Brain Injury

Question 1

What is “Brain Injury?”

Answer 1

increased intercranial volume and pressure

Question 2

The cranium contains 3 compartments.
What are they? What percentage does each take up?
Are they fixed or do they fluctuate?

Answer 2

1. Brain tissue (80%), fixed
2. Blood (10%), fluctuates
3. CSF (10%), fluctuates

Question 3

The 3 contents in the cranium make up what pressure?

Answer 3

ICP

Question 4

What should the ICP be?

Answer 4

5-15 mmHG

Question 5

Define CPP: what should its range be?

Answer 5

Cerebral Perfusion Pressure (blood flow to the brain)

(70-100 mmHG)

Question 6

What is the equation for CPP?

Answer 6

CPP = MAPP - ICP

Question 7

What is the equation for MAP?

Answer 7

Systolic + Diastolic x 2
__________________
3

Question 8

What happens if the CCP is less than 40?

Answer 8

Brain ischemia and can lead to brain infarction

Question 9

The patho of Brain injury involves munro kellies hypothesis: what is her hypothesis?

Answer 9

Physiologic minor fluctuations between the 3 compartments when they are compensating for eachother

Question 10

When trauma occurs, this is NOT a normal physiologic proccess, but what is occuring in the compartments of the cranium?

Answer 10

Fluctuation of 1 or more of the 3 compartments, causing an increase of ICP

Question 11

What is often associated with trauma causing the fluctuation between the 3 compartments?

Answer 11

Proliferation of a lesion (tumor or hemmorhage)

Question 12

Is the skull expandable?

Answer 12

NO dummy.

Question 13

When the 3 compartments are fluctating, they follow a pattern of compliance.
What is it?
1.
2.
3.

Answer 13

1. 1st compliance = displacement and or reabsorment of CSF
2. 2nd compliance = reduced blood flow (aiming to decrease ICP, but leads to problems with hypoxia)
3. Compression or displacement of the brain (DEATH!)

Question 14

Cushings Reflex:
1. What is this in resposne to?
2. Latter response to what?
3. What happens to the MAP?
4. What is the Cushing's Triad?
      1.
      2.
      3.

Answer 14

1. Ischemia
2. Latter response to increased ICP
3. MAP goes up to 270
4. 1. Widening pulse pressure (OR HTN)
   2. Reflex bradycardia
   3. Ireggular breathing

Question 15

Why does the MAP (aka BP) increase so much?

Answer 15

Trying to increase pressure to be able to overcome the pressure in order to be able to reach the brain, but it is unable to do so.

Question 16

Why does reflex bradycardia occur?

Answer 16

Reflex to the increased ICP

Question 17

Hemorrhage and Hematomas: what is the way that they form?

Answer 17

Vascular damage –> Hemorrhage –> Hematoma

Question 18

What is a hematoma?

Answer 18

Solid swelling of clotting blood

Question 19

Hematomas cause..

1. Loss of function where?
2. Which leads to loss of function where?

Answer 19

1. Loss of neural function (affeced area)

2. Loss of function at targeted area

Question 20

Hematomas are based on what?

What are the 3 we look at?

Answer 20

Location.

1. Intracerebral hematoma
2. Subdural Hematoma
3. Epidural Hematoma

Question 21

Intracerebral Hematoma:

1. Where is it?
2. Where is this putting pressure on?

Answer 21

1. In the brain tissue itself

2. Putting pressure outward to soft tissue surrounding

Question 22

Subdural Hematoma:

1. Where is it?
2. What is it putting pressure on?
3. This hematoma involves an encapsulated mass, explain the proccess of this.

Answer 22

1. Between dura matter and arachnoid matter
2. Putting pressure on the soft tissue of the brain
3. Encapsulated mass –> lysis –> increased concentration –> fluid efflux from surrounding cells into the hematoma

Question 23

Epidural Hematoma:

1. Where is it?
2. What is it putting pressure on?
3. What is the main artery affected here?
4. This is the most common hematoma with what time of injury or fracture?
5. Is this hematoma the most superficial, or the most deep?

Answer 23

1. Between dura matter and skull
2. On the brain tissue
3. Middle meningial artery
4. Head fracture or injury
5. Most superficial of the hematomas

Question 24

When do hematomas typically present? (at what age?) d/t what?

Answer 24

past age 50, d/t weakening of the vessel wall.