CSF is made in the ___ ___ and circulate through the 3rd, 4th ventricles and ______ space.
Lateral ventricles; subarachnoid space
Brain cells can function without oxygen for ____.
10 seconds
In cardiac arrest, death of brain cells occur in _____minutes.
4-6 minutes
____ is major fuel of nervous system however it has NO PLACE to STORE it.
Glucose
Are YOUNG men or women more likely to stroke?
MEN
Are OLD me or women more likely to stroke?
women
Overall, are men or women more likely to stroke?
Women
Who is more likely to stroke African Americans or Caucasians?
African Americans
Whats the difference between a Transient Ischemic Attack (TIA) and a Ischemic attack (Stroke)?
TIA: <24 hrs symptoms resolve, NO INFARCT on scans
Stroke: >24 hrs process that leads to DESTRUCTION of neural tissue and consequent brain damage
Name four causes of Ischemic stroke (which is the most common kind of stroke BTW!)
1. Large artery thrombosis (atherosclerotic disease)
2. Small penetrating artery thrombosis (lacunar-white matter)
3. Cardiogenic embolitic (Afib, PFO, valve dx)
4. Cryptogenic (no apparent cause, although further investigation usually finds one!)
ISCHEMIA vs ISCHEMIC, what's the difference?
Ischemia: decreased blood supply
Ischemic: death of tissue
What is the goal of treatment for a stroke?
Save the Penumbra!!
Right side stroke will show what s/s?
Spatial-perceptual deficits
Tendency for distraction
Impulsive behavior
Poor judgement
Deficits in L visual fields
(jump out of bed/crazy, don't know limits, no special or limb awareness)
Left side stroke will show what s/s?
Language problems (expressive aphasia, receptive aphasia, global aphasia)
Intellectual impairment
Slow/cautious behavior
Deficits in R visual fields
(Unable to communicate, disturbed thought process)
Pathophysiology of an ISCHEMIC stroke?
Blood vessels narrow/occlude
Creates a change in cerebral blood flow
Severity of stroke depends on the loss of flow (lg artery=lg damage, & vice versa)
Minimal blood at center of the infarct
Margins of infarct blood vessels dilate
Increased edema surrounding ischemia (pneumbra)
The goal of treatment for an ischemic stroke is to save the pneumbra. How do we do this?
Give TPA & ASA
Increase perfusion:
-increasing BP
-give fluids
-give O2 (2-3L for O2Sats <92)
-Temp (99.6+), bed rest
Why place a patient on a heart monitor for an ischemic stroke?
Monitor VS and rhythm (arrhythmia like Afib will decrease cerebral perfusion!)
A patient was treated with Thrombolysis for an ischemic stroke. Where do you want to keep their blood pressure? When do you start anticoagulants?
SBP ≥ 180mmHg or DBP ≥ 105mmHg
No Heparin, ASA, warfarin, clopidogrel or dipyridamole for 24hrs
(CT or MRI after tPA therapy
Monitor for bleeding)
A patient had an ischemic stroke but could not be treated w/thrombolytic therapy (too late!). Where do you want to keep their blood pressure and when should you start anticoagulants?
SBP > 220 or DBP >120
Antithrombotics started WITHIN 24 hrs
Repeat CT or MRI for 24-48hrs after stroke or PRN
Define TBI
A blow or jolt to the head!
Or a penetrating head injury that disrupts the function of the brain
TRUE or FALSE
TBI's can range from mild (brief change in mental status or consciousness) to severe (extended period of unconsciousness or amnesia after the injury).
TRUE. Can result in short or long term problems with independent function. There is a BROAD spectrum of disabilities/symptoms
TBI are diagnosed by the Glascow Coma Scale. What are the categories and what is the range for mild, moderate, severe?
GCS categories: eye opening, verbal response, & best motor response.
Severity:
Mild (13-15)
Mod (9-12)
Severe (3-8)
How do you confirm a diagnosis for a TBI?
with imaging. (CT/MRI)
There are two types of TBI. Name them.
Primary or Direct: damage caused by impact (Diffuse axonal injury, focal lesions of laceration, contusion, hemorrhage)
Secondary: from subsequent brain injury like brain swelling, infection, & cerebral hypoxia
Diffuse Axonal Injury is a Primary type of TBI. How does it happen?
Results from acceleration/deceleration (ex: shaken baby)
Explain a mild DAI (diffuse axonal injury)
Coma 6-24 hrs
follows commands by 24 hr
outcome of DEATH is UNCOMMON
Neuro deficits are common
Explain a moderate DAI (diffuse axonal injury)
Coma > 24 hrs w/out prominent brainstem signs
Outcome INCOMPLETE RECOVERY of those who survive
Explain a severe DAI (diffuse axonal injury)
Coma prolonged with brainstem signs
(Decortication/Decerebration)
Outcome is DEATH or SEVERE DISABILITY
What are the FOUR types of focal lesions of lacerations (Primary kind of TBI)?
contusions or hemorrhages
epidural (extradural) hematoma
subdural hematoma
intracerebral hematoma
Which has a worse prognosis, an epidural or subdural hematoma?
