NEURO-Brain Flashcards
(252 cards)
1
Q
Neurons purpose and primary role
A
The functional unit of the nervous system
Role=receive and send information
2
Q
Which cells make up:
Grey matter
White matter
A
Grey matter = Cell bodies and nonmyelinated axons
White matter = Myelinated axons
3
Q
What is the nucleus in the CNS
A
a collection of nerve cell bodies
4
Q
Which cells support neuronal function
A
glial cells
5
Q
What are the 4 types of glial cells
A
Astrocyte
Microglia
Ependymal cell
Oligodendrocyte
6
Q
From which cell do most brain tumors arise
A
Glial
7
Q
What are the 3 classifications of nerves in the CNS
A
- Multipolar
- Pseudounipolar
- Bipolar
8
Q
Where are multipolar neurons found
A
Most of the CNS
9
Q
Where are pseudounipolar neurons found
A
- Dorsal root ganglion
2. Cranial ganglion
10
Q
where are bipolar neurons found
A
- Retina
2. Ear
11
Q
What are 4 functions of the glial cells
A
- Creating healthy ionic environment
2 Modulating nerve conduction - controlling reuptake of neurotransmitters
- Repairing neurons following neuronal injury
12
Q
What is are 2 functions of the astrocyte
A
- Regulate metabolic environment
2. Repair neuron after injury
13
Q
What is the most abundant glial cell
A
Astrocyte
14
Q
Where are ependymal cells located (3)
A
The roof of the 3rd and 4th ventricles
Spinal canal
15
Q
What is the function of ependymal cells
A
Form the choroid plexus which produces CSF
16
Q
What is the purpose of oligodendrocytes
A
Forming the myelin sheath in the CNS
17
Q
Which cells form the myelin sheath in the peripheral nervous system
A
Schwann cells
18
Q
Which is the function of microglia
A
To act as macrophages and phagocytize neuronal debris
19
Q
What is the physiologic role of the dendrite
A
receives and processes signals
20
Q
What is the physiologic role of the soma
A
Integrate signals
21
Q
What is the physiologic role of the axon
A
Send signals
22
Q
What is the role of the presynaptic terminal
A
Release NTs
23
Q
Which 4 structures are contained in the cerebral hemispheres
A
Cerebral cortex
hippocampus
Amygdala
Basal ganglia
24
Q
Which 2 structures are contained in the diencephalon
A
- Thalamus
2. Hypothalamus
25
Which 4 structures are contained in the brainstem
1. Midbrain
2. Pons
3. Medulla
4. Reticular activating system
26
What are the 3 divisions of the cerebellum
1. Archicerebellum
2. Paleocerebellum
3. Neocerebellum
27
What structure connects the 2 cerebral hemispheres
Corpus callosum
28
What are the functions of each lobe
```
Frontal = motor cortex
Parietal = somatic sensory cortex
Occipital = visual cortex
Temporal = auditory cortex and speech centers
```
29
What areas are in the temporal lobe that facilitate speech
| Name their funciton
Wernicke's area = understanding speech
Broca's area = motor control of speech (connected via frontal lobe)
30
Where does cognition and movement take place in the cerebral cortex
Precentral gyrus of frontal lobe
31
Where does sensation take place in the cerebral cortex
Postcentral gyrus of parietal lobe
32
What is the function of the hippocampus
Memory and learning
33
What are 3 functions of the amygdala
Emotion
Appetite
Response to pain and stress
34
What is the function of the basal ganglia
Fine control of movement
35
What 2 structures are located in the basal ganglia
1. Caudate nucleus
| 2. Globus pallidus
36
What is the function of the thalamus
Acts as a relay station that directs info to various cortical structures
37
What is the function of the hypothalamus
Primary neurohumoral organ
38
What function does the midbrain serve
Auditory and visual tracts
39
What is the function of the pons
autonomic integration
40
What 3 activities are controlled by the reticular activating system
1. Control consciousness, arousal, and sleep
41
What is the function of the medulla
