Head trauma Flashcards

1
Q

CSF production, circulation and reabsorption

A

Produced by choroid plexus in lateral, 3rd and 4th ventricles

Reabsorbed by arachnoid granulation in superior sagittal sinus

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2
Q

3 layers of meninges

A
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3
Q

Which blood vessels are responsible for extradural bleed

A

Meningeal arteries, especially middle meningeal artery

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4
Q

Which blood vessel responsible for subdural bleed

A

Bridging veins

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5
Q

Which blood vessels are responsible for intra-cerebral bleed (subarachnoid haemorrhage)

A

Major blood vessels at the base of the brain

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6
Q

Brainstem parts

A

Midbrain

Pons

Medulla

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7
Q

Function of midbrain and upper pons

A

Reticular activating system (state of alertness)

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8
Q

Function of medulla

A

Cardiorespiratory centre

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9
Q

Tentorium cerebelli

A

Separates intracranial cavity into supratentorial and infratentorial

Midbrain passes through tentorial hiatus

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10
Q

Which nerve could be compressed against the tentorium

A

Oculomotor leading to a blown pupil (carries PSN, if impaired, eye only gets sympathetic)

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11
Q

Which part of brainstem herniates through tentorium due to raised ICP

A

midbrain

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12
Q

Which part of brain herniates through tentorium due to raised ICP

A

the medial part of temporal lobe known as uncus

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13
Q

Sx of uncus herniation

A

Ipsilateral pupillary dilatation (PSN fibers of CN3)

Contralateral hemiparesis (corticospinal tract of the midbrain)

Reduced GCS (reticular system)

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14
Q

Normal ICP

A

10mmHg

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15
Q

What sustained ICP is associated with poor outcome

A

>22mmHg

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16
Q

Monro-kellie doctorine

A

Total volume of intracranial content is constant

Total volume = Venous volume + arterial volume + brain + CSF

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17
Q

Cerebral perfusion pressure (CPP) formula

A

CPP = MAP - ICP

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18
Q

At what MAP is cerebral blood flow autoregulated (constant)

A

MAP of 50-150 mmHg

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19
Q

GCS depending of severity of traumatic brain injury (TBI)

A

Mild 13-15

Moderate 9-12

Severe 3-8

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20
Q

When calculating GCS and there’s discrepancy between left and right side, which score do you use

A

The best motor response (the higher score)

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21
Q

Types of skull vault (roof) fracture

A

Linear vs stellate

Depressed vs non-depressed

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22
Q

Clinical signs of basilar skull fracture

A

Periorbital ecchymosis (raccoon eyes)

Retroauricular ecchymosis (Battle’s sign)

Rhinorrhoea (CSF from nose)

Otorrhoea (CSF from ear)

CN7,8 dysfunction

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23
Q

Classic epidural haematoma presentation

A

Lucid period before deterioration

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24
Q

Which region of the brain often affected by epidural bleed

A

Temporoparietal

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25
Q

Further investigation after CT showing contusion

A

Repeat CT within 24 hours to look for change in the pattern of injury (20% of patients will end up having enough mass effect requiring evacuation)

26
Q

Definition of mild traumatic brain injury

A

GCS 13-15

witnessed loss of consciousness, definite amnesia or witnessed disorientation

27
Q

High risk indications for CT head for pt with mild traumatic brain injury

A

Any one of high risk or moderate risk:

GCS<15 for 2 hrs post-injury

Suspected open or depressed skull

Signs of basilar skull fracture

Vomiting more than 1 episodes

Age >65

Anticoagulation

28
Q

Moderate risk indications for CT head for pt with mild traumatic brain injury

A

LOC for 5 mins

Amnesia before impact >30mins

Dangerous mechanism (pedestrian struck, ejected out of the car, fall from more than 3 feet or 5 stairs)

29
Q

Initial management of moderate traumatic brain injury

A

Neurosurgery evaluation or transfer required

30
Q

Initial management of severe traumatic brain injury

A

Urgent neurosurgery consultation or transfer required

31
Q

Admission criteria for mild traumatic brain injury

A
  1. CT:
    - not available
    - skull fracture
    - CSF leak
  2. Focal neurology
  3. GCS does not return to 15 after 2 hrs
32
Q

