What to Know About Concussion and Traumatic Brain Injury

Medically Reviewed By Darragh O'Carroll, MD

Concussion is a type of traumatic brain injury (TBI). A TBI is damage to the brain that results from a blow to the head or another form of trauma. Trauma can cause the brain to move within the skull in a sudden and forceful manner, potentially causing damage. The brain damage from concussion can range from mild to severe. Although a blow to the head can cause concussion, it is not the only kind of force that can lead to concussion. Concussion can also be the result of any kind of force or trauma to the body that transmits force to the head or brain, such as whiplash.

Some people may not even realize that they have concussion when their symptoms are mild or do not start immediately. This can lead to a lack of recognition, reporting, and diagnosis of concussion. In turn, this can increase the risk of prolonged symptoms or long-term health consequences due to mismanagement of the concussion.

However, it is also possible to experience noticeable symptoms — such as a loss of consciousness — from trauma leading to concussion.

In both cases, your brain needs time to heal and recover.

Read on for more information about concussion, including its symptoms, risks, treatment options, complications, and more.

What are the symptoms of concussion?

Three American football players tackle each other on an outdoor pitch, wearing blue and white uniforms and helmets.
Inuk Studio/Stocksy United

The signs and symptoms of concussion often happen after obvious bodily injury or trauma.

However, the symptoms themselves can be very variable in their presentations. They can be subtle, mild, or less noticeable, but they may also be severe and mimic those of a stroke.

Additionally, concussion symptoms can start right away, but, in some cases, they might not show up for hours or days after a head injury. Symptoms commonly start within 24 hours following the incident. Symptoms can also be Trusted Source Centers for Disease Control and Prevention (CDC) Governmental authority Go to source short-term or last for weeks or months.

Concussion can cause an emergency situation

Without proper treatment and rest, concussion can lead Trusted Source Centers for Disease Control and Prevention (CDC) Governmental authority Go to source to long-term problems or, in rare cases, death. Always visit a doctor immediately after a head injury, even if you do not have symptoms. 

Seek immediate medical care or call 911 for anyone with potentially serious symptoms following a head and neck injury, including:

  • blurred vision
  • unequal pupil size
  • difficulty walking, difficulty moving parts of the body, or decreased coordination and balance
  • weakness or numbness
  • extreme sleepiness, drowsiness, fatigue, or an inability to wake up
  • changes in consciousness, even if very brief
  • unusual behaviors, confusion, restlessness, or agitation
  • a severe headache
  • a headache that worsens and does not go away
  • vomiting
  • symptoms that worsen over time

You should also seek emergency treatment for anyone:

  • who has consumed alcohol or taken drugs before the injury
  • who has a blood clotting disorder or who takes a blood-thinning medication
  • who has had brain surgery in the past

Get information about first aid for concussions and head injuries here.

Common symptoms of concussion

Other symptoms of concussion can include Trusted Source Centers for Disease Control and Prevention (CDC) Governmental authority Go to source :

  • confusion, brain fog, or difficulty concentrating
  • dizziness
  • headaches
  • memory problems or amnesia
  • feeling sluggish, groggy, or foggy
  • personality changes or symptoms of depression
  • nausea
  • ringing in the ears
  • sensitivity to light or sound
  • sleep changes, such as sleeping more or less than usual, drowsiness, or difficulty falling asleep
  • the sense that you do not “feel right”

Always visit a doctor after any type of head injury or bodily trauma involving the head. You need medical evaluation even if you do not have symptoms right away.

What causes concussion?

A blow, bump, or jolt to the head is a common cause Trusted Source Centers for Disease Control and Prevention (CDC) Governmental authority Go to source of concussion. Concussion is also a common sports-related injury. However, concussion can occur in other situations as well.

Any jarring force that affects the head may cause concussion. This includes blows or bumps, falls, car accidents, violent hits to the body, violent shaking, and whiplash injuries.

The resultant force on the body that affects the head can cause the brain to move forcefully within the skull. The cerebrospinal fluid that usually protects the brain is not able to cushion it against this type of force. The result is damage to brain cells and chemical changes in the brain.

What are the risk factors for concussion?

Anything that exposes you to a risk of bodily trauma that affects the head may run the risk of causing concussion.

Certain other factors also increase the risk of concussion. These factors can include:

  • being female (as assigned at birth), as suggested by a 2013 study Trusted Source PubMed Central Highly respected database from the National Institutes of Health Go to source into concussion risk factors
  • having had a concussion previously in life
  • participating in contact and high risk sports, such as football, soccer, hockey, skiing, and boxing

Having had concussion previously can also increase the risk of any following concussions being worse. This is because brain damage can accumulate, leading to further brain injury and health problems.

As having a history of concussion is a significant predictor of experiencing further concussion or head trauma, avoiding concussion in the first instance is essential.

Reducing your risk of concussion

The American Association of Neurological Surgeons (AANS) suggests that you may be able to prevent yourself or the people you care for from experiencing concussion by taking certain measures, including:

  • childproofing your home with stair gates, bed rails, window guards, and furniture anchors to protect young children
  • getting regular exercise to improve balance and strength
  • avoiding contact or high risk sports, or practicing the appropriate technique when playing such sports
  • taking care to avoid falls, such as by removing rugs, installing grab bars, or removing mobility hazards
  • wearing a seatbelt every time you are in a vehicle and properly adjusting your car’s head restraint
  • making sure any protective equipment used is appropriate for the age, size, and activity of the person using it, such as by using age-appropriate car seats and seatbelts for children that correspond to their weight and size

Reducing risk during sports

There are certain habits you can adopt to reduce the risk of yourself or someone else experiencing concussion while practicing sports or exercise.