Autonomic integration
42
Where does autonomic integration occur in the brain
The pons and medulla in the brainstem
43
What are the functions of the following cerebellum
```
Archicerebellum = maintains equilibrium
Paleocerebellum = regulates muscle tone
Neocerebellum = coordinates voluntary muscle movement
```
44
Which cranial nerves are sensory ONLY
CN 1, 2, 8
45
Which cranial nerves are motor ONLY
CN 3, 4, 6, 11, 12
46
Which cranial nerves have both motor and sensory function
CN 5, 7, 9, 10
47
What is the mnemonic for the function of CNs
Some Say Marry Money But My Brother Says Bad Business to Marry Money
48
Which cranial nerves function as motor nerves for the eyes
CN 3
CN 4
CN 6
49
Which muscles and direction does CN 3 control
Inferior oblique = extorsion, elevation
Inferior rectus = infraduction
Superior rectus = supraduction
Medial recuts = adduction
50
Which muscles and direction does CN 4 control
Superior oblique = intorsion, depression
51
Which muscles and direction does CN 6 control
Lateral recuts = abduction
52
Which cranial nerve is the only located centrally
The optic n
| It is surrounded by dura
53
What is tic douloureux
Trigeminal neuralgia of CN 5
Generates excruciating neuropathic pain in face
54
What is a mnemonic for the 5 branches of the facial n (CN 7 )
Two Zebras Bit My Carrot
55
Which CN is injured in Bell's Palsy and what is the result
CN 7
| Ipsilateral facial paralysis
56
Which CN perform parasympathetic output
CN 3, 7, 9, 10
57
Which nerve is responsible for most parasympathetic activity
Vagus (CN 10)
| Responsible for 75%
58
What are 3 functions of CSF
1. Cushion
2. Provides buoyancy
3. Delivers optimal conditions for neuro fxn
59
Where is CSF located
1. Ventricles (left and right laterals, third, and fourth)
2. Cisterns around brain
3. Subarachnoid space in brain and SC
60
What is the purpose of the BBB
To separate CSF from plasma
61
What is the structure of the blood brain barrier
Has tight junctions that restrict passage of large molecules and ions
62
How is the BBB affected by tumors, injury, infection or ischemia
It becomes dysfunctional
63
Where is the BBB not present in the brain (5)
1. Chemoreceptor trigger zone
2. Posterior pituitary gland
3. Pineal gland
4. Choroid plexus
5. Parts of hypothalamus
64
Why are substances easier to pass the BBB in neonates
Because the BBB is poorly developed
65
```
Key facts:
CSF volume =
Specific gravity =
CSF pressure =
Rate of production =
```
CSF volume = 150 mL
Specific gravity = 1.002 - 1.009
CSF pressure = 5 - 15 mmHg
Rate of production = 30 mL/hr
66
Which structures connect the ventricles
| Which ventricles are connected
Foramen of Monro
-Lateral to 3rd vent
Aqueduct of Sylvius
-3rd to 4th vents
67
What structures follow the 4th ventricle, draining CSF into the subarachnoid space
(list in order)
Foramen of Luschka
| Foramen of Magendie
68
The mnemonic for CSF flow through the brain
Lover My 3 Silly 4 Lorn Magpies
69
```
How do electrolyte levels of CSF compare to plasma
K+
pH
Glucose
Protein
```
```
K+ = half of plasma level
pH = more acidic
Glucose = much lower (60)
Protein = exponentially lower
```
70
What are 2 types of hydrocephalus
1. Obstructive
| 2. Communicating
71
What is the difference between obstructive and communicating hydrocephalus
Obstructive = CSF flow is obstructed (d/t mass, injury etc)
Communicating
1. decreased absorption by arachnoid villi (i.e. hemorrhage)
2. Overproduction
72
Define cerebral autoregulation
The brain's ability to maintain constant BF over a wide range of MAPs
This ensures a steady state of BF in response to normal fluctuations
73
What is the equation for cerebral blood flow
CBF = CPP/ cerebral vascular resistance
74
What is the optimal global cerebral blood flow and % of CO
