CNS Injury

Question 1

What is Monro-Kellie Doctrine?

Answer 1

CSF + CBV (Cranial Venous V + Cranial Arterial V) + Brain Volume + Mass = Constant

Question 2

What is the implication of CPP = MAP-ICP

Answer 2

ICP increases => cerebral perfusion decreases

Question 3

What is the shared common symptom of herniation?

Answer 3

Progressive lethargy and poor responsiveness (obtundation)

–> hallmark of increased ICP and is an emergency

Question 4

List the name of 4 different herniation

Answer 4

1. Subfalcine herniation
2. Uncal herniation
3. Central herniation
4. Tonsillar herniation

Question 5

Subfalcine herniation

Answer 5

cingulated gyrus herniates beneath falx cerebri, often kinks anterior cerebral –> causing stroke

Question 6

Uncal herniation (aka transtentorial herniation)

Answer 6

uncus herniates across the tentorial edge and into the post. fossa

Question 7

What are the 2 effects of uncal herniation?

Answer 7

1. compress midbrain and ipsilateral cerebral peduncle –> producing ipsilateral third nerve palsy & contralateral hemiparesis/hemiplegia
2. Duret hemorrhage in brainstem because of disruption of ascending reticular activating system

Question 8

Central herniation

Answer 8

downward pressure centrally –> bilateral uncal herniation

Question 9

Tonsillar herniation

Answer 9

tonsil herniate downward into foramen magnum –> compress medulla –> abnormal cardiac/respiratory response

Question 10

Tonsillar herniation most commonly is encountered in the setting of a mass lesion in the ……………

Answer 10

Posterior fossa

Question 11

Cushing’s reflex, which consists of

………………. in the setting of high intracranial pressure, is an example of problem when …….. compressed

Answer 11

1. bradycardia and hypertension

2. medulla

Question 12

Explain how the release of lots of glutamate leading to vasogenic edema

Answer 12

1. Release lots of glutatmate (excitotoxicity) cause Ca++ to enter cell
2. influx Ca++ activate enzymes damage cell structure & BBB
3. additional brain swelling = vasogenic edema

Question 13

What are the 2 big categories of TBI due t contact forces?

Answer 13

1. Skull fracture

2. Epidural Hematomas

Question 14

Signs of Basilar fracture (4)

Answer 14

1. CSF rhinorrheoa & otorrhoea
2. Raccoon eyes = bilateral periorbital hematoma
3. Battle’s sign
4. Facial nerve palsy

Question 15

How do we acquire “Growing fracture”?

Answer 15

Starting from linear fracture –> CSF pulsation with heart beat –> growing with time

Question 16

What are 5 types of skull fractures?

Answer 16

1. Linear
2. Depressed
3. Basilar
4. Diastatic
5. Growing

Question 17

Other name for “Epidural Hematoma”?

Answer 17

Intracranial extradural ARTERIAL hemorrhage

Question 18

Epidural hematomas associated with skull fractures, frequently due to injury to ……

Answer 18

middle meningeal artery

Question 19

Characteristics of Epidural hematomas?

Answer 19

1. Injury to middle meningeal artery (frequently)
2. Lucid interval
3. Low mortality rate => 2nd brain damage = time to intervene
4. lenticular (oval-y) shape