Test #1 Flashcards
What is the parietal lobe responsible for
Sensory, reading, writing (sensory and academic skills)
What is the cerebellum responsible for
Coordination and voluntary movements
What is the temporal lobe responsible for
Memory, hearing, learning, feelings
What is the occipital lobe responsible for
Visual reception and interpretation and being able to read
What is the frontal lobe responsible for
Problem solving, speaking, emotions, personality (this lobe makes you, “you”)
What are the 4 meninges layers (protective layers of the brain) (starting from the outside and working in)
- Dura mater (think tough - this is on the outside)
- Arachnoid
- Subarachnoid space (trabecula for fluid)
- Pia mater (think soft - this is on the inside)
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What is the monroe-kellie hypothesis
That the volume in the brain is a fixed amount (it can’t accommodate for an increase in brain/fluid - something would have to decrease)
What can cause an increase in brain volume 2
- Cerebral edema
- Occupying lesions like hematomas or tumors
What can cause an increase in blood volume within the skull 4
- Hypercapnia/hypoxemia (causes vasodilation, which increases cerebral blood volume)
- Obstruction of venous outflow (positioning of the head/neck, medical devices (c-collar))
- PEEP
- Valsalva maneuvers (anything bearing down increases the pressure in the head
What can increase the cerebrospinal fluid 3
- Hydrocephalus (cerebrospinal fluid isn’t draining)
- Obstruction of cerebrospinal fluid outflow (caused by masses, lesions and infections)
- Decreased cerebrospinal fluid absorption (caused by subarachnoid hemorrhage)
Why is increased ICP bad
Because anything that causes a high pressure in the skull disrupts the brain from getting oxygen
What is a normal ICP range
Between 5-15 mmhg
When are we worried if the ICP reaches a certain level
If ICP reaches above 15, and anything above 20 must be treated
How do we calculate the cerebral perfusion pressure (CPP)
Take the MAP - ICP
How do you calculate MAP
SBP +2(DBP) / 3
What is the normal cerebral perfusion pressure (CPP)
60-100
What CPP levels are we concerned about
Less than 50 = ischemia and neuronal death
Less than 30 = incompatible with life
How do you calculate MAP
SBP + 2(DBP)
/ 3
In order for autoregulation of cerebral blood flow (CBF), what does the CPP and MAP need to be? Why?
CPP should be within 50-150
Map should be within 60-130
Anything above or below makes it difficult for CBF to regulate
How does autoregulation of CBF work
CBF can adjust the diameter of the blood vessels supplying the brain, so this is why the pressure in vessels is important
Will autoregulation of CBF work if there is prolonged ischemia
No
What is CBF dependent on? What is CPP dependent on?
CBF is dependent on CPP, and CPP is dependent on ICP (remember CPP is MAP - ICP)
What are signs of increased ICP 7
- Irritability (being a huge jerk) (kids - have a high pitched cry)
- Headache
- Vomiting
- Decreased LOC (flat affect to coma)
- Decrease in motor function (decorticate (flexor) and decerebrate (extensor) posture)
- Pupil changes (blown pupils, fixed/dilated pupils) (anything abnormal with pupils, think that something is wrong in the brain)
- Changes in VS (bradycardia in kids - huge red flag)
What causes a buildup of CO2?
Shallow breathing, not taking many breaths… (you’re not breathing off enough CO2)
How does CO2 affect cerebral blood flow?
