Brain injury


The National Institute for Health and Clinical Excellence (NICE) defines a head injury as any trauma to the head other than shallow injuries on the surface of the face.

A severe head injury may cause:

  • loss of consciousness
  • fits or seizures, when the body suddenly moves uncontrollably
  • problems with the senses, such as loss of hearing or double vision

Glasgow Coma Scale

Head injuries are assessed by healthcare professionals using the Glasgow Coma Scale (GCS). This is a scale from 3 to 15 that is used to identify how serious the injury is and how severely the brain has been damaged (with 3 being most severe and 15 least severe).

A head injury is usually classed as being severe if someone has a GCS score of eight or less. See Diagnosing severe head injury for more information.

Brain injury

A severe head injury can cause brain damage (a brain injury). Even though the brain is protected by the bone covering of the skull, the surface of the brain can tear or bruise as it bumps against the skull. This can damage blood vessels and nerves.

These injuries can cause bleeding, blood clots or a build-up of fluid, which puts pressure on the brain. This can sometimes lead to a brain injury, which can be either temporary or permanent. Brain injuries can have many different effects, including:

  • emotional effects
  • behavioural effects
  • physical effects

How common are head injuries?

Head injuries are more common in men and children. The most common causes of head injuries are falls, assaults and road traffic accidents.


Severe head injuries should always be treated in hospital. See Symptoms of severe head injury for signs of a severe head injury. Treatment in hospital will involve:

  • observing the condition for any changes
  • running tests to check for further damage
  • treating any other injuries

Of the people admitted to hospital due to a head injury, 1-3% could develop a serious complication that may require surgery. Most people (around 97%) are able to go home after 48 hours.

The rate of death after a head injury is 0.2%. This means that for every 1,000 people who attend an accident and emergency (A&E) department at a hospital with a head injury, two of them may die. 

If you have a head injury, it could affect your ability to drive. It is your legal obligation to inform the Driver and Vehicle Licensing Agency (DVLA) about a medical condition that could have an impact on your driving ability. Go to the Directgov website to find out how to tell the DVLA about a medical condition


The brain controls thought, memory and emotion. It sends messages to the body controlling movement, speech and senses.


Last updated: 04 October 2011

Symptoms of a severe head injury

If a severe head injury is not correctly treated, it can cause serious brain damage. This type of head injury always requires urgent medical attention. The symptoms of a severe head injury can include:

  • unconsciousness (either very briefly or for a longer period of time)
  • difficulty staying awake or still being sleepy several hours after the injury
  • having a seizure or fit (when your body suddenly moves uncontrollably)
  • difficulty speaking, such as slurred speech
  • vision problems or double vision
  • difficulty understanding what people say
  • reading or writing problems
  • balance problems or difficulty walking
  • loss of power in part of the body, such as weakness in an arm or leg
  • pins and needles (a prickling or burning feeling) in the hands or feet
  • amnesia (memory loss), such as not being able to remember what happened before or after the injury
  • clear fluid leaking from the nose or ears (this could be cerebrospinal fluid, which normally surrounds the brain)
  • a black eye (with no other damage around the eye)
  • bleeding from one or both ears
  • new deafness (loss of hearing) in one or both ears
  • bruising behind one or both ears
  • a lasting headache since the injury 
  • vomiting since the injury
  • irritability or unusual behaviour
  • visible trauma (damage) to the head, such as an open, bleeding wound  

If any of these symptoms are present, particularly loss of consciousness even for a short time, go immediately to the accident and emergency (A&E) department of your local hospital or call 999 and ask for an ambulance.

Also call 999 for an ambulance if the person with the head injury is not breathing. For more information about accidents and resuscitation, see Accidents and first aid.


The brain controls thought, memory and emotion. It sends messages to the body controlling movement, speech and senses.

Last updated: 04 October 2011

Causes of a severe head injury

In the UK, road traffic accidents are one of the most common causes of severe head injuries. This includes accidents that involve more than one vehicle and those that involve a pedestrian or cyclist.

