Grayson's Deck: Neurologic Diseases (Exam III) Flashcards
1
Q
The brain consumes _______ % of cardiac output at rest.
The brain consumes _______ % of O2-inspired O2.
A
20%
20%
2
Q
What vessels provide the blood flow to the brain?
A
- 80% via the carotid arteries
- 20% via the vertebral arteries
3
Q
Name the pertinent vasculature of the circle of Willis.
This card is just to look at the picture on the other side.
A
4
Q
What factors affect cerebral blood flow?
A
- CMR (cerebral metabolic rate)
- CPP (cerebral perfusion pressure)
- ICP
- PaCO₂
- PaO₂
5
Q
How much O₂ is required by the brain per minute?
A
3 mlO₂ / 100g / min
6
Q
What is the average cerebral blood flow?
A
50ml/100g/min
7
Q
What drugs and/or metabolic states will decrease CMR?
A
- Hypothermia
- Anesthetic drugs (VAA, prop, etomidate, etc)
8
Q
What drugs and/or metabolic states will increase CMR?
A
- Hyperthermia
- Seizures
- Ketamine
- N₂O
9
Q
What temperature range do we generally want to keep our patients in?
A
36 - 42° C
10
Q
When is hypothermia mediated EEG suppression achieved?
A
18 - 20° C
11
Q
Hypothermia will cause a ___% decrease for every 1°C decrease.
A
7
12
Q
What would a temperature of > 42°C do to the brain?
A
Denature proteins and destroy neurons (↓CBF)
13
Q
At what cerebral blood flow rates would one expect irreversible brain damage?
A
10ml/100g/min
14
Q
How is Cerebral Perfusion Pressure (CPP) calculated?
A
CPP = MAP - ICP
15
Q
How is MAP calculated?
A
MAP = DBP + ⅓(SBP - DBP)
16
Q
At what CPP and MAP does the brain exhibit autoregulation (myogenic response) ?
A
CPP of 50 - 150 mmHg
MAP of 60 - 160 mmHg
17
Q
With what pathologies is a loss of CPP seen?
A
- Brain tumors
- Head trauma
- Volatile anesthetics
18
Q
What can cause a rightward shift in the brain autoregulation curve?
A
- Chronic HTN
- SNS activation
19
Q
What can cause a leftward shift in the brain autoregulation curve?
A
VAA’s
20
Q
Name the three components of the brain that form the Monroe-Kellie Doctrine.
A
- Brain 80%
- Blood 12%
- CSF 8%
21
Q
What is the Monroe Kellie Doctrine?
A
Any increase in one component of the intracranial space (blood, brain tissue, CSF) must be met with an equivalent decrease in another to prevent increased ICP.
22
Q
What is the normal CPP range?
A CPP below _________ mmHg will result in slowing of EEG.
A
80 - 100 mmHg
50 mmHg
23
Q
An ICP > ____ mmHg will compromise CPP.
What is normal ICP?
A
30 mmHg
5-15 mmHg
24
Q
What pathologic processes or disease states are known to cause an increase in ICP?
A
- Tumors
- Hematomas
- Blood in CSF
- Infection
- Aqueductal Stenosis
25
At what CPPs would one expect to see EEG slowing?
What about irreversible brain damage?
- EEG slowing: < 50mmHg
- Brain damage: < 25 mmHg
26
What are the two types of hydrocephalus? Which is more common?
- Obstructive (most common)
- Communicating
27
What would occur from PaO₂ levels of < 50-60 mmHg in the brain?
- Vasodilation
- ↑CBF
28
Severe hypoxia will have what effect on cerebral blood flow?
↓O₂ = ↑CBF
29
PaO₂ exhibits an _______ mechanism in the brain similar to intracranial MAP.
autoregulation
30
PaCO₂ between this range will experience a linear change in vasodilation and cerebral blood flow.
20 - 80 mmHg
31
PaCO₂ levels are directly proportional to ______ of the cerebral vasculature.
vasodilation
32
A PaCO₂ increase of 1mmHg will correspond to an increase in CBF by how much?
1mmHg PaCO₂ increase = 1-2mls/100g/min increase in CBF.
33
A patient's PaCO₂ is increased by 10mmHg, how much would you expect CBF to increase if the patients brain was measured to weigh 250g?
