Raised Intercranial Pressure

Question 1

Give the classification of injury given according to the structure involved for head and spinal injury

Answer 1

Scalp: lacerations
Skull: fractures (may be linear, depressed, etc)
Meninges: vascular injury, lacerations
Brain/cord: contusions, lacerations, diffuse axonal injury (DAI), diffuse vascular injury

Question 2

What is concussion?

Answer 2

Instantaneous loss of consciousness, temporary respiratory arrest and less of reflexes following a sudden change in the momentum of the head

Question 3

What structure is hypothesised to be involved in the pathogenesis of concussion?

Answer 3

Brainstem, particularly the reticular activating system

Question 4

What is the difference between a penetrating and closed injury?

Answer 4

Penetrating injury involves direct disruption of tissue

Closed injury involves movements and compression of neural and vascular structures within bony confines

Question 5

List 5 secondary effects of traumatic injury

Answer 5

Ischaemia
Hypoxia
Cerebral swelling
Infection
Epilepsy

Question 6

What is the difference between an “open” and “closed” skull fracture?

Answer 6

Open communicates with surface (i.e. breaks through the skin), closed does not

Question 7

What is a comminuted skull fracture?

Answer 7

A skull fracture in which the bone splinters

Question 8

What clinical symptoms may be seen with a basal fracture?

Answer 8

Blood/CSF draining from nose and/or ears

Question 9

What is the blood vessel typically damaged in an epidural/extradural haematoma?

Answer 9

Middle meningeal artery

Question 10

Which blood vessels are damaged in a subdural haematoma? What is the typical course of a subdural haematoma?

Answer 10

Subdural veins are damaged

May be acute or chronic

Question 11

What are contusions and what are their 2 classifications?

Answer 11

Haemorrhagic necrosis (bruising)
May be coup (at impact site) or contrecoup (occur when head is not immobilised at the time of injury and the opposite side of the brain is bruised)

Question 12

Where do contusions tend to occur?

Answer 12

At the base of the brain (site of many protuberances), particularly the inferior frontal lobes and inferolateral temporal lobes

Question 13

Why do the sites of cerebral contusions stain orange?

Answer 13

Macrophages phagocytose blood and necrotic tissue, leaving haemosiderin behind

Question 14

What is DVI?

Answer 14

Diffuse vascular injury, in which small blood vessels tear to produce small sites of haemorrhage

Question 15

What are the histological findings in DAI?

Answer 15

Areas of swelling due to transection of axons

Axonal “spheroids” can be observed within a few hours of injury and are visualised using a silver stain

Question 16

List 3 long term sequelae of brain trauma

Answer 16

Infections
Hydrocephalus
Epilepsy
Chronic traumatic encephalopathy

Question 17

What are the pathogenic factors underlying chronic traumatic encephalopathy following brain trauma?

Answer 17

Brain atrophy due to neuronal loss
Abnormal deposition of Tau protein
Often diffuse deposition of A-beta plaques in cortex

Question 18

How many mLs of blood and CSF are in the cranium?

Answer 18

~150mL each

Question 19

What is the initial response to an expanding brain lesion?

Answer 19

To expel as much CSF and venous blood as possible

Question 20

When does brain perfusion cease in raised ICP?

Answer 20

When ICP > arterial pressure

Question 21

List 7 potential causes of raised ICP

Answer 21

Trauma
Tumour
Infarction
Haemorrhage
Infection
Cerebral oedema
Overproduction, obstruction to flow or absorption of CSF

Question 22

Distinguish between the 2 main subtypes of cerebral oedema and their causes

Answer 22

Vasogenic: due to BBB disruption with increased vascular permeability
Cytotoxic: due to increased intracellular fluid secondary to neuronal, glial or endothelial cell membrane injury (e.g. in stroke)

Question 23

What is the difference between vasogenic and cytotoxic cerebral oedema in terms of the affected areas and therapies?

Answer 23

Vasogenic predominantly involves the white matter and can be treated with steroids
Cytotoxic involves both grey and white matter and is not responsive to steroids

Question 24

What are the 3 main types of herniation?

Answer 24

Subfalcine (herniation of cingulate gyrus under falx cerebri)
Transtentorial/uncal (herniation of medial temporal lobe through the tentorium cerebelli)
Transforaminal/tonsillar (herniation of cerebellar tonsils through the foramen magnum)

Question 25

List 5 major sites of CSF block

Answer 25

Interventricular foramen (foramen of Monro)
3rd ventricle
Cerebral aqueduct (aqueduct of Sylvius)
Medial aperture (foramen of Magendie) and lateral apertures (foramen of Luschka)
Basal cisterns/subarachnoid spaces