Trauma

Question 1

list the 3 meninges from outer to inner

Answer 1

dura, arachnoid, pia

Question 2

blood-brain barrier is made of what 3 structures*

Answer 2

tight junctions between nonfenestrated capillary endothelial cells; basement membrane; astrocyte foot processes

Question 3

blood-brain barrier: ____ and ____ cross slowly by _______, whereas _____ cross rapidly via _____*

Answer 3

glucose; amino acids; carrier-mediated transport mechanisms; nonpolar/lipid-soluble substances; diffusion

Question 4

vasogenic edema: pathogenesis, gray or white matter, common causes

Answer 4

extracellular edema caused by disruption (increased permeability) of blood-brain barrier involving inflammatory cytokines and chemokines (responds to steroids); white matter; brain tumors and infarction

Question 5

cytotoxic edema: pathogenesis, gray or white matter, common causes

Answer 5

intracellular edema caused by dysfunctional membrane pumps causing cellular swelling from sodium (and then water); gray matter; ischemia/infarct, meningitis, trauma, seizures, hepatic encephalopathy

Question 6

subfalcine herniation: pathogenesis, major consequence

Answer 6

cingulate gyrus herniates under falx cerebri; compression of anterior cerebral artery leading to infarction

Question 7

downward transtentorial (central) herniation: pathogenesis, major consequences

Answer 7

caudal displacement of brain stem –> tearing of vessels in midbrain/pons –> Duret hemorrhages (usually fatal)

Question 8

uncal herniation: pathogenesis, major consequences

Answer 8

downward displacement of medial temporal lobe (uncus) through tentorial opening due to asymmetric expanding lesion;

1. ipsilateral CN III compression (pupillary dilatation, “blown pupil,” “down-and-out” gaze)
2. ipsilateral PCA compression: contralateral homonymous hemianopia
3. compression of brainstem against the tentorial edge opposite the direction of herniation (can lead to false localization of motor deficit-ipsilateral paresis)

Question 9

cerebellar tonsillar herniation: pathogenesis, major consequences

Answer 9

tonsillar herniation into foramen magnum; medullary compression results in cardiorespiratory arrest and death

Question 10

hydrocephalus: pathogenesis

Answer 10

enlargement of ventricles associated with increase in CSF volume

Question 11

communicating hydrocephalus: pathogenesis

Answer 11

decreased absorption at arachnoid granules

Question 12

where do contusions usually occur?

Answer 12

orbital surfaces and temporal tips

Question 13

dx: wedge-shpaed, superficial hemorrhage in cortex and meninges, microscopically shows perivascular accumulation of blood and edema after a few hours

Answer 13

acute contusion

Question 14

gross morphology of old contusions

Answer 14

gyri indented, cavitated, with brown/orange discoloration; macrophages with hemosiderin, fibrillary astrocytes

Question 15

dx: histology shows cavitation with hemosiderin-laden macrophages on orbital surfaces

Answer 15

old contusion

Question 16

most common locations of contrecoup contusions

Answer 16

frontal and temporal poles (opposite the point of impact)

Question 17

loss of consciousness after a major motor vehicle accident WITHOUT lucid interval and unconscious until death –> what is the diagnosis, what histological changes would you expect, and what gross morphology would you expect?

Answer 17

diffuse axonal injury; axonal swellings; petechial hemorrhages in white matter

Question 18

loss of consciousness after a major motor vehicle accident WITH lucid interval –> what is the diagnosis and what vessel is torn?

Answer 18

epidural hematoma; middle meningeal artery

Question 19

mild trauma in elderly individual with brain atrophy, headache, confusion, imaging shows crescent-shaped hemorrhage that crosses suture lines –> what is the diagnosis and what vessel is torn?

Answer 19

subdural hematoma; bridging veins

Question 20

mild repetitive traumatic brain injury in a football player causing aggression, dementia, parkinsonism –> what is the diagnosis and what is the pathogenesis?

Answer 20

chronic traumatic encephalopathy; extensive deposition of tau in form of neurofibrillary and glial tangles and TDP-43 inclusions

Question 21

dx: hematoma that does not cross suture lines

Answer 21

epidural hematoma

Question 22

what type of hematoma is always life-threatening?

Answer 22

epidural hematoma