Noninflammatory Muscle Disorders (Bertorini) Flashcards Preview

MS/Rheum > Noninflammatory Muscle Disorders (Bertorini) > Flashcards

Flashcards in Noninflammatory Muscle Disorders (Bertorini) Deck (89):
1

type to neuropathy that causes sensory or autonomic problems.

peripheral

2

Gower’s sign

Myopathy

the patient needs to use his hands to raise from the floor and then ”climb over his legs” in figures to achieve the standing position

3

In what type of neuropathy will pts have sensory deficits

peripheral neuropathy

4

1. have proximal muscle atrophy and weakness

2. have distal muscle atrophy and weakenss

myopathy

Peripheral neuopathy

5

winging of the scapula

myopathy

*occurs because the weak muscles cannot fix the scapula to the rib cage.

6

Some neuropathies affect individual nerves and these are called_________

mononeuropathies

7

In what type of neuropathy is muscle fatigue a hallmark

disease of neuromuscular transmission

8

involves fasciculations

motor neuron disease
(sometimes in peripheral neuropathy/polyneuropathy)

9

development of droopy eyelids or ptosis (arrows) after sustained upward gaze

disease of neuromuscular transmission
i.e. myasthenia gravis

10

Decreased or absent muscle stretch reflexes

peripheral neuropathy/polyneuropathy
motor neuron dz (most, but not all)

*in late stage myopathy, these are gone/decreased

11

proximal muscle weakness

disease of neuromuscular transmission
myopathy

12

weakness fluctuates

disease of neuromuscular transmission

13

sensory loss

peripheral neuropathy/polyneuropathy

14

distal muscle weakness

peripheral neuropathy/polyneuropathy

15

increased muscle stretch reflex

ALS (motor neuron dz)
*** this is an exception, most motor neuron dz has decreased muscle stretch reflexe

16

often involves extraocular muscles

disease of neuromuscular transmission

17

When the motor neuron depolarizes, it causes the muscle fibers of that motor unit to also depolarize and their individual action potentials summate (A+B+C+D) forming the potentials that are called ...

motor unit action potentials (MUAPs)

18

describe normal muscle fiber type distribution

motor neurons innervate either type I or type II muscle fibers (only fibers of one type are innervated by each motor neuron) they are intermixed with fibers from other motor neurons in an almost “checkerboard” pattern

19

atrophic fibers stain dark with many stain, but in particular _____ stain

nonspecific esterase

Trauma --> periph neuropathy/motot neuron dz --> atrophy/weakness and stains with NON-SPECIFIC ESTERASE

20

atrophic and angular fibers

periph neuropathy
motor neuron dz

21

Sprouting of axons from the other intact neurons take over and reinnervate previously denervated fibers, thus more fibers of single neurons remain, forming groups of both fiber types seen histologically. This is called ...

fiber type grouping

22

fiber type grouping results in what changes on an EMG

1. larger AP
(bc more fibers are innervated by a single neuron

2. decreased # of AP
(bc there are fewer motor neurons)

Recall, fiber type grouping occurs after neuronal or axon damage --> sprouting of axons to reinnervate

23

lost checkerbaord pattern is the result of

sprouting (fiber type grouping)

24

Larger Motor Unit Action Potentials on EMG

motor neuron dz
periph neuron dz

25

elevated CK or CPK

myopathy

*necrotic muscle fibers leak some of the sarcoplasmic components

26

asynchronous depolarization of individual fibers of the motor unit causes ______ AP on EMG

What neuromuscular dz type causes it?

polyphasic

myopathy

27

when the muscle contraction is very weak, there is a (normal or decreased) number of motor unit action potentials

normal

28

fewer fibers innervated by a motor neuron registers on EMG as ....

more fibers innvervated by a motor neuron registers on EMG as...

