Neuromuscular Flashcards
0
Q
myopathy
A
condition that is damaging muscles
1
Q
neuropathy
A
condition that is damaging nerves
2
Q
neuromuscular junction (myoneural) disease
A
condition that is damaging the neuromuscular junction at the motor end-plate on muscles
3
Q
dying back
A
refers to a process in which the longest nerve fibers are injured and die
4
Q
demyelinative
A
refers to a process that damages the myelin sheath
5
Q
wallerian degeneration
A
happens to an axon after it has been cut off from its cell body
distal end of the cut axon degenerates
6
Q
epineurium
A
refers to connective tissue wrapping the nerve
7
Q
perineurium
A
refers to CT wrapping the fasicules within the nerve
8
Q
endoneurium
A
connective tissue wrapping each individual axon within the nerve
9
Q
myelin
A
wrapping of cell membranes around an axon that speeds up conduction
10
Q
entrapment neuropathy
A
condition where nerve is caught between tougher tissues, contributing to chronic irritation and damage
11
Q
carpal tunnel
A
nerve entrapment of the wrist is the most common site (median nerve)
12
Q
schwann cells
A
cells that make myelin in the peripheral nervous system
13
Q
meralgia paresthetica
A
entrapment of the lateral femoral cutaneous nerve at the level of the inguinal ligament
14
Q
polyneuropathy
A
generalized damage to peripheral nerves; usually effect longest nerve first
15
Q
charcot marie tooth
A
family of hereditary neuropathies that usually begin to show clinical signs in late childhood and adolecence and progresses slowly
16
Q
lambert-eaton myasthenic syndrome
A
autoimmune (and often paraneoplastic) condition that produces weakness
17
Q
paraneoplastic syndrome
A
refers to remote effects of a tumor; most often it represents a condition in which antibodies directed at a tumor damage other tissues of the body
18
Q
myasthenia gravis
A
condition in which there is antibody-mediated destruction of acetylcholine receptors producing weakness and fatigability of muscle
19
Q
nerve conduction study
A
test of speed and amplitude of conduction of peripheral nerve fibers
20
Q
electromyography
A
needle study in which the electrical activity of muscle fibers is recorded; it can detect damage to muscles and is sensitive to muscle fibers that have been disconented from their nerves
21
Q
sensory receptors
A
transduction
elementary sensory deficit–ataxia, hypesthesia, paresthesia pain
22
Q
nerve fibers
A
conduction
sensory motor defects/weakness
23
Q
motor end-plants
A
neuromuscular transmission
simple motor defect- weakness, wasting, muscle twitching, cramps, myotonia
24
striated muscle fibers
contraction
| motor defect- weakness, wasting, occasionally pseudohypertrophy
25
cell bodies of sensory nerve fibers
DRG close to spinal cord
26
somatic motor nerve fibers originate frm
motor neurons in ventral horn of spinal cord
27
where do somatic motor nerve fibers termintae
muscle fibers at NMJ or on muscle spindles
28
why are autonomic nerve fibers unique
there are 2 neurons in sequence
29
where do autonomic motor nerve fibers terminate
glands, organs, smooth muscle fibers
30
fiber Aa
large (est) motor axons
muscle strestch and tension sensation
60-100 m/s
15 microns
31
Ab fibres
touch, pressure, vibration, jt position sensation
30-60 m/s
12-14 microns
32
Ay fibers
gama efferent motor axons
15-30 m/s
8-10 microns
33
Ad fibers
sharp pain, very light touch, temperature sensation
10-15 m/s
6-8 microns
34
B fibers
symp preganglionic motor axons
3-10 m/s
2-5 microns
35
C fibers
dull, aching, burning pain and temp sensation
| <1 micron
36
size of axon correlates positively with
speed
37
B and C fibers are not
myelinated
38
all proteins come from the
cell body
39
trophic factors
```
class of protein compounds that travel in nerve; critical to health of innervated tissues
-- loss of trophic factors; either the death of neurons or atrophy of peripheral tissues
```
40
motor unit
physiological unit of motor neuron and all the fibers it innervates
41
fasiculations
spontaneous discharge of indiviudal motor axons and contraction of the motor unit from irritation of axons; visible on skin surface as random, involuntary twitches
often normal because of temporary irriation of motor nerve fibers, but persistent fasciculations indicate DAMAGE TO ANTERIOR HORN CELLS OR AXONS
42
fibrillation
spontaneous contraction of individual muscles that is not visible from the skin surface; need electromyography to detect- fairly eliable sign of damage to motor nerver fiebers OR muscle disease
43
conditions that damage motor units usually result in
overall muscle weakness + high firing rates of individual motor units that are still intact
44
damage to upper motor neurons makes it impossible to
reach high firing rates of motor units during voluntary contraction
45
motor neuron disease
general term of conditions that result from degeneration of anterior horn cells (lower motor neurons) and upper motor neurons of the cerebral cortex that give rise to descending tracts taht control movement
46
upper motor neuron signs
spasticity
increased reflexes
upgoing toes
47
lower motor signs
atrophy
fasciculations
decreased reflexes
48
signs of both upper nad lower motor neuron disease
ALS
49
ALS mainly affects adults
40-60 years old
50
patho of ALS
degeneration of anterior horn cells in spinal cord, CN motor nuclei
51
what is spared in ALS
EYE MOVEMENTS
52
in ALS arms show___ while legs show____
LMN signs
| UMN signs
53
prognosis ALS
3-5 years
| death via weakness of resp musculature + infection
54
primary lateral sclorosis
signs only of UMN
55
progressive muscular atrophy
signs of only LMN-->over time normal ALS
56
if signs only of cranial musculature
progressive bulbar palsy
57
absence of this gave a certain family ALS
superoxide dismutase
58
Rilzule
slightly delays progression of disease by decreasing glutamate neurotransmission, decreases fast Na channel act
59
Werdnig-Hoffman disease
inheritied condition of infants; anterior horn cell degeneration only
60
Kugelberg-Welander
inherited condition of children and young adults; anterior horn cell only
61
general symptoms of peripheral neuropathy
positive- pain/synesthesia
negative- loss of sensation, weakness, reflexes
irritative- fasciculations/paresthesias
62
etiology of mononeuropathy
usually trauma- acute or chronic
63
most common mononeuropathies due to
entrapment of nerves at anatomically vulnerable sites
64
Tinel sign of mononeuropathy
nerve becomes very mechnically sensitive at site of injury that can be elicited by gentle tapping over the site of injury
65
where does ulnar nerve entrapment happen?
