The symptoms of a head injury can occur immediately or develop slowly over several hours or days. Even if the skull is not fractured, the brain can bang against the inside of the skull and be bruised. The head may look fine, but complications could result from bleeding or swelling 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 -- other than a concussion or contusion -- and require emergency medical treatment:

• Changes in, or unequal size of pupils
• Convulsions
• Distorted features of the face
• Fluid draining from nose, mouth, or ears (may be clear or bloody)
• Fracture in the skull or face, bruising of the face, swelling at the site of the injury, or scalp wound
• Impaired hearing, smell, taste, or vision
• Inability to move one or more limbs
• Irritability (especially in children), personality changes, or unusual behavior
• Loss of consciousness, confusion, or drowsiness
• Low breathing rate or drop in blood pressure
• Restlessness, clumsiness, or lack of coordination
• Severe headache
• Slurred speech or blurred vision
• Stiff neck or vomiting
• Symptoms improve, and then suddenly get worse (change in consciousness)