EPIDURAL IS WORSE (instant)
Subdural: hours, days, or weeks. Can lead to chronic progressive dementia.
Who is at risk for getting a subdural hematoma?
Elderly, alchoholics, basically anyone who falls easily!
↑ age = ↓ brain size = more jiggle room
What causes hydrocephalus?
Damage to flow or absorption of CSF.
Direct pressure causes degeneration of surrounding white matter.
Results in neuro changes (declining memory & cognitive ability)
May cause coma in ↑ ICP is acute.
What are some s/s of hydrocephalus?
Enlarged ventricles = pressure
↑ICP
Decreased memory/cognition
Sleepy/coma
HA, N/V
seizures
(infants, eye bulging & head swellling)
midline deviations can occur
Congenital hydrocephalus is considered non-communicating. What does this mean?
There is an obstruction so the CSF in the ventricular system does not properly communicate w/the subarachnoid space.
This could be from structural lesions (malformation or myelomeningcele)
Acquired hydrocephalus is considered communicating. Explain more about this.
There are too few or poor functioning arachnoid villa so they are unable to absorb the CSF.
This is seen in adults w/subarachnoid hemorrhage, meningitis, head injury, or neoplasia.
What is normal pressure hydrocephalus and who usually gets it?
Accumulation of CSF causes ventricles of the brain to enlarge but may not cause ↑ ICP like other types of hydrocephalus.
Occurs in adults 60yr+.
10% of pt w/symptoms of dementia have it!
How do you diagnose normal pressure hydrocephalus?
Have patient walk 20 ft and measure time (do this 3x and take best of 3)
Md then does LP and removes some CSF
3 hrs later, repeat the walk test
(if ↑ speed or ability, likely to have NP hydrocephalus)
What does adequate Cerebral blood flow depend on?
Cerebral blood volume
Cerebral blood flow
Cerebral Perfusion pressure
How do you calculate cerebral perfusion pressure?
MAP - ICP = CPP
What cerebral perfusion pressure do you need for cell nourishment?
60-100
What cerebral perfusion pressure do you need after injury?
>70
How is cerebral perfusion pressure regulated?
By constriction or dilation of vessels.
CO2 is potent vasodilator so we purposefully hyperventilate or keep pt alkalotic (so you get vasoconstriction) to increase brain perfusion.
(also can give O2)
What is a normal intracranial pressure?
5-15
What happens to cerebral flow if ICP increases?
Flow decreases. If ICP>CPP then get hypoxia & hypercapnia which causes brain damage!!!
Besides an increase in CSF, what else can cause increased ICP?
edema
hemorrhagee
neoplasia
What are the cardinal signs of increased ICP?
HA
vomiting without nausea
ocular palsies
altered LOC
back pain
papilledema
Cushing's triad
What is papilledema?
Optic disk swelling caused by increased ICP
The hydrostatic pressure pushes fluid out and that fluid is reabsorbed by papilla nerve of eye.
Get enlarged blind spot which can cause permanent vision loss
What will you see if ICP gets so high that displacement of brain tissue occurs?
Dilated pupils & inward facing eye
What is CUSHING's triad? (seen when ↑ICP)
↑ BP, ↓ RR, ↓ HR (think opposite of shock)
Wide pulse pressure
Abnormal breathing
What is the Monroe Kellie Hypothesis?
The pressure/volume relationship between ICP, volume of CSF, blood & brain tissue, & cerebral perfusion pressure.
States that the cranial compartment is incompressible.
Fixed volume inside cranium (any ↑ of one constituent must be compensated by a ↓ of another)
According to the Monroe Kellie Hypothesis, an increase in edema will cause a _____ in CSF & blood flow.
DECREASE
What is a coma?
A type of altered consciousness state
In an irreversible coma (aka cerebral death) there will be hemeostatic mechanisms left intact but they are unarousable.
No sleep wake cycles, eyes remain closed
Altered arousal = ____
Altered content of thought = _____
coma
awareness
Describe a Persistant Vegitative State ("minimally conscious state)
Sleep/wake cycle
BP, resp, & digestion are normal
eyes may open but no tracking or sustained function
inconsistent evidence of perception & communication
Describe Vegetative state
Absence of awareness of self and environment
Inability to interact with others
Absence of sustained or reproducible voluntary behavioral responses
