A concussion is easy to underestimate, especially when there is no loss of consciousness, visible injury or immediate sense that something is wrong. But physicians warn that even a seemingly minor head injury can affect how the brain works, with symptoms that may show up right away or emerge hours later. From sports to falls and car accidents, concussions are common and knowing what to watch for is key to helping patients recover safely.
The AMA's What Doctors Want Patients to Know™ series gives physicians a platform to share what they want patients to understand about today's healthcare headlines and how to take charge of their health through preventive care.
For this installment, Baibing Chen, MD, a neurologist with Henry Ford Health in Detroit, took time to discuss what patients should know about concussions.
Henry Ford Health is part of the AMA Health System Member Program, which provides enterprise solutions to equip leadership, physicians and care teams with resources to help drive the future of medicine.
A concussion is a type of traumatic brain injury
Dr. Chen describes a concussion as "a type of mild traumatic brain injury," though he adds "there's really nothing about it that's mild, but that's how we categorize different types of traumatic brain injury."
Ultimately, a concussion is "a rapid acceleration or deceleration of the brain inside the skull after there's an impact or a traumatic event," he said. "That sudden movement disrupts the cell membranes and causes shifts in neurochemicals and neurotransmitters in the brain, causing a temporary energy crisis."
Concussions are quite common
“There are up to 3.8 million concussions reported in the U.S. every year, but this is probably an underestimated number, because a lot of people—especially boys and men—tend to not report it," Dr. Chen said
"You see reports that girls and women have higher concussion rates, but this may not be the whole story. It may be that men are less likely to report concussions," he said.
Athletes, older adults and children are at risk for concussions
"Some athletes—for example, those who play sports such as hockey, football, soccer, lacrosse or rugby—are at high risk for concussions," Dr. Chen said. "In all of these sports, you have the potential of being hit on the head with a ball, equipment or by somebody else. That sudden hit can cause a disruption in the cell membranes in the brain after a traumatic event."
"Kids, like my toddler for example, are just not steady," he said. "He climbs everywhere, he falls and he hits his head all the time. So, we can understand why young kids are more prone to concussions."
"And then as people get older, you have issues like cognitive decline, skeletal muscular decline and loss of balance," Dr. Chen said. "These issues can cause people to more easily fall and hit their head, causing a traumatic brain injury that way."
Recognize symptoms of a concussion
Concussions can manifest through a range of symptoms. "The most common ones are headache, dizziness, nausea, feeling dazed like you don't remember what happened and balance problems," said Dr. Chen. "Some of these symptoms that occur acutely may also become more chronic or last longer term."
Other symptoms of a concussion include noticing that "your thinking is slower, your memory going forward might be a little bit slower, you might be more irritable and some people may even become more aggressive," he said, adding that symptoms can also include difficulty sleeping.
Symptoms of a concussion can be different in babies
In babies, symptoms may present as changes in behavior, such as trouble feeding, more vomiting or changes in sleep patterns.
"If a baby usually sleeps really well and all of a sudden is waking up a couple times a night, then that's something to pay attention to," Dr. Chen said. "Of course, one night is not a huge issue, but if you see that over multiple days or weeks, then you might suspect something's going on. Behavior changes in babies are important to pay attention to."
A concussion can last as long as four weeks
"For most people, concussions last about two to four weeks," Dr. Chen said, adding that he often does not see those patients because they get better on their own without complications that extend beyond that period.
"Who I do see are the people whose symptoms don't go away that soon. They say their symptoms have been persistent for the past three or six months," he added. "There is so much variability between individuals and the severity of the concussion itself."
Loss of consciousness isn't needed to have a concussion
"One myth is that you need to lose consciousness to have a concussion," Dr. Chen said. "That's not true. In fact, in most cases, you don't lose consciousness."
"As neurologists, we most commonly see concussions from sports, falls from high surfaces, car, motorcycle and bicycle accidents, and domestic violence," he said, adding that many of these may not result in a loss of consciousness.
However, Dr. Chen said he encourages anyone who loses consciousness to seek medical care, adding that "if you have persistent vomiting, severe confusion, weakness, numbness on one side versus the other, unequal pupils or you start having seizures, you definitely need to see a medical professional."
"Something that I always warn people about—especially young people—is that if you get knocked on the head, lose consciousness and then regain it, you need to go see a doctor," he said. "What rarely happens, but what I've seen and that can be deadly, is what we call an epidural hematoma, where blood collects between the dura—the surface covering your brain—and the skull."
