What is a traumatic brain injury?
Traumatic brain injury (TBI) is an injury to the brain caused by an external force to the head, such as a strong blow or a knock. There are many possible causes, such as road traffic collisions, falls, assaults, sporting injuries and workplace accidents. Even a seemingly minor knock to the head can cause a mild and often temporary form of TBI known as concussion.
What causes a traumatic brain injury?
Traumatic brain injuries (TBIs) are caused by incidents in which there is a strong force to the head. The brain may get damaged from being shaken around inside the skull or it may be directly injured, for instance from an object penetrating through the skull.
TBIs are most commonly caused by:
falls;
assaults;
road traffic collisions.
Other causes of TBI include workplace accidents, domestic abuse, heavy objects falling onto the head, striking the head against a hard object or surface, blast injuries and sporting accidents.
Even seemingly minor accidents in which the head is struck can cause a mild TBI (often referred to as concussion) such as hitting one’s head against a car door or a low shelf. In the sporting world, concussion can be caused by players knocking their heads against one another, the ground or sporting equipment.
Dean's story
"I’d been working with a friend on the day of the accident. The route took us along country lanes – and it was then that it happened. The driver of another car didn’t give way at the signs and hit us, sending our van rolling six times into a ditch.
“At the hospital, I had to have surgery on my head and stomach. They put bolts into my skull to relieve pressure from the fluid that was building up around my brain, and put me in an induced coma to help my brain recover as much as possible. I still have scars on my body, and all the way around my head.”
Find out more about Dean’s experience of TBI and how Headway helped
What happens in a TBI?
There are three types of head injuries that can affect the brain. These are: closed, open and crushing head injuries.
Closed head injuries
In this type of injury, the head is rapidly rotated, knocked or rocked back and forth, for example when a car is hit from behind at traffic lights or during a sporting accident. In these injuries, there is no visible breakage of the skin or open head wound, so it is not always obvious that the brain has been affected.
The brain fits tightly inside the skull, with very little extra space to move around. When there is a strong force to the head, the brain is rapidly shaken around inside, causing its nerve fibres to stretch, twist and tear from the force.
The force from such accidents can also cause the brain to collide with the front of the skull, which has sharp, bony ridges. This can damage blood vessels in the brain, leading to bleeding in or around the brain known as a brain haemorrhage. In turn, the leakage of blood can raise pressure, causing further damage to brain tissue.
Open head injuries
In this type of injury, an object or skull fragment penetrates the skull and the coverings of the brain to directly damage brain tissue. This could be from a sharp object hitting the head or from an object penetrating through the skull. Damage from these injuries may affect particular functions or abilities, depending on the area of the brain that is injured.
Crushing head injuries
In this type of injury, the head is caught between two hard objects or surfaces, such as the wheel of a car and the road. The pressure crushes the skull, which in turn can damage the brain through pressure, bleeding or injury from bone fragments. There can be bleeding or bruising to the brain.
Call 999 immediately if you or someone else has had a head injury and they are unconscious or struggling to stay awake. You should also call 999 if there are problems with seeing, hearing, walking, balance, understanding, speaking or writing, a seizure, or bruising around the eyes without direct eye injury, bleeding from the ears or clear fluid coming out of the ears or nose following a head injury.
You should go to A&E if you have had a head injury followed by vomiting, a headache that does not get better, changes in your behaviour or thinking skills or if you were unconscious but have now woken up. You should also go to A&E if you take anticoagulant medicine, have a blood-clotting condition or any other concerning symptoms after head injury. Do not drive yourself to A&E.
Call NHS 111 for any other concerns or if you are unsure what to do following a head injury.
Additional medical complications may develop in the minutes, hours or days after a TBI. These are known as secondary injuries. This is why it is important to monitor for symptoms after a head injury and to follow medical advice given.
For instance, severe blood loss or impaired blood flow can disrupt the brain’s vital oxygen supply, causing a type of injury called anoxic or hypoxic brain injury. Bleeding in or around the brain (brain haemorrhage), swelling (oedema) of brain tissue or a build-up of cerebrospinal fluid (hydrocephalus) can increase pressure on the brain, damaging brain tissue. Pooling of blood, known as subdural haematomas, may also occur following bleeding and increase pressure within the skull.
