Traumatic Brain injury is a major cause of disability and death in Australia and world wide. The most common causes are Motor Vehicle Accidents, falls and assault. A traumatic brain injury can lead to alterations in a persons cognitive, social and emotional functioning that not only impact on one person, but an entire family.

What is traumatic Brain Injury?

A Traumatic Brain Injury or TBI is an injury to the brain resulting from a blow to the head or other external force that generally results in a period of unconsciousness and result in temporary or permanent brain impairment. This may be the result of a car accident, assault, fall or sporting accident. A traumatic brain injury can be described or classified in a number of different ways depending on how it happened. Firstly, a traumatic brain injury may be described as a closed or open brain injury:

A closed brain injury - closed injuries mean that injury to the brain has occurred without the skull being broken or penetrated and the brain has not been exposed. An example of a closed head injury is when the rapid movement of the head backward and forward (acceleration-deceleration movement) causes the brain to move inside the skull slamming against the inside of the skull.

An open brain injury - A traumatic brain injury may result from the head hitting an object or an object piercing the skull and brain tissue (open or penetrating head injury). In an open brain injury the skull and membrane lining of the brain have been fractured or pierced.

A traumatic brain injury can be focal or diffuse. In a focal injury, damage is isolated to one specific area of the brain, usually at the site of impact. In diffuse injuries damage is wide spread and involves damage to communication pathways, known as axons, which may have been stretched or torn through the traumatic event. As this damage is at the microscopic level Imaging tests such as CT scans and MRI's may not detect this type of damage.

How do we know how severe the injury is?

A traumatic brain injury can range from a mild brain injury, or sometimes thought of as concussion, to severe or profound brain damage. A widely used indicator of severity is the Glasgow Coma Scale (GCS). This scale measures a person’s level of consciousness on a scale of 3-15, with 3 being the lowest level of consciousness. Scoring is based on verbal, motor and eye-opening reactions to stimuli. Generally, a score of 13 or above on the GCS is considered a mild brain injury or concussion, 9-12 as moderate and 8 or below severe. Other reliable indicators of severity of damage include how long the person is in coma and the length of time with post-traumatic amnesia. The length of Post Traumatic Amnesia is considered the best indicator of the extent of cognitive and functional impairment after TBI [1].

Depending on whether the injury is diffuse or focal, the effects of a brain injury may vary. A diffuse brain injury may result in a wider range of effects whereas focal injuries may have specific effects depending on which area of the brain is damaged. For example, localised damage to the temporal lobe may lead to specific problems with short-term memory. However it should be kept in mind that the brain is a complex organ and that many of its functions are not located in one specific area, but is the result of interactions between many different parts of the brain.

In a diffuse brain injury you may see many different effects including difficulties with concentration, attention span, impulsivity and fatigue.

What is the difference between an acquired brain injury and traumatic brain injury?

There can be some confusion about the various terms used to refer to a brain injury. The term ‘acquired brain injury’ refers to any form of damage to the brain that occurs after birth. It is a general term that includes both traumatic brain injury and non-traumatic forms of damage to the brain. Types of Non-traumatic brain injury include stroke, tumour and infection. The ways the brain is damaged in non-traumatic types of brain injury are different to the causes of traumatic brain injury.

How is the brain damaged is in a closed or open brain injury?

A brain injury can be diffuse or focal, often the two occur together. Diffuse damage involves damage to axons, the brain’s communication pathways, which occurs when the axons are stretched or severed. Types of focal injuries include contusions (bruised brain tissue), which often occur under the sight of impact, lacerations (torn brain tissue), and or haematoma (a collection of blood inside or around the brain), which can be the result of haemorrhaging. A traumatic brain injury can also result in brain haemorrhaging, which involves bleeding in the brain or outside the brain.

A traumatic brain injury can lead to secondary injuries, which arise due to the brain’s reaction to the first injury. These further injuries include brain swelling and haemorrhaging. Complications such as brain swelling, put pressure on brain tissue, which can restrict oxygen supply to other parts of the brain, which can lead to cell death. Often treatment of a traumatic brain injury is focused on controlling these secondary effects to prevent further damage.

How is Traumatic Brain Injury Diagnosed & Treated?

When a person suffers a TBI generally they are brought to the hospital emergency room for initial diagnosis and treatment. This stage generally focuses on assessing and stabilizing the person’s condition. Once the person is assessed as not being in immediate medical danger a complete neurological evaluation is performed to rule out conditions requiring neurosurgical attention, such as hematomas, depressed skull fractures, and elevated intra-crantial pressure (ICP) and to asses the severity of the injury [2].

Different imaging tests may be used in diagnosis including [2]:

• Computed Tomography (CT) Scans – provides a three dimensional view of the structure of the brain and can be used to detect abnormalities for example, fractures or contusions. A CT scan can also be used to examine other structures of the body. When someone has a CT scan they are required to lie flat and have their head placed within a large cylinder for a series of x ray images to be taken.
• Magnetic Resonance Imaging (MRI) – The MRI uses electromagnetic radio waves to produce either 3-D or 2-D images of the brain (or other parts of the body). MRI produces more detailed images of soft tissue and organs compared to a CT scan and can differentiate between similar tissues effectively.
• X-Radiation (composed of X-rays) is a form of electromagnetic radiation used as a diagnostic tool that reveals damage to structure of the brain. It is also used to assess other areas of the body.
• Inter Cranial Pressure (ICP) Monitor – part of the monitor is implanted inside the skull, just above the brain, or into one of the brain's ventricles to monitor changes in intracranial pressure. The risk of increased ICP is that it can can restrict blood circulation in the brain, shift brain structures, and can restrict blood supply to the brain causing cell death and further brain damage through hypoxia.

What are the possible short and long- term effects of TBI?

This will depend on the location and extent of the resulting damage and ongoing rehabilitation. Each person is different and recovery and effects will also vary according to pre- injury personality and life factors, however some of the common effects include:

• Increased Irritability
• Cognitive difficulties, such as memory difficulties, short attention, and difficulties with executive functions
• Impulsivity
• Anger
• Fatigue
• Post -Traumatic Headaches
• Depression

Picture of Traumatic brain injury in Australia

Statistics on brain injury in Australia can be found in reports by the Australian Institute of Health and Welfare (AIHW). These reports are based on hospital data collected over specified time periods. According to recent report of hospital separations (hospital discharge data) due to traumatic brain injury in Australia for the period 2004-05 (AIHW 2008) [3]:

• 22,710 people were hospitalised with either TBI as a primary (the main reason for a person’s hospitalisation) or additional diagnosis (it was not the primary reason for hospitalisation) to other medical complications in Australia.
• Rates of traumatic brain injury were found to be generally higher for younger people and seniors.
• Younger males were hospitalised at higher rates than females across all age groups.
• The most common causes of traumatic brain injury for those presenting to a hospital with TBI as the primary diagnosis were falls, transportation and assault.
• Concussion and brief loss of consciousness occurred in many patients (60%) who presented to hospital in this time with a primary diagnosis of TBI.

 

References & Resources

[1] Rehabilitation After Traumatic Brain Injury: http://www.mja.com.au/public/issues/178_06_170303/kha11095_fm.html

[2] Neurology Channel (viewed April 7, 2009): http://www.neurologychannel.com/diagnostictests/CTscan.shtml

[3] Hospital Separations Due to Traumatic Brain Injury (2004-05): http://www.aihw.gov.au/publications/index.cfm/title/10505