Response To Traumtic Brain Injury Flashcards
How is blood flow to the brain regulated?
Myogenic mechanism of vasodilation and vasoconstriction of blood vessels.
What is the most common cause of death and disability?
Traumatic brain injury.
What are common causes for traumatic brain injury?
Road traffic collisions
Falls
Violence
Non-accidental injuries of children
What is primary traumatic brain injury?
Occurs at the moment of trauma.
What is secondary traumatic brain injury?
Changes in the brain after the trauma which causes further destruction.
What are the types of primary brain injury?
Separated into a focal brain injury and diffuse brain injury which includes:
Intracranial haemorrhage
Penetrating wound
Skull fracture
Laceration
What is a focal brain injury?
Localised primary brain trauma, such as contusions(bruise) and lacerations.
What is a diffuse brain injury?
Primary brain injury with widespread lesions such as:
Hypoxia
Diffuse brain swelling
Diffuse axonal swelling
What is intracranial pressure?
Pressure exerted by Cerebrospinal fluid on the brain tissues, with normal range being 7-15 mmHg.
What is mean arterial pressure?
Average blood pressure produced in one cardiac cycle.
What is cerebral perfusion pressure?
Pressure required to maintain blood supply to the brain. It is the sum of mean arterial pressure- intracranial pressure.
Therefore increased intracranial pressure will result in a drop in cerebral perfusion, resulting in brain ischaemia.
What is the normal range for cerebral perfusion pressure?
50-70 mmHg.
What is the response when mean arterial pressure is low?
Results in a drop in cerebral perfusion pressure, so myotonic mechanism of vasodilation occurs, increasing cerebral blood volume and eventually resulting in increased blood pressure.
What is the Monro-Kellie hypothesis?
Cranium contains the brain, arterial + venous blood supply and cerebral spinal fluid which contribute to pressure. When one of these components is high, the other components reduce in volume to maintain a standard intracranial pressure however, this is only within a limit.
What is diffuse axonal injury?
A fall or blunt injury of the head causes injury of the brain as it rotates against the skull in a coup and contracoup injury. This results in extensive damage to the grey matter with a shearing force of stretching and tearing applied to axons.