Q: A lot of people assume that a stroke is related to a heart attack. Can you describe the differences?
They are actually very similar diseases. An ischemic stroke is the exact same disease in the brain as a heart attack is in the heart. A coronary artery block in the heart is the same thing as a blockage of a blood vessel supplying the brain. That's why people are now calling strokes "brain attacks."

Q: Are there specific risk factors for stroke?
People who are older tend to be more likely candidates for stroke, but there are other risk factors that greatly increase your chance of having a stroke. By far the most important one is high blood pressure. Blood pressure medication substantially reduces your stroke risk. The other important risk factors are diabetes (which is very common and tends to effect people when they are older), obesity, and cigarette smoking. In addition to high blood pressure, I'd say that those are the three big risks.

One other important risk factor is heart disease, especially arrhythmias. A lot of times clots form in the heart and float up the circulation. If a clot floats to your pinky, it's no big deal. On the other hand, if it floats to your brain, it's a crisis.

Q: Do strokes ever affect younger individuals?
Younger people can suffer from stroke, but the causes are a little bit different. In young people, one common cause is accidental tearing of an artery-something that we call a dissection-and that's pretty hard to prevent. It tends to be much more of a surprise; it's usually accidental and it's just bad luck.

Q: What are some of the warning signs of stroke?
Heart attacks are very dramatic-you get pain in the chest and it radiates down your left arm and it hurts. And when you're in pain, you know it and you want to do something about it. What's unfortunate about strokes is that they often don't offer us many warning signs when they're happening.

The most important warning signs to recognize are weakness or numbness, loss of feeling on one side of the body, loss of balance, inability to walk, slurred speech, headache, and loss of vision, which might be in one eye or off to one side of your visual field. I think that those are the most important signs of having a stroke.

There's a very dramatic story I was told once about a surgeon. He was at the breakfast table with his wife sitting across from him. Suddenly, she notices that he is pouring his orange juice into his lap. He is sitting there glassy-eyed and she, of course, freaks out. He was having a stroke right there. If he had been alone, he would not have been able to act on it. Fortunately, his wife quickly figured out that he was having a stroke when she noticed that his speech was slurred and that one side of his body wasn't moving.

Q: Why is rapid treatment critical for stroke?
We have very effective treatments for stroke, but they only work within the first few hours. The first three hours are golden treatment hours, after which most of the damage has been done. Perhaps that window will grow as we develop more treatments, but, for now, when a stroke patient comes to the hospital, we treat them with the extreme urgency with which we treat somebody with a gunshot wound to the head.