Other possible causes of severe head injuries include:

  • accidents at home
  • sports-related injuries
  • industrial accidents, such as falls while at work
  • assaults


In the UK:

  • around three-quarters of people with head injuries are male
  • up to one-fifth of people with head injuries are 65 years of age or over
  • nearly half of people with head injuries are children
  • nearly two-thirds of head injuries in adults involve alcohol
Last updated: 04 October 2011

Diagnosing a severe head injury

If you have a head injury and you need to visit your GP or a hospital, or if you need to call an ambulance, the healthcare professionals treating you will ask:

  • how you were injured
  • when you were injured
  • if you have been drinking alcohol
  • if you have taken any illegal drugs

If you cannot remember how your injury occurred, ask someone who saw your accident to describe it to you, if possible.

You will be asked about your symptoms, for example:

  • whether you have lost consciousness
  • whether you have a headache
  • whether you have been sick

If you are with someone who has a head injury, provide as much information as possible about the accident and the person’s symptoms. This will help with the diagnosis and treatment.

Your GP or the paramedics or doctors who are treating you will assess your condition using the Glasgow Coma Scale (GCS).

Glasgow Coma Scale

After a head injury, healthcare professionals use the Glasgow Coma Scale (GCS) to assess how severely your brain has been damaged. The GCS scores you on:

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

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

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

A score of three (the lowest possible score) means that you cannot open your eyes and you cannot move or make a noise. The score indicates that your body is in a deep coma (a sleep-like state where you are unconscious for a long time).

Depending on your score, head injuries are classed as:

  • minor: a score of 13 or more
  • moderate: a score of 9-12
  • severe: a score of 8 or less

Based on your assessment, you may be:

  • allowed to go home
  • referred to hospital (if you are not already at a hospital)
  • sent for further testing and treatment

Going home

You will only be allowed to go home after a head injury if:

  • an examination shows that you are at low risk of brain injury
  • your symptoms have not met the criteria for being referred to hospital (see below)

You will need someone to take you home because you will not be allowed to drive until you have completely recovered. If possible, you will also need someone to stay with you for the first 48 hours after your injury.

Your GP or the doctors treating you will give you advice about what to do and what not to do in the weeks following your injury. See Recovering from a severe head injury for more information about caring for a head injury at home.

Referral to hospital

You will be referred to the emergency department of a hospital (if you are not already at one) if any of the following apply to you:

  • you have any of the symptoms listed in Symptoms of severe head injury
  • you have a GCS score of 14 or less
  • you were involved in a ‘high-energy’ head injury, for example if your injury was caused by a car or bike accident or a fall from a height of more than 1m (3ft) or five stairs
  • you have previously had brain surgery
  • you have previously had, or still have, a bleeding or clotting condition (a condition that affects the blood’s ability to thicken properly)
  • you are currently taking an anticoagulant (blood-thinning) medicine, such as warfarin  
  • you are currently drunk or you have been taking illegal drugs
  • you are 65 years of age or over 
  • it is possible that the injury was not accidental, for example you deliberately hurt yourself or someone else hurt you on purpose
  • the healthcare professional with you is concerned about your diagnosis

Further testing

In some cases, further tests may be necessary to determine how serious your head injury is and whether you are at risk of developing any complications. The tests you need and how urgently you need them will depend on:

  • your symptoms
  • your GCS score
  • your medical history
  • the circumstances of your injury

Tests that you may possibly need to have are described below.

Computerised tomography (CT) scan

computerised tomography (CT) scan involves having a series of X-rays taken of your body at different angles. This produces a detailed image of the inside of your body.

A CT scan can be used to examine the bone, muscle and tissue in your neck, to check for any damage and to identify whether there is any bleeding or inflammation (swelling) in your brain.


An X-ray uses radiation to take pictures of the bones inside your body. An X-ray may not help diagnose a brain injury, but it can be used to check for any breaks or fractures in your skull or other bones in your body.

Magnetic resonance imaging (MRI) scan

magnetic resonance imaging (MRI) scan uses strong magnetic fields and radio waves to produce a detailed image of the inside of your body.