45 - 55 mL/100g tissue/min
15% CO
75
At what threshold of CBF does membrane failure and cell death occur
<15 mL/100g tissue/min
76
What are 5 determinants of CBF
1. CMRO2
2. CPP
3. PaCO2
4. PaO2
5. Venous pressure
77
CMRO2 =
3.0 - 3.8 mL/O2/100g tissue/min
78
Describe the relationship between CMRO2 and CBF
They are coupled
| If more O2 is needed the BF will increase
79
What is the utilization of O2 in the brain
60% for electrical activity
| 40% for cellular integrity
80
What factors decrease CMRO2
1. Decreased temperature
2. Halogenated anesthetics (uncoupled)
3. Propofol
4. Etomidate
5. Barbiturates
81
What 4 factors increased CMRO2
1. Hyperthermia
2. Seizures
3. Ketamine
4. N2O
82
At what body temperature does EEG suppression occur
18 - 20*C
83
How much does CMRO2 decrease when temperature decreases
Decreased by 7% for every 1*C decrease
84
Which factor uncouples CMRO2-CBF
Halogenated anesthetics
85
At what MAP is CBF autoregulated
60 - 160 mmHg
86
What happens to CBF when CPP is below the level of autoregulation (2)
1. CBF becomes pressure dependent
| 2. Increases risk of cerebral hypoperfusion
87
What is the range of CPP autoregulation
50 - 150 mmHg
88
What happens to CBF when CPP is above the level of autoregulation
1. CBF becomes pressure dependent
| 2. Risk of cerebral edema and hemorrhage
89
What is the minimum MAP to maintain CPP with a normal ICP
55 - 65 mmHg
90
What 3 factors control cerebral autoregulation
1. Local metabolism
2. Myogenic mechanisms
3. Autonomic innervation
91
What is CPP dependent on when autoregulation is impaired
Blood pressure
92
What are 3 variables that can reduce the effectiveness of autoregulation
1. Intracranial tumor
2. Head trauma
3. Volatile anesthetics
93
How is autoregulation affected by HTN
The curve shifts right
The low threshold for autoregulation is increased, and pts become less tolerant of HoTN for CBF
Pt are at higher risk of cerebral ischemia with HoTN
94
What is normal CBF when PaCO2 is 40 mmHg
50 mL/100g tissue/min
95
How much does an increase or decrease in PaCO2 alter CBF
For every 1 mmHg increase in PaCO2, CBF increased by 1 - 2 mL/100g tissue/min
It is opposite for decrease in PaCO2
96
At what PaCO2 does maximal cerebral vasodilation occur
80 - 100 mmHg
97
At what PaCO2 does maximal cerebral vasoconstriction occur
25 mmHg
98
How is cerebral vascular resistance controlled
By the pH in the CSF around the arterioles
99
How does the pH of CSF alter cerebral vascular resistance (increased v decreased)
Increased CVR:
INC CSF pH (dec PaCO2) => INC CVR -> dec CBF
ex: resp alkalosis
Decreased CVR:
dec CSF pH (INC PaCO2) => dec CVR => INC CBF
ex: respiratory acidosis
100
Describe cerebral steal concept
Healthy brain tissue has vascular tone and can alter diameter
Ischemic or atherosclerotic areas are already maximally dilated
When healthy vessels vasodilate, the "steal" flow from the already maximally dilated ischemic areas
101
Describe the Robinhood effect in relation to cerebral blood flow
Use of hyperventilation to constrict health cerebral vessels to increase flow to ischemic regions
Hypocapnia could increase harm from left shift of O2 dissociation curve, which releases less O2
102
How does PaO2 affect cerebral vessel diameter
PaO2 < 50 - 60 mmHg = vasodilation and INC CBF
PaO2 > 60 mmHg = CBF unaffected
103
How does venous pressure affect cerebral volume
High venous pressures reduce venous drainage and INCREASE cerebral volume
104
What is the consequence of increased venous pressure
Reduce drainage
Increase cerebral volume
Back pressure on the brain, reducing the arterial/venous gradient (difference between MAP - CVP)
105
What conditions impair venous drainage (4)
1. Jugular compression d/t head position (head flex or turned)
2. Increased intrathoracic pressure d/t cough or PEEP
