neurosurgical emergencies

Question 1

GCS score components (3)

Answer 1

1. eye;
2. motor;
3. verbal

Question 2

what is the GCS eye response component

Answer 2

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

Question 3

what is the GCS motor response component

Answer 3

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

Question 4

what is the GCS voice response component

Answer 4

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

Question 5

what does a GCS of <8 indicate

Answer 5

coma

Question 6

what GCS is worrying

Answer 6

<12

Question 7

what examination is essential when assessing for brain injury and why

Answer 7

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

Question 8

what is the monroe-kellie doctrine

Answer 8

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

Question 9

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

Answer 9

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

Question 10

cerebral pressure perfusion equation

Answer 10

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

Question 11

what is normal and ischaemic cerebral perfusion pressure

Answer 11

70-100 is normal
<60 is ischaemic

Question 12

what is normal ICP

Answer 12

7-15 mmHg

Question 13

what is cerebral auto regulation

Answer 13

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

Question 14

when might auto regulation not be maintained

Answer 14

traumatic brain injuries

Question 15

why is drowsiness seen in COPD pts

Answer 15

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

Question 16

CT appearance of extra dural haematoma

Answer 16

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

Question 17

extradural haemorrhage treatment

Answer 17

emergency surgery to drain + repair source of bleed

Question 18

what usually causes an extradural haemorrhage

Answer 18

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

Question 19

subdural haematoma CT presentation

Answer 19

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

Question 20

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

Answer 20

1. O2 levels
2. glucose levels
3. exciatory NT levels

Question 21

why might a pt be put into a deep coma

Answer 21

to decrease the metabolic demand of the cells in the brain

Question 22

what is a chronic subdural haematoma

Answer 22

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

Question 23

epi of chronic subdural haematoma

Answer 23

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

Question 24

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

Answer 24

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

Question 25

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

Answer 25

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

Question 26

what is the fisher scale

Answer 26

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

Question 27

fisher scale categories (4)

Answer 27

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%;

Question 28

what causes rebleeding of SAH

Answer 28

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

Question 29

common complication of SAH

Answer 29

hydrocephalus

Question 30

communicating (3) vs obstructive (4) hydrocephalus

Answer 30

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