An MRI scan can measure changes in blood flow in the brain and detect damage to the brain or spinal cord.

Test results

Depending on your test results, you may be allowed to go home, but usually you will be kept in hospital for a short time. This is to make certain that your injury has not caused any serious problems.


The brain controls thought, memory and emotion. It sends messages to the body controlling movement, speech and senses.


Last updated: 04 October 2011

Treating a severe head injury

Once the severity and nature of your head injury has been diagnosed, you will be given appropriate treatment. A severe head injury must always be treated in hospital. This is to minimise the risk of complications.

Initial treatment

When you arrive at the emergency department of a hospital or if you call an ambulance, the doctors or paramedics (members of the emergency medical services) treating you will prioritise any injury that may be life threatening. This could mean:

  • checking that your airway is clear
  • checking that you are breathing, and starting cardio-pulmonary resuscitation (CPR or mouth-to-mouth) if you are not
  • stabilising your neck and spine, for example using a neck brace
  • stopping any severe bleeding
  • providing pain relief if you are in a lot of pain
  • splinting any fractured or broken bones (strapping them into the correct position)

Once you are stable, further treatment will be arranged, as necessary, including any tests that you need to help determine the severity of your injury. See Diagnosing severe head injury for more information about the tests you may have.


If you need to stay in hospital for observation, the doctors and nurses who are treating you will check:

  • your Glasgow Coma Scale (GCS) score (a scale of 3 to 15 that assesses the extent of damage to your brain)
  • the size of your pupils (the black circles in the middle of each eye) and whether they react to light
  • how well you can move your arms and legs
  • your breathing
  • your heart rate
  • your blood pressure
  • your temperature
  • the level of oxygen in your blood

These checks will be made every half an hour until your GCS score is 15 (the highest possible score). A GCS score of 15 indicates that you know where and who you are, you can speak and move as instructed and your eyes are open. After this, checks will be made less frequently.

Any changes in your condition or behaviour will also be closely monitored. If your condition worsens, you may need to have further tests, such as a computerised tomography (CT) scan (a scan that produces images of the inside of your body). 

Cuts and grazes

If you have any external cuts or grazes to your head, these will be cleaned and treated to prevent further bleeding or infection. Deep or large cuts may require stitches (sutures) to keep them closed until they heal. Local anaesthetic (a painkilling medication) may be used to numb the area around the cut so that you do not feel any pain.


Neurosurgery is any kind of surgery that is used to treat a problem with the nervous system (the brain, spinal cord and nerves). In cases of severe head injury, neurosurgery is usually carried out on the brain.

Neurosurgery is required in 1-3% of people with a severe head injury. Every year in the UK, it is estimated that just under 4,000 people have neurosurgery following a head injury.

Possible reasons for neurosurgery include:

  • a haemorrhage (severe bleeding) inside your head, which puts pressure on the brain and may result in brain injury (brain damage) and, in severe cases, death
  • a haematoma (blood clot) inside your head, which can also put pressure on the brain
  • cerebral contusions (bruises on the brain), which can develop into blood clots
  • skull fracture (see below)

These conditions will be identified during tests, such as a CT scan, and a neurosurgeon (an expert in surgery of the brain and nervous system) may come and speak to you or your family about whether surgery is necessary.

As the above conditions can be serious and may require urgent treatment, in some cases there may not be time to discuss the surgery before it is carried out. After the operation, your surgeon will take the time to discuss the details of the surgery with both you and your family.

One possible type of surgery that may be required is a craniotomy.


A craniotomy is a type of surgery that involves making a hole in your skull (the bone in your head that surrounds your brain) so that the surgeon can access your brain. This will be carried out under general anaesthetic so that you are unconscious and cannot feel anything.

Once your surgeon has access to your brain, they will remove any blood clots that may have formed and repair any damaged blood vessels. Once any bleeding inside your brain has stopped, the piece of skull bone will be replaced and reattached. 

