What is a Concussion? Understanding Symptoms, Causes, and Prevention

A concussion is classified as a mild traumatic brain injury (TBI) that temporarily disrupts normal brain function. While often referred to as “mild,” it’s crucial to understand that a concussion is still a brain injury that requires proper recognition and management. The effects of a concussion are typically short-term, but can significantly impact various aspects of daily life, including concentration, memory, balance, mood, and sleep patterns.

Concussions are usually the result of a blow to the head or body that causes the brain to move rapidly inside the skull. This movement can lead to chemical changes in the brain and sometimes damage brain cells. It’s important to note that not every impact to the head results in a concussion, but any significant force should be evaluated for potential injury.

While some concussions may cause a brief loss of consciousness, the majority do not. Falls are the leading cause of concussions across all age groups. Furthermore, concussions are prevalent in contact sports like football and soccer. Fortunately, with appropriate care and rest, most individuals make a full recovery from a concussion.

Recognizing the Signs: Concussion Symptoms

Concussion symptoms can be subtle and may not appear immediately after the injury. They can evolve over hours or even days and persist for varying durations – from days to weeks, or in some cases, even longer.

Hallmark symptoms immediately following a mild traumatic brain injury often include headache, confusion, and amnesia, particularly retrograde amnesia concerning the event that caused the concussion.

Physical symptoms of a concussion can manifest as:

Headache: This is one of the most common and persistent symptoms.
Tinnitus: Ringing, buzzing, or hissing sounds in the ears.
Nausea: Feeling sick to the stomach.
Vomiting: Expelling stomach contents.
Fatigue or Drowsiness: Feeling unusually tired or sleepy.
Blurred Vision: Difficulty focusing or seeing clearly.

Beyond physical symptoms, concussions can also present with cognitive and sensory changes such as:

Confusion or Feeling in a Fog: Difficulty thinking clearly or feeling disoriented.
Amnesia: Memory loss, especially regarding the injury event.
Dizziness or “Seeing Stars”: Vertigo or visual disturbances.

Witnessing someone experiencing a concussion, you might observe:

Temporary Loss of Consciousness: Although not always present.
Slurred Speech: Difficulty forming words clearly.
Delayed Response to Questions: Slow or hesitant answers.
Dazed Appearance: Appearing confused or blank.
Repetitive Questioning: Asking the same questions repeatedly due to forgetfulness.

It’s crucial to be aware that some concussion symptoms are delayed and might not emerge until days after the initial injury. These delayed symptoms may include:

Concentration and Memory Problems: Difficulty focusing and remembering information.
Irritability and Personality Changes: Increased agitation or shifts in mood.
Sensitivity to Light and Noise: Discomfort or pain from bright lights or loud sounds.
Sleep Disturbances: Trouble falling asleep, staying asleep, or changes in sleep patterns.
Emotional Lability or Depression: Feeling unusually emotional, sad, or hopeless.
Altered Taste and Smell: Changes in the ability to taste or smell.

Concussion Symptoms in Children

Identifying concussions in infants and toddlers can be more challenging as they cannot verbally express their symptoms. Be alert for these clues in young children following a head injury:

Dazed Appearance: Looking confused or out of it.
Listlessness and Easy Fatigability: Unusual tiredness and lack of energy.
Irritability and Crankiness: Increased fussiness and crying.
Loss of Balance and Unsteady Gait: Difficulty walking or maintaining balance.
Excessive Crying: Crying more than usual and being difficult to soothe.
Changes in Eating or Sleeping Habits: Refusal to eat, changes in feeding patterns, or altered sleep schedules.
Decreased Interest in Toys: Lack of engagement with favorite toys or activities.
Vomiting: Especially repeated vomiting episodes.

When is it Necessary to See a Doctor for a Concussion?

It’s vital to know when to seek medical attention after a head injury for yourself or your child.

Schedule an appointment with a healthcare professional within 1 to 2 days if:

You or your child experiences any head injury, even if immediate emergency care seems unnecessary. It is especially important for children and adolescents to be evaluated by a healthcare professional trained in managing pediatric concussions.

Seek emergency medical care immediately for an adult or child who sustains a head injury and exhibits any of the following danger signs:

Repeated Vomiting or Nausea: Persistent or forceful vomiting.
Loss of Consciousness Longer Than 30 Seconds: Prolonged unconsciousness.
Worsening Headache: Headache that intensifies over time.
Fluid or Blood Drainage from Nose or Ears: Clear or bloody discharge.
Vision or Eye Changes: Pupils becoming larger than normal, unequal pupil size, or any visual disturbances.
Persistent Tinnitus: Ringing in the ears that does not subside.
Weakness in Arms or Legs: Loss of strength or coordination in limbs.
Behavioral Changes: Unusual or erratic behavior.
Confusion or Disorientation: Not recognizing people or places, significant confusion.
Slurred Speech or Speech Changes: Difficulty speaking or changes in speech patterns.
Obvious Changes in Mental Function: Decline in cognitive abilities.
Changes in Physical Coordination: Stumbling, clumsiness, or balance problems.
Seizures or Convulsions: Uncontrolled muscle spasms or jerking movements.
Persistent or Recurring Dizziness: Dizziness that doesn’t resolve or comes and goes.
Worsening Symptoms: Any concussion symptoms that are progressively getting worse.
Large Head Bumps or Bruises: Significant swelling or bruising on the head, particularly around the eyes (raccoon eyes) or behind the ears (Battle’s sign), especially concerning in infants under 12 months old.