elbow
66
ulnar entrapment symptoms
weakness and atrophy of the intrinsic hand muscles common
| may be sensory loss over the small digits and the ulnar side of the hand on the palmar and dorsal side
67
Signs and symptoms of radial nerve entrapment
main part of radial nerve injured-->wrist drop; diminished sensation of hand
superficial branch-->sensory loss on dorsum of hand
deep branch-->weakened extensors of fingers
68
THoracic outlet syndrome
heterogenous group of disorders that involve some mechanical compression of structures in upper thorax
subclavian artery/axillary artery-->vascular TOS
lower brachial plexus-->neurogenic TOS
69
etiology of radiculopathy
younger indiv- interverebtral disc herniation
| older indiv- more often due to degen change sin disc, bone and joints (thickening of tissues, thinning of discs)
70
s/s radiculopathy
pain along distribution of nerve root
deeper, constant aching pain
weakness and reflex loss
71
radiculopathy should be considered when
symptoms follow a well-defined nerve root dist and whenever distal symptoms are coupled iwth pain int he bacj or neck
72
mononeuropathy multiplex
involvement of several isolated nerves
| DM polyneuropathy is most common, or any condition causing systemic vasculitis (SLE, polyarteritis, nodsa, lyme disease)
73
Neuralgic amyotrophy
aka idiopathic brachial neuralgia, parsonage-turner syndrome
idiopathic conditiosn affecting brachial plexus; need specialty eval if etiology is not clear
74
treatment diabetic poly neuropathy
control diabetes
| IVIG, steroids
75
polyneuropathy causes
DM
high alc--vit B12 def
excess pyridoxine
heavy metals, organic solvents, industrial exposures
chemo, aed, haart
SLE, sjorgen, wegner, polyarteritos (autoimmune)
chronic conditions- tertiary syphillis, lyme disease, hiv
leprosy
metabolic
abnormal blood proteins
76
which nerves affected first
longest
77
Guilliane Barrer syndrome
immune attack on myelin; may follow viral or diarrheal illness by 1-2 weeks
ascending weakness, rapid course
78
diagnosis GB
elevated protein in CSF, no white cells CSF
79
treatment
IVIG may shorten clinical course
80
chronic inflammatory demyelinating polyradiculoneuropathy
chronic immune-mediated neuropathy
asymmetric weakness and sensory loss
high protein CSF
relapsing.progress poly neuropathy
81
symptom of charcot marie tooth disease
high arches/curled toes
82
hereditary motor sensory neuropathy
clear pattern of inheritance
83
HMSN 1
demyelinative form
84
HMSN II
axonal form
85
end plate
each muscle has one and only one;a cts as a plug for a nerve terminal branch
Ach is the NT
86
minature end plate potentials
intermittent discharges at end-plate region of fairly constant amplitude and duration; not capable of triggering APs
87
Myasthenia Gravis highest incidence in
young adult women
| small spike in late middle aged men who have thymic tumors
88
pathophys of MG
antibodies against nAChRs of NMJ
thymic epithelial cells have surface proteins with epitopes that cros react with AChR at NMJ
decreases post syn AChRs-->decrease safety factor-->APs less likely to fire
89
signs of myasthenia gravis
ptosis/diplopia
problems speaking and swalloing
repetitve or sustained use of muscle**-->depeletion Ach-->ultimate failure of conductio
90
progressive generalized weakness in the
first two years
91
treatment of MG
```
thymectomy
corticosteroids
immunosuppressive drugs
human immunoglobulin
plasma exchange
```
92
Myasthenic syndrome/lambert eaton syndrome caused by
MAYBE a carcinoma (bronchogenic small-cell carcinoma)
93
pathophys MS/lambert eaton syndrome
nerve impulse-->defective Ca channel fx in presyn membrane-->reduced # quanta release from nerve
94
symptoms MS/Lambert eaton syndrome
weakness that tends to improve with exercise-->repetitive stimylation causes facilitation rather than the fatigue seen with MG
95
treatment Ms/LE
remove tumor
| 4-aminipyridine (acetylcholine releasing agents)
96
botulism
another well-known and fortunately rare disorder of transmitter release blockade
97
general s/s of myopathies
symmetrical, proximal muscle weakness
possible cramping of muscles (with exercise)
rarely symmetrical, aching discomfort in muscles
98
enzyme that proves thereis a muscle disease
CK levels
99
other tests
EMG
| muscle bx
100
muscular dystrophies
