Head Injury

Question 1

equation for cerebral perfusion pressure (CPP)

Answer 1

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

Question 2

what is the goal CPP, MAP and ICP after head injury

Answer 2

CPP = >60mmHg
MAP = >80mmHg
ICP = <20mmHg

Question 3

signs of anterior cranial fossa skull base fracture

Answer 3

raccoon/panda eyes
CSF rhinorrhoea (contains glucose)
subconjunctival bruising

Question 4

signs of middle cranial fossa injury

Answer 4

battle sign over mastoid area

bleeding from EAM or CSF otorrhoea

Question 5

what is the difference between primary and secondary brain injury

Answer 5

primary - occurs on impact

secondary - due to the consequences of the injury (neuronal damage, haematoma, swelling, ischaemia, infection)

Question 6

what are the types of haematoma

Answer 6

extradural
sub dural
intracranial

Question 7

what is a common cause of indirect brain damage in haematoma

Answer 7

tentorial or tonsillar herniation

Question 8

common site of extradural haematoma

Answer 8

temporal/temporoparietal regions

Question 9

what are the different types of brain herniation

Answer 9

subfalcine herniation
lateral tentorial herniation
central tentorial herniation
tonsillar herniation

Question 10

what is a subfalcine herniation

Answer 10

displacement of brain under falx cerebri (usually first herniation to occur)

Question 11

what is the first radiological sign of a space-occupying haematoma

Answer 11

mid-line shift

Question 12

after subfalcine herniation, what type of herniation occurs next

Answer 12

lateral tentorial

Question 13

what is lateral tentorial herniation and what does it cause

Answer 13

herniation of medial temporal lobe through tentorial hiatus

causes midbrain compression and damage

Question 14

what does lateral tentorial herniation lead to

Answer 14

central tentorial herniation

Question 15

what does central tentorial herniation lead to

Answer 15

tonsillar herniation - herniation of cerebellar tonsils through formen magnum

Question 16

what is a long-term complication of dural tear

Answer 16

infection (meningitis or cerebral abscess)

Question 17

clinical effects of lateral tentorial herniation

Answer 17

deterioration of consciousness
limb weakness on same side of lesion
pupil dilatation with failure to react to light (CNIII compression)

Question 18

clinical effects of central tentorial herniation

Answer 18

loss of upward gaze
deterioration of consciousness
pupils initially small, become moderately dilated and fixed to light
diabetes insipidus (pressure on pituitary and hypothalamus)

Question 19

clinical effects of tonsillar herniation

Answer 19

may cause upward cerebellar herniation
neck stiffness and head tilt
depressed consciousness
respiratory irregularities (leads to respiratory arrest)

Question 20

why does cerebral ischaemia often occur after head injury

Answer 20

autoregulation (which should cause vasodilatation) is defective
results in hypotension and reduced ICP leading to decreased cerebral perfusion
results in hypoxia and ischaemia

Question 21

when should a head CT be requested in head trauma

Answer 21

suspected skull fracture
disorientated patient (GCS <13 on admission or <15 after 2 hours)
patient on anti-coagulation
focal neurological signs
post traumatic seizure
vomiting > once
loss of consciousness and age>65/dangerous mechanism of injury/anterograde amnesia>30 mins

Question 22

what vessels are affected in subdural haemorrhage

Answer 22

bridging veins between cortex and venous sinuses causing bleeding between dura and arachnoid

Question 23

causes of subdural haemorrhage

Answer 23

trauma (up to 9 months ago)
decreased ICP
dural metastases
anticoagulation

Question 24

symptoms and signs of subdural haematoma

Answer 24

fluctuating levels of consciousness 
physical/intellectual slowing
sleepy
headache 
personality change 
unsteadiness 
seizures 
local neurological symptoms (hemiparesis, unequal pupils) - late

Question 25

what does subdural haemorrhage look like on CT

Answer 25

crescent shaped collection of blood around one hemisphere | midline shift

Question 26

management of subdural haemorrhage

Answer 26

evacuation (1st line) | craniostomy (2nd line)

Question 27

causes of extradural haematoma

Answer 27

fractured temporal or parietal bone | trauma to temple

Question 28

clinical manifestations of extradural haemorrhage

Answer 28

``` deterioration of consciousness (no initial loss of consciousness) lucid interval if has been drowsy severe headache vomiting confusion fits brisk reflexes upgoing plantar hemiparesis ```

Question 29

What does extradural haematoma look like on CT

Answer 29

'lens' rounded shape midline shift possible dilated contralateral 4th ventricle

Question 30

management of extradural haemorrhage

Answer 30

clot evacuation

Question 31

what are late effects of head injury

Answer 31

epilepsy CSF leak into nose/middle ear cognitive problems

Question 32

what is a depressed head fracture

Answer 32

skull trauma which blows bones inwards depressing brain segments

Question 33

difference between simple and compound depressed skull fractures

Answer 33

simple - no laceration, no need to remove bone fragments (does not reverse neuronal damage) compound - overlying laceration, risk of infection

Question 34

what is NOT a clinical feature of depressed bone fracture

Answer 34

loss of consciousness

Question 35

typical cause of depressed bone fracture

Answer 35

blow from a sharp object

Question 36

investigation for depressed skull fracture

Answer 36

head CT