Nervous System And Neuromuscular Pathology Flashcards
(154 cards)
1
Q
How does the pupillary light reflex go
A
In on 2 and out on 3
2
Q
How do you test the pupillary light reflex
A
Dim lighting
3
Q
Shining light into the right eye
A
Activates sensory arc following optic tracts bilaterally or pretectal nucleus (area) in midbrain
4
Q
What does the pretectal nucleus do once it is activated by light
A
Each pretectal nucleus sends axon projections bilaterally to the left and right edinger Westphal nucleus to activate pre ganglionic parasympathetic neurons
5
Q
When the parasympathetic neurons are stimulated by the edinger westphal nucleus in the pupillary light reflex, what happens
A
Post ganglionic parasympathetic neurons in the left and right ciliary ganglion activate pupillary constrictor muscle in both eyes (direct and consensual)
6
Q
Pupillary light reflex and damage to the right optic nerve
A
- if light is shined into the left eye, there is a direct and consensual response because of the projections from the left optic nerve tot he right CNIII
- if light is shined into the right eye, there is neither a direct or consensual response because no light can send any signal back to even get to the bilateral projections of CNIII
7
Q
Pupillary light reflex and damage to the right optic tract
A
- light shined into the left eye has a direct and consensual reasoned
- light shined into the right eye induces a normal pupil constriction for both direct and consensual since it is past the optic chiasm and has bilateral projections
8
Q
Which causes more of a problem, optic nerve lesion or an optic tract lesions
A
Optic nerve
9
Q
Pupillary light reflex and damage to the right CN3
A
- Light shined in the left eye induces normal direct response but no consensual pupillary constriction in the right eye
- light shined in the right eye does not have a direct response In the right eye, but a normal consensual response in the left eye
10
Q
Why is accommodation not a specificity test only of the midbrain
A
Reflex circuitry for acocmmodation is not yet well destablished: may involve visual cortex or unconscious visual processing in tectum
11
Q
Motor arc of pupil constriction in accommodation is mediated by what
A
Parasympathetics from the edinger westphal via CN3 as with light induced constriction
12
Q
Pupils are abnormally asymmetrical in size
A
Anisocoria
13
Q
What are the questions you need to ask when you see unequal pupil size
A
- is it due to impaired pupillary constriction in the larger pupil?
- is the asymmetry due to impaired pupillary dilation in the smaller pupil
- does the asymmetry remain the same after testing for dilation and light reflex?
14
Q
Left afferent pupillary defect
A
- light not getting through the left eye
- light shined into left eye will not elicit direct or consensual response
- light shined in right eye will elicit a direct and consensual
- this is called Marcus Gunn Pupil
15
Q
Opiate drugs and the pupils
A
Inhibit sympathetic and cause pin point pupils
16
Q
Afferent pupillary defect, aka “Marcus Gunn pupil”
A
- impaired sensory arc of the reflex such that both the direct and consensual response are impaired to light on the side of the causal lesion
- requires verification in intact motor arc on both sides
- afferent pupillary defect refers to this finding of a sensory arc defect, but can result from a variety of lesions: retina, or optic nerve damage
17
Q
Acute Adie’s pupil
A
-impaired constriction response to light and accommodation due to impaired motor component. Specific cause is not proven but involves partial degeneration of ciliary ganglion or post-ganglionic parasympathetic projections. Pattern of denervation in iris is segmental (partial). Possibly due to inflammatory damage
MOTOR
18
Q
Chronic Adie’s tonic pupil
A
-involves ectopic re-innervation of iris by parastympathetic projections that would normally target the ciliary body. Thus, light reflex remains impaired, but accommodation testing shows improved pupil constriction response with delayed reversal to baseline pupil size, hence the term Adie’s tonic pupil or Adie’s myotonic pupil
