Strokes can be tricky: They tend to come without warning and don’t announce themselves like other types of illnesses.
“Humans’ usual way of sensing danger is pain, and unfortunately most strokes don’t come with pain,” says David Y. Huang, MD, PhD, neurologist and director of UNC Hospitals Comprehensive Stroke Center.
So how do you know when to head to the emergency department?
The acronym BE FAST—loss of Balance, Eyes (loss of vision or double vision), Facial drooping, Arm weakness, Speech difficulties and Time to call emergency services—is used as a benchmark for when to get help. That is, if someone is experiencing any of those symptoms, you should call 911 immediately. (Calling 911 is preferred to driving to the emergency department, as stroke care can begin in the ambulance.)
But it’s important to know that strokes manifest in myriad ways, and BE FAST doesn’t cover every warning sign. Here, Dr. Huang explains what happens to the body during a stroke and what it means for those who might experience it.
What Happens During a Stroke
“What generally all strokes have in common is that brain cells die,” Dr. Huang says. There are different types of brain cells, but the most critical ones are the neurons, which act like wires that transmit signals from cell to cell. There are other cells in the brain that can be affected, such as the cells that insulate neurons, like plastic coating around a wire.
Because each part of the brain controls certain functions, the results of a stroke will differ depending on which part of the brain is damaged. “When the average person experiences a stroke, they will develop some sort of weakness or a deficit,” Dr. Huang says. That deficit could be:
- Speech problems (slurred speech, inability to understand or produce language)
- Weakness or numbness on one side of the body
- Vision issues (double vision, inability to see or process what you’re seeing)
- Impairment of a motor activity
“Depending on the cell that dies and in what part of the brain damage occurs, you get certain degrees of damage. If you kill neurons, the damage is pretty much as permanent as it gets,” Dr. Huang says. “You might have other neurons that can recover some function, but it’s not going to be great function. But if you injure the insulating cells, there is some level of recovery with that.”
This is one of the biggest differences between strokes and heart attacks. “Unlike heart attacks, where you damage heart tissue but your heart hopefully keeps pumping, in the brain, stroke can present in varying different ways: Your left side might be weak, your right side might be weak, you might not be able to speak or you could have blurry vision, and that function might not be recovered,” Dr. Huang says. “It’s more complex, which can make it hard to diagnose a stroke.”
To make matters more complicated, most brain cells don’t have nerves, which means they can’t sense pain. “When you have a stroke, more often than not, you’re not going to feel pain,” Dr. Huang says. “So again, unlike heart attack, where you might have pain that signals people to go to the emergency room, with a stroke, you probably won’t feel anything. That’s why some people tend to go, ‘Hmm, I guess I’ll just sleep this off’— because there’s not this huge warning sign that something really bad is happening.”
Different Types of Strokes
There are two main types of strokes: ischemic and hemorrhagic. Most strokes are ischemic, caused by a blockage of a blood vessel. In this case, the blockage doesn’t allow nutrients such as oxygen and glucose to get to the brain, which causes brain cells to die.
Hemorrhagic strokes are caused by a rupture of a blood vessel. The rupture can be very small within the brain tissue, which forces blood into the tissue, or an aneurysm, a weakened area in an artery, can rupture and pool blood into the space outside of the brain. Unlike with ischemic strokes, people who have hemorrhagic strokes may experience a headache.
“Unlike brain cells, the outside lining of the brain does have the ability to sense pain,” Dr. Huang says. Because hemorrhagic strokes put pressure on the brain, it’s possible for the lining of the brain to perceive that pressure, resulting in a person getting a severe headache as a symptom of the stroke.
“But it’s not a hard-and-fast rule,” he says. “Long story short: You can never tell, and you should seek help immediately.”
What About “Ministrokes”?
The term “ministroke” is commonly used to describe a stroke with mild symptoms, but Dr. Huang says that belittles the seriousness of stroke.
“A ministroke is a really bad term, and we as neurologists are trying to eradicate it and get doctors to understand that there really is no such thing as a ministroke,” Dr. Huang says.
Instead, Dr. Huang breaks down “ministroke” into two categories: transient ischemic attacks (TIAs) or strokes with mild symptoms (mild stroke).
With a TIA, people will experience stroke symptoms, but those deficits will resolve and people will return to normal within 24 hours. Doctors will start people on a preventive track to reduce the risk of a future stroke, though no rehabilitation is needed. A preventive track consists of medications (and sometimes surgical procedures) to reduce the chance of future strokes as well as modifying stroke risk factors, such as controlling blood pressure, high cholesterol and diabetes. If appropriate, smoking cessation counseling is provided.
Conversely, after a mild stroke, a person will experience a deficit, though it might not manifest as significant damage. “This means they might have a bit of slurred speech or their coordination is a little clumsy and so on, and though they might seem OK, they are not back to 100 percent,” Dr. Huang says. People who experience a mild stroke will probably need some form of therapy—physical, occupational or speech therapy—to make a full recovery.
The tricky part is that mild strokes are commonly misdiagnosed as TIAs, and a deficit left untreated can cause additional problems or disability. For example, imagine that a patient has had a mild stroke and, because it was not debilitating, he or she is sent home from the hospital without therapy.
“But if they’re having trouble swallowing and no one picks that up, the next thing you know they could start choking on their food,” Dr. Huang says. “Oftentimes they need therapy, but no one has identified that they need it, so they go on with their lives and don’t optimize their recovery.”
It’s important to note that in both TIAs and mild strokes, a person may first exhibit severe stroke symptoms. Because stroke severity is classified by long-term damage rather than initial symptoms, the difference between a more serious stroke event and a TIA is that with a TIA, you will suddenly get better. For a mild stroke, if it’s treated appropriately, you can regain most function.
Either way, doctors can only differentiate between a TIA, a mild stroke or a more significant stroke through a physical exam and testing.
“We never know which way it’s going to go: You can have a severe stroke that gets better or a mild stroke that gets worse,” Dr. Huang says. “The reason why it’s important for people to come quickly after experiencing symptoms is that doctors have a big toolkit that we can use to not just treat strokes but actually prevent them while they’re happening. The sooner the patient gets to the hospital, the more chances we have to be able to treat them.”
If you or someone near you is experiencing stroke symptoms, call 911 immediately. For long-term care, find a neurologist near you.