Neurologic Diseases (Exam III) Flashcards
1
Q
What vessels provide the blood flow to the brain?
A
- 80% via the carotid arteries
- 20% via the vertebral arteries
2
Q
Name the pertinent vasculature of the circle of Willis.
This card is just to look at the picture on the other side.
A
3
Q
What factors affect cerebral blood flow?
A
- CMR (cerebral metabolic rate)
- CPP (cerebral perfusion pressure)
- ICP
- PaCO₂
- PaO₂
4
Q
How much O₂ is required by the brain per minute?
A
3 mlO₂ / 100g / min
5
Q
What is the average cerebral blood blow?
A
50ml/100g/min
6
Q
What drugs and/or metabolic states will decrease CMR?
A
- Hypothermia
- Anesthetic drugs (VAA, prop, etomidate, etc)
7
Q
What drugs and/or metabolic states will increase CMR?
A
- Hyperthermia
- Seizures
- Ketamine
- N₂O
8
Q
What temperature range do we generally want to keep our patients in?
A
36 - 42° C
9
Q
When is hypothermia mediated EEG suppression achieved?
A
18 - 20° C
10
Q
what 2 things will kill neuro patients
A
hypotension and hypoxia
11
Q
Hypothermia will cause a ___% decrease in CMRO2 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
outside of here, flow is pressure dependent
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
80 - 100 mmHg
23
Q
An ICP > ____ mmHg will compromise CPP.
A
30
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
What levels of PaCO₂ are maintained in the brain?
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.**
*Someone check my math and the question itself*.
34
At what PaCO₂ levels does max cerebral vasodilation occur?
80 - 100 mmHg
35
At what PaCO₂ levels does nax 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 are the compensatory mechanisms for higher ICP
-displacement of CSF from cranial to spinal compartment
- an increase in CSF resportion
- decrease in CSF production
- -decrease in total CBF
39
What range is normal for ICP?
5 - 15 mmHg
40
What symptoms are seen with abnormally high ICP?
- Headache
- N/V
- Papilledema
- ↓LOC
41
What does Cushing's Triad indicate?
What is the triad?
**↑ICP**
- ↑sBP
- ↓HR
- ↓RR (Cheyne-Stokes)
42
What is the most common site of brain herniation?
Uncal
*↑ICP forces temporal uncus into the infratentorial space (see 3 on the figure below)*.
43
Why do the pupils become fixed and dilated with uncal herniation?
CN-3 (oculomotor) crosses near tentorium and is compressed by the herniation.
44
How can ICP be qualitatively assessed with ultrasound?
By measuring the optic nerve diameter.
↑ICP = ↑ optic nerve sheath
45
How can elevated ICP be treated?
*Long list*
- Elevate HOB 30°
- Hyperventilate
- Drain CSF
- Mannitol (0.5-1g/kg)
- Diuretics
- Corticosteroids
- Surgical decompression
46
Increased hematocrit will result in what?
- ↓ CBF
- ↑ viscosity
47
Decreased hematocrit will result in what?
- ↑ CBF
- ↓ viscosity
48
What is the optimal hematocrit in the presence of elevated ICP?
30 - 34%
49
What is luxury perfusion?
Combination of ↓CMRO₂ and ↑CBF
| you dont need that much blood flow but for some reason you have i t
## Footnote
seen with induced hypotension with iso, and also vessels max dilated with acute cerebral infarctions
50
Hypothermia ______ CBF and CMR.
decreases
51
What is intracerebral steal?
When blood flow is shunted away from an ischemic area that needs that blood flow.
52
How is intracerebral steal treated?
**Reverse Steal**.
Hyperventilation → vasoconstriction of healthy areas → flow redistributed to ischemic regions.
53
What is CN I?
Olfactory - smells
54
What is CN II?
Optic - vision
55
What is CN III?
Oculomotor - vision (convergence, pupillary accomodation)
## Footnote
stressed 3/4/6
56
What is CN IV?
Trochlear - vision (convergence, pupillary accommodation)
57
What is CN V?
Trigeminal - Face
58
What is CN VI?
Abducens - vision (convergence, pupillary accommodation)
59
What is CN VII?
Facial -symmetry, smile, anterior tastes
60
What is CN VIII?
