TBI

Question 1

Systemic processes that influence secondary TBI

Answer 1

1. Hypoxia 2. Hypotension 3. Anemia 4. Hypoerthermia 5. Hypo/Hypercarbia 6. Sepsis 7. Acid Base disturbances

Question 2

Signs of herniation

Answer 2

1. Dilated and unreactive (1mm difference) 3. Extensor posturing on motor exam 4. No mptpr response (not from spinal cord injury) 5. Drop in GCS >2pts wih best initial score

Question 3

How is TBI categorized?

Answer 3

Minor GCS 14-15 Moderate GCS 9-13 Severe GCS

Question 4

What proportion do mild, moderate and severe head injuries contribute to total head injuries?

Answer 4

Mild- 80% Moderate- 10% Severe- 10%

Question 5

List 4 factors that cause cerebral vasoconstriction:

Answer 5

Alkalosis Hypocarbia Hypertension Reduced cerebral metabolic demand

Question 6

List 5 factors that cause cerebral vasodilation:

Answer 6

Acidosis Hypercarbia Hypotension Increased cerebral metabolic demand (eg. pyrexia, agitation) Hypoxia

Question 7

What is the calculation for CPP?

Answer 7

CPP = MAP – ICP Normal CPP > 50 Normal ICP 5-15 mmHg Between CPP 50-160mmHg CBF is constant due to autoregulation Autoregulation is lost outside of that range of CPP

Question 8

How does chronic hypertension affect autoregulation?

Answer 8

Causes a shift in the autoregulation curve to the right (ie. Require a higher MAP to maintain constant CBF)

Question 9

Describe the difference between direct and indirect head injury and provide 2 examples of each:

Answer 9

Direct injury— injury results from direct contact between an external object/applied force and the cranium i.e. direct blow to head, compression, contusion, avulsion Indirect injury— injury results from forces created without direct contact with an external object and the cranium i.e. acceleration-decceleration injuries, tangential penetrating injuries (even if cranium not penetrated,

Question 10

List 7 signs of basilar skull fracture

Answer 10

Hemotympanum CSF Rhinorrhea CSF Otorrhea Blood in the ear canal Battles Sign (Retroauricular hematoma) Raccoon Eyes (Periorbital ecchymosis) Cranial Nerve Deficits

Question 11

What is the Monroe-Kellie doctrine?

Answer 11

Cranial vault is a fixed volume Any increase in volume results in an increase in ICP unless one of the other elements (blood, parenchyma, CSF) decreases in volume

Question 12

What is Cushing’s Reflex?

Answer 12

Hypertension, Bradycardia & diminished respiratory effort Marks severely raised ICP and imminent or active herniation Full triad is only present in 30% of life-threatening ICP elevation cases

Question 13

What are the brain herniation syndromes

Answer 13