3. Vena cava thrombosis
4. Vena cava syndrome
106
What is normal ICP
| When does cranial HTN occur
5 - 15 mmHg
ICP > 20 mmHg
107
What are 8 s/sx of intracranial HTN
1. HA
2. N/V
3. Papilledema
4. Pupil dilation
5. Focal neuro deficits
6. Decreased LOC
7. Seizures
8. Coma
108
What is the Monro-Kelllie doctrine
The equilibrium of pressure-volume between brain, blood, and CSF within the cranium
Increase of one compartment must be countered by decrease in another to maintain normal pressure
109
What is Cushing's triad
HTN
Bradycardia
Irregular respirations
110
Where is the most common site of herniation
Temporal uncus
| Applies pressure to oculomotor nerve (CN 3)
111
What is the pathophysiology of fixed, dilated pupil with cerebral herniation
Cerebral herniation at the temporal uncus puts pressure on the oculomotor n (CN 3) making it ischemic
112
What is the gold standard of ICP measure
Intraventricular catheter
113
How can ICP be measured
Intraventricular cath
| Subdural bolt over cerebral cortex
114
What 2 brain factors alter cerebral volume
1. Cerebral swelling
| 2. tumor
115
What 2 blood factors alter cerebral volume
1. Increased CBF
| 2. Bleeding
116
What 4 CSF factors alter cerebral volume
1. INC CSF production by choroid plexus
2. dec CSF removal by arachnoid villi
3. Obstruction of reabsorption d/t bleed, infxn, tumor
4. Passage of fluid across the BBB
117
How does increased ICP affect CPP
CPP is reduced
118
How is CPP preserved when ICP is increased
BP must increase
119
What is the cause of irregular respirations with intracranial HTN in the Cushing's triad
Compression of the medulla
120
What are 6 types of brain herniations
1. Cingulate
2. Central
3. Uncal
4. Cerebellotonsillar
5. Upward
6. Transcalvarial
121
Where is the most common site of brain herniation
Temporal uncus (transtentorial herniation)
122
What are 7 methods to decrease cerebral blood volume
1. Mild hyperventilation
2. Avoid hypoxemia (PaO2<60 mmHg)
3. Avoid vasodilators
4. Use cerebral vasoconstrictors
5. HOB >30*
6. Avoid neck flexion
7. Reduce intrathoracic pressure (dec PEEP/cough)
123
What are 2 methods to decrease CSF
1. Drain with intraventricular cath or VP shunt
| 2. Administer acetazolamide or furosemide
124
What are 2 medications to decrease cerebral edema
1. Diuretics
| 2. Steroids
125
What method is used to decrease cerebral mass
Surgical debulking or hematoma evacuation
126
What are 4 areas of ICP reduction
1. Volume reduction
2. CSF reduction
3. Edema reduction
4. Mass reduction
127
How long does the effect of hyperventilation and dec PaCO2 on CBF last. Why
6 - 20 hrs
| The pH of the CSF equilibrates with PaCO2
128
What cerebral vasodilators should be avoided in pts with increased ICP
NTG, nitroprusside
129
How is venous drainage facilitated
1. HOB >30*
2. Avoid neck flexion or extension which compresses jugular veins
3. Avoid T-burg
4. Reduce intrathoracic pressure
- dec PEEP
- avoid bucking, coughing, straining
130
What 2 drugs can reduce CSF production
Acetazolamide
| Furosemide
131
What medication can reduce cerebral edema and mass
Mannitol
132
Dose for mannitol
0.25 - 1.0 g/kg
133
In which setting of increased ICP should steroids not be used
TBI
134
What type of brain tumor should not receive steroids
Functional pituitary adenoma
135
What is the primary function of the Circle of Willis
To provide redundancy of blood flow to brain
If one side is occluded, the other should be able to perfuse the affected area
136
Which artery supplying the brain is unpaired
Basilar artery
137
Where does the basilar artery supply
Posterior circulation, brainstem
138
Which arteries arise from the basilar artery
Anterior inferior cerebellar a
| Superior cerebellar a
139
Describe the flow of blood from the aorta to structures in the posterior foss
