Head injuries are common and can happen in a variety of ways, for example through falls, road traffic accidents, sports injuries and assaults. A head injury can cause a range of symptoms depending on whether the brain has been injured, and how severely. Most head injuries are minor but in some cases they can cause severe brain damage.
Concussion is the most common type of minor injury to the brain. Many people who go to the emergency department (A&E) of a hospital with a head injury will have concussion. Some people may have lost consciousness (they were 'knocked out') for a short time and afterwards appeared to be back to normal. People with concussion might not remember what happened just before or after the incident. Tests such as CT scans may not show up any problems, but there can still be tiny areas of damage. These can cause symptoms in the weeks or months after the injury, for example headaches, dizziness and problems with concentration and memory.
When a head injury causes a severe injury to the brain it is known as 'traumatic brain injury'. Signs of a traumatic brain injury usually appear in the first few hours after injury and may lead to serious complications that need immediate treatment. The main complications are:
bleeding inside the skull – called 'intracranial haemorrhage' or an 'extradural or subdural haematoma' – which puts pressure on the brain and needs to be treated quickly, sometimes through an operation
general bruising and swelling in the brain, which may need treatment in intensive care.
There are many levels of consciousness, ranging from normal consciousness to a deep coma. A person is in a coma if they are unconscious and unaware of what is going on around them and they do not open their eyes even in response to pain. Doctors, nurses, ambulance crews and others looking after people with head injuries use the Glasgow Coma Scale (GCS) to assess a person's level of consciousness after a head injury. The scale measures 3 aspects of consciousness: eye-opening, verbal response (for example, speaking) and the responsiveness of the body (for example, the response to pain). The person's score in each area is added up to give a maximum score of 15 (normal consciousness) and a lowest level of 3 (severe coma). A special scale is used for babies and children. If a person has a condition such as dementia or a learning disability that may affect their GCS score, the professionals assessing the person should take this into account.