An increase in CO2 causes the cerebral blood vessels to dilate (relax), which leads to an increase in CBF
A decrease in CO2 causes the cerebral blood vessels to constrict, which leads to a decrease in CBF
Why is it important to maintain a normal CO2 level for someone with a head injury
Because we don’t want to increase CBF in a way that will cause more edema in the brain, so we want to keep CO2 at a normal to keep vessels constricted
For any acute unconscious patient, what should we suspect
Increased ICP
What is the pathophysiology of ICP
An increase in ICP does what to CPP
It decreases CPP (remember that ICP is not allowing for proper perfusion)
What are signs of ICP
- Irritability (brain is not getting enough glucose)
- Headache
- Vomiting
- Changes in LOC
- Loss in consciousness
- High pitched cry (in kids)
- Pupil changes
- Decrease in motor function (contralateral hemiparesis or hemiplegia) (decorticate (flexor) and decerebrate (extensor) posturing)
- VS changes (bradycardia - especially in kids, and an altered RR)
How would you describe decorticate and decerebrate posturing
Decorticate is when the arms are flexed towards your center and decerebrate is when your arms are extended out by your sides
What is interesting about decorticate and decerebrate
You can have both at the same time, where one side of your body is decorticate and the other is decerebrate
What is an emergent sign of brain herniation
Dilated pupil
What is cushing’s triad 5
Late signs of increased ICP, where there is the following:
- Increased systolic BP
- Widening pulse pressure (SBP and DBP are getting further apart)
- Bradycardia with a full and bounding pulse (tachycardia at first)
- Irregular breathing pattern (like cheynes-stokes)
- Decreased respirations
Why is it important to recognize cushing’s triad
It can indicate brainstem compression and impending death, so we treat as a medical emergency
What is a ventriculostomy
It is placed within areas of the brain and can be used to monitor ICP or drain fluid
If we don’t want to drain any CSF, what device can you use in the brain
ICP “bolt”
What 4 things should we know about external ventricular drains
- Must be level with the tragus
- Surgeon determines where to set the pressure
- Must remain as sterile as possible
- Cannot use alcohol swabs
How should we position someone with ICP
- Keep HOB at or above 30
- Keep head facing forward (neck at midline)
- Keep legs flat (do not have knees bent)
NEVER have the patient laying flat (HOB should always be elevated - we want to encourage blood flow down and away from the head)
Can we put someone in Trendelenburg? What about reverse Trendelenburgs?
Never in Trendelenburg, we can put in reverse Trendelenburg
Besides positioning, what other nursing interventions can we do for someone with ICP 5
- Avoid hyperthermia (treat with ice packs, Tylenol, fans, cooling blankets)
- Provide bowel care to avoid straining
- Reducing environmental stimuli
- Maintain PaO2 of 100 or greater and CO2 between 30-35
- Provide pain control
Why do we want to avoid hyperthermia in ICP patients
A fever can increase blood flow, which can be deadly for ICP patients
What is our drug of choice for head injuries
IV Tylenol - helps treat fever and pain, without reducing LOC
How can we manage an increase in ICP 7
- Maintain CPP between 60-100
- *Avoid hypotension (want to have enough pressure to overcome an increase in pressure (basically the brain is being squeezed because of an increase in ICP, so you want your BP to have enough pressure to overcome this ICP pressure)) (hypotension can cause a decrease in perfusion)
- Monitor RR
- Labs
- Fluid
- Electrolytes
- ## Neuro checks
What type of fluids do we want to avoid giving in an increase ICP pt
Hypotonic solutions (like 5% dextrose or 0.45% sodium chloride)
If we have to turn a pt with ICP, how should we turn them
Very, very slowly
What is our drug of choice for pain and fevers for someone with ICP
IV Tylenol for pain and fever (we like this over an opioid, because it doesn’t effect their neuro or respiratory)
What type of fluid should ICP pts not have
Hypotonic, where it can cause cells to swell
How can we manage seizures
- Benzos and anticonvulsants
- May need to be intubated if reoccurring
- May need continuous EEG if reoccurring
Why are prolonged seizures bad
Seizures cause you to use up a lot of glucose, and the brain needs glucose
What is our drug tx for ICP 4
- Mannitol (osmotic diuretic, that pulls blood off the brain into vascular space)
- Hypertonic saline 3% (movement of water out of edematous swollen brain cells and into blood vessels)
- Corticosteroids to treat vasogenic edema (tumor in your brain), not given for head injuries
- Vasopressors to help maintain CPP
What is interesting about a hypertonic solution, like 3% saline 2
- It burns
- Have to watch sodium and potassium levels very closely
If someone is receiving hypertonic saline, what should we be monitoring
Their sodium closely
Is early feeding important when treating a pt with increased ICP
Yes
What is good to know about mannitol 3
- Requires a filter for administration
- Look for crystal formation, which can occur if med is cold, do not give and send back to pharmacy
- Requires close monitoring of urine output and serum sodium level
What is a decompressive craniectomy
Last line of tx for severe increased ICP, where a portion of the skull is removed to allow the brain to swell outwards
What are the risks associated with a decompressive craniectomy 5
- Hemorrhage
- Infection
- CSF leak
- Delayed wound healing
- Sinking flap syndrome
What is herniation
When the brain swells and moves to an area of lower pressure, like moving down towards the brain stem (which is bad)
What is contraindicated if increased ICP is suspected? Why?
