Noninflammatory Muscle Disorders (Bertorini) Flashcards Preview

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

Flashcards in Noninflammatory Muscle Disorders (Bertorini) Deck (89)
Loading flashcards...
1
Q

type to neuropathy that causes sensory or autonomic problems.

A

peripheral

2
Q

Gower’s sign

A

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
Q

In what type of neuropathy will pts have sensory deficits

A

peripheral neuropathy

4
Q
  1. have proximal muscle atrophy and weakness

2. have distal muscle atrophy and weakenss

A

myopathy

Peripheral neuopathy

5
Q

winging of the scapula

A

myopathy

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

6
Q

Some neuropathies affect individual nerves and these are called_________

A

mononeuropathies

7
Q

In what type of neuropathy is muscle fatigue a hallmark

A

disease of neuromuscular transmission

8
Q

involves fasciculations

A

motor neuron disease

sometimes in peripheral neuropathy/polyneuropathy

9
Q

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

A

disease of neuromuscular transmission

i.e. myasthenia gravis

10
Q

Decreased or absent muscle stretch reflexes

A

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

*in late stage myopathy, these are gone/decreased

11
Q

proximal muscle weakness

A

disease of neuromuscular transmission

myopathy

12
Q

weakness fluctuates

A

disease of neuromuscular transmission

13
Q

sensory loss

A

peripheral neuropathy/polyneuropathy

14
Q

distal muscle weakness

A

peripheral neuropathy/polyneuropathy

15
Q

increased muscle stretch reflex

A

ALS (motor neuron dz)

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

16
Q

often involves extraocular muscles

A

disease of neuromuscular transmission

17
Q

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 …

A

motor unit action potentials (MUAPs)

18
Q

describe normal muscle fiber type distribution

A

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
Q

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

A

nonspecific esterase

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

20
Q

atrophic and angular fibers

A

periph neuropathy

motor neuron dz

21
Q

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 …

A

fiber type grouping

22
Q

fiber type grouping results in what changes on an EMG

A
  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
Q

lost checkerbaord pattern is the result of

A

sprouting (fiber type grouping)

24
Q

Larger Motor Unit Action Potentials on EMG

A

motor neuron dz

periph neuron dz

25
Q

elevated CK or CPK

A

myopathy

*necrotic muscle fibers leak some of the sarcoplasmic components

26
Q

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

What neuromuscular dz type causes it?

A

polyphasic

myopathy

27
Q

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

A

normal

28
Q

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

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

A

smaller AP

Larger AP

29
Q

How is the motor unit potential altered in myopathes

A

small in size and short in duration

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

30
Q

pale muscle fibers in picture micrograph

A

= necrotic fiber = myopathy

31
Q

slow conduction velocitys or low AP amplitude

A

peripheral neuropathy

32
Q

smaller AP and normal # AP

Why?

A

myopathy

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

33
Q

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

A

demyelinating neuopathy

34
Q

normal conduction studies/velocity

A

everything but peripheral neuropathy

35
Q

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

A

myopathy

36
Q

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

A

distal latency

37
Q

How is a nerve conduction velocity measured?

A

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
Q

larger AP and decreased number AP

A

motor neuron dz

peripheral neuopathy

39
Q

normal number and amplitude of AP

A

neuromuscular transmission defect

40
Q

result of repetitive nerve stimulation test in neuromuscular transmission defect

A

progressive decrease in amplitude

41
Q
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)
A

myopathy

42
Q

floppy infants at birth

A

congenital myopathy

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

43
Q

hereditary and progressive myopathies

A

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
Q

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

A

myotonic dystrophies

45
Q

characterized by the presence of progressive weakness and atrophy

A

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
Q

progressive weakness in the shoulder and hip muscles

A

various Limb-girdle muscular dystrophies

47
Q

mutation causes lack of dystrophin

A

Duchenne’s Muscular Dystrophy

FRAMESHIFT MUTATION

48
Q

Duchenne’s Muscular Dystrophy mode of inheritence

A

X linked

49
Q

presentation of Duchenne’s Muscular Dystrophy

A
MALE
progressive muscle weakness
elevated serum CK
abnormal heart
psedohypertrophy 
low IQ
50
Q

muscle changes in Duchenne’s Muscular Dystrophy

A

atrophy and necrosis
segmental fiber over contraction
connective tissue prolieration