Aorta => subclavian aa. =. vertebral aa. => basilar a => posterior fossa and spinal cord
140
Where do the vertebral arteries enter the skull
Foramen magnum
141
Describe the flow of blood from the aorta to the cerebral hemispheres
Aorta => carotid aa. => internal carotid aa. => circle of Willis => cerebral hemispheres
142
Where does the anterior circulation enter the skull
Foramen lacerum
143
How does venous blood drain from the cerebral cortex and cerebellum drain
Via the superior sagittal sinus and dural sinuses
144
How does venous blood drain from the basal structures
Via the inferior sagittal sinus, great cerebral vein, and the straight sinuses
145
Where do the cerebral venous pathways converge
The confluence of sinuses posterior to the occipital lobe
146
How does blood drain from the confluence of sinuses out of the cranium
Via the transverse sinus, then sigmoid sinus and finally the paired jugular veins
147
What are 6 risk factors for ischemic stroke
1. HTN
2. Smoking
3. DM
4. Hyperlipidemia
5. Excessive EtOH
6. Elevated homocysteine levels
148
What must be ruled out prior to thrombolytic treatment for patients with suspected ischemic stroke
Intracerebral hemorrhage
149
What is the time frame for receiving thrombolytic agents with suspected ischemic stroke
Within 4.5 hours after symptom onset
150
What is the timeframe for embolectomy following ischemic stroke
Within 6 hours of symptom onset
151
Why is HTN common following ischemic CVA
Elevated BP supports CPP and cerebral oxygenation
152
What effect does HoTN have on patients experiencing an ischemic stroke
Worsens ischemia
153
What is the goal BP for pts with ischemic stroke
185/110 mmHg
154
How can elevated glucose impact outcomes for patients with ischemic stroke
During cerebral hypoxia (from ischemia), glucose is converted to lactic acid.
Cerebral acidosis destroys brain tissue and leads to poor outcomes
Monitor and treat elevated serum glucose
155
Where does arterial bleeding occur in the brain
Subarachnoid space between the arachnoid and pia mater
156
Where does venous bleeding occur in the brain
Between the dura and the arachnoid
157
What causes aneurysm rupture
When there is increased transmural pressure (increased MAP over ICP)
158
What are the causes of morbidity related to aneurysm rupture
1. Obstructive hydrocephalus
2. Rebleeding
3. Vasospasm
159
What are s/sx of aneurysm rupture
1. Worse headache
2. N/V
3. Photophobia
4. Focal Neuro deficits
5. Photophobia
160
How does SAH lead to meningismus
The meninges become irritated from blood spreading throughout the SA space
161
How does a rupture aneurysm put someone at risk for hydrocephalus
The blood can block CSF flow causing obstructive hydrocephalus and increasing ICP
162
What is the goal for intraoperative SBP during aneurysm surgery
120 - 150 mmHg
163
What are the risks of HoTN technique during aneurysm surgery
CPP reduction may be inadequate
| Autoregulation is impaired in pts following SAH so HoTN isn't well tolerated for cerebral perfusion
164
Why is cerebral vasospasm following SAH a major cause of morbidity and mortality
It causes delayed contraction of the cerebral arteries which can lead to infarction
165
How are cerebral vasospasms monitored and when are they most likely
Most likely to occur 4 - 9 days after SAH
Monitored by frequent neuro checks and daily TCDs
166
What is the gold standard of vasospasm diagnosis
Cerebral angiography
167
What is the goal of vasospasm treatment
To maintain cerebral perfusion pressure
| CPP = MAP - ICPorCVP
168
Why is hypertension a goal for vasospasm prevention
Ischemic areas of the brain already have maximal dilation, so perfusion is pressure dependent, requiring increased MAP by 20 - 30 mmHg above baseline
