June 19, 2013
By Harvey B. Simon, M.D.
Harvard Medical School
We've all seen it happen. Two outfielders collide; one is okay, but the other lies stunned on the grass before rising slowly and staggering into the dugout with glazed eyes.
A kid falls from a tree, hitting his head on the grass; he sees stars but insists on climbing back up.
A businessman skids on the ice, ramming his car into a snow bank. The airbag and seatbelt prevent him from striking the windshield, but he doesn't remember a thing about the accident, even after his weekend of grogginess and week of headaches have cleared up.
We've all seen it happen because it's so common. The Centers for Disease Control and Prevention (CDC) reports there are 1.6 to 3.8 million concussions in the United States each year.
Male athletes have long dismissed concussions as simply "getting a ding" or "having your bell rung." But neurologists (doctors who specialize in brain and nervous system disorders) take a different view. They say that a concussion can be a warning bell for much more serious problems. Here's the latest on this most common of all head injuries.
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What Is a Concussion?
A concussion is a disturbance in brain function due to a head injury. In medical terms, a concussion is one type of mild traumatic brain injury (TBI). It causes an altered mental state, such as confusion and memory loss.
There are three myths about concussions.
- They cause a loss of consciousness. In reality, only a small number of people actually lose consciousness or black out.
- They occur only after blows to the head. It's true that direct impact is the leading cause of concussions, but a whiplash injury or any other event that produces an abrupt acceleration or deceleration of the head can cause a concussion; violent spinning can do the same.
- They are "brain bruises" or contusions. In fact, most concussions don't produce any brain swelling or bruising, or at least not enough to show up on brain imaging studies.
Neurologists don't fully understand what causes concussions. The best evidence suggests they are due to temporary disturbances in the metabolism and electrical activity of brain cells. Over time the cells recover, but severe or repeated concussions can lead to permanent brain damage.
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How To Recognize Symptoms
Some concussions are so mild that they escape notice. Others are serious enough to cause a loss of consciousness. And while some people develop symptoms immediately, others don't develop problems for days or even weeks. That means it can be tricky to recognize a concussion. To help, the CDC has divided symptoms into four groups:
- Physical: Headache; fuzzy or blurry vision; nausea or vomiting; dizziness; sensitivity to noise or light; poor coordination or balance; feeling tired or lacking energy; slurred speech
- Thinking/remembering: Confusion; difficulty answering questions, following instructions and thinking clearly; feeling slowed down; difficulty concentrating; difficulty remembering new information
- Emotions/mood: Irritability; sadness; being more emotional than usual; nervousness or anxiety
- Sleep: Sleeping more or less than usual; trouble falling asleep
And if these symptoms are not bad enough, concussions can produce the post-concussion syndrome — fatigue, low-grade headaches, impaired focus and attention, poor memory, disturbed sleep, irritability and depression that lasts for weeks or even months
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Although most people recover from mild concussions, they are serious events. A person who has had a concussion is four to six times more likely to have another concussion than someone who has never had a head injury.
A second head injury during the early recovery phase can sometimes trigger the "second impact syndrome" that causes life-threatening brain swelling. And even without such a disaster, repeated concussions, even months or years apart, can produce permanent mental impairment.
The problem of "punch drunk" boxers led the American Medical Association to call for a ban on the sport in 1983. But it took another 25 years for the National Football League to acknowledge the problem of chronic traumatic encephalopathy (CTE) in former players. CTE causes major problems, such as dementia and depression, but even mild concussions can cause subtle mental problems.
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You can help prevent a concussion by taking certain precautions:
- Wear approved headgear for sports.
- Wear a helmet when biking or on a motorcycle.
- Always wear your seatbelt.
- Reduce your risk of accidents and falls away from the playing field.
Even when you take precautions, concussions can still happen. Parents, coaches, trainers and doctors all have a role in caring for the injured athlete. It's a big responsibility, and it's made even more difficult by the urge to get back into the game. That makes field evaluation and management more important than ever.
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A Tool To Screen Concussions on the Field
Organized sports teams should have at least one person who is trained to recognize concussions. If a health care professional is not available, a coach, trainer or parent should be able to fill in.
It's a good idea to learn to use this tool to screen for concussions in the field. It's called the Westmead Post-traumatic Amnesia Scale. It's a series of questions for the injured person:
- What is your name?
- What is the name of this place?
- Why are you here?
- What month is it?
- What year is it?
- What town are we in?
- How old are you?
- What is your birthday?
- What time is it?
- See if you can remember three items (such as a name, a color and a number) for a few minutes.
If a person misses even one of these items, you should presume he's had a concussion. That means he should be pulled out of the game.
Every concussion is potentially serious, and all victims should be referred to a doctor for formal evaluation. A quick response is in order when there is loss of consciousness or other evidence of a serious concussion. But even after the evaluation, you should remain vigilant at home. Here are the signs to look for in the injured person:
- Worsening headaches
- Blurred or double vision
- Disturbed thinking or speech
- Grogginess or confusion
- Dizziness, nausea or vomiting
- Impaired coordination
- Weakness of numbness in any part of the body
Remember that an expert medical evaluation, which will usually involve a computed tomographic scan (CT) or magnetic resonance imaging (MRI) study of the brain, can detect brain bleeding and other problems that can be life-threatening without treatment.
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Getting Back to Work or Play
In the past people resumed their normal activities, including competitive sports, much too quickly. But now that doctors know the brain is at high risk until it has fully recovered from a concussion, activity should be restricted until the person feels completely well and has passed formal neurological tests. And even then, people should resume activity gradually. During the recovery period it may also be necessary to reduce mental work and stress.
It's taken too long, but concussions are finally getting the attention and respect they deserve. More research is needed, but while we're waiting for new medical insights, it's worth repeating the simple rule that's often overlooked: When in doubt, sit it out.
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Harvey B. Simon, M.D. is an Associate Professor of Medicine at Harvard Medical School and a member of the Health Sciences Technology Faculty at Massachusetts Institute of Technology. He is the founding editor of the Harvard Men's Health Watch newsletter and author of six consumer health books, including The Harvard Medical School Guide to Men's Health (Simon and Schuster, 2002) and The No Sweat Exercise Plan, Lose Weight, Get Healthy and Live Longer (McGraw-Hill, 2006). Dr. Simon practices at the Massachusetts General Hospital; he received the London Prize for Excellence in Teaching from Harvard and MIT.