week 1 neuroanatomy 4 of 4 Flashcards
slide 176-234 (147 cards)
1
Q
A
2
Q
what is another term for luxury perfusion in the brain
A
cerebral steal
3
Q
define cerebral steal
A
stealing blood from one area of the brain to another- “blood robbery”
4
Q
blood vessels in ischemic brain regions characteristic?
A
maximally dilated with an exhausted cerebrovascular reserve
5
Q
blood vessels in non ischemic brain regions characteristic?
A
blood vessels have tone
6
Q
what happens to the brain blood vessels (non ischemic and ischemic) when a vasodilator such as nitroprusside is administered
A
vessel in non ischemic brain dilate. flow to nonischemic brain increase- flow to ischemic brain decreases
7
Q
when a patient is hypoventilated -so CO2 can accumulate- what happens to the brain blood vessels (nonischemic and ischemic)
A
vessel in non ischemic brain dilate. flow to nonischemic brain increase- flow to ischemic brain decreases
8
Q
vasodilators or hypoventilation help promote _______ in brain blood vessels
A
cerebral steal
9
Q
what is the robin hood effect
A
inverse steal
10
Q
how does inverse steal occur
A
when a patient with an ischemic region of brain is hyperventilated (decrease PCO2) blood vessels in non ischemic brain constrict and blood is diverted to ischemic brain.
11
Q
defined as redistributing more cerebral blood flow from well perfused non ischemic area (rich) to ischemic area (poor)
A
inverse steal (robin hood effect)
12
Q
the result of hyperventilation to ischemic brain
A
improves blood flow to ischemic brain
13
Q
CEREBRAL STEAL non ischemic brain -blood flow -vessel diameter ischemic brain -blood flow -vessel diameter
A
non ischemic brain blood flow increases vessel diameter increases ischemic brain blood flow decreases NO CHANGE (maximally dilated)
14
Q
INVERSE STEAL non ischemic brain -blood flow -vessel diameter ischemic brain -blood flow -vessel diameter
A
non ischemic brain blood flow decreases vessel diameter decreases ischemic brain blood flow increases vessel diameter NO CHANGE(maximally dilated)
15
Q
what is the result of shivering
A
heat production
16
Q
Thyroid Hormone (TH) increase heat production by stimulating what pump
A
na/k/atpase
17
Q
activation of beta receptors in brown fat produces two increased responses?
A
increase sympathetic activity increase basal metabolic rate
18
Q
who controls heat loss in the brain
A
anterior hypothalamus
19
Q
how does the body loose heat when overheated? 4 things
A
increase sweating cutaneous vasodilation radiation convection
20
Q
the thermostat in the hypothalamus compares core body temperature to ??
A
the set point temperature
21
Q
what do Pyrogens do to the bodies set point temperature? what does this result in?
A
increases the set point- resulting in shivering
22
Q
what is the role of COX inhibitors (aspirin) and steroids in the production of prostaglandin
A
COX inhibitors decrease the production of prostaglandin
23
Q
what do pyrogens increase the production of? this leads to …
A
increases production of interleukin - 1 - increase production of prostaglandin E -increase set point temperature - more heat generated- fever
24
Q
the most common 1 degree brain tumor with grave prognosis with less than 1 year life expectancy.
A
astrocytoma
25
where is astrocytoma found in the brain
treatment?
found in cerebral hemisphere
resection, radiation and chemo
26
what portion of the adult brain tumor are metastases
Half
27
Neurons never give rise to cancer. WHY?
neurons dont divide- so they can't give rise to cancer
28
the majority of childhood 1 degree tumors are found where
infratentorial (region of the brain is the area located below the tentorium cerebelli.)
29
the majority of adult 1 degree tumors are found where
supratentorial (located above the tentorium cerebelli)
30
intracranial tumors clinical presentation is due to mass effects such as...
seizures, dementia, focal lesions.
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do 1 degree brain tumors undergo metastasis
rarely
32
intracranial tumors Oligodendroglioma how frequent? rate of growth?
relatively rare slow growing
33
intracranial tumors ependymoma found where?
can cause?
prognosis?