Nerves regenerate, but some go to iris instead of to the ciliary body
19
Q
Impairment in light reflex but with preserved accommodation response
A
Light-near dissociation
20
Q
What are some conditions in which light-near dissociation occurs
A
- Adie’s tonic pupil
- neusosyphillis, accompanied by irregular shaped pupils, called Argyll-Robertson pupil
- some diabetics
- can occur in parinaud syndrome: dorsal midbrain compression (pineal tumor)
21
Q
Pupillary motor arc is mediated by
A
Sympathetic NS
22
Q
When the sympathetic to the head are damaged, what pupillary defect do we get
A
Horners syndrome
23
Q
Emotional pupillary response
A
Starts in the hypothalamus and goes down to T1 and T2 and then back up the sympathetic
24
Q
Things that can lead to horners
A
Lateral pons infarct
Lateral medulla infarct
25
Anterior ischemic optic neuropathy (AION)
Ischemia of anterior optic nerve (portion in the orbit) is a common cause of sudden vision loss, especially >50 y/o
26
What is the blood supply that supplies the anterior optic nerve that is involved in a tier or ischemic optic neuropathy
Short ciliary arteries derived from ophthalmic artery
27
Arteritis AION
In temporal arteritis, inflammatory process concludes arteries, treatable with glucocorticoids
28
What are some things that could cause AION
Atherosclerosis, HTN, diabetes, smoking, nocturnal hypotension (vision loss on waking)
29
Presentation of AION
Painless, visual field loss may be total, sector, or scotoma
30
What will you see on ophthalmic exam in AION
Reduced cup-to-disc ratio
31
What is a common precursor to MS
Optic neuritis
32
Optic neuritis
-inflammatory de-myelination of the optic nerve(s)
33
Etiology of optic neuritis
- inflammatory process triggered during or after resolution of viral infection
- pro-inflammatory chemical exposure
- vitamin B12 deficiency
34
Onset of optic neuritis
30-45 years but can be later
35
Incidence of females to males in optic neuritis
2:1
36
___% of patients with optic neuritis later develop multiple sclerosis
50
37
Presentation of optic neuritis
Monocular vision loss, eye pain especially during eye movements
38
Visual loss in optic neuritis
Central scotoma, reduced acuity around scotoma, impaired color detection. Can be complete monocular vision loss
39
Ophthalmic exam for optic neuritis
-depends on whether inflammation extends to optic disc or is limited to retro-bulbar segment of optic nerve. Thus optic disc can be swollen and inflamed or normal. Prior episodes can lead to optic disc pallor
40
Additional diagnostic testing for optic neuritis
Afferent pupillary defect, VEP
41
VEP in optic neuritis
- EEG recordings of primary visual cortex responding to alternating checkerboard stimulus
- abnormally long latency of cortical response with normal amplitude consistent with de-myelination (atonal degeneration would result in reduced amplitude of the evoked response)
42
Temporal profile of optic neuritis
- onset variable
- acute, subacute, chronic
- Duration <2 weeks followed by full or partial recovery
- recovery can take 6 weeks to months
- 1/3 of patients have 1 or mote recurrences
- repeat episodes are more likely to yield residual damage and deficits
43
Is optic neuritis usually permanent
No
44
Reasons to suspect a different diagnosis from optic neuritis
- over the age of 45
- absence of associated eye pain (argues against inflammatory pathology)
- bilateral visual loss
- 1st episode and visual loss lasting more than 2 weeks, absence of recovery
45
DDx for optic neuritis
```
Glaucoma
Retinal artery occlusion
Optic nerve ischemia
Compressive lesion
CNS infection
```
46
Radiological evidence of optic neuritis
MRI showing de-myelination lesions
47
Short term treatment for optic neuritis
Glucocorticoids
48
Pathophysiology of MS
-autoimmune de-myelinating disorder of the CNS only
NO PNS INVOLVEMENT!
