Exam 2: PNS Flashcards
1
Q
Myasthenia
A
Painless weakness
2
Q
Pathology of any portion of motor unit may cause
A
Skeletal muscle dysfunction
3
Q
Axon neuropathy involved direct injury to
A
Axon
4
Q
Areas of injury for PNS damage
A
Lower motor neuron/ peripheral axon
NMJ
Innervated myoctyes
5
Q
Myelin in PNS created by
A
Schwann cells
6
Q
2 types of neuropathy
A
Axonal
Demyelinating
7
Q
Wallerian degeneration
A
Distal to injury breaks down
8
Q
Demyelinating neuropathy involves damage to
A
Myelin or Schwann cells
9
Q
Peripheral neurons have ability to
A
Regrow
Remyelinate
10
Q
With regrowth and demyelination of PNS…
A
Low axon density
Low amplitude on NCV
11
Q
Demyelinating neuropathy spares
A
Axon
12
Q
Segmental demyelination
A
Random demyelination
13
Q
Repair of demyelinating neuropathy
A
Thin myelin
Short internodes
14
Q
Mononeuropathy always involves either
A
Entrapment
Trauma
15
Q
Polyneuropathy involves
A
Many nerves damaged from metabolic problems
16
Q
Stocking and glove paresthesia observed in
A
Polyneuropathy
17
Q
Rubbery legs, ascending paralysis, and respiratory failure observed in
A
GBS
18
Q
Guillain-Barre Syndrome (GBS)
A
Acute motor neurons demyelination
Autoimmune
19
Q
Age and sex MC in GBS
A
Males
15-35 or 50-60
20
Q
Causes of PNS injury
A
Malnutrished Toxic Vascular Inflammatory Genetic
21
Q
Most cases of GBS ___
A
Self-resolve
22
Q
___ near motor nerve roots in GBS
A
Macrophages
23
Q
Treatment for GBS
A
Ventilation
IV ABs
24
Q
Chronic inflammatory demyelinating polyneuropathy (CIDP)
A
Chronic version of GBS
Sensorimotor abnormalities at least 2 months
25
Schwann cells resembling onion bulbs observed in
CIDP
26
Age and sex MC for CIDP
Males 2X
| 40-60 yo
27
Microangiopathy drives
Diabetes problems
28
In diabetes, ROS damages
Vasa nervorum
29
Nerve injury in diabetes begins with
Decrease sensation
30
Treatment for diabetic peripheral neuropathy
Glucose control
Daily inspection
Analgesics
Anticonvulsants
31
Diabetic peripheral neuropathy injures both
Myelin and axons
32
Microangiopathy in diabetes peripheral neuropathy damages PNS neurons especially in the
Retina
| Kidney
33
Neuropathic arthropathy involves progressive degeneration of
Weight bearing joints
Foot, ankle, hip
TM and MP joints
34
Neuropathic arthropathy can be a complication of any neuropathy, particularly
DM
Spinal cord injury
Syphilis
Leprosy
35
Neuropathic arthropathy causes decrease sensation, cause
Unperceived trauma
36
Environmental exposure that damages peripheral nerves affects
Longest neurons
37
Mononeuritis multiplex
Neuronal damage from vasculitis
38
Charcot-Marie-Tooth disease
Inherited conditions of axonal or demyelinating neuropathy
39
CMT disease due to
PMP22 mutation
40
Variable severity is observed in CMT disease, common symptoms are
Pes cavus
| Altered gait
41
Myasthenia gravis
Autoimmune attack on post-synaptic ACH receptors
42
Extraocular weakness, including ptosis and diplopia, seen in
Myasthenia gravis
43
60% cases myasthenia gravis due to ____ and 20% due to ____
Thymus hyperplasia
| Thymoma
44
Age and sex for myasthenia gravis
Females MC : 20-30
| Males: 50-70
45
Tensilon test inhibits ___ and is used in ___
Antibodies
Myasthenia gravis
46
Lambert-Eaton Syndrome (LES)
Autoantibodies against pre-synaptic Ca2+ channels
47
Symptoms worsening throughout the day is characteristic of
Myasthenia gravis
48
LES inhibits ___, causing girdle weakness
ACH release
49
LES improves with
E-stimulation
50
Elderly autoimmune attack
LES
51
Paraneoplastic syndrome can cause
LES
52
Tetanus
