General Neuropathology Flashcards
(211 cards)
1
Q
Involuntary actions
A
maintain homeostasis
Regulated by ANS
2
Q
Voluntary actions
A
Reflex activities
3
Q
Meninges: Dura Mater
A
Outer layer
4
Q
Meninges: Arachnoid
A
Middle layer
5
Q
Subarachnoid space
A
Contains cerebrospinal fluid (CSF)
6
Q
Meninges: Pia mater
A
Adheres to surface of brain
7
Q
Meninges other parts
A
Subdural space
Arachnoid
8
Q
Protection of the Brain
A
BBB
9
Q
Blood-brain barrier Role (LCL)
A
Limits passage
Controls balance of electrolytes, glucose, and proteins in brain
Lipid-soluble substances pass easily
10
Q
BBB and neonates
A
Poorly developed in neonates
11
Q
Blood-CSF barrier
A
At the choroid plexus for CSF
12
Q
Each hemisphere is divided into four major lobes.
A
Frontal
parietal
temporal
occipital
13
Q
Longitudinal fissure
A
separates two hemispheres
14
Q
Cortex
A
“Gray matter” – nerve cell bodies
15
Q
Corpus callosum
A
“White matter” – myelinated nerve bundles (tracts)
Connect the hemispheres
16
Q
Right and left hemispheres similar in
A
structure, not necessarily in function
17
Q
Dominant hemisphere
A
Side of brain that controls language
18
Q
Dominant hemisphere- in most people
A
Left hemisphere
19
Q
Broca area
A
Motor speech
20
Q
Wernicke area
A
comprehends language
21
Q
Functional Areas – Diencephalon
A
Central portion of the brain
22
Q
Functional Areas – Diencephalon contains what?
A
Contains the thalamus and hypothalamus
23
Q
Functional Area - Diencephalon - Thalamus role
A
Relay station for incoming sensory impulses
24
Q
Hypothalamus
Key role
What does it control?
A
Key role in maintaining homeostasis of the body
Controls autonomic nervous system and much of the
endocrine system
25
Hypothalamus regulates (BRESS F)
```
Body temperature,
Regulation of sleep cycles
Emotional responses
Sex drive
Stress response,
Fluid and food intake,
```
26
Functional Areas – Brainstem 3 parts
Midbrain
Pons
Medulla oblongata
RAS
27
Functional Areas – Brainstem- Midbrain
Visual activities
28
Functional Areas – Brainstem- Pons (HS)
Helps regulate respiration
| Several nuclei of cranial nerves
29
Functional Areas – Brainstem- Medulla oblongata (CCN)
Control center for respiratory and cardiovascular
function
Coordination of cough reflex, swallowing, vomiting
Nuclei for several cranial nerves
30
RAS (Reticular-Activating System)/Reticular formation
Network of nuclei and neurons throughout brainstem
31
RAS and connection
Connected to many parts of the brain
| Determines the degree of awareness of the cerebral cortex
32
*Anesthetic drugs and RAS
inhibit RAS causing reversible loss of consciousness
33
Cerebellum Role
Coordination of movements
| Maintenance of posture & equilibrium
34
Cerebellum receives input from
Receives input from proprioceptors in muscles &
joints
Input from visual and vestibular pathways
35
Cranial Nerves: How many pairs and where does it originates?
12 Pairs
| Originate from various parts of the brain
36
Cranial nerve numbered how?
Numbered from ventral to dorsal
37
Cranial nerves may contain
–Motor only
–Sensory only
–Both (mixed)
38
Spinal Cord is protected by
Protected by vertebral column, meninges, CSF
39
Spinal Cord continuous with
Continuous with medulla
40
Where does the SC end?
Ends at lower border of L1-L2
| Conus medullaris, cauda Equina
41
White and gray matter
Core
42
Posterior horns
Interneurons (association neurons)
43
Anterior horns
Cell bodies of motor neurons
44
Spinal nerves named by
Named by location in the vertebral column where
| they emerge
45
Nerve Roots Ventral anterior root
Motor (efferent) fibers (VME)
46
Dorsal (posterior) root
Sensory (afferent) fibers (DSA)
47
What are reflexes?
Automatic, rapid, involuntary responses to a
| stimulus
48
Sensory stimulus, what is it?
From receptor – conducted along afferent fiber
49
What is a Synapse?