10mmHg x 1-2mls x 2.5 =
**25 - 50 mls/min increase in CBF.**
34
At what PaCO₂ levels does max cerebral vasodilation occur?
80 - 100 mmHg
35
At what PaCO₂ levels does max cerebral vasoconstriction occur?
25 mmHg
36
What does increase venous pressure do to the brain?
- ↓ venous drainage
- ↑ cerebral blood volume
37
What things will increase cerebral venous pressure?
- Jugular compression (cervical collar, head rotation, etc.)
- ↑ intrathoracic pressure (coughing, PEEP)
- Vena Cava thrombus
38
What range is normal for ICP?
5 - 15 mmHg
39
What symptoms are seen with abnormally high ICP?
- Headache
- N/V
- Papilledema
- ↓LOC
40
What does Cushing's Triad indicate?
What is the triad?
**↑ICP**
- ↑sBP (Hypertension)
- ↓HR (Bradycardia)
- Respiratory Abnormalities (Cheyne-Stokes)
41
What is the most common site of brain herniation?
Uncal
*↑ICP forces temporal uncus into the infratentorial space (see 3 on the figure below)*.
42
Why do the pupils become fixed and dilated with uncal herniation?
CN-3 (oculomotor) crosses near tentorium and is compressed by the herniation.
43
How can ICP be qualitatively assessed with ultrasound?
By measuring the optic nerve diameter.
↑ICP = ↑ optic nerve sheath
44
How can elevated ICP be treated?
*Long list*
- Elevate HOB 30°
- Hyperventilate (transient fix)
- Drain CSF
- Mannitol (0.5-1 g/kg) - give quickly
- Diuretics
- Corticosteroids
- Surgical decompression
45
Decreased hematocrit will result in what?
- ↓ viscosity
- ↑ CBF
46
Increased hematocrit will result in what?
- ↑ viscosity
- ↓ CBF
47
What is the optimal hematocrit in the presence of elevated ICP?
30 - 34%
48
What is luxury perfusion?
Combination of ↓CMRO₂ and ↑CBF
49
Hypothermia ______ CBF and CMR.
decreases
50
What is intracerebral steal?
When blood flow is shunted away from an ischemic area that needs that blood flow.
51
How is intracerebral steal treated?
**Reverse Steal**.
Hyperventilation → vasoconstriction of healthy areas → flow redistributed to ischemic regions.
52
What is CN I?
Exam?
Olfactory - smells
ID of odors
*Cranial 1 gave me a whiff, is that C diff?*
53
What is CN II?
Exam?
Optic - vision
Snellen Chart
*2nd nerve helps me see right. Central and Peripheral sight.*
54
What is CN III?
Exam?
Oculomotor - vision (convergence, pupillary accomodation)
Accommodation - convergence; reaction to light
*Pupils are constricting, third nerve, eyes are moving.*
55
What is CN IV?
Exam?
Trochlear - vision (convergence, pupillary accommodation)
Accommodation - convergence; reaction to light
*Trochlear nerve works the superior oblique; hard to look down if it's weak.*
56
What is CN V?
Exam:
Trigeminal - Face
Facial sensation: palpation of masseter/temporalis muscles
*Trigeminal nerve works mastication, it's sensory and motor, deals with face sensation.*
57
What is CN VI?
Exam?
Abducens - vision (convergence, pupillary accommodation)
Accommodation, convergence; reaction to light
*Abducens is 6th, does eye abduction. Motor nerve for motion helps prevent double vision.*
58
What is CN VII?
Exam?
Facial -symmetry, smile, anterior tastes
Facial symmetry, smile; taste anterior 2/3
*Facial is the 7th, test facial expression, it's sensory and motor, 2/3 of taste sensation.*
59
What is CN VIII?
Exam?
Acoustic - hearing
Normal conversation; tuning form
*Vestibulocochlear (Acoustic), 8th nerve, body balancer. Used for the sound sensor.*
60
What is CN IX?
Exam?
Glossopharyngeal - Gag; posterior taste
Gag reflex, posterior 1/3
*Glossopharyngeal nerve, senses tase from the 1/3 back of the tongue, 9th nerve, it helps us swallow.*
61
What is CN X?
Exam
Vagus
Swallow and say 'Ah'
*10th nerve is Vagus, helps us speak and say stuff, custard only if dysphagia.*
62
What is CN XI?
