neurosurgical emergencies Flashcards

1
Q

GCS score components (3)

A
  1. eye;
  2. motor;
  3. verbal
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2
Q

what is the GCS eye response component

A

4.eyes open spontaneously
3.eyes open to verbal command
2.eyes open to pain
1.no eye opening

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3
Q

what is the GCS motor response component

A

6.obeys command
5.localises pain
4.withdraws from pain
3.flexion response to pain
2.extension response to pain
1.no motor response

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4
Q

what is the GCS voice response component

A

5.orientated
4.confused
3.inappropriate words
2.incomprehensible sounds
1.no verbal response

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5
Q

what does a GCS of <8 indicate

A

coma

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6
Q

what GCS is worrying

A

<12

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7
Q

what examination is essential when assessing for brain injury and why

A

pupil examination -> mass effect can compress the tentorium cerebelli where CN III sits resulting in pupil abnormalities -> usually unilateral but bad sign if bilateral

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8
Q

what is the monroe-kellie doctrine

A

the principle of homeostatic intracerebral volume regulation, which stipulates that the total volume of the parenchyma, cerebrospinal fluid, and blood remains constant i.e. if the volume of one component increases it must come at the expense of the others

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9
Q

when does the brain enter the decompensatory phase (raised ICP)

A

when the limit of compensation by the other 2 components is reached e.g. haemorrhage may cause CSF to decrease in volume but this can only be up until a point and the brain cant compensate anymore

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10
Q

cerebral pressure perfusion equation

A

CPP = MAP (mean arterial pressure) - ICP (intercranial pressure)

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11
Q

what is normal and ischaemic cerebral perfusion pressure

A

70-100 is normal
<60 is ischaemic

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12
Q

what is normal ICP

A

7-15 mmHg

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13
Q

what is cerebral auto regulation

A

the ability of the cerebral vasculature to maintain stable blood flow despite changes in blood pressure (within a certain range) -> ICP is maintained

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14
Q

when might auto regulation not be maintained

A

traumatic brain injuries

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15
Q

why is drowsiness seen in COPD pts

A

hypercapnia (CO2 retention) results in venous dilation -> raised ICP

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16
Q

CT appearance of extra dural haematoma

A

biconvex (lemon) shape in specified region (the dura is adhered tightly to sutures -> blood cannot cross suture lines)

17
Q

extradural haemorrhage treatment

A

emergency surgery to drain + repair source of bleed

18
Q

what usually causes an extradural haemorrhage

A

clear head trauma to temporal/parietal areas, esp pterion -> MMA ruptured

19
Q

subdural haematoma CT presentation

A

cresent shaped rostral to caudal laterally-> crosses suture lines as beneath the dura

20
Q

what can a microdyalisis device be used to measure (3)

A
  1. O2 levels
  2. glucose levels
  3. exciatory NT levels
21
Q

why might a pt be put into a deep coma

A

to decrease the metabolic demand of the cells in the brain

22
Q

what is a chronic subdural haematoma

A

an old collection of blood in the subdural space that irritated the bvs and initatees inflammatory responses-> bvs become leaky and allow fluid to be secreted resulting in mass effect and even midline shift

23
Q

epi of chronic subdural haematoma

A

elderly pts on blood thinners w Hx of head trauma weeks ago

24
Q

what kind of pts does haemorrhage in the BG and internal capsule usually occur in and why

A

hypertensive pts -> lenticulo striate arterries are easily ruptured due to HTN

25
Q

why should haemorrhage in the BG/internal capsule not be operated on (unless massive)

A

to reach this area, lots of healthy brain must be damaged -> harm may be worse than the good outcome

26
Q

what is the fisher scale

A

the best known system of classifying the amount of subarachnoid haemorrhage on CT scans, and is useful in predicting the occurrence and severity of cerebral vasospasm

27
Q

fisher scale categories (4)

A

grade 1:
​no subarachnoid (SAH) or intraventricular haemorrhage (IVH) detected;
incidence of symptomatic vasospasm: 21% ;

grade 2:
​diffuse thin (<1 mm) SAH;
no clots;
incidence of symptomatic vasospasm: 25%;

grade 3:
​localised clots and/or layers of blood >1 mm in thickness;
no IVH;
incidence of symptomatic vasospasm: 37%;

grade 4:
​diffuse or no SAH;
ICH or IVH present;
incidence of symptomatic vasospasm: 31%;

28
Q

what causes rebleeding of SAH

A

rupture of fibrin cap on aneuyrsm -> most don’t survive this second rebleed

29
Q

common complication of SAH

A

hydrocephalus

30
Q

communicating (3) vs obstructive (4) hydrocephalus

A

communicating :
- all 4 ventricles are enlarged
- lumbar puncture can be done
- may be caused by IVH, aneurysmal SAH, meningitis

obstructuve:
- dilation of lateral and 3rd ventricles with small, compressed or normal sized 4th
- asymmetry or enlargement of lateral ventricles when obstruction is at foramen of Monro
- may be caused by posterior fossa mass lesions, intraventricuar mass lesions, aqueductal stenosis
- NO LUMBAR PUNCTURE