Traumatic Head and Spinal Cord Injury and Raised Intracranial Pressure Flashcards Preview

MD1 Neuroscience > Traumatic Head and Spinal Cord Injury and Raised Intracranial Pressure > Flashcards

Flashcards in Traumatic Head and Spinal Cord Injury and Raised Intracranial Pressure Deck (67):
1

What are the direct effects of trauma?

Scalp
- Lacerations
- Bruises
Skull
- Fractures
Meninges
- Vascular injury
- Lacerations
Brain/spinal cord
- Contusions
- Lacerations
- Diffuse axonal injury
- Diffuse vascular injury

2

What are contusions?

Bruises on surface of brain

3

How many vessels does diffuse vascular injury in the brain involve?

Single vessel or multiple tiny ones

4

What is concussion?

Clinical term
Instantaneous loss of consciousness
Temporary respiratory arrest
Less of reflexes
Possible seizure
Follows sudden change in momentum of head
- Direct blow
- Decceleration
Pathogenesis uncertain
- Maybe effect at brainstem level

5

What is the Glasgow coma scale?

Scale of neurological status
Enables standardisation between different groups of patients
- Therapies and outcomes can be assessed
Indicates level of brain injury

6

What three aspects are taken into account in the Glasgow coma scale?

Eye opening
Best verbal response
Best motor response

7

What is the maximum score that you can get on the Glasgow coma scale?

15 > okay

8

What is a penetrating injury?

Direct disruption of tissue

9

What is a closed injury?

Movement and compression of neural and vascular structures within bony confines

10

What are the secondary effects of traumatic head injury?

Ischaemia
Hypoxia
Cerebral swelling
Infection
Epilepsy

11

When do secondary effects of traumatic injury happen?

Delayed
Can contribute to immediate clinical outcome

12

When does infection occur in traumatic head injury?

Later in clinical course if patient survives

13

What does it mean if infection takes place after a traumatic head injury?

Brain or CSF breached

14

When does epilepsy occur in traumatic head injury?

Late in clinical course

15

Describe skull fractures

Radiate from point of impact
Can be depressed - bone pushes down on underlying brain
Important to diagnose because indicator of high energy transfer injury - brain has also moved around inside skull

16

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

Open if communicates with surface, but closed if it doesn't

17

What is a comminuted skull fracture?

Bone splinters
Can chop away at brain tissue

18

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

Basal fracture

19

What most commonly ruptures in an extradural haematoma?

Middle meningeal artery

20

Why is an extradural haematoma much more likely to happen in a younger patient than an older one?

As people age, dura becomes increasingly adherent to skull
So in younger people, dura not attached > high pressure bleed not compressed

21

What ruptures in a subdural haematoma?

Subdural veins

22

What kind of subdural haematomas are there?

Acute
Chronic

23

Why are subdural haematomas more common in older patients?

As you age, brain shrinks and dura adheres to skull
Veins entering sinuses under more tension
More vulnerable to rupture
Can get from quite low energy transfer

24

What is the most common injury to brain tissue?

Contusions

25

Where do coup injuries happen?

At impact site

26

Where do contrecoup injuries happen?

Opposite side of brain to site of impact

27

Where do stereotypical contusions tend to occur?

Base of brain
- Inferior frontal lobes
- Inferolateral temporal lobes

28

What can directly damage brain tissue?

Force itself
Torn blood vessels

29

What reactive process do contusions involve?

Haemorrhagic necrotisation

30

Where must force be applied for contusions at the base of the brain to occur?

Anywhere

31

Why do people sometimes develop anosmia with contusions to the base of the brain?

Olfactory bulb pulverised

32

What happens to a contusion if the person survives?

Contusion resolves
Damaged tissue phagocytosed
Visible shrinkage of brain in these areas

33

How does the brain get lacerated?

Penetration by foreign body or skull fragments

34

How do missile injuries cause damage to brain tissue?

Via shock waves

35

Where is a particularly vulnerable site where cerebral tissue can tear?