The AANS also outlines measures for sports that include:

  • always supervising younger children and not allowing them to use equipment inappropriate for their age and size
  • avoiding diving into bodies of water that are less than 9 feet deep
  • not participating in sports when injured, ill, or tired
  • wearing appropriate clothing and equipment for the activity
  • avoiding the use of clothing or equipment that impedes vision
  • following the rules of the environment for the safe and proper performance of the sport or activity
  • replacing equipment or protective gear that is damaged or compromised

Treating concussion

If your concussion is minor, you may be able to care for your condition at home.

At-home treatment and care advice often includes:

  • resting and avoiding stress
  • consulting your doctor before returning to Trusted Source PubMed Central Highly respected database from the National Institutes of Health Go to source activities
  • holding an ice pack wrapped in a cloth to the affected area for short periods of time for any pain or swelling
  • having supervision from another adult for the first 24 hours after the incident to help monitor your condition
  • taking acetaminophen (Tylenol) for pain relief

Avoid taking aspirin, ibuprofen (Advil, Motrin), or naproxen sodium (Aleve, Naprosyn) for pain relief following a concussion, especially in the first 24 hours after injury. These medications can present a risk of bleeding.

In addition to resting, be sure to eat healthily, get plenty of sleep, and stay hydrated with water. Avoid alcohol, and ask your doctor about the safety of any medications you take. Consult with your doctor before traveling.

Depending on your symptoms and the nature of your injury, your doctor may request further observation or brain imaging, such as an MRI scan, to identify or rule out more severe damage or complications of brain injury that would require further treatment.

What are the potential complications of concussion?

Further health complications can also occur as a result of severe concussions.

Potential complications of a concussion include Trusted Source Centers for Disease Control and Prevention (CDC) Governmental authority Go to source :

  • cumulative brain effects after more than one concussion or TBI, which can lead to permanent disability or brain health problems
  • mild cognitive impairment
  • memory problems
  • post-concussion syndrome, which causes headaches, dizziness, mood changes, and brain fog that can continue for months or years after concussion
  • post-traumatic seizures
  • depression
  • chronic traumatic encephalopathy, which is a neurodegenerative disease that can occur decades after the initial injury
  • second impact syndrome, which is potentially life threatening swelling of the brain when a second episode of concussion occurs before the first one has fully resolved

Although second impact syndrome is rare, deaths usually occur when the first concussion remains undiagnosed and the person sustains a second concussion.

Always seek medical care after a head injury, even a minor one, and never return to sports or activities if you still have symptoms of concussion. If your symptoms return Trusted Source PubMed Central Highly respected database from the National Institutes of Health Go to source with an activity, stop the activity and contact your doctor immediately.


Researchers in a 2022 article Trusted Source PubMed Central Highly respected database from the National Institutes of Health Go to source about concussion suggest that the outlook for someone experiencing concussion is usually positive, noting that symptoms can improve within the 2 weeks following injury.

However, the researchers also note that this recovery time can be very variable and depend heavily on the severity of the symptoms you experience within the first days following the injury. Because of this, the outlook for each person will be individual.

Variable factors can include the severity of the concussion, your age, and your overall health.

Ask your doctor what to expect based on your specific circumstances. Do not return to activities or sports until your doctor approves of you doing so.


Below are some other frequently asked questions that people have about concussions. Dr. Darragh O’Carroll, M.D. — who is a specialist in emergency medicine — has provided the answers.

What happens to the brain during concussion?

Concussion is a physical, rotational, or acceleration force transmitted to the brain that temporarily changes the brain’s metabolism and normal chemical reactions.

The severity and number of symptoms experienced after concussion will depend on the direction and magnitude of the force that caused the concussion.

How do you check for concussion?

Symptoms after experiencing force can indicate concussion.

The symptoms of concussion are very variable, and they can include loss of consciousness, temporary memory loss, headache, blurred vision, nausea, vomiting, and dizziness. Severe concussions can even result in seizures.

Physicians will also perform a baseline neurological test to determine baseline neurologic and reaction capabilities, and if they suspect concussion, they will repeat the same neurological test.

How long do concussions last?

Mild concussions typically last 1–2 weeks, but moderate or severe concussions may last 6 months or longer.

How long does concussion take to heal?

Normally, a mild concussion will take around 2 weeks to heal, though the healing time may depend on additional factors.

What happens if concussion goes untreated?

Untreated concussions can cause permanent damage, especially if followed by another concussion while the brain is still healing.

A concussed brain is much more prone to subsequent injuries and may contribute to the development of chronic traumatic encephalopathy.

When is it safe to sleep with concussion?

It is safe to sleep with concussion as long as a person does not have an altered level of consciousness and has not vomited more than two times. These symptoms can indicate bleeding inside the skull and increased pressure.

If in doubt, contact your physician or nearest emergency or urgent care.


Concussions can be common, particularly due to sports-related activities.

They occur when force or impact causes the brain to bump against the skill. This may cause brain injury and damage. Causes of concussion can include bumps and direct impacts to the head and other bodily trauma that can affect the head, such as whiplash.

Symptoms can include head pain, confusion, vision changes, sleep problems, memory impairment, and changes in consciousness, and they vary in severity. Symptoms can also take a while to appear, and they may not appear immediately after any incident.

Although mild cases of concussion can be manageable at home, complications can be severe, and further medical attention may be necessary.

Always contact a licensed medical professional after sustaining an injury to the head and neck, whether symptoms are present or not.

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Medical Reviewer: Darragh O'Carroll, MD
Last Review Date: 2022 May 31
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