Other surgical procedures

Depending on the type of damage to your brain, there are a number of other possible surgical procedures. Ask your surgeon for more information or see below if you have one of these conditions:

Skull fractures

Your skull can fracture (crack) during an injury to your head. If this happens, you will usually have an X-ray to determine the extent of the injury.

There are different types of skull fractures, including:

  • simple (or closed) fracture, where the skin has not broken and the surrounding tissue is not damaged
  • compound (or open) fracture, where the skin has broken and the surrounding tissue may be damaged
  • linear fracture, where the break in the bone looks like a straight line
  • depressed fracture, where part of the skull is crushed inwards

Open fractures may be more serious because there is a higher risk of infection if the skin is broken. This is because bacteria could enter the wound through the open skin. Depressed fractures may also be more serious because small pieces of bone can press inwards against the brain.

Treating skull fractures

Most skull fractures will heal by themselves, particularly if they are simple, linear fractures. The healing process can take many months, although any pain will usually disappear in around 5-10 days.

If the fracture is open, you may be prescribed antibiotics (medicines to treat infections that are caused by bacteria) to prevent an infection.

If the fracture is very severe or depressed, you may need to have surgery to help prevent any damage to the brain. This will usually be carried out under general anaesthetic.

During your operation, any pieces of bone that have been pressed inwards can be removed and returned to their correct position. If necessary, metal wire or mesh may be used to reconnect the pieces of your skull.

Once the bone is back in place, it should heal naturally. If you wish, your surgeon will explain the procedure that you are having in more detail.

After surgery

Depending on how serious your operation was, you may need to recover in an intensive care unit (ICU). This is a small, specialised ward where your condition will be constantly monitored. 

In an intensive care unit, you may be placed on a ventilator. This is an artificial breathing machine that moves oxygen-enriched air in and out of your lungs. The ventilator takes over some of your body’s usual responsibilities, such as breathing, giving your body time to recover.

Once you are well enough, you will be moved to a ward and your condition will be observed, as described above.


The brain controls thought, memory and emotion. It sends messages to the body controlling movement, speech and senses.

Blood supplies oxygen to the body and removes carbon dioxide. It is pumped around the body by the heart.

Blood vessel
Blood vessels are the tubes in which blood travels to and from parts of the body. The three main types of blood vessels are veins, arteries and capillaries.

To haemorrhage means to bleed or lose blood.

Body tissue is made up of groups of cells that perform a specific job, such as protecting the body against infection, producing movement or storing fat.

Last updated: 04 October 2011

Complications of a severe head injury

Severe head injuries can cause serious complications. This is mainly because a serious injury to the head can potentially damage the brain, sometimes permanently.

In particularly severe cases, a serious head injury can result in death. This is why your condition will be closely monitored when you are admitted to hospital. This will allow any complications that arise to be dealt with promptly and effectively.


If your skull is fractured during a head injury, your risk of developing an infection may be increased. Skull fractures can occasionally tear the membrane (the thin layer of cells) that surrounds the brain. If this happens, bacteria can enter the wound and cause an infection.

It is important to keep any external wounds on your head clean so that they do not become infected. You may be prescribed antibiotics (medicines to treat infections that are caused by bacteria).


A coma is where you are unconscious and unresponsive for a long time. Some people who have a severe head injury may enter a coma. Most comas only last a few days or weeks, but sometimes they can last for years.

Many people recover from comas. However, in some severe cases, the patient never regains consciousness or goes into a vegetative state.

Vegetative state

A person in a vegetative state may seem to be awake and may show some limited physical response, but they have no awareness of their surroundings. They may be able to breathe or eat on their own, but they cannot speak or understand what is said to them.

Headway, the brain injury charity, estimates that at any particular time in the UK, there are around 100 people in a vegetative state.

Brain injury 

A severe head injury can damage the brain in several ways. For example, a blood clot may form and put pressure on the brain. This can lead to a variety of complications. Some types of brain injury are only temporary, whereas others result in permanent damage. The effect of any brain injury will depend on:

  • where on the head the injury occurs
  • the type of injury, for example if the skull is fractured
  • the severity of the injury, for example if it requires surgery

The different effects of a brain injury are described below.

