CNS Injury I Flashcards by Lindsey Herrera

Translational acceleration from high velocity–> rupture of the bridging veins that connect the cortical brain surface to the sagittal sinus–> hemorrhage into the subdural space–> _______ and _______.

elevated intracranial pressure, distant secondary cerebral injury

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What causes “retraction balls?”

shearing of axons

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This is bradycardia and HTN in the setting of high ICP.

Cushing’s reflex

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What do free radical mediators do?

break down of the BBB–> interstitial (vasogenic) edema–> brain swelling –> increased ICP —> further hypoxia –> dysautoregulation –> herniation

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Epidural hematomas typically result from ______.

intracranial, extradural arterial bleeding

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What is Cushing’s reflex?

bradycardia and HTN in the setting of high ICP

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What is a cerebral contusion?

contusions on the brain caused by an impact or high velocity translational injury

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What is a subdural hematoma?

hemorrhage into the subdural space because of rupture of bridging veins that connect the cortical surface of the brain to the sagittal sinus

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The principal mechanisms involved in head injuries are either _____ or _____.

contact
acceleration/deceleration

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This injury occurs at the moment of impact and is largely irreversible.

primary injury

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What is a Kernohan’s notch?

when a transtentoral (uncal) herniation compresses the opposite cerebral peduncle against the tentorial edge, causing hemiparesis that is ipsilateral to the mass lesion

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This causes break down of the BBB–> interstitial (vasogenic) edema–> brain swelling –> increased ICP —> further hypoxia –> dysautoregulation –> herniation

free radical mediators

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What causes subdural hematomas?

translational acceleration from high velocity

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What are some consequences of a cerebral contusion?

hemorrhage into areas of damaged brain –> mass effect –> herniation with 2a brain injury

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____ in its mild form is thought to underlie the phenomenon of concussion.

Diffuse axonal injury (DAI)

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What is the tx for an epidural hematoma?

surgical removal

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The highest incidence of head injury occurs in what social class, age, and gender?

economically disadvantaged
age 24-35
males

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This is death due to 2nd concussion while still suffering from the 1st one.

second impact syndrome

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How is elevated ICP treated?

endotracheal intubation controlled ventilation to a pCO2 of 35mmHg elevation of the head IV osmotic diuretics (mannitol) ventricular catheters drug induced coma w/ barbs

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A transtentorial (uncal) herniation compresses the _____ and its ______, usually producing an ipsilateral 3rd nerve palsy and contralateral hemiparesis or hemiplegia.

midbrain; ipsilateral cerebral peduncle

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Contact phenomena result from _____.

an object striking the head

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This is neuron damage and death by overreaction of receptors for glutamate (NMDA and AMPA).

excitotoxicity

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What is the end result of elevated ICP?

reduction and cessation of cerebral blood flow

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A ____ compresses the midbrain and its ipsilateral cerebral peduncle, usually producing an ipsilateral 3rd nerve palsy and contralateral hemiparesis or hemiplegia.

transtentorial (uncal) herniation

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In \_\_\_\_\_, the cingulate gyrus is pushed away from the expanding mass and herniates beneath the falx cerebri

subfalcine herniations

This is when the cerebellar tonsils are herniated downward into the foramen magnum (coning) due to mass lesion in the posterior fossa.

tonsillar herniation

These are traumatic separations of the skull at suture lines.

diastatic fractures

What other lesion is a subdural hematoma often associated with?

underlying cerebral contusions

What is a secondary injury?

injury from inadequate resuscitation

This is astrocyte swelling due to K+ influx.

cytotoxic edema

What is the Glascow-Coma Score (GCS)?

an assessment of the head injured pt that correlates w/ the likelihood that the pt has an intracranial mass lesion and the outcome

What is a Duret hemorrhage?

hemorrhage in the brainstem characteristic of uncal herniation --\> disruption of ascending RAS

In \_\_\_\_\_, the uncus herniates across the tentorial edge and downward into the posterior fossa.

transtentorial (uncal) herniation

What is the mortality rate for cerebral contusions?

less than 20%

Name 5 types of skull fractures.

1. linear 2. depressed 3. basilar 4. diastatic 5. growing

What is the tx for a subdural hematoma?