In the spinal cord or for cranial reflexes in the brain
50
Efferent impulse serve to
to elicit the response
51
Connecting and interneurons
Transmit sensory information to the brain
52
Neurotransmitters; ACh
Excitatory @ NMJ
53
ACH found in
In ANS and brain
54
Neurotransmitters Epi & Norepi ? Found where?
Excitatory
| Brain and Sympathetic Nervous System
55
Neurotransmitters: Dopamine, serotonin? Found where?
Excitatory
| Brain
56
Neurotransmitters GABA
(inhibitory)
| Brain
57
Sympathetic & Parasympathetic Branches
Motor and sensory innervation
| Involuntary
58
Preganglionic fibers are found where?
In brain or spinal cord
59
Postganglionic fibers are found where?
Outside the CNS
60
Sympathetic Nervous System
“Fight-or-flight” response
| Increases general level of activity in the body
61
Preganglionic fibers arise from
thoracic and first two lumbar segments.
62
SNS Ganglia located in
chains or trunks
63
***SNS Neurotransmitters
Preganglionic
Postganglionic
acetylcholine
| norepinephrine
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SNS Receptors
Alpha and beta receptors
65
Parasympathetic Nervous System
| Originates
in the brainstem and sacral spinal
| nerves
66
Parasympathetic Dominates
digestive system and aids recovery after sympathetic activity
67
Parasympathetic NS Ganglia
scattered and close to target organ
68
****Parasympathetic Neurotransmitter release (pre and pos synaptics)
both presynaptic and postsynaptic releases Acetylcholine
69
ACH Receptors
Nicotinic and muscarinic
70
Autonomic Hyperreflexia ocurs
Occurs with spinal cord injury at or above T6.
71
In autonomic Hyperreflexia Pathophysiology
| SEBBB
Strong sensory input (ex. from full bladder) sends signal up S.C. –
Evokes massive reflex sympathetic surge resulting in vasoconstriction and severe hypertension. Baroreceptors send signal to Brain.
Brain sends inhibitory signals, which are blocked by the injury.
Brain also sends Vagus N. signal = ↓ HR, however, the bradycardia fails to control the HTN.
72
Autonomic Hyperreflexia Can be triggered by
visceral (bladder/bowel) or cutaneous stimulation (ex. Surgical incision).
73
% of patient developing autonomic hyperreflexia
85% of pts with injury above T6 will develop it.
74
Autonomic hyperreflexia Unlikely to occur at all in
patients with lesion below T10.
75
Autonomic Hyperreflexia Symptoms in awake patient: BSN
Blurred Vision
Severe HA
Nasal Stuffiness (due to reactive cutaneous vasodilation above level of injury)
76
Autonomic Hyperreflexia
Most likely to occur intra-op. at beginning of case with
| initial surgical incision and/or at end of case as anesthetics are wearing off.
77
Treatment of Autonomic Hyperreflexia
Vasodilators with a short half-life (such as sodium nitroprusside)
78
CSF Provides
cushion for brain and spinal cord
79
CSF is Formed by
choroid plexuses in the ventricles
80
CSF Flows through
ventricles into subarachnoid space
81
Equal amounts of CSF need to
be produced and reabsorbed to maintain intracranial pressure (ICP)
82
Normal CSF production in adults is about
21 mL/hour or 500ml /day.
83
The total volume at any given time, however, is only about
150 mL.
84
CSF flow pattern
◘from lateral ventricles to 3rd ventricle via
foramen of Monroe, then passes into 4th ventricle via
aqueduct of Sylvius.
◘Then passes from 4th ventricle to cerebellomedullary
cistern via the foramen of Magendie.
◘From the cerebellomedullary cistern, it enters the
subarachnoid space, circulates around the brain and
spinal cord, and then is reabsorbed in the arachnoid
villi (“granulations”) above the cerebral hemispheres
85
CSF Obstruction leads to
Hydrocephalus and/or ICP
86
CSF flow numbered
| CLTA Fc FCA
1. Choroid Plexus
2. Lateral Ventricle
3. Third Ventricle
4. Aquaduct of Sylvius
5a. Fourth ventricle
5b. Choroid plexus of fourth ventricle
6. Foramen of Magendie
7. Cerebellomedullary Cistern
8. Arachonoid villus
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Characteristics of Normal CSF
| Pressure
9-14 mmHg
| 150 mmH2O
88
CSF and Isoflurane
decreases CSF production
89
CSF and Desflurane
increases CSF production
90
Other Drugs that decrease production:
| SAF CSV
```
Sevoflurane
Acetazolamide
Furosemide
Corticosteroids
Spironolactone
Vasoconstrictors
```
91
Supratentorial lesions
| Results in widespread impairment
Occur in the cerebral hemisphere
| Lead to focal dysfunction in a specific area
92
Infratentorial lesions
Below tentorium or in brainstem
| Affects many motor & sensory fibers
93
2 IMPORTANT effects of INFRATENTORIAL LESIONS
Respiratory and circulatory function may be impaired.