Secondary management of severe traumatic brain injury with raised ICP

A

Mannitol

Brief hyperventilation (reduces CO2, vasoconstriction)

Hyperosmotic saline

Surgery

Barbiturates

33
Q

PCO2 aim for hyperventilation

A

No less than 25 mmHg - 30 mmHg (3.3 to 4.7kPa)

34
Q

PCO2 aim for severe traumatic brain injury

A

<35mmHg

35
Q

Blood pressure aim in brain injury

A

SBP<100 between 50 to 69

SBP <110 between 15 to 49 and older than 70

36
Q

ICP goal for TBI

A

5-15mmHg

37
Q

Reversal agent for morphine

A

Nalaxone

38
Q

Reversal agent for benzos

A

flumazenil

39
Q

How much shift of midline structures indicate the need for surgery

A

A shift of 5mm or more

40
Q

Reversal for antiplatelet agents eg aspirin

A

Platelets

(may need repeat or desmopressin)

41
Q

Reversal for warfarin

A

Vit K and Prothrombin complex

42
Q

Reversal for heparin

A

protamine

43
Q

Reversal for LMWH

A

protamine

44
Q

Reversal for direct thrombin inhibitors (eg dabigatran)

A

Idarucizumab (praxbind)

45
Q

Reversal for rivaroxaban

A

none

46
Q

Use of mannitol

A

Osmotic diuretic

For the acute neurological deterioration of pt under observation (A bolus of 1g/kg, over 5mins before transferring to CT)

47
Q

Contraindication to mannitol use

A

Hypotension (SBP <90)

Mannitol does not lower ICP in hypovolaemia and is an osmotic diuretic, leading to a further drop in BP, and cerebral ischaemia

48
Q

Monitoring with Mannitol

A

ICP monitor, keep <320mOsm

49
Q

Use of hypertonic saline for raised ICP

A

IN concentrations of 3% to 23.4%

Preferable agent in hypotension as doesn’t act as a diuretic, however, equally ineffective in hypotension

50
Q

Use of barbiturates in raised ICP

A

Only used after other measures both surgical and medical have failed

Long half-life, so needs monitoring for longer (before declaring brain death)

Don’t use in hypovolaemia or hypotension

51
Q

Use of anticonvulsants in TBI

A

Can inhibit brain recovery, so only use when essential

No evidence for late epilepsy prevention

52
Q

Factors increasing the risk of late epilepsy post-TBI

A

Seizures occurring within the first week

Intracranial haematoma

Depressed skull fractures

53
Q

Which anticonvulsants used for post TBI seizures

A

Phenytoin +/- diazepam/lorazepam

If not, general anaesthesia

54
Q

Dosing of phenytoin for post TBI seizure

A

Loading on 1g given at 50mg/min

Maintaining on 100mg/8hrs

55
Q

Management of scalp depression

A

Generally need operative elevation eg when

  • open contaminated
  • degree of depression > thickness of adjacent skull

In less severe depression, just closure of scalp over suffices

56
Q

Indication for use of prophylactic abx in TBI

A

Penetrating brain injury

Open skull fracture

CSF leak

57
Q

Management of objects that penetrate the intracranial compartment or infratemporal fossa that remain partially exteriorised

A

Must be left in place until the possible vascular injury has been evaluated and definitive neurosurgical management established

58
Q

Surgical management of intracranial mass lesions

A

If in remote areas/no access to imaging or neurosurgery: Burr hole craniotomy

Otherwise, bone flap craniotomy

59
Q

Definition of brain death

A

no possibility of recovery of brain function

60
Q

Criteria for brain death

A

GCS=3

Nonreactive pupils

Absent brainstem reflexes (eg oculocephalic, corneal and gag reflex)

No spontaneous ventilatory effort on formal apnoea testing

Absence of confounding factors such as alcohol, drug intoxication or hypothermia

61
Q

Investigations that could help establishing brain death

A

Electroencephalography

CBF studies

Cerebral angiography

62
Q

Oculocephalic reflex

A

AKA doll’s eye reflex

If brainstem affected eyes move with the head