Exam
Spinal accessory - shrugging, chin flexion against tension
*Accessory nerve is the 11th, so shrug your shoulders and test head resistance.*
63
What is CN XII and Test?
Hypoglossal - Tongue protrusion
*The hypoglossal nerve is the 12 nerve, deals with tongue movement.*
64
Injury to this cranial nerve results in bell's palsy.
CN 7
65
Eye movement in controlled by what cranial nerves?
3, 4, 6
66
What is the Glascow Coma Scale?
see picture below
67
What level of the spinal cord is affected with paraplegia?
T2 - T12
68
What level of the spinal cord is affected with quadriplegia?
C5 - T1
69
What level of the spinal cord is affected diaphragmatic paralysis?
Above C5
70
What is spinal shock?
Loss of vascular tone w/ flaccid paralysis below site of injury.
71
When would one see bradycardia with a spinal injury?
If the injury is at **T1 - T4**.
72
What signs/symptoms are seen with anterior cord syndrome (anterior spinal artery syndrome)?
- Loss of pain and temperature
- Retention of vibration and proprioception
73
What signs/symptoms are seen with central cord syndrome?
- Encountered during incomplete spinal injuries
- Motor deficit in upper extremities
- Pain and temperature decreased in lower extremities
74
What signs/symptoms are seen with Brown-Sequard syndrome?
- Lateral hemiplegia
- Loss of proprioception/vibration on injured side.
- Loss of pain/temperature on the contralateral side.
75
What should be known about dermatomes?
*Nothing, this is too much. Save this for another time. Take the L on this one for this test.*
76
Are more strokes ischemic or hemmorrhagic?
- **Ischemic** (80%)
- Hemmorrhagic (20%)
77
Which type of stroke is more likely to cause death?
Hemmorrhagic (4x more likely)
78
What are specific risk factors for hemmorrhagic stroke?
- HTN
- Cigarettes
- Cocaine
- Female
79
What are specific risk factors for ischemic stroke?
- HTN
- Cigarettes
- HLD
- DM
- EtOH
80
Where is bleeding located with an epidural hematoma?
In between the dura and the skull
81
What intracranial bleed is characterized by:
lucidity → unconscious → conscious → unconscious
Epidural hematoma
82
Where is bleeding in subdural hematomas located?
Between the dura mater and the arachnoid mater.
83
What intracranial bleed is often characterized as the "worst headache of one's life"?
Subarachnoid hemorrhage
84
What location is often the site of bleeding in subarachnoid hemmorhaging?
Circle of Willis (usually aneurysmal rupture)
85
Cerebral _______ is one of the complications often caused by subarachnoid hemorrhage.
vasospasm
*Often occurs 3rd day post bleed and peaks 5-7 days in*.
86
How is cerebral vasospasm treated?
*This is a complication caused by subarachnoid hemorrhage.*
Triple "H" Therapy
- HTN
- Hypervolemia
- Hemodilution
87
What type of hemorrhage occurs within the brain tissue itself?
Intracerebral (intra-parenchymal) hemorrhage.
88
What factors possibly increase the risk of developing Parkinson's?
- Welding
- Herbicides
- Pesticide
- Genetics
89
What s/s are associated with Parkinson's disease?
- Muscle rigidity
- Pill-rolling tremor
- Bradykinesia
- Postural instability
90
What drugs will counteract levodopa and are contraindicated in Parkinson's patients?
- Metoclopramide
- Haloperidol
- Droperidol
- Promethazine
91
What treatments are used for Multiple Sclerosis?
- Corticosteroids
- Interferon
- Azathioprine
- Methotrexate
92
What induction agent is a good first-line agent for treatment of acute seizures?
Propofol
93
What drugs may be used to located seizure foci due to their EEG potentiating effects?
Etomidate
Methohexital
94
What are the s/s of seizures whilst under anesthesia?
- ↑HR
- HTN
- ↑ ETCO₂
95
What is anterior ischemic optic neuropathy (AION) ?
What should be known about AION?
- Vision loss post-op
- sudden and painless
- Asymmetric optic disc swelling
96
What is posterior ischemic optic neuropathy (PION) ?
What should be known about PION?
- Vision loss post-op
- More common than AION
- No initial findings on exam
97
What risk factors exist for developing ischemic optic neuropathy (ION) ?
- Positioning
- Anemia
- ↓BP
- Excessive fluids
- Excessive vasopressors