| Level of consciousness may be impaired. ( RAS location)
94
Brain Tumors
| Classified as either ______ and ______. Results in
Primary or Metastatic
| ↑ ICP
95
Supratentorial tumors more common in ______present with: HSN
Adults
◘ HA
◘Seizures
◘Neurologic Deficits
96
Infratentorial tumors more common in_____ present with:
children
◘ Obstructive Hydrocephalus
◘ Ataxia
97
Increased ICP: The Brain is
encased in rigid skull.
98
Increase ICP what is not compressible?
Fluids, blood, and CSF are not compressible. Skull contents have elasticity to withstand small transient ↑ ICP.
99
****What causes increase in pressure of ICP ? Leading to >
Significant increases in fluid or mass causes ↑ pressure. Leads to ischemia and infarct of brain tissue
100
****Normal ICP
< 14mmHg
101
****Intracranial HTN is indicated with ICP?
Sustained pressure > 15mmHg =
102
Increased ICP is common in many neurologic problems such as BITOT
```
Brain hemorrhage,
Infection,
Trauma,
Obstsruction of CSF and cerebral edema
Tumors,
```
103
***3 Causes of Cerebral Edema
Vasogenic
Cytotonic
Interstitial
104
***Vasogenic Cerebral Edema
BBB breakdown allows protein into extracellular tissue space. Draws H2O in
105
****Cytotoxic Cerebral Edema
Neuron damage from hypoxia/ischemia = ↑ Na & H2O in
| brain cells.
106
***Interstitial Cerebral Edema
CSF forced into interstitium 2o to hydrocephalus = ↑ ICP
107
If increase in ICP is significant enough, can cause
Herniation
108
Transtentorial herniation(CR)
Cerebral hemispheres, diencephalon, midbrain are
displaced downward
Resulting pressure affects flow of blood and CSF; RAS and respiration
109
Uncal herniation (UC)
Uncus of the temporal lobe is displaced downward.
Creates pressure on CN III, the posterior cerebral
artery, and RAS
110
***Infratentorial (cerebellar, or tonsillar) herniation
| CCC
Cerebellar tonsils are pushed downward through the foramen magnum.
Compresses brainstem and vitalcenters → infarction
Causes death
111
Increased ICP Early signs: LPSVP
◘ ↓ level of consciousness or responsiveness (compression of RAS)
◘↓ pupillary response (compression C.N. III)
Severe HA
Vomiting
Papilledema
112
Why severe HA with increasing ICP ?
From stretching dura and walls of large blood vessels
113
Increased ICP Vomiting
Often projectile, without nausea – pressure on emetic center in medulla
114
Papilledema with Increased ICP
Caused by ↑ ICP and swelling of optic disc
115
Why_____ pupillary response with Increase ICP
↓; (compression C.N. III)
116
Increased ICP signs and Symptoms (PHEVV)
* Papilledema (optic disc swelling)*
* HA
* Enlarged blind spot
* Visual disturbances
* Vision loss
117
Papilledema
Blurred Disc Margins
| Normal disc margin is SHARP
118
VS with increased ICP (think cushing)
↑BP, ↓pulse, ↓respiration (opposite of shock)
119
Development of cerebral ischemia – first effect of ↑ ICP
is ↓ cerebral blood flow
120
Vasomotor centers respond in attempt to
increase arterial blood supply to brain (Cushing reflex)
121
Increased ICP Systemic vasoconstriction
Increase of systemic blood pressure – more blood to brain to relieve ischemia
122
Increased ICP Baroreceptor response
In carotid arteries
| Increased blood pressure; bradycardia
123
Increased ICP Vital signs
Chemoreceptors respond to ↓ PaCO2 levels
Reduction of respiratory rate
Improved cerebral circulation relieves ischemia for a short time (Increasing ICP causes ischemia to recur – cycle repeats)
124
Pulse pressure with Increased ICP
Widening pulse pressure
125
ICP continues to rise –
blood pressures rises
| Increased pulse pressure is significant in pts. with ICP.