51
Q

pathophys of Duchenne’s Muscular Dystrophy

A

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
Q

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

A

exon skipping

53
Q

milder form of duchenne’s muscular dystophy

A

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

54
Q

mode of inheritance of myotonic dystrophy

A

AD

55
Q

genetic defect assc with myotonic dystrophy

A

inc CGT repeated on chrom 19 (encodes a kinase)

56
Q

genetic defect in proximal myotonic dystrophy

A

chrom 3

57
Q

Mental retardation in newborns of myotonic mothers is called

A

congenital myotonic dystrophy

due to anticipation

58
Q

more severe phenotypes in younger generations

A

anticipation

=myotonic dystrophy

59
Q

aquired myopathies are due to

A

autoimmune disease or infections

=Inflammatory myopathy

60
Q

what autoimmune diseases have been known to cause inflammatory myopathy

A

polymyositis, dermatomyositis, inclusion body myositis, sarcoidosis

61
Q

trichinosis

A

infectious agent known to cause inflammatory myopathy

62
Q
Cataracts
Balding
Diabetes
Central sleep apnea
Megaesophagus; megacolon
Heart conduction defects
Percussion and grip myotonia
Facial, neck, and distal weakness
A

myotonic dystrophy

63
Q
elevated serum CK
abnormal heart
psedohypertrophy 
low IQ
winging of the scapulae
lordosis
large calf muscles
A

Duchenne’s Muscular Dystrophy

64
Q

exercise intolerance with muscle pain and weakness
myoglobinuria
rhabdo

A

metabolic myopathy

65
Q

pathophys of metabolic myopathy

A

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

66
Q

deficiency in muscle phosphorylase causes…

A

Mc Ardie’s Dz

–> glycogen cannot bread down (it accumulates) therefore, ATP cannot be made during exercise

67
Q

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

A

endocrine myopathies

68
Q

present with severe proximal weakness resembling amyotrophic lateral sclerosis

A

hyperparathroidism

69
Q

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

A

Hypothyroidism

70
Q

glycogen accumulation

A

Mc Ardie’s Dz

71
Q

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

A

toxic myopathy

72
Q

causes of toxic myopathies

A
cholesterol lowering drugs
Herbicides 
anesthetics
narcotics
GCS 
ethanol

CHANGE your shit if you get toxic myopathy

73
Q

compound action potential becomes larger during fast stimulation rates

A

presynaptic disorders of neuromuscular transmission

74
Q

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.

A

myasthenia gravis

75
Q

etiology of myasthenia gravis

A

abs that bind and destroy Ach receptorts

76
Q

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

A

Edrophonium or Tensilon

77
Q

Tx for myasthenia gravis

A
Anticholinesterase 
immunosuppressants to dec Abs
Plasma Exchange 
thymectomy 
corticosteriods 

CAP IT

78
Q
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
A

eaton lambert syndrome

79
Q

etiology of Eaton Lambert syndrome

A

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

= affects both NICOTINIC and MUSCARINIC activity

80
Q

Therapy for eaton lambert syndrome

A

AchE inhibitors
immunosuppressives
phasmaphoresis
corticosteropds

81
Q

muscle fiber vacuolization

A

toxic myopathy

82
Q

fluctuating muscle weakness that worsens with muscle activity

A

myasthenia gravis

83
Q

Transient improvement in muscle power following exercise

A

eaton lambert syndrome

84
Q

muscle pain during exercise

A

Mc Ardie’s Dz

85
Q

+/- lung tumor

A

eaton lambert syndrome

86
Q

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

A

metabolic myopathies

Mc Ardies is an example

87
Q

muscle spasms not weakness

A

hypothyroidism

88
Q

dry mouth

A

eaton lambert syndrome

89
Q

difficulty relxing

A

myotonic dystrophy