CNS Trauma Flashcards

1
Q

What components make up the blood brain barrier?

A

tight intercellular junctions
endothelium has low pinocytotic rate and basement membrane
dynamic interaction of endothelium with astrocytes and pericytes

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2
Q

What types of substances can cross the BBB?

A

small substances and small lipophilic molecules

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3
Q

What types of substances are unable to cross the BBB?

A

large substances and hydrophilic molecules (require active transport)

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4
Q

What is cerebral edema?

A

accumulation of excess fluid in intracellular or extracellular spaces of the brain

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5
Q

What is the major consequence of cerebral edema?

A

increased intracranial pressure

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6
Q

What is another name for vasogenic edema?

A

extracellular edema

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7
Q

What is vasogenic edema?

A

disruption (increased permeability) of BBB
results in shift of fluid from intravascular to the extravascular compartment
predominately involves white matter

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8
Q

What are the most common causes of vasogenic edema?

A

primary or secondary brain turmors
abscesses
contusions
intracerebral hematomas

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9
Q

What is another name for cytotoxic edema?

A

intracellular edema

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10
Q

What is cytotoxic edema?

A

occurs secondary to cellular energy failure
results in a shift of water from the extracellular to intracellular comparment
intracellular swelling-large amounts of Na enters cells, H2O follows
histologically brain tissue vacuolation
predominately in gray matter

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11
Q

What are the most common causes of cytotoxic edema?

A
ischemia/infarct
meningitis
trauma
seizures
hepatic encephalopathy
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12
Q

What can increased intracranial pressure lead to?

A

decreased perfusion and/or herniation syndromes

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13
Q

What is a subfalcine herniation?

A

cingulate gyrus herniates under the falx

may result in ACA compression, leading to infarct

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14
Q

What causes subfalcine herniation?

A

asymmetric expanding hemispheric lesions

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15
Q

What is a transtentorial uncal herniation?

A

medial temporal lobe displaced through tentorial opening because of asymmetric expanding lesion

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16
Q

What are complications of transtentorial uncal herniation?

A

ipsilateral CNIII nerve compression with pupillary dilation
contralateral peduncular compression (kernohan’s notch) causing ipsilateral hemiparesis
PCA compression (ipsi or bilateral)
duret hemorrhage

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17
Q

What is a duret hemorrhage?

A

fatal brainstem hemorrhage

secondary to progression of uncal herniation and resultant tearing of vessels in the midbrain/pons

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18
Q

What is cerebellar tonsillar herniation?

A

caudal cerebellar structures “tonsils” attempting to escape through the foramen magnum

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19
Q

What causes tonsillar herniation?

A

symmetric expansion of supratentorial contents into posterior fossa or expanding mass lesion in posterior fossa

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20
Q

What is a complication of cerebellar tonsillar herniation?

A

medullary compression resulting in cardiorespiratory arrest

21
Q

What is hydrocephalus?

A

enlargement of ventricles associated with increase in CSF volume

22
Q

What causes communicating/non obstructive hydrocephalus?

A

decreased absorption at arachnoid granulations

23
Q

What causes non-communicating/obstructive hydrocephalus?

A

obstruction within ventricular system, preventing communication between the ventricles proximal and distal to the obstruction
(ie/tumor, congenital malformation, thick meninges at base of brain)

24
Q

What are the two types of head trauma?

A

blunt/nonmissile (most common)

penetrating/missile

25
What is primary damage seen in head trauma?
immediate | scalp lac, skull fx, cerebral contusions, cerebral lacs, intracranial hem, DAI
26
What is secondary damage seen in head trauma?
``` delayed ischemia hypoxia cerebral swelling infection ```
27
What typically results from focal injury?
focal neurological deficits/epilepsy
28
What typically results from diffuse injury?
coma/vegetative state
29
Describe the 3 types of skull fractures
linear: single fracutre line, through entire thickness of skull comminuted: multiple linear fractures radiate from point of impact depressed: bone fragments displaced inward
30
What is a concussion?
pathophysiologic process induced by traumatic biomechanical forces (also called mild TBI) constellation of physical, cognitive, emotional and or sleep-related sx that may or may not involve loss of consciousness
31
What is a contusion?
superficial bruise of the brain usually at crests of gyri occur overlying rough area of inner skull (ie/orbital and temporal regions)
32
How do acute contusions appear?
wedge shaped | superficial hemorrhage in cortex and meninges
33
How do old contusions appear?
gyri indented, cavitated, with brown/orange discoloration
34
What is the difference between a coup and contrecoup contusion?
coup contusions occur at the point of impact while contrecoup contusions occur directly opposite the point of impact
35
Describe diffuse axonal injury
occurs with deceleration/acceleration injury and/or angular accel loss of consciousness at onset WITHOUT lucid interval unconscious or disabled until death
36
What lesions are seen with DAI?
clusters of petechial hemorrhages and soft hemorrhagic foci acutely hydrocephalus ex vacuo, thinned corpus callosum and gray discoloration of white matter chronically
37
What microscopic changes are seen with DAI? (needed to confirm DAI dx)
axons are disrupted, axonal transport continues and causes axonal swellings acute: axonal swellings, positve for B amyloid protein and silver stains subacute: microglia and axonal swellings chronic: degeneration of involved fiber tracts
38
What commonly causes epidural hematomas?
skull fx & mca tear | slow accumulation because of adherence between skull and dura
39
What are the signs/symptoms of an epidural hematoma?
lucid interval
40
What are signs/symptoms of a subdural hematoma?
headache, confusion
41
What causes a subdural hematoma/
tearing of bridging veins extending from subarachnoid space to dura more common in elderly w/brain atrophy
42
How does chronic subdural hematoma occur?
recurrent bleeds from friale vessels in granulation tissue, originally injury occurred months ago
43
What does a chrnoic subdural hematoma look like?
well organized membrane enclosing the hematoma
44
How do subarachnoid hemhorrages occur?
contusions, lacerations, skull base fractures, escape of blood from ventricular system
45
Why does post-traumatic hydrocephalus occur?
obstruction of CSF resorption due to subarachnoid space hemorrhage
46
What are sequelae of brain trauma?
post-traumatic hydrocephalus post-traumatic epilepsy chrnoic traumatic encephalopathy
47
What is chronic traumatic encephalopathy associated with?
mild repetitive traumatic brain injury | ie/in athletes and veterans
48
What are the signs/symptoms of chronic traumatic encephalopathy?
initially: impulsivity, aggression, depression, short-term memory loss eventually: dementia, gait, speech abn, parkinsonism
49
What pathology is seen in chronic traumatic encephalopathy?
extensive deposition of tau in form of neurofibrillary and glial tangles and TDP-43 inclusions