169
What are the components of triple H therapy
Hypervolemia
HTN
Hemodilution
170
Why is hemodilution a goal of vasospasm and what is the target Hct
Liberal hydration supports blood pressure and CPP
Hemodilution reduces blood viscosity and cerebrovascular resistance
CBF improves
171
Which CCB is used for vasospasm and by what mechanism does it attenuate vasospasm
Nimodipine
It increases collateral blood flow. It doesn't actually relieve the spasm
172
How are medically refractory vasospasm treated
With intra-arterial vasodilators (verapamil and nicardipine), papaverine, or milrinone
173
Why are pts with aneurysmal SAH at risk for cerebral salt-wasting syndrome
Treatment
The brain releases natriuretic peptide, leading to volume contraction, hyponatremia, and sodium wasting by the kidneys
Treatment = isotonic crystalloids
174
what are the 6 categories of motor response for GCS
1. No motor response
2. Abnormal extension to pain
3. Abnormal flexion to pain
4. Withdrawal from pain
5. Localizes to pain
6. Obeys command
175
What re the 5 categories of verbal response for GCS
1. No verbal response
2. Incomprehensible sounds
3. Inappropriate words
4. Confused
5. Oriented
176
What are 4 categories of eye opening response for GCS
1. no eye opening
2. Eye opening to pain
3. Eye opening to sound
4. Spontaneous eye opening
177
What are 8 additional anesthetic considerations for a patient with an acute TBI
1. Full stomach
2. Unstable c-spine
3. Intracranial HTN
4. Airway issues
5. Unknown volume status
6. Hypoxia
7. Other injuries
8. Intoxication
178
What are 3 coagulant treatments for head injury in patients taking warfarin
1. FFP
2. PCC
3. Recombinant factor 7a
179
What are coagulant treatment options for head injury patients taking clopidogrel or aspirin
1. Reverse with platelet transfusion
| 2. Us of recombinant factor 7a
180
What 2 interventions can worsen neurological outcomes for patients with TBI
1. Prolonged hyperventilation (low PaCO2)
| 2. Steroids
181
How do hypertonic vs hypotonic solutions affect cerebral volume
Hypertonic saline = restores intravascular volume and decreases brain water
Hypotonic solution = increases cerebral edema
182
Which IV fluids are linked to poor neurological outcomes and should be avoided in patients with TBI
1. Hypotonic solutions
2. Glucose-containing solutions
3. Albumin
183
Define partial or focal seizure
Activity is localized to a particular cortical region
184
Define generalized seizures
Activity affects both hemispheres
185
What is a Jacksonian march
When a partial seizure progresses to generalizes seizure
186
What is tonic vs clonic movement with generalized seizure
```
Tonic = whole body rigidity
Clonic = repetitive jerking motions
```
187
What is a surgical treatment for generalized seizures
Vagal nerve stimulator
| Resection of foci
188
What are criteria for status epilepticus
1. Seizure duration >30 minutes
| 2. 2 grand mal seizures w/o regaining consciousness in-between
189
What are 6 acute treatments for status epilepticus
1. Phenobarbital
2. Thiopental
3. Phenytoin
4. Benzos
5. Propofol
6. GA
190
What are causes of new-onset seizures in an adult
1. Structural brain lesion (tumor, head trauma, CVA)
| 2. Metabolic cause (hypoglycemia, drug toxicity, withdrawal)
191
How do inhalation agents affect seizure activity
They tend to reduce EEG activity in a dose-dependent fashion
192
Why are s/sx of seizure activity under GA
1. Tachycardia
2. HTN
3. Increased EtCO2 d/t increased O2 consumption
193
Which agents should be avoided in pts with history of seizure and why
Ketamine can induce seizure activity
| Meperidine, the active metabolite accumulation is capable of producing sz activity
194
Which 3 medications can be used to determine seizure location during cortical mapping.
