NUPY7_Traumatic brain injury

Question 1

clinical scale used to grade severity of traumatic brain injury

Answer 1

Glasgow coma scale

Question 2

Mechanism of cytotoxic edema

Answer 2

Failure of Na‑K‑ATPase pump due to ATP depletion

Question 3

Mechanism of vasogenic edema

Answer 3

Damage to blood brain barrier (BBB) –>movt of protein rich exudates into extracellular spaces.

Question 4

Mechanism of interstitial edema

Answer 4

During hydrocephalus, intraventricular pressure increases –> breakdown of ventricular ependymal lining –> transependymal migration of CSF into extracellular space.

Question 5

Mechanism of osmotic edema

Answer 5

Conditions which either decrease serum osmolality or increase brain tissue osmolality will produce abnormal osmotic pressure gradient with net flow of fluid into the brain parenchyma

Question 6

Type of edema seen in traumatic brain injury

Answer 6

Mechanical shearing with primary impact–> immediate diffuse BBB disruption–> early vasogenic edema
Vasogenic edema–> increased ICP–> neuronal ischemia–> cytotoxic edema

Question 7

Cushing’s triad of increased intracranial pressure

Answer 7

irregular, slow respirations
bradycardia
systolic hypertension

Question 8

Radiologic features of diffuse cerebral edema

Answer 8

• Loss of the normal differentiation between gray and white matter
• effacement of sulci
• compression of ventricles

Question 9

Atrophy/ edema?

Answer 9

edema
(Note widened gyri with flat surface and narrowed sulci)

Question 10

Clinical presentation of this pattern of herniation

Answer 10

compression of the anterior cerebral artery and its branches–>infarct of area supplied by ACA–>contralateral lower limb weakness

subfalcine herniation

Question 11

Clinical presentation of this pattern of herniation

Answer 11

• Compression of ipsilateral cerebral peduncles –> Contralateral weakness
• Compression of III cranial nerve –> ipsilateral fixed and dilated pupil (blown pupil)

Uncal herniation

Question 12

What is subfalcine herniation?

Answer 12

cingulate gyrus is displaced under the falx

Question 13

What is uncal herniation?

Answer 13

medial aspect of the temporal lobe (uncus) is compressed against the free margin of the tentorium, just anterior and adjacent to the midbrain

Question 14

What is central transtentorial herniation?

Answer 14

downward movement of the thalamic structures through the tentorial opening with compression of the upper midbrain

Question 15

clinical presentation of central transtentorial herniation

Answer 15

• Miotic pupils and drowsiness
• contralateral hemiparesis
• progressive compression of the brainstem and RAS, with initial damage to the midbrain, then the pons, and finally the medulla

Question 16

Pattern of herniation?

Answer 16

Uncal - note the pressure groove where the medial temporal lobe is being pushed below the tentorium

Question 17

Kernohan Woltman sign

Answer 17

Large uncal herniation–> compression of contralateral cerebral peduncle–> ipsilateral hemiparesis

Question 18

Idenitfy this morphologic finding associated with transtentorial herniation

Answer 18

Duret hemorrhages

Question 19

Why do Duret hemorrhages ocur in transtentorial herniation?

Answer 19

distortion or tearing of penetrating veins and arteries supplying the upper brainstem.

Question 20

**Based on the clinical presentation, identify the brain structure that is most likely compressed due to herniation:
loss of motor localization to pain
sighs, yawns
small pupils, minimal reaction to light
confusion

Answer 20

Diencephalon

Question 21

Based on the clinical presentation, identify the brain structure that is most likely compressed due to herniation:
Prominent grasp reflex
pupils fixed at mid position
decorticate posturing

Answer 21

midbrain

Question 22

Based on the clinical presentation, identify the brain structure that is most likely compressed due to herniation:
irregular breathing
loss of oculovestibular reflex
reduced muscle tone
tendon reflexes are difficult to elicit

Answer 22

pons

Question 23

Based on the clinical presentation, identify the brain structure that is most likely compressed:
No presence of respiratory effort even in the presence of a sufficiently high PCO2

Answer 23

Medulla

Question 24

Pattern of herniation?

Answer 24

Tonsillar herniation

Question 25

Clinical presentation of this pattern of herniation

Answer 25

early compression of the medulla--> respiratory arrest--> and death. | tonsillar herniation

Question 26

Gross morphologic finding associated with diffuse axonal injury

Answer 26

petechial hemorrhages in the corpus callosum

Question 27

Microscopic morphologic finding in diffuse axonal injury

Answer 27

Axonal swellings (spheroids) Retraction balls

Question 28

Most commopn anatomic areas affected in diffuse axonal injury

Answer 28

**white matter tracts** in the midline of the brain - corpus callosum, subcortical white matter, grey-white junction of the cerebral cortex

Question 29

mechanism of damage in diffuse axonal injury

Answer 29

traumatic acceleration/ deceleration --> shearing force that disrupts axons through mechanical stretch-->tears in axonal fibers.

Question 30

Where does blood collect in epidural hematoma?

Answer 30

between the duramater and the cranium (skull)

Question 31

Main cause for an epidural hematoma

Answer 31

Temporal skull fracture--> rupture of middle meningeal artery.

Question 32

Can an epidural hematoma lead to herniation?

Answer 32

Yes, depending on the rate of bleeding, there can be a rise in intracranial pressure-->uncal herniation and III nerve compression-->ipsilateral pupil dilation

Question 33

Radiologic features of an epidural hematoma

Answer 33

* Hyperdense, extraaxial, biconvex lens-shaped (lenticular) mass in the temporo-parietal region * Does not cross suture lines

Question 34

trauma-->initial loss of consciousness--> a complete transient recovery -->a rapid progression of neurological deterioration

Answer 34

Lucid interval

Question 35

Epidural/subdural hematoma?

Answer 35

Epidural hematoma | Hyperdense, extraaxial, biconvex lens-shaped (lenticular) mass

Question 36

Epidural/ subdural hematoma?

Answer 36

Subdural hematoma | Crescent-shaped, hyperintense, concave toward the cerebral hemisphere

Question 37

Radiologic features of a subdural hematoma

Answer 37

* Crescent-shaped, hyperintense, concave toward the cerebral hemisphere * can cross suture lines, does not cross the midline

Question 38

Where does blood accumulate in a subdural hematoma?

Answer 38

between the duramater and arachnoid mater

Question 39

Why are older adults at risk of subdural hematoma?

Answer 39

1. Cerebral atrophy -->stretching of bridging veins 2. Many are on anti-coagulant therapy

Question 40

Can a subdural hematoma lead to brain herniation?

Answer 40

Yes. Large acute subdural hematoma--> rise in ICP--> uncal herniation--> ipsilateral pupil dilatation, contralateral hemiparesis.

Question 41

4 month old infant Vomiting, fussy, refusing feeds swollen anterior fontanelle What's likely to be seen on imaging of the brain?

Answer 41

subdural hematoma

Question 42

2 signs of abusive head trauma

Answer 42

1. Bilateral congested retinal hemorrhages 2. Swollen anterior fontanelle due to a subdural hematoma