"What we see is a 'lucid interval' where people get knocked out, then wake back up and seem to be OK. But as that blood continues to expand, it compresses the brain and they fall asleep again and don't wake up," Dr. Chen said. "That's why you should always get checked. Some doctors will recommend a CT scan of the head to make sure there's no bleeding. Others might observe for six to 24 hours. Either approach is fine, but you definitely have to be more careful in the rare circumstances that an epidural hematoma develops."
A concussion feels like brain fog
People with a concussion often describe it as "your brain feeling a little bit foggy," said Dr. Chen. "You feel like your memory is a little bit impaired."
Others have described a concussion as "feeling like you've aged a lot. They describe it as 'I feel like I'm in my 80s, I can't remember anything, I can't think straight, I can't focus,'" he explained. "Or if they have a balance issue, they feel like the room is always spinning or they have headaches."
Diagnosing a concussion is based on history and symptoms
A patient's history and symptoms play a key role in diagnosing a concussion, according to Dr. Chen. "I see a lot of patients who come to me as a neurologist in clinic and say that the emergency department physician who checked them after a car accident said they didn't have a concussion because the CT scan or MRI were fine."
"One of the things people don't understand is that a concussion is not a structural change. Most of the time, it's completely fine and you're not going to see anything," he said. "What happens at a molecular level and the changes in the different neurochemicals are things you're not going to see with a CT scan or an MRI."
"Instead, I'll listen to their symptoms. They may say they have been feeling dizzy, can't focus, have persistent migraines every day and are light sensitive," Dr. Chen said. "Based on their symptoms, that means you have a concussion."
Gradually return to activity after a concussion
"We used to treat a concussion the way we treated a sprained ankle—if you hurt something, you stayed in bed and didn't do anything until you were fully recovered," said Dr. Chen. "But now the field has evolved significantly. You should never just stay in a dark room. Even if you're light sensitive, you shouldn't just avoid movement. You should gradually return to activity."
The key to keep in mind, though, is "don't do any activities that worsen your symptoms. Slowly add in activity as you become better,” he said.
Skip these after a concussion
Still, there are several things that people should avoid after a concussion. For example, "you should not exercise intensely," said Dr. Chen, emphasizing "do not immediately go back to a sport such as football after a concussion. Always be on the more cautious side."
Additionally, "do not drink alcohol or take other drugs such as marijuana after a concussion," he said. "You can continue to take most prescribed medications, though you should talk with your doctor about blood thinners."
"If we're not sure whether the injury is severe enough for someone to sustain a head injury that causes bleeding, we may want to be careful about taking NSAIDs or blood thinners," Dr. Chen added. "You even need to be careful about over-the-counter medicines such as Aleve, Motrin or aspirin."
It's OK to sleep after a concussion
Another myth around concussions is that you can't sleep, according to Dr. Chen.
"In the case of epidural hematomas, you should definitely have people check on you—that's very important," he said. "But you can sleep. Sleep is very important for any concussion because sleep is when your brain can actually repair itself."
"Sleep is the most important preventative medicine that we have overall, and it's definitely very important for any sort of recovery from a concussion," Dr. Chen said, adding that if someone lost consciousness, they should be checked on for at least the first 24 hours, but they should be allowed to sleep.
There are prolonged complications with concussions
Some people can experience post-concussion syndrome, a collective syndrome where a patient has persistent headaches, memory problems, mood changes, sensitivity to light and noise, and balance problems, according to Dr. Chen.
"If you keep getting concussions, research over the past decade has shown that you run the risk of developing chronic traumatic encephalopathy, or CTE," he said. "The more concussions you have, the higher your long‑term risk of declining brain health.
"One concussion by itself does not automatically mean you will develop long‑term problems, but no concussion is truly harmless," Dr. Chen added. "Each injury places stress on the brain, and risk becomes more significant when injuries are repeated, especially before full recovery."
Take steps to prevent a concussion
There are measures people can take to help prevent concussions, said Dr. Chen, including wearing helmets and trying to prevent hits to the head.
"That's very difficult in a lot of sports, but many sports are taking steps to prevent concussions," he said. "For example, the NFL has introduced these really huge, soft-shell padded helmets, which go a long way in protecting football players."
"Other things like wearing seatbelts—which I hope most people do—and strength and balance training are important,” he said, “because the stronger your body is, the less likely it is that an impact will cause a major injury."
"Even in a car crash, when you’re experiencing whiplash, stronger neck muscles may help prevent further injury," Dr. Chen added. "If you have a good baseline to begin with, your recovery might also be faster afterward."