* surgical removal of the blood clot * control of intracranial pressure * restoration of cerebral blood flow

In conditions of extremely elevated extracellular K+, \_\_\_\_\_\_.

the glutamate transporter reverses

What is excitotoxicity?

neuron damage and death by overreaction of receptors for glutamate (NMDA and AMPA)

Name the 3 largest causes of brain injury.

1. Motor vehicles 2. recreation 3. violence

What are the steps in the concussion grading scale?

* grade 1 = confusion w/o amnesia or LOC * grade 2 = confusion and amnesia * grade 3 = LOC

\_\_\_\_\_ injuries result from rapid head movement that can create shear, tensile, and compressive strains.

Acceleration/deceleration

What does translational acceleration from high velocity cause?

subdural hematomas

\_\_\_\_\_\_ typically result from intracranial, extradural arterial bleeding.

Epidural hematomas

What does the Monroe-Kelly doctrine state?

the volume of the CSF + volume of blood in the cerebral systems + the volume of brain + volume of any mass lesion MUST = the volume of the intracranial compartment (constant)

This is a fracture in an infant resulting from dural tears and herniation of the arachnoid into the fracture site--\> CSF pulsations --\> bone loss.

a growing fracture

What are the common symptoms of brain herniation syndromes?

* progressive lethargy * poor responsiveness (obtundation) * headache * nausea * vomiting

What causes second impact syndrome?

loss of autoregulation of CNS vasculature--\> cerebral vessels lose tone--\> congested with blood --\> increased ICP --\> widespread ischemia and vasogenic edema

This is a hemorrhage in the brainstem characteristic of uncal herniation --\> disruption of ascending RAS,

a Duret hemorrhage

What is the tx for a cerebral contusion?

* med mgmt. to prevent brain swelling * possible surgical evac

DX? * headache * dizziness * poor attention * inability to concentrate * memory problems * fatigue * irritability * depressed mood * intolerance of bright light or loud noise * sleep disturbance

concussion

A transtentorial (uncal) herniation compresses the midbrain and its ipsilateral cerebral peduncle, usually producing ______ and \_\_\_\_\_\_.

an ipsilateral 3rd nerve palsy; contralateral hemiparesis or hemiplegia

Name 2 characteristic locations of cerebral contusions.

1. anterior cranial fossa (frontal lobe) 2. greater wing of the sphenoid (temporal lobe)

What is a basilar skull fracture?

high velocity blunt injury causes cribiform plate or petrous bone fractures, resulting in CSF leaks

This results from high velocity rotational acceleration/deceleration.

diffuse axonal injury (DAI)

In \_\_\_\_\_, the pt is always unconscious at time of injury.

Diffuse axonal injury (DAI)

This is a high velocity blunt injury that causes cribiform plate or petrous bone fractures, resulting in CSF leaks and possible meningitis.

a basilar skull fracture

Acceleration/deceleration injuries result from rapid head movement that can create \_\_\_\_\_\_\_.

shear, tensile, and compressive strains

What causes an epidural hematoma?

skull fractures in the distribution of the middle meningeal artery

Acceleration/deceleration injuries result from ______ that can create shear, tensile, and compressive strains.

rapid head movement

What is a depressed skull fracture?

comminuted bone fragments that may be driven into the brain

What is a diastatic fracture?

traumatic separations of the skull at suture lines

This is downward central pressure that causes bilateral uncal herniation.

central herniation

This is when a transtentoral (uncal) herniation compresses the opposite cerebral peduncle against the tentorial edge, causing hemiparesis that is ipsilateral to the mass lesion.

a Kernohan's notch

This is hemorrhage into the subdural space because of rupture of bridging veins that connect the cortical surface of the brain to the sagittal sinus.

a subdural hematoma

What is a growing fracture?

fracture in an infant resulting from dural tears and herniation of the arachnoid into the fracture site--\> CSF pulsations --\> bone loss

What is the mortality rate for an epidural hematoma?

less than 20% (if evacuation wi 1 hour)

What is the classic presentation of an epidural hematoma?

