2a. Traumatic Brain Injury (TBI) Flashcards
What is TBI? (+definition)
And where is it characterized by? (2x)
Traumatic brain injury = damage to living brain tissue caused by an external mechanical force or motion, characterized by …
(1) a period of altered consciousness
(2) a clinical diverse picture with a broad spectrum of cognitive, emotional, and behavioral disorders
What is an open brain injury?
When an object fractures the skull, enters the brain, and injures the brain tissue
(far less more common than closed injuries and more often results in death)
What is a closed brain injury?
When the head accelerates and then rapidly decelerates or collides with an other object.
The brain tissue is damaged by the violent smashing, shaking, stretching, and twitching of the brain and additionally by physiological reactions following the injury
What is a primary injury?
Immediate damage that occurs at the time of impact
What is a secondary injury?
Damage caused by the effects of the physiological processes set in motion by the primary injury
What are 3 types of primary injuries?
And give explanations on these types.
- Bruising of brain parenchyma
- Laceration of nerve fibers
- Disruption of blood vessels
Explanation:
- When the external mechanical force is linear, it results in a contusion (=kneuzing)
- When the external force or motion is more rotational, it may result in tearing of the fibers
- Might be caused by both linear and rotational forces
What is accelaration?
The damage is the result of a moving object that hits the fixed head or the skull is moved by a forceful blow
What is deceleration?
The damage is the result of opposite movements, so the head is moving against a stationary object
What is a coup?
Disruption of the tissue at the point of impact
What is a contre-coup?
(Indirect) disruption of tissue located opposite to the site of impact
Mechanisms of primary injuries
What is Newton’s law of inertia?
And where does it result in?
Acceleration/deceleration process: the brain lags behind when the head is suddenly moved, so it continues to move at the original velocity against the bony ridges within the skull, causing bruises and micro-bleedings.
Where does it result in?
If the force is strong enough, both a coup and contre-coup lesion may result. It primarily results in contusions of the grey matter/parenchyma, frequently found in the orbitofrontal and temporal brain regions, since here is the base of the cranium very rough.
What is hyperextension?
Sudden backward acceleration of the skull causes the brain to move forward, striking the front of the skull.
What is hyperflexion?
The head recoils forward and suddenly stops, the brain shifts backward, striking the back of the skull.
Mechanisms of primary injuries
What is the result of rotating forces?
They cause diffuse axonal injury (DAI), due to the damage of axons by rotational forces
Mechanisms of primary injuries
What is the result of the disruption of blood vessels?
A rupture of a blood vessel may lead to heavy bleeding (primary injury) but it also causes swelling and intercranial pressure (secondary injuries).