L20 - Traumatic Brain Injury

Question 1

State some examples of causes of Brain injury?

Answer 1

RTC (road traffic collisions) 
Falls 
Assaults 
Sports Injuries 
Firearms

Question 2

What are risk factors for brain injury?

Answer 2

Alcohol.
Recreational drugs. 
Young adults. 
Elderly. 
Younger children.

Question 3

Define a primary brain injury?

Answer 3

The initial insult to the brain at the time of injury.

Question 4

State some examples of primary brain injury?

Answer 4

• Bleeding within skull
• Contusions (bruising) of the brain tissue
• Contracoup injury
• Diffuse axonal injury
• Penetrating injury

Question 5

What is a contracoup injury?

Answer 5

Coup injury
- occurs under site of impact with an object
Contracoup
- occurs on the side opposite the area that was hit

Question 6

What is a diffuse axonal injury?

Answer 6

Result of traumatic shearing forces that occur when head is rapidly accelerated or decelerated.
- Immediate disconnection of axons

Question 7

Describe an extradural haematoma

Answer 7

Convex, inwards.
Spread limited by dural adhesion to skull.

LIP LIKE

Question 8

Describe a subdural haematoma

Answer 8

Area of increased density spreading around surface of cerebral hemisphere.

BANANA LIKE

Question 9

Describe a secondary brain injury?

Answer 9

Occurs from insults to the brain after the initial injury.

- Hypoxia, hypovolaemia and cerebral oedema.

Question 10

Define hypovolaemia?

Answer 10

Volume depletion.

Can be due to a loss of both salt and water or just a decrease in BV.

Question 11

Describe what may occur in the presence of a brain oedema?

Answer 11

• Raise in ICP
• Cerebral herniation
• raised ICP may lead to hypoperfusion (inadequate delivery oxygen and nutrients) of brain
• may cause cerebral ischaemia

Question 12

What causes an extradural haematoma?

Answer 12

Middle meningeal artery bleeds into extradural space.

Question 13

Describe diffuse axonal injury?

Answer 13

• Results from widespread axonal shearing
• often no signs on inital CT head
• can result in raised ICP from swelling

Question 14

Briefly state the different types of skull fractures?

Answer 14

Simple
Depressed
Basal fractures
- more difficult to see on X-ray

Question 15

What particular physical signs are associated with Basal skull fractures?

Answer 15

Battle's sign, periorbital bruising. 
Produce bleeding into middle ear. 
CSF rhinorrhoea (clear fluid coming out of nose, contains glucose unlike mucus)

Question 16

Describe penetrating trauma?

Answer 16

Damage occuring directly from object piercing skull and disrupting brain tissue.

Question 17

State some causes that may lead to secondary brain injury?

Answer 17

Hypoxaemia
Hypotension
Raised ICP

Question 18

During the pre-hospital care of a patient suffering a suspected brain injury it is important too…

Answer 18

Ensure adequate oxygenation and blood pressure to prevent hypoxic-ischaemic brain injury.

Question 19

Describe what may occur during the pre-hospital care of a brain injury patient?

Answer 19

ABCDE assessment
Sedation, tracheal intubation with ventilation if GCS < 8
Control of bleeding
IV access and IV fluids / blood to maintain BP and cerebral perfusion.

Question 20

Describe the Monro-Kellie

hypothesis

Answer 20

Sum of volumes of brain, CSF, and intracranial blood is constant.
Once skull reaches critical volume - any further expansion in the size of space-occupying lesions will result in a dramatic rise in ICP.

Question 21

The pressure gradient driving blood flow to the brain is known as the…

Answer 21

Cerebral perfusion pressure CPP.

- often tightly controlled through autoregulation, despite variations in arterial BP.

Question 22

Significant increases in ICP may result in…

Answer 22

Reduced CPP

- potentially causing further hypoxic-ischaemic damage

Question 23

What is the formula for calculating cerebral perfusion pressure?

Answer 23

Mean arterial pressure - ICP

Question 24

What are some signs of raised ICP?

Answer 24

Reduced conscious level.
Pupillary abnormalities e.g. dilation, bilateral ptosis.
Cushing’s triad
- late sign, often pre-terminal

Question 25

What is Cushing's triad?

Answer 25

1. High BP 2. Bradycardia 3. Irregular breathing pattern

Question 26

What two component's can adapt most easily to accommodate an increase in the volume of intracranial contents?

Answer 26

Intracranial blood - esp in the venous compartment - CSF Once these compensatory mechanisms are exhausted. further increases in vol result in large rises in ICP.

Question 27

What are simple measures to help prevent / treat raised ICP?

Answer 27

Elevation of head of bed to 30 degrees | - improves jugular venous outflow, lowers ICP.

Question 28

What is CVP? | - Central Venous Pressure

Answer 28

Circulating blood flows into the RA via inferior and superior vena cava. Pressure in the right atrium is known as the central venous pressure.

Question 29

Give an example of how Diuretics can be used to decrease ICP?

Answer 29

e. g. Mannitol - intravascular osmotic agent, can draw fluid fro both normal and abnormal brain. - decreased ICP through cerebral autoregulation,

Question 30

Give examples of further treatment for raised ICP?

Answer 30

- Osmotic therapy - Hyperventilation - Sedation - Craniectomy

Question 31

How may Mannitol aid in decreasing a raised ICP?

Answer 31

Decreased blood viscosity | - resulting in reflex vasoconstriction and decreased cerebrovascular volume.

Question 32

How may hyperventilation lead to a decreased ICP?

Answer 32

Reduced PaCO2 - vasoconstriction - reduced ICP

Question 33

Give problem with using hyperventilation to treat raised ICP?

Answer 33

Vasoconstriction can cause cerebral ischaemia therefore this is not generally recommended.

Question 34

Once ICP of patient has stabilised what are the next steps?

Answer 34

``` Begin to withdraw sedation. Assess ventilatory needs. Assess neurological deficits. Other less acute injures via tertiary survey (e.g. broken fingers) Rehab ```

Question 35

What are the categories of traumatic brain injury?

Answer 35

Mild / moderate / severe

Question 36

What are the measures for severity of traumatic brain injury?

Answer 36

1. Post traumatic amnesia 2. Glasgow coma score - <8 is very severe 3. Loss of consciousness

Question 37

Describe post traumatic amnesia?

Answer 37

Reduced ability to lay down new memory. Confusion, agitation, wandering of patient. Requires supportive care. Lasts from hours to months. GOAT assessment helps identify improvements.

Question 38

Frontal Lobe

Answer 38

``` Problem solving Emotional traits Reasoning (judgement) Speaking Voluntary motor activity ```

Question 39

Temporal lobe

Answer 39

Understanding language Behaviour Memory Hearing

Question 40

Brainstem

Answer 40

``` Breathing Body temp Digestion Alertness / sleep Swallowing ```

Question 41

Cerebellum

Answer 41

Balance Coordination and control of voluntary movement Fine muscle control

Question 42

Occiptal lobe

Answer 42

Vision | Colour perception

Question 43

Parietal lobe

Answer 43

``` involved in sensory Knowing right from left Sensation Reading Body orientation ```

Question 44

How may the brain recover after injury?

Answer 44

``` Neurons do not regenerate. Neuroplasticity - brain can reorganise itself - new pathways develop - undamaged areas of brain take over from damaged areas ```