* post impact injury * lucid interval prior to progressive obtundation and coma

In diffuse axonal injury (DAI), MRI shows _____ in large white matter tracts and near the gray-white junction bc of its density difference.

punctuate hemorrhages

What causes a diffuse axonal injury (DAI)?

high velocity rotational acceleration/deceleration

DX? * mild traumatic brain injury * alteration of mental status caused by biomechanical forces * may or may not have lost consciousness * confusion and amnesia

concussion

In diffuse axonal injury (DAI), MRI shows punctuate hemorrhages in ______ and near the gray-white junction bc of its density difference.

large white matter tracts

Why is second impact syndrome fatal?

once the course begins it's nearly impossible to stop

What is a linear skull fracture?

high impact injury causing fracture of the calvarium

\_\_\_\_\_ phenomena result from an object striking the head.

Contact

How does vasogenic edema occur?

excitotoxicity causes BBB compromise --\> increased permeability --\> brain swelling

What physiological process does progressive lethargy and poor responsiveness (obtundation) indicate?

an acute rise in ICP

What is tonsillar herniation?

the cerebellar tonsils are herniated downward into the foramen magnum (coning) due to mass lesion in the posterior fossa

In \_\_\_\_, the anterior cerebral artery is often kinked and a stroke frequently occurs.

subfalcine herniations

In subfalcine herniations, the ______ is pushed away from the expanding mass and herniates beneath the \_\_\_\_\_.

cingulate gyrus; falx cerebri

What happens with widespread simultaneous neuronal depolarization?

an immediate spike in extracellular K+

How does secondary brain injury occur?

* hypoxia * altered blood flow * release of free radical mediators

What do skull fractures in the distribution of the middle meningeal artery cause?

an epidural hematoma

What is second impact syndrome?

death due to 2nd concussion while still suffering from the 1st one

Name 4 distinct herniation syndromes.

1. subfalcine herniation 2. central herniation 3. uncal herniation 4. tonsillar herniation

What can arise from a basilar skull fracture?

meningitis bc of the CSF leaks

What can precipitate a herniation syndrome and why?

a lumbar puncture in the setting of an intracranial mass lesion due to the differential pressure this creates btw the cranial and subarachnoid space

In \_\_\_\_\_, MRI shows punctuate hemorrhages in large white matter tracts and near the gray-white junction bc of its density difference.

Diffuse axonal injury (DAI)

What is central herniation?

downward central pressure that causes bilateral uncal herniation

What causes cytotoxic edema?

astrocyte swelling due to K+ influx

What is the mortality rate from a subdural hematoma?

40-60%

At what anatomical locations can brain herniations occur?

* across the falx * across the tentorium * the foramen magnum

This is when excitotoxicity causes BBB compromise --\> increased permeability --\> brain swelling.

vasogenic edema

What are the most common s/s of concussion?

* headache * dizziness * poor attention * inability to concentrate * memory problems * fatigue * irritability * depressed mood * intolerance of bright light or loud noise * sleep disturbance

Pathologically high levels of glutamate can cause excitotoxicity by \_\_\_\_\_.

allowing high levels of Ca++ into the cell

This fracture is diagnosed when comminuted bone fragments are seen that may be driven into the brain.

a depressed skull fracture

What is a primary brain injury?

one that occurs at the moment of impact and is largely irrversible

Anyone with a witnessed LOC needs \_\_\_\_.

a CT scan

This states that the volume of the CSF + volume of blood in the cerebral systems + the volume of brain + volume of any mass lesion MUST = the volume of the intracranial compartment (constant).

the Monroe-Kelly doctrine

This is injury from inadequate resuscitation.

secondary injury

In transtentorial (uncal) herniation, the _____ herniates across the tentorial edge and downward into the \_\_\_\_\_.

uncus; posterior fossa

What is a concussion?

* mild traumatic brain injury * alteration of mental status caused by biomechanical forces * may or may not have lost consciousness * confusion and amnesia

Name 5 causes of brain herniation syndromes.

1. trauma 2. ischemia 3. neoplasm 4. infection 5. hydrocephalus

This is a high impact injury causing fracture of the calvarium.

a linear skull fracture

What does tonsillar herniation result in?

medulla compression --\> abnormal cardiac and respiratory responses