Concussion and Return to Activity for Athletes

It is absolutely critical that athletes do not return to play or vigorous activity immediately following a concussion. Experts universally recommend that athletes of all ages, whether children, adolescents, or adults, should not return to play on the same day of a suspected concussion. Even if a concussion is only suspected, it’s prudent to refrain from any activities that could risk further injury. A gradual and supervised return to both learning and physical activity is essential and must be guided by a healthcare professional, tailored to individual symptoms and recovery progress.

What Causes a Concussion?

Concussions are caused by a force that causes the head and brain to move rapidly back and forth. This sudden movement can cause the brain to bounce or twist within the skull, stretching and damaging brain cells and triggering chemical changes.

Common events leading to concussions include:

Falls: The most frequent cause, especially for young children and older adults.
Direct Blows to the Head: Impact from objects or collisions.
Car Accidents: Sudden deceleration and impacts during motor vehicle collisions.
Blast Injuries: Explosions, particularly in military or combat situations.
Sports Injuries: Collisions and impacts in contact sports like football, soccer, hockey, and boxing.

During a concussion, the brain’s delicate tissue is subjected to acceleration and deceleration forces, causing it to collide with the inner walls of the skull. This forceful movement disrupts normal brain function, usually temporarily. In some instances, a concussion can lead to bleeding in or around the brain, which can result in more severe complications like prolonged drowsiness, confusion, and in rare cases, death. Therefore, close monitoring after any head injury is crucial, and immediate emergency care is necessary if symptoms worsen.

Risk Factors for Concussion

Certain factors and activities can elevate the risk of experiencing a concussion:

Activities Increasing Fall Risk: Especially for young children and older adults, environments or situations prone to falls.
High-Risk Sports: Participation in contact sports such as American football, hockey, soccer, rugby, and boxing.
Inadequate Safety Equipment and Supervision: Lack of proper protective gear or adult supervision during high-risk sports and activities.
Motor Vehicle Accidents: Driving or being a passenger in vehicles.
Pedestrian and Bicycle Accidents: Incidents involving pedestrians or cyclists and vehicles.
Military Combat: Exposure to explosions and head trauma in combat situations.
Physical Abuse: Acts of violence leading to head injuries.
History of Previous Concussion: Individuals who have had a concussion are at higher risk for subsequent concussions.

Potential Complications of Concussion

While most people recover fully from a single concussion, potential complications can arise:

Post-Traumatic Headaches: Persistent headaches that can last for days or weeks following the injury.
Post-Traumatic Vertigo: A sensation of spinning or dizziness that can linger for days or weeks.
Persistent Post-Concussive Symptoms (Post-Concussion Syndrome): In some individuals, a cluster of symptoms such as headaches, dizziness, and cognitive difficulties can persist longer than expected. If these symptoms last beyond three months, it is termed persistent post-concussive syndrome.
Effects of Multiple Brain Injuries: Research is ongoing to understand the long-term consequences of repeated head injuries, including subconcussive injuries (head impacts that don’t cause immediate symptoms).
Second Impact Syndrome: A rare but life-threatening complication where a second concussion occurs before the symptoms of a previous concussion have resolved. This can lead to rapid brain swelling, potentially resulting in death. Athletes must never return to play while still experiencing concussion symptoms.

Prevention Strategies for Concussion

Taking proactive steps can significantly reduce the risk of concussions:

Wear Protective Gear During Sports and Recreation: Always use appropriate helmets and protective equipment for activities like biking, skateboarding, skiing, snowboarding, and contact sports. Ensure gear fits correctly, is well-maintained, and used consistently. Follow sports rules and promote good sportsmanship.
Buckle Up Seat Belts: Consistent seat belt use in vehicles can prevent serious injuries, including head injuries, during car accidents.
Make Your Home Safe: Ensure adequate lighting in the home and remove tripping hazards from floors to prevent falls, a major cause of head injuries.
Protect Children: Install safety gates on stairways and window guards to minimize the risk of falls for young children.
Regular Exercise: Engage in regular exercise to strengthen leg muscles and improve balance, reducing the risk of falls.
Concussion Education: Educate coaches, athletes, parents, and the community about concussion recognition, management, and prevention to increase awareness and promote safety.

By Mayo Clinic Staff

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