11 - Traumatic Head and Spinal Injury

Question 1

Name for direct trauma to scalp

Answer 1

Laceration

Question 2

Effects of direct trauma to meninges

Answer 2

Vascular injury, lacerations

Question 3

Effects of direct trauma to brain or spinal cord

Answer 3

Contusions, lacerations, diffuse axonal injury, diffuse vascular injury

Question 4

Concussion
1
2
3

Answer 4

• Instantaneous loss of consciousness, temporary respiratory arrest, loss of reflexes.
• Follows sudden change in the momentum of the head.
• Pathogenesis uncertain. Maybe effect is at brainstem level (reticular activating system).

Question 5

Leading cause of death in Western countries, under 40 years old

Answer 5

Traumatic CNS injury

Question 6

Two broad types of CNS trauma

Answer 6

1) Penetrating injury (direct disruption of tissue)

2) Closed injury (movement and compression of neural and vascular structures within bony confines)

Question 7

Features of skull fractures
1
2
3
4
5

Answer 7

• Tend to radiate from the point of impact.
• Can be depressed.
• If communicate with surface called “open”. If not, “closed”.
• If splintering of bone – “comminuted”.
• Blood/CSF from nose and/or ears may result from basal fractures.

Question 8

Significance of skull fractures

Answer 8

Indicates a high-energy transfer injury

Question 9

Cause of epi- or extradural haematoma

Answer 9

Middle meningeal artery damage

Question 10

Cause of subdural haemartoma

Answer 10

Subdural vein injury.

Can be acute or chronic

Question 11

Why are extradurals more common in younger people?

Answer 11

With age, dura becomes more adherent to skull

Question 12

More urgent type of haematoma

Answer 12

Extradural, because it is from an arterial bleed.

Question 13

More common type of haematoma in elderly populations

Answer 13

Subdural.
Dura becomes more adherent to skull with age, stretching the dura out more. Venous sinuses are made up of walls of dura, these become more likely to rupture if they are under greater tension

Question 14

Contusion

Answer 14

Haemorrhagic necrosis (bruise)

Question 15

Coup

Answer 15

Contusion at the site of impact

Question 16

Contrecoup

Answer 16

Occurs when head is not immobilised at the time of injury and involves the opposite side of the brain

Question 17

Location of sterotypic contusions in head injury

Answer 17

At base of the brain
EG: inferior frontal lobes, inferolateral temporal lobes.
These often occur no matter where coup and contrecoup injuries are.
Occurs from brain dragging over uneven surface of cranial floor

Question 18

Common finding with any sort of head injury

Answer 18

A degree of subarachnoid haemorrhage

Question 19

Appearance of old cerebral contusions

Answer 19

Areas of depressed, shrunken brain tissue.
Brain rarely heals by fibrosis.
Gliotic brain with remains of haemosiderin.

Question 20

Brain laceration

Answer 20

Penetration of brain by foreign body or skull fragment

Question 21

Effect of missile brain injury

Answer 21

Eg bullet wound.
Injury not just at the area where the missile penetrated, but also sends out shockwaves through cerebral tissue that can be damaging.

If sufficient energy transfer, cerebral tissue can tear at vulnerable sites eg ponto-medullary junction.

Question 22

Diffuse axonal injury

Answer 22

Axons can be mechanically shorn over a wide area.

Question 23

What often accompanies diffuse axonal injury?

Answer 23

Diffuse vascular injury

Question 24

Histological appearance of severed axon

Answer 24

Axoplasm continues flowing for a while out of severed axon, leading to a blob-like appearance at site of severance.

Can be visualised with silver stains

Question 25

Long-term effects of diffuse axonal injury

Answer 25

Greatly-enlarged lateral and third ventricles. | This is because damaged white matter is removed, undergoes gliosis. This results in loss of tissue.

Question 26

Effect of compression of spinal cord

Answer 26

'Toothpaste' effect, as cord is so soft. Can lead to a central haemorrhagic necrotic core either side of site of injury in spinal cord

Question 27

``` Long-term sequelae of brain trauma 1 2 3 4` ```

Answer 27

1) Infections 2) Hydrocephalus 3) Epilepsy 4) Chronic traumatic encephalopathy

Question 28

Chronic traumatic encephalopathy 1 2 3

Answer 28

1) Brain atrophy due to neuronal loss 2) Abnormal deposition of tau protein 3) Often diffuse deposition of A-beta plaques in cortex

Question 29

Amounts of blood and CSF in cranial cavity

Answer 29

150mL of each

Question 30

Initial response to swelling of brain

Answer 30

Expulsion of as much CSF as possible. Compression of ventricles. Expulsion of venous blood. After this, ICP starts to rise

Question 31

Effect of increasing ICP

Answer 31

Herniations of brain tissue through dural openings (EG foramen magnum). As ICP approaches arterial pressure, brain perfusion ceases

Question 32

Amount of CSF produced each day

Answer 32

~400mL

Question 33

``` Potential causes of increased ICP 1 2 3 4 5 6 7 ```

Answer 33

1) Trauma 2) Tumour 3) Infarction 4) Haemorrhage 5) Infection 6) Cerebral oedema (which can complicate any of the above) 7) Overproduction, diminished absorption of CSF

Question 34

Two main subtypes of cerebral oedema

Answer 34

1) Vasogenic | 2) Cytotoxic

Question 35

Vasogenic cerebral oedema

Answer 35

From blood brain barrier disruption with increased vascular permeability. Mostly involves white matter Responds to steroid therapy

Question 36

Cytotoxic cerebral oedema

Answer 36

Increased intracellular fluid secondary to neuronal, glial or endothelial cell membrane injury. Affects grey and white matter. Doesn't respond to steroid therapy.

Question 37

Transtentorial herniation

Answer 37

Herniation of brain under tentorium cerebelli from a cerebral hemisphere lesion (eg: a haematoma).

Question 38

Structure through which CSF drains

Answer 38

Aqueduct of Sylvius

Question 39

Effect of subfalcine and transtentorial herniations

Answer 39

Brainstem is pushed downwards, vessels of brainstem are torn (as they are fixed in place). Haemorrhage.