Found in 4th ventricle Can cause hydrocephalus Poor prognosis
34
intracranial tumors meningioma how common is this 1 degree brain tumor?
occurs where?
rate of growth?
resectable?
2nd most common 1 degree brain tumor Occurs in convexities of brain and parasigittal region Arise from arachnoid cells external to brain (NOT dura) Slow growing Resectable
35
intracranial tumors
pituitary adenoma
how common?
vision effects?
Most commonly prolactinoma Bitemporal hemianopia “ tunnel vision” Hyper or hypo pituitarism are sequelae (consequence)
36
Intracranial Tumors
Schwannoma how common is this first degree brain tumor?
is it resectable?
what cranial nerve does it disrupt?
3rd most common 1 degree brain tumor. Schwann cell origin; often localize to VIII nerve - acoustic schwannoma Resectable (able to be removed with surgery)
37
etiology of stroke
Atherosclerosis Small or large artery disease
38
Risk factors stroke (7)
Diabetes, HTN, Smoking, A fib, Cocaine, Male gender, Advance age
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Acute onset of focal neurological deficits resulting from diminished blood flow is defined as
stroke
40
ischemic stroke occurrence
87%
41
hemorrhagic stroke occurrence
13%
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History/PE stroke
Aphasia
Hemiparesis
Loss of vision
Coma
Cranial nerve palsies
Ataxia
TIA: neurological deficit \< 24 hrs
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Differential stroke
Tumor, hematoma, abscess, MS, Metabolic (hypoglycemia) neurosyphilis
44
Evaluation (tests/blood work) stroke
CT w/o contrast ( to differentiate ischemic vs. hemorrhagic) MRI CBC, glucose , coag, lipid profile EKG and echo Vascular studies
45
Treatment stroke
Heparin and aspirin
Monitor ICP
Thrombolysis
Don’t over-treat hypertension (may diminish cerebral perfusion)
46
Prevention stroke
Aspirin or clopidogrel
Carotid endarterectomy if stenosis is \>60%
Anticoagulation
Management of hypertension
47
Transmissible spongiform ecephalopathies (TSEs) can occur in humans and other animals what is an example of this
mad cow disease (Creutzfeldt-Jakob Disease)
48
T/F TSEs are neurologic degenerative diseases that can be transmitted within or between species
True! can be transmitted within or between species
49
do TSE's abnormal prions trigger an immune response
no
50
Transmissible spongiform ecephalopathies (TSEs) how does death of the host occur?
nerve cell death leading to sponge like holes in brain tissue from insoluble aggregates of abnormal prions in the brain
51
symptoms of Transmissible spongiform ecephalopathies
dementia
weakened muscles
loss of balance
52
name the human form of TSE
CJD (Creutzfeldt-Jakob disease)
53
Sudden onset of brain electrical activity is defined as
seizures
54
seizure presentation
loss of consciousness, sensory or motor or behavior abnormalities
55
what can precede a seizure
an aura - subjective sensation / feeling
56
diagnostic for seizures
EEG
57
\_\_\_\_arise from discrete region, no loss of consciousness
focal (partial)
58
adult causes of seizures
tumors, trauma, stroke, infection
59
elderly causes of seizures
stroke, tumor, trauma, metabolic, infection
60
children causes of seizures
genetic, infection (febrile), trauma, congenital, metabolic
61
Todds paralysis is defined as
focal deficit after the attack
62
complex seizures signs and symptoms
loss of consciousness hallucinations confusion amnesia
63
simple partial seizure may involve
motor, sensory or autonomic function. NO loss of consciousness
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evaluation of seizures
Rule of systemic causes EEG CT/MRI
65
treatment of seizures
Phenytoin Carbamazepine
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sustained seizure activity lasting at least 30 minutes
status epilepticus
67
status epileptics is a medical emergency due to risk of
hypoxia
aspiration
rhabdomyolysis
multiple trauma
68
treatment of seizure
Establish airways “ABC”
Adequate oxygenation
Glucose +thyiamine
Lorazepam – short term control
Phenytoin or phenobarbital
69
Inflammation and demyelination of PNS motor neurons Associated with viral infections e.g. HZV
Guillain-Berré syndrome
70
