Severe head injuries require immediate medical attention because there's a risk of serious brain damage.
These pages focus on severe head injury.
Symptoms of a severe head injury can include:
Dial 999 immediately to request an ambulance if you're with someone who experiences any of these symptoms after a head injury.
Alternatively, take them immediately to your nearest A&E department.
You should also go to A&E if someone has injured their head and:
If you have had a severe head injury and there's a chance you may have a brain injury, you'll have a CT scan to assess the seriousness of the injury.
The Glasgow Coma Scale (GCS) is often used to assess head injuries. This is a scale from 3 to 15 that identifies how serious your head injury is, based on your symptoms and whether the brain has been damaged (with 3 being most severe and 15 the least severe).
A GCS score of 13 or above would indicate a minor head injury. A score of 9 to 12 would be a moderate head injury.
If a person has a severe head injury, they'll have a score of 8 or less.
Some people with significant head injuries have a high GCS score initially, but their score decreases when they're reassessed at a later stage.
If you have a severe head injury, you'll be closely monitored and frequently reassessed to check your condition.
Severe head injuries always require hospital treatment.
This may involve:
Most people are able to go home within 48 hours. But a small number of those admitted to hospital require skull or brain surgery.
When you're discharged from hospital, your doctor will advise you on the best way to help your recovery when you return home.
A severe head injury can result in pressure being placed on the brain because of bleeding, blood clots or a build-up of fluid.
This can sometimes lead to brain damage, which can be temporary or permanent.
A severe head injury can also cause other potentially serious complications, including:
It can be difficult to predict or avoid a head injury, but there are some things you can do to reduce the risk of serious injury.
Wearing a safety helmet during certain activities, such as skiing or cycling, may also help to prevent a serious head injury.