10 - Acute Head Trauma Flashcards

1
Q

what are the risk factors for acute head trauma?

A
  • male
  • young (15-30) and old (65+) due to fraility
  • urban areas
  • substance misuse inc alcohol
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2
Q

what is the main way to reduce risk of head injury?

A

primary prevention:
* seat belts
* helmets alcohol prevention/limits
* health and safety

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3
Q

why is it important to ask medication history with head injury pts?

A

are they on anticoagulants? - increases damage of bleed

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4
Q

what is the primary survey for head injuries?

A

C - catastrophic haemorrhage
A - patency, managed vs unsupported and C spne
B - other injuries, apnoea, hypoxia
C - other injuries, hypo/hypertension, heart rate
D - GCS, pupils, C-spine, lateralising signs
E - primary survey (entire body)

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5
Q

alongside CABCDE protocol for head injuries, what two things should you measure?

A

glucose
temp

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6
Q

why is temperature important in pts with acute head trauma?

A

coagulopathy is altered quickly when hypothermic

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7
Q

what are 3 clinical signs of a base of skull fracture?

A
  • racoon eyes
  • battles sign
  • haemotympanum
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8
Q

how can you tell the difference between racoon eyes and black eyes?

A

in racoon eyes, the tarsal plates are usually spared from bruising

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9
Q

when does a battles sign appear?

A

24 hours after injury

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10
Q

if CSF is leaking from the tympanic membrane, what does this indicate/

A

skull fracture

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11
Q

what is haemotympanum?

A

blood build-up behind the tympanic membrane

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12
Q

according to the NICE guidelines, when should a CT be performed within 1 hour?

A
  • GCS less than 13 on initial assessment in ED
  • GCS less than 15 at 2 hours after injury
  • suspected open or depressed skull fracture
  • any sign of basal skull fracture
  • post-traumatic seizures
  • focal neuro deficit
  • more than 1 episode of vomiting
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13
Q

according to NICE guidelines when should a CT be performed within 8 hours of inury?

A
  • pt aged 65 or over
  • history of bleeding or clotting disorders
  • dangerour mechanism of injury
  • more than 30 mins retrograde amnesia of events before head injury
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14
Q

how can primary brain injury be treated?

A

it cant - it can only be prevented

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15
Q

what is the primary brain injury?

A

the original insult

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16
Q

what is the secondary brain injury?

A

the damage caused after injury b:
* hypoxia
* hypotension/hypertension
* raised ICP

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17
Q

what is the most common and detrimental forms of TBI?

A

diffuse axonal injury

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18
Q

what is the basic pathophysiology of diffuse axonal injury?

A

resistant inertia that occurs to brain at time of injury, causes shearing of axonal tracts of the white matter

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19
Q

how does diffuse axonal injury appear on CT?

A
  • relatively normal CT imaging even for severe cases
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20
Q

what is the neuroimaging hallmark of diffuse axonal injury?

A

diffuse white matter tract lesions

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21
Q

what is an extra-dural haematoma?

A

extra-axial bleed between the dura and skull bone

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22
Q

what is the most common source of injury in extradural haemotomas?

A

middle meningeal artery

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23
Q

what is the pathophysiology of extradural haemotoma?

A
  • blunt force trauma resulting in linear skull fracture, with no or minimal displacement
  • middle meningeal artery is most common source of bleeding
24
Q
A
24
Q

what does CT imaging show for extradural haematomas?

A

hyperdense biconves lesions, potentially with associated skull fractures

25
Q

what is a subdural haematoma?

A

collection of blood that forms in the subdural space (between dura mater and arachnoid mater)

26
Q

what is the pathophysiology of subdural haematomas?

A

tearing of the bridging veins that cross from cortex to dural sinuses

27
Q

what is one of the main risk factors for subdural haematomas?

A

increasing risk with increasing age

28
Q

how do subdural haematomas appear on CT?

A

cresenteric bleed over the brain

29
Q
A
30
Q

what are the clinical features of subdural haematoma?

A
  • LOC/altered conciousness
  • headache + confusion
  • raised ICP
  • focal neurology
31
Q

what are the clinical features of extradural haematoma?

A
  • initial LOC, followed by lucid period, furthe drop in drowsiness
  • headache
  • nausea + vomiting
32
Q

what are the clinical features of a traumatic subarachnoid haemaorrhage?

tSAH

A
  • LOC
  • severe headache
  • vomiting
  • photophobia
  • neck stiffness
  • seizures
  • neurology
33
Q

what significantly reduces favourable outcomes in secondary brain injury?

A

hypoxia + hypotension

34
Q

what does the Monro-Kellie doctrine describe?

A

the relationship between the contents of the cranium and intracranial pressure

35
Q

what are the normal values for intracranial pressure?

A

5-15mmHg

36
Q

explain the mumro kellie principle?

A
  • the skull is a fixed volume that cannot expand
  • normally, 3 components exist in equilibrium to maintain normal ICP - brain tissue, blood, CSF
  • new components (like bleed/mass) can disrupt equilibrium
  • compensatory mechanisms (drainage of venous volume and CSF can compensate for a while)
  • after that, pt begins to decompensate and ICP rises
37
Q

how is mean arterial pressure calculated?

A

CO x SVR

38
Q

what is MAP?

A

mean arterial pressure - the pressure pushing blood to the brain

39
Q

what is ICP?

A

intracranial pressure - the pressure that MAP has to overcome to get into the brain

40
Q

what is CPP?

A

cerebral perfusion performance - pressure of blood going through the brain

41
Q

in healthy individuals, CPP can fluctuate between what?

A

50-150

41
Q

in head injury pts, CPP should not fall below what?

A

70

42
Q

what is the initial mechanism of oedema?

A

CYTOTOXIC
* fluid retained in cytoplasm
* loss of NaK ATPase
* glutamate gated Ca channels open
* Ca draws water in

initial mechanism of oedema

43
Q

what is the delayed mechanism of oedema?

A

VASOGENIC
* breakdown of BBB
* fluid and protein extravasation into parenchyma

44
Q

name 3 herniation syndromes?

A
  • subfalcine
  • transtentorial
  • tonsillar
45
Q

what is a subfalcine herniation?

A

midline shift on CT

46
Q

what is a transtentorial herniation?

A

pressure on brainstem and oculomotor nerve

47
Q

what is a tonsillar herniation?

A
  • through the foramen magnum
  • effects medulla - cardiorespiratory centre
48
Q

what are the 4 main points of medical management for head trauma?

A
  • maintain physiology
  • improved venous drainage
  • reverse coagulopathy
  • anti-epileptics if indicated
49
Q

what levels show that physiology is maintained in head trauma?

A
  • MAP >90 or CPP > 60
  • normocapnia
  • normothermia
  • normoglycaemia
  • avoid hypoxia
50
Q

how do you improve venous drainage in head trauma?

A
  • head up
  • no restrictions
51
Q

what are 3 further medical management steps for managing head trauma?

A
  • sedaation and paralysis
  • hyperventilation (CO2 4-4.5)
  • osmotherapy (hypertonic sodium chloride, mannitol)
52
Q

what are 3 surgical management techniques for head trauma?

A
  • remove mass - burr hole
  • remove CSF - external ventricular drain
  • remove skull - decompressive craniectomy
53
Q
A