CNS Trauma

Question 1

What percent of head-injury deaths occur prior to hospitalization?

Answer 1

66% (thus, primary-prevention measures are crucial)

Question 2

Trauma is the leading cause of death up to age _________.

Answer 2

45

Question 3

What are the four categories of cerebral injury given in this PowerPoint?

Answer 3

• Ischemic/hypoxic
• Contact phenomenon (getting hit with something)
• Penetrating head trauma (GSW, stabbing)
• Accelerational (falling, stopping suddenly)

Question 4

Describe the four types of skull fractures.

Answer 4

Linear: a crack in the skull
Depressed: indentations
Basilar: anything affecting the base of the skull
Growing: an indentation followed by “popping” back out and resorbing

Question 5

Which kind of cranial fracture is associated with CSF leak?

Answer 5

Basilar – gravity pulls the CSF down, leading to leakages

Question 6

Diagnosis of basilar skull fractures is done predominantly by ___________.

Answer 6

clinical features –the convoluted base of the skull is difficult to detect fractures on

Question 7

What symptoms suggest basilar skull fractures?

Answer 7

CSF rhinorrhea or otorrhea 
Racoon eyes
Subconjunctival hemorrhage
Battle's sign (a late-appearing ecchymosis posterior to the ear) 
Facial nerve palsy
Bleeding from external auditory meatus

Question 8

What kind of hematoma is often associated with skull fractures?

Answer 8

Epidural

Question 9

The lucid interval is characteristic of _________ hematomas.

Answer 9

epidural (symptoms appear later, like an EPilogue appears later in a book)

Question 10

Epidurals occur when the ______________ is ruptured (blood vessel).

Answer 10

middle meningeal (frequently from skull fractures cutting the artery)

Question 11

What blood vessels tear in subdural hematomas?

Answer 11

The superficial cerebral veins

Question 12

What kind of injury leads to subdural hematomas?

Answer 12

Rapid translational injuries (e.g., stopping suddenly or being shaken); think of the reason: your brain moves suddenly and stretches the veins that connect the brain to the dura

Question 13

Describe the shape of the blood (appearing on CTs) for epidural and subdural hematomas.

Answer 13

Epidural = lentiform, because the dura prevents it from spreading into the parenchyma
Subdural = crescent

Question 14

What is one reason that subdural hematomas typically have a poorer outcome than epidural hematomas?

Answer 14

Subdural hematomas require a more traumatic injury that will often cause brain contusions; the increased intracranial pressure from the bleeding is added to the intracranial pressure from the bruise’s inflammation.

Question 15

Rotational injuries lead to damage that requires _________ to notice.

Answer 15

microscopic examination

Question 16

What histologic finding is characteristic of rotational injury?

Answer 16

Axonal spheroids (retraction balls of Cajal) 24 hours after injury

Question 17

What parts of the brain are most commonly the sites of axonal spheroids?

Answer 17

The corpus callosum and brainstem

Question 18

The brain accommodates to ________ increases in pressure.

Answer 18

long-lasting (that is, the brain does not compress to acute changes in pressure)

Question 19

Intracranial compensation occurs by decreasing what two fluids?

Answer 19

Venous blood and CSF

Question 20

Once the compensations of the venous blood and CSF are exhausted, __________ occurs.

Answer 20

rapid increase in ICP

Question 21

What is the most dire sequela of uncal herniation?

Answer 21

The pressure put on the brainstem – the midbrain in particular

Question 22

Transtentorial herniation often presents with ____________.

Answer 22

contralateral hemiparesis and ipsilateral mydriasis (a “blown pupil,” per Dr. Ojemann) due to compression of the corticospinal tract and oculomotor nerve (which carries the parasympathetic input to the pupillary constrictor)

Question 23

Central herniation can be very serious. What structure herniates in this condition and why is that a big problem?

Answer 23

The thalamus pushes over –into the third ventricle – and pushes down onto the brainstem.

Question 24

Why does traumatic brain injury lead to increase in cerebral blood flow?

Answer 24

The mechanical damage (such as pressure or acceleration) leads to widespread release of neurotransmitter; the excess activity leads to astrocyte-mediated vasodilation.

Question 25

Ischemia and trauma both lead to excess release of ___________.

Answer 25

glutamate

Question 26

Cerebral perfusion pressure (CPP) is equal to ______________.

Answer 26

MAP - ICP; the difference between blood pressure and pressure within the skull

Question 27

What mnemonic did Dr. Ojemann give for the priorities of treating a traumatic brain injury?

Answer 27

ABC
Airway patency
Breathing
Circulation

Question 28

If you’re examining a patient for a Glasgow coma score and you’re rating one half of a bilateral response, how do you score?

Answer 28

You score the best half; for instance, if they have hemiplegia then you only give the motor score for their better half.

Question 29

Notably, __________ reflexes are not included in the GCS score.

Answer 29

brainstem

Question 30

What makes tearing of the bridging veins (i.e., the event that leads to a subdural) more likely?

Answer 30

Cortical atrophy

Question 31

During excitotoxicity, _________ is released by astrocytes (instead of being taken up).

Answer 31

glutamate

Question 32

What triggers cytotoxicity?

Answer 32

Excess potassium outside the cells (released due to excitotoxicity)

Question 33

___________ is a better predictor of mortality than hypoxia in a patient with a severe TBI.

Answer 33

Hypotension

Question 34

What is normal intracranial pressure?

Answer 34

-3 – 15 mmHg

Question 35

Describe the three peak ages for incidence of TBI.

Answer 35

0 - 4: child abuse
24 - 35: recreation + MVAs
65 and older: falls

Question 36

What are DAIs and what type of injury leads to them?

Answer 36

Diffuse Axonal Injuries; rotational forces

Question 37

What are the four most common types of cerebral herniation?

Answer 37

Sub/transfalcine
Central
Uncal
Tonsillar

Question 38

Performing a lumbar puncture on a patient with increased intracranial pressure can induce ____________.

Answer 38

herniation, because you’re removing some of the column of pressure that’s resisting the pressure from the cranium

Question 39

Describe the pathogenesis of vasogenic edema.

Answer 39

TBI induces widespread release of glutamate; glutamate induces depolarization and thence calcium entry into cells; excess calcium within cells activates proteases and damages the cytoskeleton, leading to damage to the blood-brain barrier and leakage of plasma into the brain.

Question 40

In the context of head injuries, what is PTA?

Answer 40

Post-traumatic amnesia

Question 41

By definition, what is a concussion?

Answer 41

Alteration in mental status caused by blunt trauma to the head

Question 42

CT scanning is indicated for anyone who had witnessed ___________ following a concussion.

Answer 42

loss-of-consciousness