Acoustic - hearing
61
What is CN IX?
Glossopharyngeal - Gag; posterior taste
62
What is CN X?
Vagus
63
What is CN XI?
Spinal accessory - shrugging shoulders
64
What is CN XII?
Hypoglossal - Tongue protrusion
65
Injury to this cranial nerve results in bell's palsy.
CN 7
66
Eye movement in controlled by what cranial nerves?
3, 4, 6
67
What is the Glascow Coma Scale?
see picture below
68
What level of the spinal cord is affected with paraplegia?
T2 - T12
69
What level of the spinal cord is affected with quadriplegia?
C5 - T1
70
What level of the spinal cord is affected diaphragmatic paralysis?
Above C5
71
What is spinal shock?
Loss of vascular tone w/ flaccid paralysis below site of injury.
72
When would one see bradycardia with a spinal injury?
If the injury is at **T1 - T4**.
73
What signs/symptoms are seen with anterior cord syndrome?
- Loss of pain and temperature
- Retention of vibration and proprioception
- § Motor deficits possible throughout
§ Biggest difference is what they feel and what they are able to do
74
What signs/symptoms are seen with central cord syndrome?
- Motor deficit in upper extremities
- Pain and temperature decreased in lower extremities
- § Usually encountered during incomplete spinal cord injuries
§ Most common incomplete SCI
75
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.
- usually from a lateral SCI in the cervical or thoracic region
76
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.*
77
Are more strokes ischemic or hemmorrhagic?
- **Ischemic** (80%)
- Hemmorrhagic (20%)
78
Which type of stroke is more likely to cause death?
Hemmorrhagic (4x more likely)
79
What are specific risk factors for hemmorrhagic stroke?
- HTN
- Cigarettes
- Cocaine
- Female
80
What are specific risk factors for ischemic stroke?
- HTN
- Cigarettes
- HLD
- DM
- EtOH
81
Where is bleeding located with an epidural hematoma?
Inbetween the dura and the skull
82
What intracranial bleed is characterized by:
lucidity → unconscious → conscious → unconscious
Epidural hematoma
83
Where is bleeding in subdural hematomas located?
Between the dura mater and the arachnoid mater.
84
What intracranial bleed is often characterized as the "worst headache of one's life"?
Subarachnoid hemorrhage
85
What location is often the site of bleeding in subarachnoid hemmorhaging?
Circle of Willis (usually aneurysmal rupture)
86
Cerebral _______ is one of the complications often caused by subarachnoid hemorrhage.
vasospasm
*Often occurs 3rd day post bleed and peaks 5-7 days in*.
87
How is cerebral vasospasm treated?
Triple "H" Therapy
- HTN
- Hypervolemia
- Hemodilution
88
What type of hemorrhage occurs within the brain tissue itself?
Intracerebral (intra-parenchymal) hemorrhage.
89
What anti-cholinergic is best for Alzheimer's patients?
Why is this?
Glycopyrrolate (doesn't cross the BBB)
90
What factors possibly increase the risk of developing Parkinson's?
- Welding
- Herbicides
- Pesticide
- Genetics
91
What s/s are associated with Parkinson's disease?
- Muscle rigidity
- Pill-rolling tremor
- Bradykinesia
- Postural instability
92
What drugs will counteract levodopa and are contraindicated in Parkinson's patients?
- Metoclopramide
- Haloperidol
- Droperidol
- Promethazine
93
What treatments are used for Multiple Sclerosis?
- Corticosteroids
- Interferon
- Azathioprine
- Methotrexate
94
What induction agent is a good first-line agent for treatment of acute seizures?
Propofol
95
What drugs may be used to located seizure foci due to their EEG potentiating effects?
Etomidate
Methohexital
96
What are the s/s of seizures whilst under anesthesia?
- ↑HR
- HTN
- ↑ ETCO₂
97
What is anterior ischemic optic neuropathy (AION) ?
What should be known about AION?
- Vision loss post-op
- sudden and painless
- Asymmetric optic disc swelling
98
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
99
What risk factors exist for developing ischemic optic neuropathy (ION) ?
- Positioning
- Anemia
- ↓BP
- Excessive fluids
- Excessive vasopressors