Lumbar puncture - you will cause a decrease in pressure when you make that puncture, and the brain will rush to that low area of pressure
What is brain death
Irreversible cessation of ALL brain activity
How do they test for brain death
- Apnea testing
- Reflex tests - like caloric reflex test (put ice water in ear, and the eyes deviate to the side of the cold water if they’re not brain dead)
With head injuries, what should you always suspect
A cervical spine injury until proven otherwise (any trauma that meets certain criteria gets a backboard and c-collar)
What are the different types of skull fractures 8
- Linear
- Depressed
- Simple
- Comminuted (broken in two places)
- Compound (an opening, like a cut or where you can see the bone)
- Open (can see the dura)
- Closed
- Basilar (fracture in the base of the skull)
What are the signs of a basilar skull fracture 2
- “raccoon eyes”
- “Battle sign” mastoid bruising behind ear
What are you at a huge risk for if you have a basilar fracture
CSF leaking and leading to an infection
What is the monroe-kellie hypothesis
That the volume in the brain is a fixed amount (it can’t accommodate for an increase in brain/fluid - something would have to decrease)
What is a halo test? How does it work?
It helps us to determine if leaking fluid is actually CSF or if it is something else, like mucous.
Take a 4x4 and swab the fluid, and if it’s CSF, then the fluid will form a halo due to the glucose (CSF fluid has glucose) (mucous doesn’t have glucose)
What is interesting about a hypertonic solution, like 3% saline 2
- It burns
- Have to watch sodium and potassium levels very closely
What is a decompressive craniectomy
Last line of tx for severe increased ICP, where a portion of the skull is removed to allow the brain to swell outwards
What are the different types of skull fractures
- Linear
- Depressed
- Simple
- Comminuted (broken in two places)
- Compound (like an open, where you can see bone)
- Open (can see the dura)
- Closed
- Basilar (fracture in the base of the skull)
What is interesting about skull fractures
They lessen the chance of increased ICP, because the brain has somewhere to swell
With an open or depressed skull fracture, what is the pt at risk for
Meningitis (because CSF may be open to the air)
If you see a pt having drainage from their ears or their nose, should you swab it
No - you don’t want to put your swab into their ear or their nose, instead leave a piece of gauze to collect the drainage
What is the difference between primary and secondary brain injury
Primary injury is the injury caused by the trauma, whereas secondary is complications from that brain trauma like ischemia, inflammation, etc)
What is the lowest score you can assign someone based on the glasgow coma scale
3
What are the 3 different levels, minor, moderate and severe on the glasgow coma scale
Minor = 13-15
Moderate = 9-12
Severe = 3-8
What are diffused brain injuries
Generalized injuries like concussions or diffuse axonal injuries
What are focal brain injuries
Localized injuries like a hematoma or contusion
What if a pt has a glascow coma scale less than 8
We intubate (“anything less than 8 we intubate”), because we are worried that they can’t protect their airway
What is a concussion
A mild TBI, which occurs at a microscopic level and is not detectable on imagining
If you are suspecting a concussion, should you still get imagining
Yes, to rule out a more severe injury
How do most concussions present
- May have a loss of consciousness
- Amnesia
In order to be diagnosed with a concussion, what must be present
The pt must have at least one brain symptom, like being dazed or confused
What can happen to pts after they have a concussion
They can develop post concussive syndrome
What is post concussive syndrome 3
- Develops 2 weeks to 2 months after the injury
- Can last for 3 or more months
- Causes difficulty in functioning at previous level
What are symptoms of post concussive syndrome 7
- Headache
- Lethargy
- Trouble concentrating
- *Sleep disturbances (big - if you’re not sleeping, you’re brain can’t heal)
- Personality and behavioral changes
- Shortened attention span
- Changes in memory
What is second impact syndrome
When you experience a second concussion while still healing from the first concussion
What is chronic traumatic encephalopathy
- Can only be diagnosed through an autopsy