49
Specific mechanisms of MS
Involves autoimmune attack against oligodendrocytes by T lymphocytes
-could target myelin basic protein or other components of the myelin sheath or other antigens on aoligodendrocytes. Axons are not directly affected
50
Presentation of MS
Multi-focal distribution for 2 or more focal lesions within CNS
-2 or more “attacks” separated in time (like one month apart)
51
If someone has a single lesion could that habe MS
No
52
Epidemiology of MS
```
1 per 1000
2x as many females
20-40 years
Caucasians
Higher altitude
```
53
Original hypothesis of MS
- small breaches of blood Brian barrier
- Ab against myelin basic protein
- followed by direct T cell attack
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Newer hypothesis of MS
- inflammation triggered by microglia
- T cell invasion of CNS from blood
- release cytokines that are toxic to oligos
- following oligo cell death, macrophages attack debris and myelin sheath
- astrocytes form glial scar around zone of damage
55
Genetic risks of MS
- siblings 2.6% risk
- 25% concordance in identical twins
- 2.5% concordance in Sam sex fraternal twins
- mutations in IL-2 and IL-7
56
MRI evidence of MS
2 or more white matter lesions (plaques)
- plaques can be distributed anywhere at differnt levels
- often appear as fingers extending from periventricular zones
- MRI with contrast can highlight plaques
57
CSF analysis in MS
- oligoclonal bands
- presence of bands at specific molecule weights
- 85% sensitivity for MS (not found in all MS pateints)
- 92% specificity for MS (present in some other diseases)
- elevates lymphocyte count
58
Mental status in MS
- specific conginitive defects (visual defects, working memory deficits
- psychiatric symptoms: depression, fatigue, manic
59
Cranial nerves and MS
```
Oculomotor deficits (inter nuclear ophthalmoplegia)
-lesion at the MLF causing the abducens and CNIII to not communicate properly
```
60
Cerebellum and MS
Poor coordination
61
Motor exam in MS
Weakness
62
Sensory exam in MS
Sensory loss, Lhermitte’s sign (flexing neck induces electrical shock running down back into legs
63
Autonomic implications of MS
Sweating, bladder/bowl/sexual dysfunction
64
Temporal profile of MS
- 1st attack and medical eval often revels evidence for prior episodes
- 50% have prior episode of optic neuritis
- relapsing-remitting cycle
- can become chronic and progressive
65
Short term MS treatment
Glucocorticoids
66
Long term Tx for MS
Immunomodulatory agents
| -interferons
67
Factors that can trigger or transiently intensify an attack
- infection
- over heating
- dehydration
- sleep deprivation
68
Neuromyelitis optica (NMO)
MS look alike disorder
- devic syndrome
- de-myelination of the optic nerves and spinal cord (2 lesions)
69
Presentation of neuromyelitis Optica
Bilateral visual loss, level-down sensory and motor deficits
70
Distribution of neuromyelitis optica
Multi-focal (hence resembling MS)
71
Pathophysiology of neuromyelitis optica
Auto-immune attack involving Ab to aquaporin 4
72
Diagnosis of neuromyelitis optica
Aquaporin-4 AB
73
Temporal profile of neuromyelitis optica
Acute and stable
74
Pathophysiology of progressive multifocal leukoecephalopathy
- multiple cocci of white matter de-myelination and damage in the CNS
- viral infection of oligodendrocytes
- infection is rarely symptomatic, but can lead to leukoencephalopathy
- usually occurs in immunosuppressed patients
- usually co-morbid
75
Onset and course of progressive multifocal leukoencephalopathy
Subacute and progresive
76
Progression of progressive multifocal leukoencephalopathy
Can be fatal, treatment is anti-retroviral Rx
77
Neurological deficits in progressive multifocal leukoencephalopathy
Varies depending on the location of lesions
78
What can progressive multifocal leukoencephalopathy progress too
Dementia (differs from MS)
79
Pain in progressive multifocal leukoencephalopathy
None
80
