner to rule out any other medical conditions.
What is a Stroke?
A stroke is a brain attack that can happen at any time to anyone. A stroke occurs when the blood supply to the brain is cut off. The brain cells are deprived of oxygen, and without oxygen, the cells start to die. The brain cells that die during the stroke can no longer be controlled by you. You lose your ability to control that part of your brain.
Moreover, how the stroke affects a person depends on the area the stroke occurred. Along with this, it depends on how much damage is done. There are two kinds of strokes, among them, one is related to a migraine.
Migraine or Bad Headache?
A migraine is a severe and painful headache that can be accompanied by sensory warning signs. These signs include:
- Flashes of light
- Tingling in the legs and arms
- Blind spots
- Raised sensitivity to sound and light.
A migraine attack can last for hours and even days. It is a common condition that can occur anytime. Worldwide, an estimated 1 billion people suffer from migraines.  The causes of a migraine are still unknown. It is believed that a migraine occurs because of abnormal brain activity. This action causes a temporary alteration in the nerve signals, blood flow and chemicals in the brain.
The factors that trigger a migraine attack in people are different. Some of them are:
- Allergies and allergic reactions
- Perfumes or distinct odors
- Smoking or exposure to smoke
- Anxiety and depression
- Sleeping tablets or contraceptive pills
- Skipping meals
- Foods that contain tyramine.
What is Migraine with Aura?
Migraines are composed of four phases. Aura normally occurs in the second phase before the pain phase. Aura is perceptual disturbances like:
- Pins and needles in the legs and arms
- Stiffness in the shoulders or neck
- Confusing thoughts
- Zigzag lines in the visual field
- Having trouble speaking
- Blank patches in the vision
- Blind spots
- Unpleasant smells
Women are three times more affected by a migraine than men, whereas men are more prone to have a stroke. According to a report, the chance of ischemic stroke is higher in women from age 35 to 45. These women experienced migraines both with and without aura. The risk of stroke is increased by the use of oral contraceptives, smoking, and high blood pressure.
In the Ischemic stroke, less blood and oxygen is supplied to the brain and can be the result of a clot. Another type of stroke is a hemorrhagic stroke. In this attack, a weak or damaged artery bleeds into tissue. The connection of a hemorrhagic stroke to a migraine is small.
There have been some reports which have shown a higher risk of stroke in young women with a migraine.
Can a Stroke Happen During a Migraine Attack?
It is easy for some people to confuse their migraine symptoms with a stroke, while other people are worried, they are at greater risk of getting a stroke during a migraine attack. It has been difficult for medical science to link this 'casual relationship' of a migraine and stroke together.
A migraine and stroke can occur in some people at the same time. The stroke that occurs during the migraine attack is called Migrainous Infarction. In this condition, the symptoms of aura are persistent and can be visible in an MRI brain scan. The report shows that a stroke like this is separate from the migraine attack. It is possible that a person might be having a stroke and mistake it for a migraine attack. The migraine aura can copy transient ischemic attacks. To complicate matters, a headache during a stroke, maybe similar to a migraine.
Relationship Between a Migraine and a Stroke
A migraine is considered as an independent cause of ischemic stroke. Supporting evidence came from a review in 2009, that consisted of twenty-five different studies and the results were:
It was shown in a review of nine studies that the relative risk of ischemic stroke in with any form of a migraine was 1.73.
The participants with an aura migraine showed higher risk of stroke. On the other hand, the risk for those without a migraine was insignificant.
The below-mentioned group had more chances of an ischemic stroke:
- Women with a migraine
- Smokers who had a migraine with aura
- Participants with a migraine less than 45 years of age
- Women who had a migraine with aura and were using an oral contraceptive.
Furthermore, the relationship between a migraine and hemorrhagic stroke was more clearly established in another review, which included eight studies that found the risk of hemorrhagic stroke in participants with a migraine was 1.48.
In 1997, a review was published after analysing some studies in terms of 100,000 women per year. The result showed that in women under the age of 35:
- NO migraines and NO oral contraceptive pill = 1.3 per 100,000 women every year has a risk of stroke.
- YES Migraine without aura and NO oral contraceptive pill = 4 per 100,000 women every year were at a risk of stroke.
- YES Migraine with Aura and NO pill = 8 per 100,000 women every year were at a risk of stroke.
- NO Migraine and YES pill = 5 per 100,000 women every year were at a risk of stroke.
- YES Migraine without Aura and YES oral contraceptive pill = 14 per 100,000 women every year at risk of a stroke.
- YES Migraine with Aura and YES oral contraceptive pill = 28 per 100,000 women each year are at a risk of stroke.
Other studies revealed that 8 per 100,000 women might die in a road accident every year and 167 per 100,000 women per year may die from a cigarette smoking related condition.
In 2004, a study in America was conducted known as Women’s Health Study. It observed 39,754 health women professionals over a period of nine years. During this course, it was discovered that there were 309 ischemic stroke cases of the total participants. Both the women with migraine aura and without migraine aura were included. Though the relative risk seemed high, the real risk is smaller.
Moreover, this study confirmed what prior studies suggested about the connection between the migraine aura and stroke. The study proved that the risk of migraine aura with stroke was higher in the younger women. It also contained women who had other medical conditions that increased the risk of stroke, for example, blood clotting and heart diseases. These conditions symptoms were similar to the aura symptoms.
Are young women with aura migraines more at risk?
The cause of the increased risk of ischemic stroke in younger women who have a migraine is unknown. This is not because of conventional risk factors like:
- High blood pressure
- Raised cholesterol levels
Recent studies reported that the aura is linked with the adverse cardiovascular risk profile and prothrombotic factors. More research is being conducted in this area. The aim is to better understand the relationship between a migraine with aura and stroke.
Furthermore, the implications of the stroke risk in women with a migraine with aura are relatively clear. While it is considered a 'low absolute risk,' it is increased by cigarette smoking. It is therefore highly recommended not to smoke.
The best practice according to the Faculty of Family Planning is to avoid the use of contraceptive pills by women who have a migraine with aura which is supported by the World Health Organization as well. The risk of stroke due to a migraine without aura is lower than other risk factors such as smoking.
In practice, the risk of stroke is very low when using oral contraceptives in young women. There is no systematic opposition, but it is advised not to smoke. As with any medication, it is important that women who suffer migraines and are taking oral contraceptives, do not stop taking the pill suddenly, but discuss their situation with their doctor.
Being at 'risk' does not mean dying of a stroke, 25% of the people recover from the stroke while 50% might have a disability.
Migraine and Older People
After the age of 50, migraine is not considered as a risk factor for a stroke. The reason is that the primary causes for ischemic stroke are:
- High blood pressure
- Old age
- Increased blood cholesterol levels.
As people age, these factors combine with each other, so the risk of stroke from a migraine is insignificant.
Therefore, migraine with aura is a risk factor for stroke in younger women. The reason is that it affects young women before the more significant age-related factors apply, over time, migraine frequency tends to reduce.
 WHO, Atlas of headache disorders and resources in the world, 2011