Clostridium tetani increases ACH release
Spasm
53
Botulism
Clostridium botulinum inhibits ACH release
Descending paralysis
54
Floppy infant syndrome due to botulism can be due to
Soil or honey
55
Infant botulism effects ages
6 weeks - 6 mo
56
Myopathy
Primary disease of muscle
57
Type 1 myofiber type
Slow twitch
Aerobic
Fat
58
Type 2 myofiber type
Fast twitch
Anaerobic
Glycogen
59
Disuse atrophy affects
Type 2
60
Glucocorticoid atrophy affects
Type 2
61
Cushing syndrome
Elevated cortisol
62
Myasthenia
Painless muscle weakness
63
Neuropathic changes cause
Grouped atrophy
64
Cushing syndrome can be due to
External corticosteroids (MC)
Adenoma (pituitary or adrenal)
65
Features of Cushing syndrome
```
Weight gain
Moon facies
Purple striae
Buffalo hump
Insomnia
Infertility
Hirsutism
```
66
Cushing syndrome MC in
Young adult females
67
Inherited skeletal muscle disorders include
Muscular dystrophy
68
2 types of muscle dystrophy
1. Duchesse muscular dystrophy
| 2. Becker muscular dystrophy
69
Inheritance of dystrophinopathies
X- linked (xp21)
70
In muscular dystrophy, ____ outpaces repair due to mutated dystrophin
Myocyte degeneration
71
Duchenne MD
Absent dystrophin
1 in 3500 males
Childhood weakness
Fatal
72
Becker MD
Abnormal dystrophin (variable)
1 in 30000 males
May have normal life
73
___ always lethal
Duchenne MD
74
Features of dystrophinopathies
```
Clumsiness
Weakness
Fatigue
Pelvic girdle weakness -> gower sign
Pseudohypertrophy of calves
Cardiorespiratory insufficiency
```
75
In labs, high ___ observed in dystrophinopathies
Creatine kinase
76
Gower sign MC associated with
Duchenne MD
77
Graves’ disease
Autoimmunity against TSH receptor
78
Graves’ disease MC in
Females
79
Graves’ disease causes hyperthyroidism, resulting in
Elevated T3 and T4
80
Signs of Graves’ disease
```
Goiter
Exophthalmos
Pretibial myxedema
Insomnia
Weight loss
Fatigue
Irregular HB
```
81
Pseudohypertrophy of calf muscles in DMD due to
Fibrofatty inflitrate
82
Muscular dystrophies are lethal due to
Cardiorespiratory insufficiency
83
Thyrotoxic myopathy
Overproduction of thyroxine
84
Ethanol myopathy
Binge drinking
85
Graves can cause
Thyrotoxine myopathy
86
MC drug myopathy
Statins myopathy
87
Drug myopathy is usually w/o
Inflammation
88
Types of toxic myopathies
Thyrotoxic
Ethanol
Drug
89
Ethanol myopathy can progress to
Acute renal failure
90
Schwannoma
Benign peripheral nerve sheath tumor
91
Most schwannomas are
Sporadic and involve CN 8
92
Schwannomatosis
Multiple CNS and cutaneous schwannomas
93
Schwannoma aka
Acoustic neuroma
94
Schwannoma can cause
Tinnitus
Vertigo
Headache
Hearing loss
95
Neurofibromas
Benign nerve sheath tumors
96
Neurofibromatosis type 1 (NF1)
Pronounced neurofibromas
| Vascular stenosis
97
NF1 due to
Mutation in chromosome 17 (autosomal dominant)
98
Freq of NF1
1 in 3,000
99
NF1 can have 3 distinct characteristics
Lisch nodules
Axillary freckling
Cafe au lait spots
100
NF2 due to
Mutated Merlin gene
101
NF2 results in
Bilateral vestibular schwannomas
102
NF2 results in risk for CNS tumors, including
Ependymomas
Meningiomas
103
Freq of NF2
1 in 50,000
104
Malignant peripheral Nerve sheath tumor (MPNST)
Malignant Schwann tumor mixed with neuronal connective tissue
105
MPNST associated with
NF1
106
MPNST is large in infiltrative, affecting
Arms
| Legs
107
MPNST is
Painless and edematous
108
Traumatic neuroma
Non-neoplastic growth of nerve tissue, following trauma to nerve
109
Traumatic neuroma MC due to
Surgery
110
NF2 has no
Cutaneous lesions
111
Traumatic neuroma is painful and
Non-invasive