Presentation of lesions in progressive multifocal leukoencephalopathy compared to MS
In MS they are periventricual, in PML they are adjacent to cortical gray matter
81
Differences between leukoencephalopathy and leukodystrophy
leukoencephalopathy has lesions that develop and damage structures
Leukodystrophy is a disorder that involves defects in myelin structure and function
- can be genetic or acquired
- myelin formation is impaired or the myelin is structurally and functionally defective
- present during 1-2 years of life but can emerge as last as early adulthood
82
Inflammatory damage to white and grey matter, mimics MS or stroke
Acute disseminated encephalomyelitis (ADEM)
83
Inflammatory de-myelination in CNS, often with gray matter damage, typically 1-2 weeks after an infection (bacterial or viral) or after a vaccination (adverse reaction)
Acute disseminated encephalomyelitis (ADEM)
84
Distribution of acute disseminated encephalomyelitis
Multifocal or diffuse
85
Pathophysiology of ADEM
Inflammatory and rapid onset
86
Diagnosis of ADEM
Lesions in white matter and gray matter
87
Presentation of ADEM
Typically non-localizing signs, HA, lethargy, stupid, coma
-however, initial presentation can be focal, thus mimicking stroke except that localization does not conform to a single vascular territory
88
Temporal profile of ADEM
Acute to subacute, rapid onset confers similarity to stroke
89
Treatment of ADEM
Glucocorticoids
90
Headaches and the dura
The Dura lines everything and is innervated all over and can cause headaches
91
Acute onset headaches
- last several minutes to hours
- urgent/emergency likely
- hemorrhage’s
- meningitis or encephalitis
- ophthalmic events (glaucoma, iritis)
92
Subacute onset headaches
- hours to days ago
| - non emergent
93
Chronic onset headaches
- occurrence began weeks, months years ago
- tension type
- cluster type
- migraine
94
Temporal pattern of migraines
Spells, random pattern
95
Temporal pattern of tension headache
Musculoskeletal, presistnant
96
Cluster headache temporal pattern
Spells, a lot on a daily basis and Long spells without
97
Brain tumor temporal pattern
Steady ramp over time
98
Unilateral pain on headache
Cluster
| -sometimes migraine
99
Ocular or retro-orbital pain in headache
Ocular or neuro-ophthalmic causes
100
Focal pain headache
Signal intracranial mass
101
Diffuse or band like pattern headache
Tension headache (scalp)
102
Cause of tension head
Not known
103
Hypothesis of tension headache cause
MUsuloskeletal, excess muscle tone
| -occipitopfrontalis or suboccipital triangle uncles, activates local pain fibers
104
How to treat tension headache
Common Rx and osteopathic manipulative techniques
105
Presentation of cluster headache
- unilateral
- non-pulsating
- transient
- minutes to hours
- will wake the patient
- extend remission periods
106
Localization of cluster headaches
Periorbital region
| -or along path of vessels and nerve branches
107
Who gets cluster headaches more
Men
108
Rx for cluster HA
Serotonin agent that acts on the blood vessels (sumatriptan)
- constricts intracranial vessels
- lidocain
109
Migraine presentation
- minutes to hours
- <1 week
- auras
- nausea.vomitting
110
Who is more likely to get a migraine
Women
111
Localization of migraines
Hemi cranial but can be bilateral
112
Causes of migraines
- dietary, environmental factors
| - possibly due to autonomic dysregulation of vasoconstriction and dilation, stimulating local pain fibers
113
RX for migraines
Serotonin agents
CCB
Tricyclics anti-depressants
114
Tumor origin is in CNS
Primary
115
Tumor origin is outside the DNS
Secondary/metastatic
116
Which is more common, primary or secondary intracranial tumors
Secondary
117
Where do primary intracranial tumors come from
Glia. Meninges, pituitary
118
Most common forms of secondary/metastatic tumors
Lung, breast, melanoma, prostate
119
Primary tumor growth
Remains intracranial, but presence and growth can lead to seizures, compression and focal or diffuse neurological deficits, brain herniation syndromes
