TBI Flashcards
what is TBI defined as?
-an alteration in brain function or other evidence of brain pathology caused by external factors
how does Oxford head injury service define TBI?
-any blow to the head, even if not knocked out
-including the full range of head injury, from minor to very severe
-including head injury sustained as either the main injury or in conjunction with other injuries
-including cases who have died as a result of their injury
how is TBI classified?
-primary / secondary
-penetrating / non penetrating
-mild/moderate/severe
-diffuse/focal
what are the causes of TBI?
-falls
-RTA
-sporting accident
-assault
describe the epidemiology of of TBI
-no official statistics for the number of people living in Ireland with a brain injury
-10,000 people hospitalised with TBI
what are the types of damage to the brain?
-impact
-confusion
-laceration
-bleed
-shearing/rotational
-fractures
what’s the difference between coup and countercoup injuries?
Coup Injury – This occurs at the site of impact. When the head is struck, the brain slams against the inside of the skull at the point of contact, causing bruising or damage in that area.
Contrecoup Injury – This occurs on the opposite side of the impact. The brain, after hitting the initial site of impact, rebounds and strikes the opposite side of the skull, causing damage there.
what is a contusion of brain tissue?
-bruising of the brain tissue
-most commonly occur on the undersurface of frontal lobes or the tips of the temporal loves
what are the consequences of contusions?
-attention
-emotional + memory problems
what are difference types of bleeds in the brain/ intracranial hermorrhages?
-subarachnoid haemorrhage
-subdural haemorrhage
-extradural haemorrhage
what can cause subarachnoid haemorrhages?
note: this is bleeding in the subarachnoid space
causes: aneurysm rupture or high velocity injuries
what is a subdural haemorrhage?
bleeding that occurs between the dura mater (the brain’s outer protective layer) and the arachnoid membrane
what can cause a subdural haemorrhage?
-rupture of veins in subdural space
-acute high velocity trauma
-acute on chronic eg 2-10 days post injury
-chronic - older people - 10 days post injury
what is an extradural haemorrhage?
bleeding that occurs between the skull and the dura mater
what can cause an extradural haemorrhage?
-rupture of middle meningeal artery
-skull fracture
what is a diffuse axonal injury?
severe traumatic brain injury (TBI) caused by rapid acceleration, deceleration, or rotational forces that shear and damage axons
what kind of fractures can a brain injury present with?
-facial bones
-skill
-base of skull
-long bones
-ribs
-spinal bones
-pelvis bones
how are TBIs medically managed?
-ICU
-medically induced coma
-craniotomy or craniectomy
-fractures
-ICP is carefully monitored
what’s the difference between a craniotomy vs craniectomy?
craniotomy - a piece of skull is removed and the brain is accessed to evaluate for haematoma etc
craniectomy- used to reduce ICP & severe brain swelling causing herniation, bone flap is removed and either stored eg abdomen or discarded
what is a decompressive craniectomy?
removal of bone flap to allow for expansion of skull contents for management of high ICP
why is cerebral perfusion so important?
it maintains cerebral blood flow
describe systemic vs cerebral factors that can case brain ischaemia?
cerebral factors - brain swelling, ICP increase
systemic factors - hypotension, hypoxaemia, pyrexia
what is the equation to measure the cerebral perfusion pressure CPP?
CPP=MAP-ICP
what are the principles of secondary brain damage prevention for the whole body system? (excluding cerebral)
-ventilate - prevent hypoxaemia
-infuse - hypotension normally due to hypovolaemia
-pump
what are the principles of secondary brain damage prevention for cerebral factors?
-control ICP
-maximise jugular venous return
-minimise cerebral metabolism
-sedation to minimise cerebral metabolism and avoid stimulation to the brain
-morphine + midazolam (sedative)
-propofol (early)
how is elevated ICP managed?
1.physical:
-collar off
-keep PaCO2 slightly lowered
-avoid pyrexia
2. 1st ling drug - mannitol reduces blood viscosity
3. decompressive craniectomy
what is the glasgow coma scale?
a tool used to assess the level of consciousness in patients w/ brain injuries
-involves eye opening, verbal + motor response
what are the GCS limitations?
-verbal response not valid in patients who cant speak eg intubated
-orbital trauma may make eye opening impossible
-SCI invalidates the motor scale for the limbs
-other influences on the patients level of consciousness interfere with the scales ability to accurately reflect the severity of TBI
what is one of the few neurologic signs that can be assessed in an unconscious patient?
pupil reflex
what is papilloedema?
refers to the swelling of both optic discs in your eyes due to increased intracranial pressure
-vision only at risk if severe or prolonged
what are examples of cognitive symptoms that a TBI patient can have?
-attention + concentration
-making decisions
-memory problems
-executive dysfunction eg planning, control etc
-feeling unmotivated
-problems w/ language
-mental capacity issues
what is a minimally conscious state post TBI?
-patient has no apparent awareness of themselves or their environment
-periods of eye opening + closing may occur, suggesting sleep-wake cycles and there may be spontaneous movements of face, trunk or limbs
-patient does not communicate or interact with others in any way
what is post traumatic amnesia after TBI?
-when the patient cannot remember injury or time afterwards