Physical effects

Physical effects of a brain injury can include difficulty moving or keeping your balance and loss of co-ordination. You may also experience headaches or increased tiredness. 

Hormonal effects

Some head injuries can damage the pituitary gland. The pituitary gland is a pea-sized gland in the centre of the head. It hangs below the brain and produces hormones (powerful chemicals that have a wide range of effects on the body). If the pituitary gland is damaged, it may lead to the low production of hormones.

Sensory effects

Your senses may be affected by a head injury. For example, you may lose your sense of taste or smell. You may also notice blind spots in your vision or you may not be able to control your body temperature as well as before, so that you feel too hot or too cold.

Cognitive effects

Following a head injury, your ability to think, process information and solve problems may be affected. You may also experience memory problems, particularly with your short-term memory, and have difficulty with your speech and communication skills.

Emotional or behavioural effects

After a severe head injury, you may experience changes to your feelings and behaviour. For example, you may have feelings of irritation, anger or selfishness.

You may be less sensitive to other people’s feelings or lose your inhibitions and behave in a way that other people may not consider appropriate. You may also laugh or cry more than before the injury.  

Getting support

As everyone’s brain injury will be different, it is a good idea to seek further information about the possible effects and rehabilitation techniques. A number of charities and organisations may be able to help. You can find details of these in the useful links (above right). 


The brain controls thought, memory and emotion. It sends messages to the body controlling movement, speech and senses.

Bacteria are tiny, single-celled organisms that live in the body. Some can cause illness and disease and some are good for you.

Antibiotics are medicines that can be used to treat infections caused by micro-organisms, usually bacteria or fungi.

Last updated: 04 October 2011

Preventing a severe head injury

Many head injuries are the result of accidents that are very difficult to predict or avoid. However, if you have a head injury, you can reduce your risk of developing serious complications.

Safety helmets

Cyclists and motorcyclists can protect their head by wearing a properly fitting safety helmet. Safety helmets can significantly reduce the risk of a serious head injury in an accident. British standard safety helmets are a legal requirement for motorcyclists.

When cycling, always wear a properly fitting safety helmet. Cycling helmets reduce the risk of a head injury by up to 88% and the risk of an injury to your face by 65%.

Make sure that your child also knows the importance of wearing a cycle helmet and wears one every time they ride a bike. Ensure that both you and your children use lights when cycling in the dark.

Safety in the home

Following sensible health and safety guidelines can help prevent accidents in the home. The advice below will help keep your home and garden as safe as possible.

  • Keep stairways tidy so that you do not trip over anything.
  • Use appropriate safety equipment if you are doing any kind of DIY.
  • Do not stand on an unstable chair to change a light bulb. Use a stepladder.
  • Clean up any spillages to prevent someone slipping over.
  • Follow the manufacturer’s instructions when using weed killer or any other chemical products.

For more information, see the Royal Society for the Prevention of Accidents website.

Childproofing your home

It is not possible to ‘childproof’ your home completely. However, you can take steps to keep toddlers and young children safe at home. See the video about accident prevention (above) and the advice below.

  • Check that windows are lockable and cannot be opened by your child. This is particularly important for the windows in your child's bedroom.
  • Move furniture, such as beds, sofas and chairs, away from windows to prevent your child climbing up and falling out.
  • Make sure that chemicals, such as cleaning products, are out of your child's reach.
  • Do not leave hot water unattended, for example a pan of boiling water or a bath.   
  • Fit safety gates at the top and bottom of the stairs.

Safety at work

To reduce the risk of sustaining a head injury at work, always follow any necessary health and safety guidelines. For example, you may have to wear a hard hat and safety shoes when working in potentially hazardous areas.

Sport safety

Wear any necessary safety equipment when playing sports, particularly contact sports. Do not play any contact sports after a head injury without first consulting your GP.

Last updated: 04 October 2011