Diagnosing a severe head injury 

A person with a severe head injury should always be seen in an accident and emergency (A&E) department.

If any of the symptoms of a severe head injury are present, immediately go to your local A&E department or call 999 and ask for an ambulance.

The healthcare professionals treating you will first make sure you're in a stable condition, before asking some questions to help with the diagnosis and treatment of your injury.

If a friend or relative has come with you to hospital, they may be asked to describe what happened if you can’t remember.

Computerised tomography (CT) scan

You'll have a computerised tomography (CT) scan to help determine the extent of your injury and assess your risk of developing complications of a severe head injury.

The CT scan produces a detailed image of the inside of your head and shows whether there's any bleeding or swelling in your brain.

Depending on your scan results, you may be allowed to go home (see below). However, you'll usually be kept in hospital for a short period of time to make sure that your injury hasn't caused any serious problems.

The healthcare professionals treating you will assess your condition using the Glasgow Coma Scale (GCS).

Glasgow Coma Scale (GCS)

The GCS is often used to assess the severity of damage to the brain. It scores you on:

  • verbal responses (whether you can make any noise)
  • physical movements
  • how easily you can open your eyes

Your score for each is added up to give a total. A slightly different version of the GCS is used for children under five years of age.

Depending on your GCS score, head injuries are classed as:

  • minor – a score of 13 or higher
  • moderate – a score of 9 to 12
  • severe – a score of 8 or lower (the person will be unconscious)

A score of 15 (the highest possible score) means you know who and where you are, you can speak and move when asked to, and your eyes are open.

Someone with a score of 3 (the lowest possible score) will be in a coma (an unconsciousness state where a person is unresponsive and can't be woken). Their chances of survival will be small.

Based on your assessment, you may be allowed to go home or you may be referred for further testing and treatment in hospital. You may also need to have follow-up appointments at your local neurological centre or head injury clinic.

Going home

After a severe head injury, you'll only be allowed to go home if the results of your CT scan show that you don't have a brain injury and the person in charge of your care (a neurosurgeon or an A&E consultant) thinks you have a low risk of developing one.

You'll need someone to take you home, because you won't be allowed to drive until you've completely recovered. If possible, you'll also need someone to stay with you for the first 24 hours after your injury to keep an eye out for problems.

Before leaving hospital, you'll be advised about what to do and what not to do in the weeks following your injury.

Read more about recovering from a head injury

Admission to hospital

You may need to be admitted to hospital for observation following a severe head injury. This may be because:

  • scans have identified a problem
  • you have persistent symptoms of a possible neurological problem (a problem with the nervous system)
  • your GCS score hasn't returned to 15
  • you have other injuries, such as broken bones or internal bleeding 
  • you're under the influence of alcohol or drugs
  • there's no one at home to look after you

See how a severe head injury is treated for more information about what happens when you're admitted to hospital.


Page last reviewed: 12/01/2016

Next review due: 01/01/2019