A concussion is a temporary loss of normal brain function, due to the brain shifting inside the skull from a blow to the head. This can cause a sudden — but usually temporary — disruption in a person's ability to function properly and feel well.
The brain is made up of soft tissue and it's cushioned by blood and spinal fluid. When someone gets a blow to the head or hits something very hard, the brain suddenly shifts inside the skull and can knock against the skull's bony surface. This causes a concussion.
Sometimes, concussions last for a short time. Other times, a person can have symptoms of a concussion that last for days or weeks. But even concussions that seem to be short can be serious.
Anyone who sustains a head injury should stop participating and be removed from the activity or sport. Even without a loss of consciousness, it's important to watch for symptoms of a concussion.
Common initial symptoms include:
Someone with any of these symptoms should be taken to the emergency room.
Concussion symptoms may not appear initially and can develop over the first 24-72 hours. Anyone showing any signs of a concussion should be seen by a doctor. Young kids can have the same concussion symptoms as older kids and adults, but changes in mood and behavior may be less noticeable.
Though most people recover quickly from concussions, some symptoms — including memory loss, headaches, and problems with concentration — may linger for several weeks or months. It's important to watch for these symptoms and contact your doctor if they persist.
All A to Z dictionary entries are regularly reviewed by KidsHealth medical experts.
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