smaller AP

Larger AP

29

How is the motor unit potential altered in myopathes

small in size and short in duration

MUP = summation of AP for each fiber in a motor unit

30

pale muscle fibers in picture micrograph

= necrotic fiber = myopathy

31

slow conduction velocitys or low AP amplitude

peripheral neuropathy

32

smaller AP and normal # AP

Why?

myopathy

smaller AP bc muscle fibers dysfunction
normal # AP bc neurons/axons in tact

33

very slow prolonged latency and small compound muscle action potential in a...

demyelinating neuopathy

34

normal conduction studies/velocity

everything but peripheral neuropathy

35

increased number of motor unit action potentials as compared to the strength of contraction

myopathy

36

The time that it takes for the action potential to travel from the stimulus to response sight is the ...

distal latency

37

How is a nerve conduction velocity measured?

determine distal latency and proximal latency for an stretch of a nerve and divide

distance between 2 paints/latency diff btween the 2 points = conduction velocity

38

larger AP and decreased number AP

motor neuron dz
peripheral neuopathy

39

normal number and amplitude of AP

neuromuscular transmission defect

40

result of repetitive nerve stimulation test in neuromuscular transmission defect

progressive decrease in amplitude

41

Proximal weakness (often symmetrical)
Normal sensation
Normal reflexes
Elevated muscle enzyme in serum
Small (brief) motor unit potentials on EMG, with normal or “increased” recruitment on maximal effort
Polyphasic
Normal number APs, just weakened
Abnormal muscle biopsy (i.e., inflammation, glycogen storage)

myopathy

42

floppy infants at birth

congenital myopathy

e.g.
central core disease, myotubular myopathy, “nemaline” or “rod” myopathy and congenital muscular dystrophy

43

hereditary and progressive myopathies

muscular dystrophies
myotonic dystrophies

Some are caused by abnormalities or deficiencies of the muscle membrane or nuclear proteins; e.g., Duchenne’s, Becker’s, limb girdle, fascioscapulohumeral
and oculopharyngeal dystrophies

44

characterized by the presence of progressive myotonia (= difficuty relaxing contracted muscle) and weakness

myotonic dystrophies

45

characterized by the presence of progressive weakness and atrophy

muscular dystrophies

Some are caused by abnormalities or deficiencies of the muscle membrane or nuclear proteins; e.g., Duchenne’s, Becker’s, limb girdle, fascioscapulohumeral
and oculopharyngeal dystrophies

46

progressive weakness in the shoulder and hip muscles

various Limb-girdle muscular dystrophies

47

mutation causes lack of dystrophin

Duchenne's Muscular Dystrophy

FRAMESHIFT MUTATION

48

Duchenne's Muscular Dystrophy mode of inheritence

X linked

49

presentation of Duchenne's Muscular Dystrophy

MALE
progressive muscle weakness
elevated serum CK
abnormal heart
psedohypertrophy
low IQ

50

muscle changes in Duchenne's Muscular Dystrophy

atrophy and necrosis
segmental fiber over contraction
connective tissue prolieration

51

pathophys of Duchenne's Muscular Dystrophy

Frameshift mutation --> lack of dystrophin in SR membrane leads to excessive intracell Ca --> activation of neutral proteases (by Ca) --> digestion of structural proteins (troponin, Z-band, etc) --> muscle atrophy

52

restores the reading frame producing a message that although smaller, makes sense = functional protein = novel treatment for Duchenne’s MD

exon skipping

53

milder form of duchenne's muscular dystophy

becker's muscular dystrophy (not a complete absence of dysrophi, just reduced levels)

54

mode of inheritance of myotonic dystrophy

AD

55

genetic defect assc with myotonic dystrophy

inc CGT repeated on chrom 19 (encodes a kinase)