Why
1. Methohexital
2. Etomidate
3. Alfentanil
These drugs increase EEG activity and can help determine the location of szs
195
Phenytoin effect on the liver
Induces hepatic enzymes
196
How do carbamazepine and phenytoin affect nondepolarizing NMB metabolism
Contributes to resistance of nondepolarizing NMBD d/t hepatic enzyme induction
197
Risk of phenytoin extravasation
Extravasation or arterial injection can cause significant tissue injury
Fosphenytoin avoids this
198
What effect does valproic acid have on hepatic metabolism
Inhibits hepatic enzymes
199
Which anticonvulsant drugs are hepatic enzyme inducers
Phenytoin
| Carbamazepine
200
Which anticonvulsant drugs are hepatic enzyme inhibitors
Valproic acid
201
Carbamazepine effect on hepatic metabolism
Induces hepatic enzymes
202
What 4 conditions can carbamazepine illicit
1. Aplastic anemia
2. Thrombocytopenia
3. Liver dysfunction
4. Hyponatremia
203
What is the MOA of phenytoin
Blocks voltage-gated Na+ channels
| Stabilizes membranes
204
What type of kinetics does phenytoin follow
Zero order kinetics
205
Valproic acid MOA
Blocks voltage-gated Na+ channels
| Stabilizes membranes
206
What effect does valproic acid have on phenytoin metabolism and plasma level
Slows metabolism
Displaces phenytoin from plasma proteins
Increases phenytoin levels
207
Carbamazepine MOA
Blocks voltage-gated Na+ channels
| Stabilizes membranes
208
Gabapentinoid MOA
Inhibition of alpa 2-delta subunit of voltage-gated Ca++ channels in CNS
Decreases excitatory NT release
209
What is the chemical structure of gabapentinoids
Chemical analogues of GABA but do not agonize GABA
210
Which conditions are gabapentinoids useful
1. Diabetic neuropathy
2. Post-herpatic neuralgia
3. Reflex sympathetic dystrophy
211
6 side effects of phenytoin
1. Dysrhythmias/HoTN
2. Gingival hyperplasia
3. Aplastic anemia
4. Cerebellar-vestibular dysfunction
5. Stevens-Johnson syndrome
6. Birth defects
212
Describe the pathophysiology of alzheimers
Development of diffuse beta-amyloid-rich plaques
| Development of neurofibrillary tangles in the brain
213
What are consequences of plaque formation in alzheimers
1. Dysfunctional synaptic transmission
- most common in ACh neurons
2. Apoptosis
214
What is the goal of Alzheimer treatment
To restore the concentration of ACh with cholinesterase inhibitors
215
```
What class of medications are used for Alzheimer's
Example drugs:
```
Cholinesterase inhibitor
Ex: tacrine, donepezil, rivastigmine, galantamine
216
Pre-operative anesthetic considerations for patients with Alzheimer's
Avoid preop sedation, which can worsen confusion
217
Induction considerations for patients with Alzheimer's
The use of succinylcholine can be prolonged in patients taking cholinesterase inhibitors
218
Which anticholinergic is the best choice for an Alzheimer's patient and why
Glycopyrrolate
| It doesn't cross the BBB
219
What hemodynamic alterations and symptoms are patients taking cholinesterase inhibitors at risk for
1. Bradycardia
2. Syncope
3. N/V
220
What is Parkinson's disease
chronic neurodegenerative disorder of the BASAL GANGLIA
| With imbalance between dopamine and ACh
221
Which neurotransmitters are out of balance in patients with Parkinson's disease
Low dopamine levels
| Elevated Ach levels
222
What is the consequence of increased Ach in the basal ganglia
It increases GABA activity in the thalamus causing suppression (GABA = inhibitory)
223
What is the result of thalamic inhibition from increased ACh
It suppresses the cortical motor system and motor areas in brainstem
Results in overactivity of the extrapyramidal system
224
What is diagnosis of Parkinson's based on
Requires 2 of 4 cardinal signs:
1. Resting "pill-rolling" tremor
2. Skeletal muscle rigidity
3. Postural instability - loss of balance
4. Bradykinesia - very slow movements and reflexes
225
Why are 2 medications required to treat Parkinson's disease
