What Are the Symptoms of a Concussion?

A concussion is a mild traumatic brain injury (TBI). It can occur after a blow to the head or trauma to the body that causes the brain to move back and forth quickly within the skull. 

Although you may be familiar with sports-related concussions in teens and young adults, a concussion can happen to anyone at any age. In 2016, nearly 20% of people reported at least one concussion in their lifetimes.  

Here, we’ll review the causes and symptoms of concussions, as well as what to do if you think you have one.

What causes a concussion?

A concussion happens when an injury stretches and injures the nerves in the brain, causing changes in chemical signaling and blood flow. These changes then affect how the brain functions. 

The impact or force of the injury leading to a concussion can vary. Contrary to popular belief, most people with a concussion do not lose consciousness as a result of their head injury. Also, there is no evidence to suggest a difference in concussion symptoms based on where you are hit on the head. 

Common causes of concussions include:

• Falls

• Being struck in the head with an object

• Motor vehicle accident, including whiplash injury

• Occupational (work-related) injury

• Assault

• Sports-related injuries

Falls are the most common cause of TBI visits to the emergency department, especially in older adults. Sports-related injuries make up a small number of concussions but are the most well known and researched. Combat-related head trauma, including blast injuries and shrapnel wounds, also contributes to mild TBI among active military members.

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What are the symptoms of a concussion?

Symptoms of a concussion vary from person to person. They can also be different for the same person from one concussion to the next. Symptoms can include:

• Problems with thinking clearly

• Temporary memory loss

• Poor attention and difficulty concentrating

• Headache

• Dizziness

• Nausea and/or vomiting

• Noise or light sensitivity

• Balance problems

• Vision changes, like blurry vision

• Decreased energy

• Feeling “foggy” or slow

• Emotion or mood changes

• Sleep changes like sleeping more or less than usual

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Symptoms in younger children can be a bit different, as they may not be able to let others know how they are feeling after a concussion. In addition to the above symptoms, other symptoms in kids can include:

• Fussiness, crying more, or being more irritable than usual

• Inability to follow directions

• Less interest in toys or activities 

• Unsteady walking

• Change in sleep, nursing, or eating patterns

How long does it take to develop concussion symptoms and recover from them?

Concussion symptoms can develop immediately after the injury or within hours to days. Most people with a concussion recover within 1 to 2 weeks. But for some people, symptoms can last for weeks to months or sometimes longer.

What should you do if you think you have a concussion?

Rest assured that most concussions resolve without any complications. The best treatment for a concussion is time and rest. This includes resting both your body and your mind. So it’s wise not to return to school, sports, or work until you completely recover from your symptoms. 

If your symptoms linger, it’s a good idea to see your healthcare provider. They can help you sort through symptoms and get you back to work or school. 

When should you go to the ER for a possible concussion?

Head injuries can be scary, and it’s not always clear how severe a concussion is. But certain red-flag signs and symptoms can indicate that an injury is more serious. If you or someone you know has any of the following after a head injury, it’s best to seek medical attention right away:

• Significant nausea and/or repeated episodes of vomiting

• Loss of consciousness for more than 30 minutes

• Increased sleepiness or inability to stay awake

• Symptoms that aren’t improving or are getting worse

• Changes in speech, such as slurring

• One pupil that is bigger than the other

• Weakness, numbness or tingling in the face, arm(s), or leg(s)

• Recent concussion or history of repeated concussions 

• Taking blood thinner medications

• 65 years of age or older

If you decide to go to the ER for a possible concussion, your provider will gather additional information. Be prepared to discuss:

• What you remember about the injury 

• Whether or not you lost consciousness

• Any prior history of head injury or concussions

• Other symptoms, such as neck pain

• Your medical history and medication you are taking

They will also perform a physical exam. This can include checking your eyes; movement and sensation of your face, arms and legs; and testing your balance and walking. 

It’s also important to tell your healthcare provider if you take any blood thinner medications, such as warfarin (Coumadin), rivaroxaban (Xarelto), heparin, or dabigatran (Pradaxa), or have any medical problems that cause excessive bleeding or trouble clotting your blood. This can help them decide if you need any imaging of your brain to look for bleeding.

Are there tests to diagnose a concussion?

There is not one specific test that can diagnose a concussion. Healthcare providers can often make the diagnosis based on information about the injury, symptoms, and a physical examination. 

Because concussion is a functional injury, rather than a structural one, imaging tests (such as an MRI or CT) are typically not needed. These imaging tests are unlikely to show any changes and can expose people to unnecessary costs and risks like radiation.  

Is it safe to sleep if you’ve had a concussion?

It is a common myth that you should not let someone sleep after a concussion or wake them up every hour. However, rest is a critical part of concussion treatment and recovery. It is okay for someone to check on you a couple of times a night to make sure that you are breathing normally, not vomiting, and have no other concerning symptoms. As long as there are no red-flag symptoms, experts agree that you can safely sleep after a concussion. 

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Written by:

Tiffany Chioma Anaebere, MD

Tiffany Chioma Anaebere, MD, is a medical writer and a practicing emergency medicine physician and educator in Northern California. Dr. Anaebere also researches and develops novel curriculum for physician learners.

Edited by:

Mandy Armitage, MD

Mandy Armitage, MD, has combined her interests in clinical medicine with her passion for education and content development for many years. She served as medical director for the health technology companies HealthLoop (now Get Well) and Doximity.

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