Overview

A concussion is a traumatic brain injury that affects your brain function. Effects are usually temporary but can include headaches and problems with concentration, memory, balance and coordination.
Concussions are usually caused by a blow to the head. Violently shaking of the head and upper body also can cause concussions.
Some concussions cause you to lose consciousness, but most do not. Falls are the most common cause of concussion. Concussions are also common if you play a contact sport, such as football or soccer. Most people usually recover fully after a concussion.

Symptoms

The signs and symptoms of a concussion can be subtle and may not show up immediately. Symptoms can last for days, weeks or even longer.
Common symptoms after a concussive traumatic brain injury are headache, loss of memory (amnesia) and confusion. The amnesia usually involves forgetting the event that caused the concussion.
Physical signs and symptoms of a concussion may include:
Other signs and symptoms of a concussion include:
A witness may observe these signs and symptoms in the concussed person:
You may have some symptoms of concussions immediately, and some can occur for days after the injury, such as:

Symptoms in children

Head trauma is very common in young children. But concussions can be difficult to recognize in infants and toddlers because they can’t describe how they feel. Concussion clues may include:

So, You Had a Concussion. Athletic Injury? Now What?

When to see a doctor

See a doctor within 1 to 2 days if:

You or your child experiences a head injury, even if emergency care isn’t required If your child doesn’t have signs of a serious head injury, remains alert, moves normally and responds to you, the injury is probably mild and usually doesn’t need further testing.
In this case, if your child wants to nap, it’s OK to let him or her sleep. If worrisome signs develop later, seek emergency care.

Warning Signs to Watch Out For (Red Flags)

Seek emergency care for an adult or child who experiences a head injury and signs and symptoms such as: