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Brain and Behaviour Year 2 > Head Injury > Flashcards

Flashcards in Head Injury Deck (30)
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1
Q

Why is traumatic brain injury a problem

A
  • it is common
  • it significantly affects young adults
  • prevention and treatment can make a difference
2
Q

Describe the epidemiology of traumatic brain injury

A

• 6% of A&E attendance
• UK incidence 0.4 – 1%/year
• 700,000 A&E attendances
• 110,000 admissions
• 4,000 neurosurgical interventions
• falls, assaults and RTAs
- roughly 25% mortality for severe head injury
- half of adult inpatients with head injury have long term disability
- estimated that the socio-economic burden of RTAs to Europe is 180 billion euros

3
Q

the principles determinate of long term outcome from…..

A
  • principle determinate of long term outcome from polytrauma and head injury accounts for 50% of traumatic mortality
4
Q

what has made a difference to reducing the death from traumatic brain injury in the last 30 years

A
  • over the last 30 years the mortality of severe head injury has fallen from 50% to 25%
  • seatbelts reduce road traffic accident mortality by 40-60%
  • speed limits, airbags, driver education, licensing, old age fall prevention, playground safety
5
Q

what is the good thing and bad thing about the skull

A
  • the skull provides some protection to he brain from trauma
  • but if the brain swells or a haematoma takes up extra space then the brain will become squashed and this can cause the brain to become damaged
6
Q

who came up with the idea that the skull is fixed

A

Munro-kelly Doctrine

7
Q

what does the munro-Kelly Doctrine explain

A
  • It explains the relationship between the intracranial content and the intracranial pressure
8
Q

describe the physiology behind the munro-telly doctrine

A
  • this is the idea that the intracranial volume is fixed
  • the brain, CSF and blood are the usual contents
  • if something else is added to that space for example in the context of trauma that can be a swollen bruised part of the brain or haematoma
  • these to start with are compensated for by displacement of the CSF into the spine through the foramen magnum or the venous blood back into the circulation therefore this is compoesnated
  • once these compensated mechanisms are exhausted there is no where else for them to go
  • therefore the pressure ICP has to rise
  • this is uncompensated and can happen quickly
9
Q

what are the compensation mechanisms for the brain swelling

A

by displacement of the CSF into the spine through the foramen magnum or the venous blood back into the circulation therefore this is compensated as it makes more space for the brain

10
Q

when the ICP increases what happens

A
  • as the ICP increases there is effective perfusion pressure of the brain (cerebral perfusion pressure CPP) decreases
  • As the CPP falls the cerebral blood flow falls
  • therefore there is less perfusion to the brain and it becomes hypoxic
11
Q

write the equation to work out CPP

A
  • CPP=MAP-ICP
12
Q

what can happen when ICP raises

A
  • ICP can squeeze the brain out of the skull and cause herniation
13
Q

name 4 different types of herniation

A
  • subfalcine
  • uncal
  • tonsillar herniation
  • lateral tentorial and central tentorial herniation
14
Q

describe what happens in a subfalcine herniation

A
  • this is when the medial part of the hemisphere is squeezed under the fall
  • this part fo the brain is damaged and bruised and start to swell
  • usually parts of the cingulate gyrus
  • can also result in damage of some key vessels such as the anterior cerebral arteries
15
Q

describe what happens in an uncal herniation

A
  • compression of cranial nerve III
16
Q

describe what happens in tonsils herniation

A

this is when the ICP rises and the tonsils of the brain are pushed through the foramen magnum

  • this can squeeze the medulla and upper spinal cord as well as the bottom of the cerebellum
  • damages processes of breathing, control of blood pressure and pulse rate and this is often terminal
17
Q

describe what happens in lateral tentorial and central tenurial herniation

A

this is herniation through the tentorium cerebellum and the medial aspect of the temporal lobe herniates through the tentorial notch,
- this also starts to squeeze the midbrain = pupil can start to dilate

18
Q

where is the extradural space

A

this is between the periosteal layer and meningeal layer of the dura mater

19
Q

describe what shape an epidural haemotoma is

A

biconvex

- can be due to damage to a middle meningeal artery

20
Q

where is the subdural space

A

between the dura mater and subarachnoid

21
Q

where is the subarachnoid space

A

between the subarachnoid and Pia mater

22
Q

what shape is a subdural haemoatoma

A

sickled shaped

23
Q

what do sinuses do to the skull

A
  • these are associated with the nose and ears
  • make skull lighter
  • allows the skull to have responses
  • filter the air as it comes in to remove the microbes
24
Q

describe how the brain can become infection

A
  • sinuses are closed to the Brain
  • head injury can damage these spaces and cause them to fill up with blood, this happens when there is fracture to the base of the skull
  • this is important as the sinuses are usually filled with mucous and bacteria therefore if these enter the brain this can lead to assess formation and meningitis
25
Q

what can happen structurally after a traumatic brain injury

A
  • axons separate
  • the ends of the axons form retraction balls
  • neurones undergo apoptosis
  • injured cells having lost their energy and therefore sodium enters the cell and is no longer pumped out by the sodium ATPase therefore the cells lose their ion metabolism and swell and cause cytotoxic oedema
26
Q

what therapies are aimed at preventing structural changes after a traumatic Brian injury

A

• neuroprotection – therapy aimed at preventing neuronal cell death after injury with the effect of improving outcome

• brain repair – mechanisms for the generation of new neurons and growth of new axons
– the adult human brain has negligible capacity for brain repair and no therapeutic intervention has been effective in changing this

27
Q

what is the difference between a moderate and severe TBI

A

difference between moderate and severe is presentation of coma
- coma is present in severe TBI

28
Q

on the Glasgow coma scale what number is defined as a coma

A

8 or lower

29
Q

what happens to bodily systems in a coma

A
  • depresses cough, gag and swallow
  • slows ventilation (CO2 rises)
  • decreases BP
  • adequate perfusion of oxygenated blood vital
30
Q

what are the principles of management used in traumatic brain injury

A
  • prevention of primary brain injury
  • prevention of secondary brain injury
  • resuscitation
  • CT scan to identify a haemotoma
  • rapid referral to neurosurgery
  • neurointestive care