Ponto-medullary junction
Particularly in children
Very rare
Happens in severe brain trauma
Accompanies other injuries

36

What are diffuse forms of brain injury?

Traumatic/diffuse axonal injury (TAI/DAI)
Diffuse vascular injury
Secondary injury

37

What is TAI/DAI?

Axons torn

38

What is diffuse vascular injury?

Little blood vessels torn

39

How do neurochemical alternations due to trauma exert toxic effects?

Brain tissue as it's damaged releases neurotransmitters and other substances that can cause further damage to surrounding brain tissue themselves

40

What happens to the axons in DAI?

Bulbous swelling and complete interruption of axon
Axonal transport continues from cell body and collect in swelling
Axon beyond that dies

41

What are the long term effects of DAI?

Decreases white matter
Corpus callosum thins
Ventricles dilate to compensate for tissue loss
Patient severely neurologically impaired

42

Describe cord-compressive acute traumatic injury

Toothpaste effect
Soft cord tissue squeezed along adjacent spinal cord both proximally and distally
Tissue being pushed = necrotic
Can be pushed towards brainstem and cause damage there

43

What are the longer term sequelae of brain trauma?

Infections
Hydrocephalus
Epilepsy
Chronic traumatic encephalopathy

44

What can potentially be breached to cause an infection?

Scalp
Skull
Meninges
Brain tissue

45

What causes epilepsy after brain trauma?

Number of conditions, including:
- Tumours
- Infarcts
- Haemorrhages
- Trauma

46

What is chronic traumatic encephalopathy?

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

47

How much blood and CSF is in the brain?

150 mL each

48

What is the initial response to an expanding brain lesion?

Expulsion of as much CSF and venous blood as possible

49

What happens after as much CSF and blood has been squeezed out from the brain in response to an expanding lesion?

Intracranial pressure rises

50

Where does herniation of brain tissue occur?

Through dural openings

51

What happens as ICP approaches MAP?

Brain perfusion ceases
Death occurs a bit before this though

52

What are some potential causes of raised ICP?

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

53

What can cause an overproduction of CSF?

Choroid plexus papilloma

54

What are the two main subtypes of cerebral oedema?

Vasogenic
Cytotoxic

55

What is a vasogenic cerebral oedema?

Due to BBB disruption with increased vascular permeability
Predominantly involves white matter
Fluid between cells
Quite sensitive to treatment; eg: steroid therapy

56

What happens in cytotoxic cerebral oedema?

Increased IC fluid secondary to neuronal, glial, or endothelial cell membrane injury
Cells can't pump out water anymore
Common in cerebral infarction
Involves grey and white matter
Not steroid responsive

57

Where does CSF come out from the brain?

Foramenae at brainstem level

58

What is the route that CSF takes?

Out of brain
Into subarachnoid space
Down into spinal cord
Up and around cerebral vessels

59

Where is CSF absorbed into venous circulation?

Arachnoid granules that project into sinuses

60

What happens to CSF absorption with age?

Can decrease
Can cause raised ICP > has to be drained another way

61

In what order to herniations occur because of a subdural haematoma?

Subfalcine herniation of cingulate gyrus
Distorted lateral ventricles
Transtentorial herniation of medial temporal lobe
Displacement and distortion of brainstem
Tranforaminal herniation of cerebellar tonsil

62

What happens in a subfalcine herniation of the cingulate gyrus?

Brain tissue forced under falx cerebri

63

What problems do distorted lateral ventricles cause?

None

64

What happens in a transtentorial herniation of the medial temporal lobe?

Part of temporal lobe goes through same space as brainstem
Constriction of blood vessels
Occulomotor nerve close to here - eventually, compression can cause fixed dilated pupil on ipsilateral side

65

What has happened by the time the cerebellar tonsil herniates?

Patient on respirator or dead

66

What type of lesions cause a transforaminal herniation of the cerebellar tonsil earlier?

Posterior fossa expanding lesion

67

What causes brainstem haemorrhages with brainstem herniation?

Blood supply of brainstem fixed
Tissue has been pushed down but vessels can't move
Vessels tear

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