56

genetic defect in proximal myotonic dystrophy

chrom 3

57

Mental retardation in newborns of myotonic mothers is called

congenital myotonic dystrophy

due to anticipation

58

more severe phenotypes in younger generations

anticipation
=myotonic dystrophy

59

aquired myopathies are due to

autoimmune disease or infections
=Inflammatory myopathy

60

what autoimmune diseases have been known to cause inflammatory myopathy

polymyositis, dermatomyositis, inclusion body myositis, sarcoidosis

61

trichinosis

infectious agent known to cause inflammatory myopathy

62

Cataracts
Balding
Diabetes
Central sleep apnea
Megaesophagus; megacolon
Heart conduction defects
Percussion and grip myotonia
Facial, neck, and distal weakness

myotonic dystrophy

63

elevated serum CK
abnormal heart
psedohypertrophy
low IQ
winging of the scapulae
lordosis
large calf muscles

Duchenne's Muscular Dystrophy

64

exercise intolerance with muscle pain and weakness
myoglobinuria
rhabdo

metabolic myopathy

65

pathophys of metabolic myopathy

disorders of glycogen or lipid metabolim (or ETC) deprives muscle cells of energy needed for contraction and relaxation --> cannot maintain their membrane integrity

66

deficiency in muscle phosphorylase causes...

Mc Ardie's Dz
--> glycogen cannot bread down (it accumulates) therefore, ATP cannot be made during exercise

67

cause proximal muscle weakness and their muscle biopsies show non-specific findings and only selective type II muscle fiber atrophy

endocrine myopathies

68

present with severe proximal weakness resembling amyotrophic lateral sclerosis

hyperparathroidism

69

obese pt present with muscle spasms, very high serum creatine kinase levels, and hyperlipidemia

Hypothyroidism

70

glycogen accumulation

Mc Ardie's Dz

71

muscle fiber atrophy,vacuolization ,myofibrillary degeneration ,-mitochondrial dysfunction , or fiber necrosis.

toxic myopathy

72

causes of toxic myopathies

cholesterol lowering drugs
Herbicides
anesthetics
narcotics
GCS
ethanol

CHANGE your shit if you get toxic myopathy

73

compound action potential becomes larger during fast stimulation rates

presynaptic disorders of neuromuscular transmission

74

fluctuating muscle weakness that worsens with muscle activity and at the end of the day patients typically are weaker than in the morning. Patients frequently have droopy eyelids (ptosis) which increases with sustained upward gaze. They may also have double vision and proximal limb weakness and may develop difficulty swallowing and breathing.

myasthenia gravis

75

etiology of myasthenia gravis

abs that bind and destroy Ach receptorts

76

a short acting anticholinesterase drug that produce a rapid improvement of the myasthenic weakness

Edrophonium or Tensilon

77

Tx for myasthenia gravis

Anticholinesterase
immunosuppressants to dec Abs
Plasma Exchange
thymectomy
corticosteriods

CAP IT

78

decreased salivation
decreased reflexes
Transient improvement in muscle power following exercise
proximal limb weakness
fatigue
difficulty rising from sitting position
dec ability to walk or climb stairs

eaton lambert syndrome

79

etiology of Eaton Lambert syndrome

Abs against pre-synaptic voltage gated Ca channels --> impairs release of Ach

= affects both NICOTINIC and MUSCARINIC activity

80

Therapy for eaton lambert syndrome

AchE inhibitors
immunosuppressives
phasmaphoresis
corticosteropds

81

muscle fiber vacuolization

toxic myopathy

82

fluctuating muscle weakness that worsens with muscle activity

myasthenia gravis

83

Transient improvement in muscle power following exercise

eaton lambert syndrome

84

muscle pain during exercise

Mc Ardie's Dz

85

+/- lung tumor

eaton lambert syndrome

86

Weakness, MUSCLE PAIN, MUSCLE BREAKDOWN (RHABDO), MYOGLOBINURIA with exercise

metabolic myopathies
Mc Ardies is an example

87

muscle spasms not weakness

hypothyroidism

88

dry mouth

eaton lambert syndrome

89

difficulty relxing

myotonic dystrophy