noninflammatory degenerative conditions of muscles that are genetically determined, not effectively curable, and progressive; classified according to inheritance and distribution of weakness
101
epi of duchenne muscular dystrophy
most common muscular dystrophy
| sex-linked; affects young boys
102
pathophys MD
mutation in gene for the protein named dystrophin
103
Becker dystrophy
less severe for of MD; later onset
104
prognosis MD
children usually confined to wheel chair by age 10
| usually die in second to third decade
105
limb girdle muscular dystrophy
heterogenous group of disorders that has proximal leg weakness that usually progresses slowly but may arrest spontaneously
usually appears in adolescence or aduly life with proximal limb weakness
106
Facioscapulohumeral muscular dystrophy
weakness and wasting; appears in adolecence or very eary life with weakness of face and muscles attached to scapula nad prox upper limb
107
prognosis facioscapulohumeral muscular dystrophy
weakness usually progresses slow, normal life expectancy, mental retardation
108
myotonic dystrophy
due to repeats in the sequence of myotonic protein kinase gene
repeats get longer in sequential generations, with earlier onset of symptoms
abnormality of membranes that is not restricted to muscle
109
s/s myotonic dystrophy
delayed relaxation of muscles comvined with muscle atrophy
childhood/young adult life
distal
facial and neck early
-->frontal balding, testicular atrophy, diabetes, cardia arrhythmias
110
prognosis myotonic dystrophy
progresses slowly
| many victims succumb to resp failure and superimposed infection
111
metabolic myopathies-acquired
hyper and hypothyroidism
| medications-statins, hydroxychloroquine, colchicine, etoh
112
genetic metabolic myopathies
difficulties metabolizing carbs or fat (intracellular inclusions)
poorly defined conditions with occasionally myoglorinuria
nemaline myopathy, myotubular myopathy
mitochondiral myopathies
113
mitochondrial myopathies
heterogenous group of muscle diseases associated with excessive replication of somewhat defective mito that accumulate in cells
-tend to affect muscle, cns, heart
114
acquired inflammatory myopathy
sarcoidosis
| certain infectious condtions (HIV/AIDS)
115
autoimmune inflammatory myopathy
polymyositis
dermatomyositis
inclusion body myositis
116
polymyositis
30-60 years old
insidious onset of symmetrical, proximal muscle weakness, accompanied by muscle soreness
difficulty climb stairs and lift things
117
dx polymyositis
elevated inflammatory markers (ESR, CRP)
elevated muscle damage enzymes (CPK)
bx diagnostic (these tests can be normal!)
118
dermatomyositis
children 5-15 then later in adulthood (50, 60s)
insidious weakness proximal muscles
red/purple rash--mostly over eyes (heliotrope) and extensor parts of joints (knuckles, elbows, knees, tows)--may also include face, chest, elsewhere
119
treatment dermato and poly
immunosuppression
120
inclusion body myositis
late middle aged and older individuals
slowly progressive symmetrical myopathy of proximal muscles (cant climb stairs, flexors of fingers and wrist)--very insidious
121
inclusion body myositis dx
elevated CK levels
sed rate elevated
muscle bx-cytoplasmic inclusions on muscle biopsy
122
tx inclusion body myositis
does not usually respond to immunosuppression (none)
123
2 functional defects with little wasting
myotonic disorders
| perioidc paralysis
124
myotonic disorders
congenital myotonia- Cl transport abnoramlity; symptoms improve with exercise
Paramyotonia- Na channelopathy; worsens with exercise and with cold
125
dx myotonic disorders
needle insertion into muscles-->usually easily identified myotonic potentials
126
perioic paralysis
thyrotoxic perioidc paralysis
familial perioid paralysis
-generalized/temporary weakness after meals or exercise
127
dx perioid paralysis
can be made by provoking weakness with glucose load and exercise
128
large peripheral nerve fibers
well localized touch
pressure
vibration
jt position sense
129
small fibers
pain
temperature
very light touch
autonomic
130
polyneuropathy
distal, symmetrical sensory loss
| ankle jerk reflexes effected eraly
131
myopathy
proximal
symmetrical
reflexes preserved until late
no sensory loss
132
lambert eaton
weakness of hip girdle muscles with decreased patellar reflexes
often with small cell cancer, but can be idiopathic
antibody against voltage-gated Ca channels