126
Visual Signs of ICP
| Pressure on
oculomotor nerve (CN III) affects size and response of the pupils.
127
Pupil ________to lesion becomes
ipsilateral; fixed and dilated (in the case of a focal lesion)
128
ICP : As pressure increases shift
contents across the midline
| → both pupils become fixed and dilated
129
Ptosis (eyelid) may occur.
Effect of pressure on CN III
130
****Methods to Decrease ICP (VMHED)
```
Mannitol
Elevate pt.s Head ~ 30 above heart
Hyperventilate Lungs
Drain CSF
Vasoconstrictive anesthetics agents
```
131
How does Elevating the HOB help with decreasing ICP?
Encourages venous outflow
132
****How does Hyperventilating lungs help decrease ICP
Lower PaCO2 to 30-35 mmHg
| Causes arterial vasoconstriction lowering cerebral blood flow
133
Drain CSF via Lumbar cath only
Only if excessive CSF. Not for tumor or other mass, etc.
134
Decreasing ICP administer
```
vasoconstricting anesthetics (barbiturates,
propofol
```
135
Decreasing ICP with vasoconstricting anesthetics- avoid
prolonged propofol in pediatric pt.s
136
***Mannitol dosing
0.25 – 0.5 g/kg IV over 15 to 30 minutes
137
Mannitol will removes
~100ml of H2O from pt.s brain
138
***Cerebral Blood Flow/Pressure
| CBF (Cerebral Blood Flow)
50ml/100g brain tissue /min.
139
***CPP (Cerebral Perfusion Pressure)
50-150 mmHg
140
***CBF changes with
ICP, PaO2, PaCO2 and MA
141
Focal Lesions
Signs related to specific area of brain or spinal cord where lesion is located
142
Example of a Focal lesions
paresis or paralysis of the right arm from damage to left frontal lobe
143
Expanding lesions
Due to a growing tumor or hemorrhage
Additional impairment is noted as adjacent areas
become involved
144
***Damage to left hemisphere results in LLAC
Loss of intellectual ability
Logical thinking,
Analytical skills and
Communication skills
145
Damage to right hemisphere (LDSS)
Loss of interest in music& art
Development of behavioral problems
Spatial orientation and recognition of relationships may be deficient
Self-care deficits common
146
Motor Deficits Damage to upper motor neurons
Interference with voluntary movements
| Weakness or spastic paralysis on the contralateral side
147
Damage to lower motor neurons
Weakness or flaccid paralysis on the same side
| At and below the level of spinal cord damage
148
Brain Damage - Decorticate and decerebrate posturing
Severe brain damage
149
Decorticate is damage to
Damage to Cerebrum or Corticospinal Tracts
150
Decerebrate is damage to
Damage to upper brainstem
151
Somatosensory cortex in parietal lobe
Mapped by dermatomes
| Assists in evaluation of spinal cord lesions
152
Loss of somatic senses: PPTT
Touch, pain, temperature, position
153
Loss of special senses: VHST
Vision, hearing, taste, smell
154
Visual Loss: Hemianopia
Depends on site of damage in visual pathway
155
Optic chiasm compression/damage: Totally destroyed?