Levodopa is the precursor to dopamine. It is metabolized in the blood, however DA cannot cross BBB
Carbidopa prevents levodopa metabolism and allows more levodopa to enter the CNS
226
What are 3 common side effects of levodopa-carbidopa
1. Increase inotropy
2. Tachycardia
3. Orthostatic HoTN
227
Selegiline class and MOA
MAO-B inhibitor that restores dopamine concentration by reducing dopamine metabolism in CNS
Doesn't increase risk of tyramine-induced HTN crisis
228
What are Parkinson's patients at risk for with GA
1. Autonomic instability
2. Orthostatic HoTN
3. Dysrhythmias
4. Aspiration
229
Should patients taking levodopa take it on the day of surgery
YES
It has a half-life of 6 - 12 hrs
It should be given during prolonged surgeries to prevent muscle rigidity
230
How can antidopaminergic drugs impact Parkinson's patients
| Ex of drugs
They can exacerbate extrapyramidal s/sx
231
Which drugs should be avoided in Parkinson's patients
Antidopaminergic drugs
1. Metoclopramide
2. Butyrophenones (haldol, droperidol)
3. Phenothiazine (phenergan)
232
Which drug class can be used to treat acute exacerbation of Parkinsonian symptoms
Anticholinergics
| Benadryl
233
How is HoTN addressed in Parkinson's patients
Volume expansion
| Direct-acting agents (phenylephrine)
234
What medication is held if a patient is undergoing deep brain stimulation
Levodopa
235
Where are DBS electrodes inserted for Parkinson's patients
1. Subthalamic nucleus
2. Globus pallidus
3. Ventralis intermedius
236
What medications are best suited for DBS surgery
Light sedation with opioids and dexmedetomidine
237
Which medications should be avoided during DBS surgery and why
```
GABA agnoists (propofol, bzds)
GABA plays crucial role in thalamus
Avoid these drugs b/c they interfere with electrophysiologic brain monitoring
```
238
What is SBP goal for DBS surgery
<140 mmHg to avoid risk of intracranial hemorrhage
239
What is the etiology of ischemic optic neuropathy
Inadequate blood supply to the optic nerve due to venous congestion in the optic canal, reducing ocular perfusion pressure
240
Equation for ocular perfusion pressure
OPP = MAP - IOP
241
What are the characterization of ION
Anterior ischemic optic neuropathy
Posterior ischemic optic neuropathy
242
Which cranial nerve is affected in IOP
Optic nerve (CN 2)
243
Describe anterior ischemic optic neuropathy
Located anterior to the lamina cribrosa and impaired perfusion through the posterior ciliary arteries is the most likely explanation
Swelling of the optic disc
244
Describe posterior ischemic optic neuropathy
Occurs posterior to the lamina cribrosa and most likely d/t the pial vessel supply in the optic nerve
Normal optic disc (no swelling)
245
When does vision loss typically occur with ION
24 - 48 hrs after surgery
246
Which surgery is ION most common
after spinal surgery in prone position
247
What are procedural risk factors for ION
1. Prone position
2. Wilson frame use
3. Long duration of anesthesia
4. Large blood loss
5. Low ratio of colloid to crystalloid resus
6. HoTN
248
What are patient risk factors for ION
1. Male
2. Obesity
3. DM
4. HTN
5. Smoking
6. Old age
7. Atherosclerosis
249
What is the etiology of central retinal artery occlusion
Decreased perfusion of the central retinal artery (d/t reduced venous outflow from improper head position) leads to blindness
the artery arises from carotid and opthalmic aa.
250
What is the typical presentation of central retinal artery occlusion
Sudden, painless, vision loss in one eye on emergence
Examination reveals cherry red macula with pale surrounding retina
251
What are risk factors for central retinal artery occlusion
1. Using horseshoe headrest in prone position
2. Use of N2O following retinal detachment surgery with intraocular gas bubble
3. Embolism
252
Treatment for corneal abrasion
```
Abx drops (erythromycin, tobramycin)
NSAIDs
```
