Traumatic head and spinal injury Flashcards Preview

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Flashcards in Traumatic head and spinal injury Deck (45):
1

Which structures may the direct effects of trauma be seen in? Which types of trauma affect each structure?

Scalp - lacerations
Skull - fractures
Meninges - vascular injury, lacerations
Brain/spinal cord - contusions, lacerations, diffuse axonal injury, diffuse vascular injury

2

What is concussion?

A clinical term to describe instantaneous loss of consciousness, temporary respiratory arrest and loss of reflexes.

3

What causes concussion?

Sudden change in the momentum of the head
Pathology unknown (maybe RAS)

4

How is a head injury assessed clinically?

Glasgow coma scale
13 or above: mild brain injury
9-12: moderate brain injury
8 or less: severe brain injury

5

Why is the bony casing around the brain and spinal cord both a blessing and a curse?

Blessing: high energy transfer required to breach layer
Curse: Soft tissue against hard bone can cause problems

6

How is damage caused in penetrating injuries and in closed injuries?

Penetrating: direct disruption of tissue
Closed: movement and compression of neural and vascular structures within bony casing

7

What are some of the secondary effects of traumatic head injury?

Ischaemia
Hypoxia
Cerebral swelling
Infection
Epilepsy

8

How do skull fractures generally behave?

Radiate from point of impact
May be depressed

9

What are the different classes of skull fractures?

Open: communicate with surface
Closed: do not communicate with surface
Comminuted: splintering of bone

10

What does blood or CSF coming from the nose and/or ears indicate?

Basal skull fractures

11

Why is it important to diagnose skull fractures?

They are an indicator of high energy transfer energy
Therefore, potential for direct brain sequelae is high

12

Why are extradural haematomas less common in elderly people?

Dura becomes more adherent to the skull with age, so that blood cannot track through it

13

Why are subdural haematomas more common in elderly people?

Brain shrinks > veins stretched> more susceptible to rupture

14

Why can subdural haematomas be acute or chronic?

Can be self-limiting, as it is very low pressure blood
Can continue to accumulate unnoticed until it causes raised ICP

15

What are contusions?

Haemorrhagic necrosis or bruising of the brain

16

What are coup injuries?

Those that occur at the site of impact

17

What are contrecoup injuries?

Injuries that occur on the opposite side of the brain when the head is not immobilised at the time of injury

18

Why do contusions often occur at the base of the brain?

Many irregularities in the cranial floor which the brain may rub against

19

What are some common sites for contusions at the base of the brain?

Inferior frontal lobes
Inferolateral temporal lobes

20

Describe the appearance of old cerebral contusions?

Abnormal gyri
Collapsed brain tissue
Yellowish

21

Why do old cerebral contusions appear yellowish?

Macrophages have removed necrotic tissue and blood
Leave behind haemosidirin

22

What causes a traumatic cerebral haematoma?

Intra-cerebral haemorrhage when a large blood vessel is ruptured

23

Define a laceration?

Penetration by foreign body or skull fragments

24

Describe the damage caused by missile injuries?

Brain at either side of bullet path has shockwave effect
So, actual injury to brain can be much greater in diameter than the bullet itself

25

What is required for cerebral tissue to tear?

Severe enough impact with sufficient energy transfer

26

What is the most vulnerable site for cerebral tissue tearing?

Ponto-medullary junction

27

Which part of the brain is most susceptible to diffuse axonal injury?

Corpus callosum

28

Describe the microscopic appearance of diffuse axonal injury lesions in the corpus callosum?

Silver stain > axonal spheroids (area of swelling in axon, marker of transection)

29

Describe the macroscopic appearance of diffuse vascular injury?

Spotty haemorrhages

30

Describe the longterm effects of diffuse axonal injury?

Brain atrophy
Enlarged ventricles
Thin corpus callosum
Thin white matter

31

Describe the toothpaste effect in cord-compressive acute traumatic injuries?

Spinal cord squashed by bone and cartilage > cord tissue squeezed both proximally and distally

32

List some of the longer term sequelae after brain trauma?

Infections
Hydrocephalus
Epilepsy
Chronic traumatic encephalopathy

33

What is hydrocephalus?

Ventricles become dilated and brain tissue is compressed as a consequence

34

Why may hydrocephalus occur in the long term after brain trauma?

Exit for CSF may be blocked off by scar tissue

35

What are the three major components of the cranium?

Brain tissue
CSF
Blood

36

How much blood and CSF usually exists in the cranium

150mL each

37

How does the brain initially respond to an expanding brain lesion?

Expulsion of as much venous blood and CSF as possible

38

Where can herniations of brain tissue occur due to raised ICP?

Through dural openings

39

What happens as ICP approaches arterial pressure?

Brain perfusion ceases
(CPP=MAP-ICP)

40

What is a major structural sequelae of raised ICP?

Herniation of brain tissue

41

What are the causes of raised ICP?

Trauma
Tumor
Infarction
Haemorrhage
Infection
Cerebral oedema
Increased CSF

42

What are the two main types of cerebral oedema?

Vasogenic
Cytotoxic

43

Describe vasogenic cerebral oedema?

Due to BBB disruption with increased vascular permeability
Predominantly involves white matter
Responds to normal treatment

44

Describe cytotoxic oedema?

Increased intracellular fluid to cell membrane injury
Involves grey and white matter
Non-steroid responsive

45

Which three brain areas are prone to herniation with raised ICP?

Medial temporal lobe
Cingulate gyrus
Cerebellar tonsil