A concussion is a form of traumatic brain injury (TBI) that occurs after a blow or jolt to the head. This sudden movement of the head can cause the brain to bounce around or twist in the skull, creating chemical changes in your brain. A concussion can produce a temporary or permanent loss of brain function.
It may be difficult to determine whether you have a concussion because the symptoms can vary from person to person. Infants and children can present with different signs and symptoms also.
Signs and symptoms generally appear soon after the injury. However, you may not know how serious the injury is at first, and some symptoms may not be noticed for hours or even days.
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Verywell / Michela Buttignol
Symptoms of a Concussion
Following a bump, jolt, or blow to the head, you may experience a concussion. Signs of a concussion that may be observed in you by others include:
- Being unable to recall events that occur before or after the injury
- Appearing to be stunned or dazed
- Being unable to recall instructions
- Appearing confused
- Displaying clumsy movements
- Being slow to answer questions
- Losing consciousness
- Having mood, personality, or behavioral changes
For the person experiencing the concussion, the above signs may not be obvious. But there are symptoms of a concussion you may experience that others may not pick up on, including:
- A headache or pressure in the head
- Balance issues
- Dizziness
- Double or blurry vision
- Nausea and vomiting
- Issues with remembering things or feeling confused
- Feeling like you can’t concentrate
- Feeling "off" or "down"
- Sluggishness, or having a hazy, foggy, or groggy feeling in your head
Post-concussion syndrome describes a set of complex symptoms that includes headache, dizziness, neuropsychiatric symptoms, and cognitive impairment occurring after TBI.
Signs in Young Children
When a concussion happens in children or infants, they may have a difficult time communicating the symptoms they are experiencing. Because of this, parents should be aware of signs that their baby or toddler may have a concussion.
The signs that your child has a concussion can include:
- Crying
- Complaining of head pain
- Being unable to sleep, or waking at night
- Having mood changes, such as uncontrollable laughter or crying or an increased temper
- Being irritable
- Vomiting
- Having noticeable issues with concentration
- Having balance problems
- Being more sensitive to light or sound
If you are present when your child hits their head, you should immediately check for signs of concussion. Symptoms may not appear right away, so you should monitor your child for at least 48 hours afterward. If symptoms come on during that time, the child needs to be evaluated by a physician immediately. Check on your child every one to two hours if they have a concussion.
Complications
A complication that could occur following a concussion is second-impact syndrome. It arises if a second concussion occurs before the first one fully heals.
Second-impact syndrome can lead to fatal brain swelling. The risk of this complication is much higher in those who play sports, such as football or boxing. This is why it’s vital to always fully recover from a concussion prior to returning to normal activities.
Other complications that can arise following a concussion include:
- Headaches
- Vertigo (a feeling of spinning and dizziness)
- Post-traumatic epilepsy (a seizure disorder)
- Depression, anxiety, or behavioral changes
- A specific type of brain degeneration known as chronic traumatic encephalopathy (CTE)
When to See a Doctor
After a blow to the head, go to a hospital immediately if you have any of these symptoms:
- One pupil (the dark center of the eye) is larger than the other
- Can't wake up or are excessively drowsy
- A worsening headache or one that persists
- Slurring of speech
- Feelings of weakness or numbness
- Loss of coordination
- Nausea or vomiting
- Shaking or twitching
- Confusion or unusual behavior
- Passing out, even briefly
Summary
A concussion can occur after a blow or trauma to your head. The signs observed by others and the symptoms experienced by the person with the concussion may be different. You may notice symptoms immediately following the injury or a few hours or even days afterward.
If you suspect you or someone you're with, including a child, has a concussion, monitor for any changes in mood, vision, and cognitive function and seek help.
A Word From Verywell
Hitting your head or falling can be scary. Sometimes it causes no injuries other than a bump or bruise. At other times, it can be very serious. It’s always best to get any head injury looked at by a healthcare provider.
A concussion is a serious condition that needs to be addressed as soon as possible. Knowing the signs and symptoms of a concussion in yourself or a loved one will help you seek prompt treatment. Getting adequate treatment soon after a concussion reduces the risk of complications and helps prevent prolonged symptoms.
Yes. Although concussions are typically caused by a blow or bump to the head, they can also be caused by a fall or blow to the body that causes the head to jolt back and forth. If the force of the jolt is powerful enough, it can lead to a concussion.
Frequently Asked Questions
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Sometimes. Although pupil dilation isn’t always a reliable sign of a concussion, it can occur in some people. Pupil dilation following a concussion typically only occurs in one pupil, with that pupil appearing larger than the other. It could be a sign that the structure of the brain was damaged, and you should go to the emergency department immediately.
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Yes. A concussion will typically be diagnosed using a physical exam, which involves testing vision, hearing, balance, coordination, reflexes, memory, and concentration. Other tests may need to be conducted, including an MRI (magnetic resonance imaging) or a CT scan (computed tomography scan) to check for changes in the brain.
The Food and Drug Administration (FDA) recently approved a test called the Banyan BTI (Brain Trauma Indicator), a blood test designed for adults to measure levels of two protein biomarkers released from the brain into the bloodstream within 12 hours of the injury.
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Concussion symptoms can begin immediately following a head injury, but they can also develop over the course of a few hours or even a few days.
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Yes. Although concussions are typically caused by a blow or bump to the head, they can also be caused by a fall or blow to the body that causes the head to jolt back and forth. If the force of the jolt is powerful enough, it can lead to a concussion.