Lower motor neuron lesions Symmetrical ASCENDING paralysis
Guillain-Berré syndrome
71
Guillain-Berré syndrome dreaded complication
respiratory paralysis
72
what irregularities are associated with guillain barre syndrome
Cardiac and respiratory irregularities
73
Guillain-Berré syndrome diagnosis
increase CSF proteins Slow nerve conduction velocity due to DEMYELINATION
74
Guillain-Berré syndrome Treatment
Monitoring vital capacity is critical
Plasmapheresis
IV immunoglobulin
per mo- really theres no treatment- just hope it doesn't affect their diaphragm
75
slide 197
slide 197
76
Poliomyelitis:
LMN lesion due to destruction of anterior horn cell lead to flaccid paralysis
77
Multiple sclerosis:
mostly white matter demyelination; scanning speech, intentional tremors, diplopia, remission and relapses
78
Amyotrophic lateral sclerosis:
Both UMN and LMN lesion. No sensory deficit
79
Occlusion of anterior spinal artery:
spares dorsal column and tract of lissauer
80
Tabes dorsalis (3 degree syphilis):
degeneration of dorsal root and dorsal column tract; impaired proprioception and ataxia
81
Syringomyelia:
damage to spinothalamic tract; loss of pain and temperature
82
VitB12 deficiency and Friedreich’s ataxia:
demyelination of dorsal column
83
EEG activity from ketamine
Ketamine produces unusual activation
84
EEG activity from opioids
Opioids produce monophasic depression
85
EEG activity from anesthetics
Most anesthetic produce biphasic pattern Activation followed by depression
86
what are EEG useful for
assessment of cerebral perfusion
87
Reticular Activating System (RAS) what does it maintain
Maintains alert/awake state
88
is RAS on or off when sleeping
RAS is OFF when sleeping
89
complete loss of RAS activity is
coma
90
what does general anesthesia do to the RAS
GA produces sedation and hypnosis by depressing RAS
91
dorsal column tract is considered what kind of route
a direct rout
92
RAS is considered
INDIRECT ROUT for sensory information reaching to sensory strip
93
It Test the integrity of dorsal column (cuneatus and gracilis tracts) and sensory cortex Carries fine touch, pressure, vibration and proprioception sensations
Somatosensory Evoked Potential –SSEP
94
during brain and spinal cord surgeries what does the Somatosensory Evoked Potential –SSEP do examples of these surgeries (4)
detects global ischemia from HYPOXIA or ANESTHETIC OVERDOSE
Aortic reconstruction
Spinal cord tumors
Carotid endarterectomy
Instrumentation of spine
95
when is SSEP altered ( i.e. reduce intensity and delayed arrival in cerebral cortex
in case of ischemic injury to brain and spinal cord
96
what nerves are stimulated for SSEP to be recorded from the scalp
tibial, median, or ulnar nerves
97
write down the pathway from tibial nerve to sensory cortex
...slide 206
98
which somatosensory area? leg arm face
...
99
which somatosensory area? thigh thorax neck hsoulder hand fingers tongue abdomen
...
100
Stimulation of tibial nerve at ankle must be recorded at the
midline (over longitudinal fissure)
101
Stimulation of median/ulnar nerve must be recorded at
Lateral side
102
Visual evoked potential used during these 4 procedures
craniofacial procedures pituitary surgery surgery in the visual tracts occipital cortex
103
Visual evoked response tracing of amplitude versus time after stimulus. The measurement of latency and amplitude for the negative peak at
70msec
104
Components of SSEP early peak "direct" action potentials via
DORSAL COLUMN TRACT
105
Components of SSEP
Late peak
“indirect” Larger Action potentials via
RETICULAR ACTIVATING SYSTEM (RAS)
106
Amplitude of SSEP refers to
Magnitude or size of evoked potential
107
Latency of SSEP refers to
Time taken by action potential to travel from peripheral nerve -spinal cord - inner brain - cerebral cortex
108
decreasing amplitude or increasing latency indicates what about the neural pathway being monitored
indicates damage
109
An amplitude reduction of \_\_% or latency increase of \_\_% of an evoked potential is considered significant
50% 10%
110
in evoked potential what can smaller changes in amplitude and latency indicate
impending compromise
111
in evoked potential management how important is anesthetic management?