Alastair's story
Alastair Wallace, from Willesden Green in North West London, sustained a brain haemorrhage and skull fracture and, after being in an induced coma, spent two weeks in hospital where he had to wear a BMX helmet to protect his brain.
“I missed one step that day in 2019 and the next thing I woke up in hospital with half my head missing.
“I feel like I was really lucky, but it’s been a journey.”
Read more about Alistair’s experience of rebuilding life after TBI.
How are TBIs classified?
Traumatic brain injuries (TBIs) are classified as mild (often referred to as concussion), moderate or severe, to describe the injury during its early clinical assessment and help with identifying the kind of medical treatment needed. The classification given is based on clinical characteristics such as length of loss of consciousness, Glasgow Coma Scale score and length of post-traumatic amnesia. These are described below.
Length of loss of consciousness (LOC)
This refers to loss of the ability to be awake and aware of oneself and one’s surroundings. After a TBI, this can be transient (lasting only a short time) or last for much longer. If there is no LOC or LOC of less than 30 minutes, the injury is classified as mild. If the LOC lasts for 30 minutes or longer, it is classified as moderate or severe. If the LOC lasts for longer than 6 hours, the person is classified as being in a coma.
Glasgow Coma Scale (GCS) score
This is a clinical tool that is used to measure a person’s level of consciousness based on their ability to open their eyes, move and speak. A score of 13-15 indicates a mild injury, 9-12 indicates a moderate injury, and 3-8 indicates a severe injury.
Length of post-traumatic amnesia (PTA)
Post-traumatic amnesia is a temporary phase that follows a period of unconsciousness and is a normal part of the recovery process. A person with PTA is conscious and awake, but they cannot remember some things and may behave or talk in an unusual way that is often out of character. An injury with PTA lasting for less than 24 hours is classified as being mild, while anything lasting for 24 hours or longer is classified as moderate or severe.
Recent developments have led to a new classification system being developed, the CBI-M. In addition to the traditional measure of GCS, this system will include pupil response, presenting symptoms such as dizziness and headaches, brain imaging, blood biomarker results and modifying factors such as the person’s age, medication use and health conditions. This is a fairly new development and in its early stages.
How are TBIs treated?
Treatment of TBIs varies depending on the severity of injury.
Treatment of mild injuries
A person with mild TBI may be assessed by a medical professional, either at the scene of the injury or at hospital. They may undergo tests and be kept for observation before being allowed to return home. They may be able to recover with rest and symptom management, usually within a few weeks. Guidance on recovery and symptoms is available on Concussion.
Treatment of moderate or severe injuries
Moderate and severe brain injuries need emergency treatment and ongoing care in hospital. Further information on these stages is available on Hospital treatment.
What happens after a TBI is treated?
People usually make a full recovery from mild traumatic brain injuries (TBI) within a few weeks with rest and symptom management. However, some people may continue having difficulties and may develop post-concussion syndrome, requiring further professional help.
Following treatment for a moderate or severe TBI, a person will usually need to stay in hospital to recover. They will continue to be monitored by the medical team. The length of the hospital stay will depend on the type and severity of the TBI, the treatment provided and the person’s individual needs.
The person may have rehabilitation to help manage the physical, cognitive or emotional impact of the TBI. This can take place within the hospital, at a specialist brain injury rehabilitation unit or through community-based teams.
A person may be able to return directly home from hospital, but they will need to continue resting. The time needed to recover and return to usual activities varies from person to person.
For more information on these next stages, visit Treatment and rehabilitation.
Jack's story
Jack was punched in the head and fell to the ground, striking his head on the kerb. Just one punch – one moment of senseless violence – changed Jack’s life forever.
“Everything I’d worked towards had been wiped away...For the first 48 hours after the attack it was touch-and-go whether or not I survived."
Find out more about Jack's story.