120
Pain in intracranial tumor
Dull and focal or diffuse
121
Intracranial histological structure (tumor)
Encapsulated, surgically removed
-diffuse and poorly circumscribed not able to be removed
-secondary typically well circumscribed and multifocal
-
122
Which type of intracranial tumor is more likely to be diffuse and poorly circumscribed. I totally they are focal and well-circumscribed, but recurrences after surgical removal tend to be diffuse and not operable
Primary tumors
123
How do you identify intracranial tumors
Neuroimaging and biopsy analysis
124
How do you grade a intracranial tumor
1-4 based on histology and growth potential
125
Tumors develop from cell types that
Can undergo mitosis
126
Post-natal CNS neurons and mitosis
With very few exception, can NOT enter mitosis
| -glia remains the ability to do so
127
Most brain tumor types are derived from
Glia, choroid plexus, or meninges
128
Rare type of brain tumor
Primary CNS lymphoma, few lymphocytes in brain, no lymphatic
129
Neuroblastoma
From pre-natal neural stem cells
130
Medulloblastoma
In developing cerebellum
NOT MEDULLA
131
Neuromas
Schwann cells form these on nerves )acoustics neuroma)
132
Oligodendroglioma
Cerebral white matter
133
Astrocytoma or glioblastoma
Astrocytes
134
Ependymomas
Ependymal cells
135
What kind of tumors can choroid plexus form
Benign or malignant tumors (papilloma or carcinoma)
136
Meningiomas
Several common hot-spots
137
What are the implications of a space-occupying lesion
Brain compression and herniations
138
Amyotrophic lateral sclerosis
UMN and LMN cell death
139
Spinal muscular atrophy
LMN death
140
Polio and post polio syndrome
LMN cell death
| UMNs often spared
141
Peripheral neuropathies
- diabetic neuropathy
- Guillain-barre
- genetic
- de-myelinating vs axonopathy
- diagnostic methods
142
Pathology of the NMJ
MG
143
Pathophysiology of MG
Abs generated against nicotine ACH receptors, induced receptor internalization
-can also involve Abs against muscle-specific tyrosine kinase (MuSK) which normally acts to cluster nACHRs in synapse
144
Presentation of MG
Fatiguable weakness
145
Diagnostic tests for MG
Tensilon test
| -edrophonium to see if they respsone
146
Presentation of MG
- diffuse
- EOM weakness
- includes weakness of levator palpebrae
- pupillary light reflex spared (iris is smooth muscle)
- other cranial motor weakness possible
147
Temporal profile fo MG
```
Any age
Progressive
Relapsing-remitting pattern
More in women
After an infection
```
148
Lambert-Eaton syndrome
Ab mediated auto-immune attack against Ca channels
- Ab produced due to paraneoplastic syndrome (Secondary to tumor)
- limbs effected but EOMs usually spared
- AChase inhibitors not effective
- use immunosuppresive agents nad plasma phoresis
149
Difference between MG and lambert-Eaton syndrome
MG: Ab bind and block the nictoinic Ach receptors
LE: Ab bind calcium channels
150
Oculomotor myopathies
Weakness most often with eye and lid elevation, often diplopia occurs
Major etiologies: hyperthyroidism, mitochondrial DNA mutations
151
Duchenne musculat dystrophy
- mutation in dystrophin, maintenance of sarcomere
- pediatric disorder with progressive diffuse weakness, wheel chair bound
- proximal limbs most affected
- toe-walking, waddling gait, Gower’s sign (pushing off of legs with arms to stand upright)
152
Bipolar disorder
- inflated self esteem, decreased need for sleep, more talkative, flight of ideas, distractability
- mood disturbances impair social and occupational functioning
- psychotic features
- not attributable to the psychological effects of substance abuse
- followed by a very low depressive period
153
How do we treat bipolar disorder
Lithium
154
Lithium as a treatment for bi polar
Not sure why it works
- must be maintained within a precise blood concentration
- think it may stabilize amount of signaling through Ca channels
