A serious head injury occurs when the brain hits against the inside of the skull with enough force to cause brain damage. A serious head injury may result from a hard blow to the head or severe jarring or shaking of the head.

With this type of injury, the brain tissue may bruise, swell, or tear. Nerves or blood vessels within or around the brain may stretch, pull apart, or tear.

Serious injury to the brain may occur even when there is no visible bleeding or injury on the outside of the skull.

Symptoms of a serious head injury may include:

• Loss of consciousness.
• Memory loss (amnesia).
• Seizure.
• Confusion or not acting normal. A young child with a head injury may be very fussy, fretful, or may cry constantly.
• A severe headache, or a headache that continues to get worse.
• Difficulty waking up or extreme sleepiness.
• Difficulty speaking or slurred speech.
• Numbness, weakness, or loss of movement in the arms or legs.
• Loss of vision in one or both eyes, changes in the size or shape of the pupils and the reaction to light or abnormal eye movements, such as jerking motions or the eyes not working together.
• Dizziness, vertigo, or unsteadiness that prevents standing or walking.
• Persistent nausea and vomiting.
• Severe stiff neck.

A person with a serious head injury should visit a health professional immediately.

It can be hard right after a head injury to tell the difference between a mild concussion and a more serious injury. A brain bruise (contusion) or bleeding within the skull at first may cause only mild symptoms. If a person with a head injury is seen by a doctor, he or she should still be closely watched for any changes in behavior or symptoms for the next 24 hours.