Vision lost in both eyes if chiasm is totally destroyed
156
Optic chiasm Partial loss
Quadrantanopia or Hemianopia
| Depending on fibers damaged
157
Optic tract or occipital lobe damage
Loss of the visual field on the side opposite to that of the damage
158
Receptive Aphasia , damage to
damage to Wernicke Wernicke area
159
3 types of Aphasia are
Receptive , Expressive, Global
160
Expressive aphasia, damage to
damage to Broca area
161
Global aphasia damage to
damage to both areas or the fibers and tracts between them
162
***Fluent aphasia
**Pace of speech is relatively is relatively normal; includes made-up words; ***associated with damage to Wernicke area
163
Non-fluent aphasia
slow and labored with short phrases; associated with
| damage to Broca area
164
Dysarthria
Motor dysfunction of muscles used in speech, unclear articulation ;
165
Dysarthria usually a result from
cranial nerve damage or muscle impairment
166
Agraphia
Impaired writing ability
167
Alexia
Impaired reading ability
168
Agnosia
Loss of recognition or association
169
Level of Consciousness
Decreased level of consciousness or responsiveness
| Early changes with acute brain disorders
170
Levels of reduced consciousness include:
| CUM DL
```
Confusion / disorientation
Unresponsiveness to verbal stimuli
Memory loss
Difficulty in arousal
Loss of consciousness or coma
```
171
LOC Level determined w/
Glasgow Coma Scale
172
****3 Criteria of Glasgow Coma Scale (EVM)
Eye opening
Motor Response
Verbal response
173
Eye opening scoring
4 Spontaneous
3 Response to Speech
2 Response to pain
1 none
174
Motor response Scoring
```
6 Obeys commands
5 Localizes pain
4 Normal flexion to pain
3 abnormal flexion (decorticate)
2 abnormal extension (decerebrate)
1 None (Flaccid)
```
175
Verbal response scoring
```
5 oriented to time and place
4 Confused
3 inappropriate words
2 Incomprehensible
1 None
```
176
Level of Consciousness “Vegetative state”
Loss of awareness and mental capabilities
177
Vegetative state is caused by
Caused by diffuse brain damage
178
In vegetative state, what function continues? (BUS)
Brainstem function continues
Unresponsive to external stimuli
Sleep-wake cycle present
179
“Locked-in syndrome”
Individual is aware and capable of thinking but is paralyzed and cannot communicate
180
Level of Consciousness Criteria for brain death
| AAC
Cessation of brain function→ Includes cortex and brainstem / Flat or inactive EEG
Absence of brainstem reflexes or responses
181
Brain death Establishment of the certainty of irreversible brain damage
by confirmation of the cause of the dysfunction
182
Brain death evaluation
Evaluated two times by different physicians
183
Most important in brain death establishment
Absence of spontaneous respirations when ventilator
| assistance is withdrawn
184
Seizures or convulsions is Caused by
transient spontaneous excess discharge of neurons
| in the brain
185
***Seizures are Classified based on
2 factors: LOC and focus of seizure activity
186
****Seizures Caused by
Inflammation, hypoxia, or bleeding in the brain
| Often manifested by involuntary repetitive movements or abnormal sensations (aura)
187
***Seizure - Types Partial
Simple
Complex
– originate from neurons in one hemisphere
| Simple (without L.O.C.) →Complex (with L.O.C.)
188
***Seizure - Types Generalized –
originate from neurons in both hemispheres
189
Absence seizures
Petit mal
190
Akinetic seizure
Atonic
191
Tonic-clonic
Grand mal
192
Myoclonic
muscle group
193
Types of Generalized seizures
Absence, Akinetic, Tonic-clonic , Myoclonic
194
Continuous seizures (status epilepticus)
Increased metabolism of glucose and oxygen; life-threatening
195
***Seizures“Jacksonian March” refers to
partials that evolve into generalized
196
***Preferred method for brain study in epileptics
MRI
197
***Imaging, Used to identify location of seizure foci
EEG
198
****Often simultaneously used for documentation
Videography
199
Antiepileptic drugs – mechanisms:
↓ neuron excitability or ↑ neuron inhibition
200
All Antiepileptic drugs metabolized _____except:
in liver except Gabapentine, which is excreted unchanged
201
Phenytoin used for
tonic-clonic and partials
202
***Phenytoin Has many side effects including
Stevens-Johnson syndrome
203
***Phenytoin Extravasation can cause_________ charaterized by (2)
↑↑↑ vasoconstriction resulting in purple glove syndrome
Compartment syndrome
Gangrene
204
Preferred for treatment of status epilepticus
Fosphenytoin (phosphorylated produrg) safer alternative
205
IMPORTANT NOTE : Phenytoin and carbamazepine
shorten duration of nondepolarizing muscle relaxants
206
***Left (VNS) Vagal Nerve Stimulator –
surgically implanted “pacemaker” device for medically intractable seizures
207
***Left vagal nerve stimulator why left vagal nerve?
| How does it work?
Left vagal nerve chosen b/c right vagal n. has cardiac innervation.
by sending regular, mild pulses of electrical energy to the brain via the vagus nerve
208
Left (VNS) Vagal Nerve Stimulator lasts?
Surgically implanted, lasts 10 yrs.
209
****Seizures Status Epilepticus
Continuous seizure activity with 2 or more consecutive consecutive seizures seizures without without recovery recovery of consciousness consciousness
between them.
210
****Increased risk of Hypoglycemia in these pt.s
Status Epilepticus patient
| If present, should correct with IV 50ml of 50% glucose
211
BE familiar with Reflex ARC
PIC
