The signs of a head injury can occur immediately or develop slowly over several hours. Even if the skull is not fractured, the brain can bang against the inside of the skull and be bruised. (This is called a concussion.) The head may look fine, but complications could result from bleeding inside the skull.

When encountering a person who just had a head injury, try to find out what happened. If he or she cannot tell you, look for clues and ask witnesses. In any serious head trauma, always assume the spinal cord is also injured.

The following symptoms suggest a more serious head injury that requires emergency medical treatment:

• Loss of consciousness, confusion, or drowsiness
• Low breathing rate or drop in blood pressure
• Convulsions
• Fracture in the skull or face, facial bruising, swelling at the site of the injury, or scalp wound
• Fluid drainage from nose, mouth, or ears (may be clear or bloody)
• Severe headache
• Initial improvement followed by worsening symptoms
• Irritability (especially in children), personality changes, or unusual behavior
• Restlessness, clumsiness, lack of coordination
• Slurred speech or blurred vision
• Inability to move one or more limbs
• Stiff neck or vomiting
• Pupil changes
• Inability to hear, see, taste, or smell