- Leads to permanent changes in the brain due to repeated concussions
(think of football players)
What is a diffuse axonal injury (DAI)
Shearing forces cause damage to neurons and nearby blood vessels (twisting of the brain)
What can cause DAIs
- High-speed acceleration
- Deceleration
- Rotational injuries
(common in MVAs)
What does DAI cause in the brain
Multiple, small, diffuse hemorrhages located at the boundary of white and gray matter
Is a DAI found on imagining
It can be, but it may not be clear
What sucks about DAIs
Unpredictable outcomes, with 90% of pts remaining in a persistent vegetative state
What is a contusion
Bruise on the brain
Can you see contusions on imagining
Yes, because there will be bleeding
What is the issue with a contusion
It can “blossom”, where it keeps bleeding in the brain because there’s not really anything in the brain to stop the bleeding
What are the 3 mechanisms that can cause brain injuries
- Acceleration and deceleration (acceleration is the brain going with the forward motion, like being hit with a bat, and deceleration is the brain moving forward and then hitting an object that stops momentum, like hitting the ground while falling)
- Rotational (axon shearing) (like in boxing)
- Penetrating (gun shot)
What is coup-contrecoup
Coup is when the brain goes through acceleration and hits the front of your skull, and then contrecoup is when the brain rebounds via deceleration and hits the opposite part of the skull (whip lash)
Basically, what is diffuse axonal injury (DAI)
When there is some type of brain trauma through acceleration or deceleration, for example, and causes the axons to twist and shear resulting in neuronal death because those axons have been damaged
What is annoying about contusions
They can rebleed, known as “blossom”, which leads to poorer outcomes
What should we monitor, besides hemorrhage, if a pt has a contusion
Monitor for seizures (they can be more common with frontal or temporal injuries)
Where are subdural hematomas located
Below the dura and above the arachnoid layers
Where are epidural hematomas located
Below the skull and above the dura
Are epidural hematomas very serious?
Yes
Where are subarachnoid hemorrhages
Below the arachnoid mater and above the pia mater
Where are intracerebral or intraparenchymal hemorrhages
Accumulation of blood in the tissue of the brain instead of in the layers
What is the issue with DAIs
They may occur without bleeding, which can make them difficult to see on imagining
What type of bleed is usually venous
Subdural hematoma
Who commonly have Subdural hematomas
- Elderly (less brain tissue, which creates more space in-between the layers, which can lead to shearing if they fall)
- Alcohol abusers
What are the 3 different types of Subdural hematoma and when do they occur
- Acute (developing within 48 hours)
- Subacute (developing from 48hrs-2 weeks)
- Chronic (develops weeks after surgery)
What can be symptoms of an acute Subdural hematoma 7
- drowsiness
- coma
- headache
- confusion
- unilateral headache
- slowed thinking
- agitation
What can be symptoms of an subacute Subdural hematoma 4
- Headache
- Mild contralateral hemiparesis (opposite sided weakness)
- Drowsiness
- Confusion
What can be symptoms of a chronic Subdural hematoma 5
- Dementia
- Headache
- Lethargy
- Absentmindedness
- Vomiting
Does a Subdural hematoma always need to be drained
No, not always, they may just let the blood reabsorb
What is happening in an epidural hematoma
There’s a fracture, usually linear, that tears an artery or vein in the dura
What are the symptoms of an epidural hematoma
- Initial LOC
- Followed by a lucid period
- Then another LOC
What is the tx for epidural hematomas
Rapid surgical intervention to evaluate hematoma and prevent herniation (this is a very serious injury)
What usually causes subarachnoid hematomas
Ruptured cerebral aneurysm or TBI
What is happening in a subarachnoid hematomas
Blood is leaking into the CSF
What is a typical presentation of a subarachnoid hematomas 5
- “Worst headache of life” or also known as a “thunderclap” headache
- Altered LOC
- Diplopia (double vision)
- Meningeal signs (nuchal rigidity, photophobia)
- Seizures
What can cause intraparenchymal hematomas
Most commonly from uncontrolled HTN, ruptured aneurysms or trauma
What is the gold standard for evaluating a pt for a head injury (in terms of imagining)
CT, because it’s faster than an MRI