Traumatic Brain Injury
Thursday, 19 March 2009
Following the death of actress Natasha Richardson, after suffering a head injury, we have Dr Salvatore Gianasso, Senior Clinical Neuropsychologist at Headways is here to tell us more about Traumatic Brain Injury. Natasha suffered a head trauma during a beginners ski lesson, and although she appeared fine afterwards, about an hour later her condition deteriorated rapidly and recent reports suggest that she is now in a coma. Many of us are wondering how a person can suffer a seemingly minor accident, appear fine afterwards, and then find themselves in a grave situation.
What is traumatic brain injury?
A traumatic brain injury can be defined as an insult to the brain caused by an external force that may produce diminished or altered states of consciousness which results in impaired cognitive abilities or physical functioning.
A Traumatic Brain Injury can be open or closed. A closed injury is caused when
Damage can be localized or generalized, for example the acceleration and deceleration motion of a road traffic accident can cause structural damage to the front and back of brain, a fall can only cause damage to the side on which you fall, and there is also defused structural damage, which is internal.
What are the common causes?
Accidents, car crashes, falls, sports injuries and violent attacks are some of the most common causes of traumatic brain injuries
What are the symptoms of a TBI?
Ideally, when you suffer a head trauma any warning sign should be taken seriously
These can be divided into four categories:
. Sensory, eg blurred vision,
. Cognitive, eg hard to converse, not being coherent or able to think
. Motor, eg loss of use of limbs
. Emotional, eg bouts of anxiety or other emotion which you can't quite explain
If you suffer from ANY of these symptoms or anything different within 24 hours of the trauma, you should at least visit your GP, if not go straight to A&E
Do children have different symptoms?
In general children's symptoms are similar; however they may not be able to articulate them to you. For this reason it is very important to be extra vigilant if a child suffers a bang to the head.
Dr. Salvatore Gianasso's comment on why Natasha Richardson seemed okay after the accident, only to detiorate:-
This is more than likely caused by a slow growing swelling in the brain. Hence the reason why she seemed fine after the trauma, and as the swelling developed her condition went downhill. This is very common.
The number of people with Traumatic Brain Injury (TBI) is difficult to assess accurately but is much larger than most people would expect. According to the CDC (United States Centers for Disease Control and Prevention), there are approximately 1.5 million people in the U.S. who suffer from a traumatic brain injury each year. 50,000 people die from TBI each year and 85,000 people suffer long term disabilities. In the U.S., more than 5.3 million people live with disabilities caused by TBI. Patients admitted to a hospital for TBI are included in this count, while those treated in an emergency room or doctor's office are not counted.
The causes of TBI are diverse. The top three causes are: vehicle crashes, firearms and falls. Firearm injuries are often fatal: 9 out of 10 people die from their injuries. Young adults and the elderly are the age groups at highest risk for TBI. Prevention of TBI is the best approach since there is no cure.
Mechanisms of Injury
These mechanisms are the highest causes of brain injury: Open head Injury, Closed Head Injury, Deceleration Injuries, Chemical/Toxic, Hypoxia, Tumors, Infections and Stroke.
1. Open Head Injury
. Results from bullet wounds, etc.
. Largely focal damage
. Penetration of the skull
. Effects can be just as serious as closed brain injury
2. Closed Head Injury
. Resulting from falls, motor vehicle crashes, etc.
. Focal damage and diffuse damage to axons
. Effects tend to be broad (diffuse)
. No penetration to the skull
3. Deceleration Injuries (Diffuse Axonal Injury)
The skull is hard and inflexible while the brain is soft with the consistency of gelatin. The brain is encased inside the skull. During the movement of the skull through space (acceleration) and the rapid discontinuation of this action when the skull meets a stationary object (deceleration) causes the brain to move inside the skull. The brain moves at a different rate than the skull because it is soft. Different parts of the brain move at different speeds because of their relative lightness or heaviness. The differential movement of the skull and the brain when the head is struck results in direct brain injury, due to diffuse axonal shearing, contusion and brain swelling.
Diffuse axonal shearing: when the brain is slammed back and forth inside the skull it is alternately compressed and stretched because of the gelatinous consistency. The long, fragile axons of the neurons (single nerve cells in the brain and spinal cord) are also compressed and stretched. If the impact is strong enough, axons can be stretched until they are torn. This is called axonal shearing. When this happens, the neuron dies. After a severe brain injury, there is massive axonal shearing and neuron death.
4. Chemical / Toxic
. Also known as metabolic disorders
. This occurs when harmful chemicals damage the neurons
. Chemicals and toxins can include insecticides, solvents, carbon monoxide poisoning, lead poisoning, etc.
5. Hypoxia (Lack of Oxygen)
. If the blood flow is depleted of oxygen, then irreversible brain injury can occur from anoxia (no oxygen) or hypoxia (reduced oxygen)
. It may take only a few minutes for this to occur
. This condition may be caused by heart attacks, respiratory failure, drops in blood pressure and a low oxygen environment
. This type of brain injury can result in severe cognitive and memory deficits
. Tumors caused by cancer can grow on or over the brain
. Tumors can cause brain injury by invading the spaces of the brain and causing direct damage
. Damage can also result from pressure effects around an enlarged tumor
. Surgical procedures to remove the tumor may also contribute to brain injury
. The brain and surrounding membranes are very prone to infections if the special blood-brain protective system is breached
. Viruses and bacteria can cause serious and life-threatening diseases of the brain (encephalitis) and meninges (meningitis)
. If blood flow is blocked through a cerebral vascular accident (stroke), cell death in the area deprived of blood will result
. If there is bleeding in or over the brain (hemorrhage or hematoma) because of a tear in an artery or vein, loss of blood flow and injury to the brain tissue by the blood will also result in brain damage
For more information
. www.headway.ie or 1890 200 278
. www.abiireland.ie or 01 2804164