Anesthetic management often plays a critical role in the intervention.
112
Applications of SSEP
Spinal surgeries Aortic reconstruction Carotid endarterectomy
113
Factors affecting SSEP
Hypo or hyperthermia Hypotension PCO2 PO2
114
during brain surgery is a noninvasive technique for measuring neural functions, e.g. during acoustic neuroma resection where the vestibulocochlear nerve ( CN VIII) at risk
Brainstem Auditory Evoked Potential (BAEP)
115
how is Brainstem Auditory Evoked Potential (BAEP) elicited
by auditory click, tones
116
what can Brainstem Auditory Evoked Potential (BAEP) detect
Detects global ischemia or anesthetic overdose
117
can be used to monitor the optic nerve (CN II), anterior visual pathways during craniofacial procedures, pituitary surgery, and surgery in the visual tracts and occipital cortex
Visual evoked potential (VEP's)
118
how are Visual evoked potential elicited
by flashes of light
119
method of delivering stimulus for Brainstem Auditory Evoked Potential (BAEP)
ear transducer
120
I/ V anesthetics effects on evoked potential
fewer effects
121
GA and volatile anesthetics have what effect on evoke potentials
have the greatest effect on evoke potentials causing dose dependent decrease amplitude and increase latencies
122
how much (compared to other paralytics) does vecuronium have an effect on evoked potential
least effect
123
evoked potentials monitoring order for sensitivity to anesthetic agents
VEP \> SSEP \> BAEP [Very ; Somewhat ; Barely]
124
XII hypoglossal
Genioglossus muscle (tongue)
125
Monitoring Site or Method XI spinal accessory
Sternocleidomastoid and/or trapezius muscles
126
Monitoring Site or Method X vagus
Vocal folds, cricothyroid muscle
127
monitoring site or method IX glossopharyngeal
Stylopharyngeus muscle (posterior soft palate)
128
Monitoring Site or Method VIII auditory
Auditory brainstem responses
129
Monitoring Site or Method VII facial
Orbicularis oculi and/or orbicularis oris muscles
130
Monitoring Site or Method VI abducens
Lateral rectus muscle
131
Monitoring Site or Method V trigeminal
Masseter muscle and/or temporalis muscle [sensory responses can also be monitored]
132
Monitoring Site or Method IV trochlear
Superior oblique muscle
133
monitoring site or method III oculomotor
Inferior rectus muscle
134
monitoring site or method II optic
Visual evoked potentials
135
monitoring site or method I olfactory
No monitoring technique
136
Neurocranium consists of 8 bones
Frontal Ethmoid Sphenoid Occipital Temporal (pair) Parietal (pair)
137
Viscerocranium consists of 15 irregular bones
Mandible Ethmoid Vomer Maxilla (pair) Inferior nasal choncha (pair) Zygomatic (pair) Palantine (pair) Nasal (pair) Lacrimal (pair)
138
Neurophysiologic monitoring with EMG and evoked sensory and motor responses has become an important tool - these methods have demonstrated
reduce morbidity and have become a standard of care provide greater assistance to the surgeon indispensable intraoperative diagnostic tool
139
what type of anesthesia is preferred during motor evoke potential
IV anesthetics as it suppresses MEP less than inhaled agents
140
motor evoke potential is monitor in patients with what
neurologic disease
141
with use of total IV anesthesia. MEP's are successfully obtained in more than what percent of patients
90%
142
failures with MEP are associated with what two things
preexisting neurotic disorders or equipment failure
143
The pathway synapses in the anterior horn of the spinal cord and the response travels to the muscle via the neuromuscular junction (NMJ). The response is typically recorded near the muscle as a compound muscle action potential (CMAP). what evoked potential is this
motor evoked potential
144
Motor evoked potentials
are produced by stimulation of the motor cortex (hollow arrow). The response can be recorded epidurally over the spinal column as a D wave followed by a series of I waves.
145
slide 222
slide 222
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