Noninflammatory Muscle Disorders (Bertorini)

Question 1

type to neuropathy that causes sensory or autonomic problems.

Answer 1

peripheral

Question 2

Gower’s sign

Answer 2

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

Question 3

In what type of neuropathy will pts have sensory deficits

Answer 3

peripheral neuropathy

Question 4

1. have proximal muscle atrophy and weakness

2. have distal muscle atrophy and weakenss

Answer 4

myopathy

Peripheral neuopathy

Question 5

winging of the scapula

Answer 5

myopathy

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

Question 6

Some neuropathies affect individual nerves and these are called_________

Answer 6

mononeuropathies

Question 7

In what type of neuropathy is muscle fatigue a hallmark

Answer 7

disease of neuromuscular transmission

Question 8

involves fasciculations

Answer 8

motor neuron disease

sometimes in peripheral neuropathy/polyneuropathy

Question 9

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

Answer 9

disease of neuromuscular transmission

i.e. myasthenia gravis

Question 10

Decreased or absent muscle stretch reflexes

Answer 10

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

*in late stage myopathy, these are gone/decreased

Question 11

proximal muscle weakness

Answer 11

disease of neuromuscular transmission

myopathy

Question 12

weakness fluctuates

Answer 12

disease of neuromuscular transmission

Question 13

sensory loss

Answer 13

peripheral neuropathy/polyneuropathy

Question 14

distal muscle weakness

Answer 14

peripheral neuropathy/polyneuropathy

Question 15

increased muscle stretch reflex

Answer 15

ALS (motor neuron dz)

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

Question 16

often involves extraocular muscles

Answer 16

disease of neuromuscular transmission

Question 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 …

Answer 17

motor unit action potentials (MUAPs)

Question 18

describe normal muscle fiber type distribution

Answer 18

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

Question 19

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

Answer 19

nonspecific esterase

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

Question 20

atrophic and angular fibers

Answer 20

periph neuropathy

motor neuron dz

Question 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 …

Answer 21

fiber type grouping

Question 22

fiber type grouping results in what changes on an EMG

Answer 22

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

Question 23

lost checkerbaord pattern is the result of

Answer 23

sprouting (fiber type grouping)

Question 24

Larger Motor Unit Action Potentials on EMG

Answer 24

motor neuron dz

periph neuron dz

Question 25

elevated CK or CPK

Answer 25

myopathy *necrotic muscle fibers leak some of the sarcoplasmic components

Question 26

asynchronous depolarization of individual fibers of the motor unit causes ______ AP on EMG What neuromuscular dz type causes it?

Answer 26

polyphasic myopathy

Question 27

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

Answer 27

normal

Question 28

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

Answer 28

smaller AP Larger AP

Question 29

How is the motor unit potential altered in myopathes

Answer 29

small in size and short in duration MUP = summation of AP for each fiber in a motor unit

Question 30

pale muscle fibers in picture micrograph

Answer 30

= necrotic fiber = myopathy

Question 31

slow conduction velocitys or low AP amplitude

Answer 31

peripheral neuropathy

Question 32

smaller AP and normal # AP Why?

Answer 32

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

Question 33

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

Answer 33

demyelinating neuopathy

Question 34

normal conduction studies/velocity

Answer 34

everything but peripheral neuropathy

Question 35

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

Answer 35

myopathy

Question 36

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

Answer 36

distal latency

Question 37

How is a nerve conduction velocity measured?

Answer 37

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

Question 38

larger AP and decreased number AP

Answer 38

motor neuron dz | peripheral neuopathy

Question 39

normal number and amplitude of AP

Answer 39

neuromuscular transmission defect

Question 40

result of repetitive nerve stimulation test in neuromuscular transmission defect

Answer 40

progressive decrease in amplitude

Question 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) ```

Answer 41

myopathy

Question 42

floppy infants at birth

Answer 42

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

Question 43

hereditary and progressive myopathies

Answer 43

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

Question 44

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

Answer 44

myotonic dystrophies

Question 45

characterized by the presence of progressive weakness and atrophy

Answer 45

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

Question 46

progressive weakness in the shoulder and hip muscles

Answer 46

various Limb-girdle muscular dystrophies

Question 47

mutation causes lack of dystrophin

Answer 47

Duchenne's Muscular Dystrophy FRAMESHIFT MUTATION

Question 48

Duchenne's Muscular Dystrophy mode of inheritence

Answer 48

X linked

Question 49

presentation of Duchenne's Muscular Dystrophy

Answer 49

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

Question 50

muscle changes in Duchenne's Muscular Dystrophy

Answer 50

atrophy and necrosis segmental fiber over contraction connective tissue prolieration

Question 51

pathophys of Duchenne's Muscular Dystrophy

Answer 51

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

Question 52

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

Answer 52

exon skipping

Question 53

milder form of duchenne's muscular dystophy

Answer 53

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

Question 54

mode of inheritance of myotonic dystrophy

Answer 54

AD

Question 55

genetic defect assc with myotonic dystrophy

Answer 55

inc CGT repeated on chrom 19 (encodes a kinase)

Question 56

genetic defect in proximal myotonic dystrophy

Answer 56

chrom 3

Question 57

Mental retardation in newborns of myotonic mothers is called

Answer 57

congenital myotonic dystrophy due to anticipation

Question 58

more severe phenotypes in younger generations

Answer 58

anticipation | =myotonic dystrophy

Question 59

aquired myopathies are due to

Answer 59

autoimmune disease or infections | =Inflammatory myopathy

Question 60

what autoimmune diseases have been known to cause inflammatory myopathy

Answer 60

polymyositis, dermatomyositis, inclusion body myositis, sarcoidosis

Question 61

trichinosis

Answer 61

infectious agent known to cause inflammatory myopathy

Question 62

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

Answer 62

myotonic dystrophy

Question 63

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

Answer 63

Duchenne's Muscular Dystrophy

Question 64

exercise intolerance with muscle pain and weakness myoglobinuria rhabdo

Answer 64

metabolic myopathy

Question 65

pathophys of metabolic myopathy

Answer 65

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

Question 66

deficiency in muscle phosphorylase causes...

Answer 66

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

Question 67

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

Answer 67

endocrine myopathies

Question 68

present with severe proximal weakness resembling amyotrophic lateral sclerosis

Answer 68

hyperparathroidism

Question 69

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

Answer 69

Hypothyroidism

Question 70

glycogen accumulation

Answer 70

Mc Ardie's Dz

Question 71

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

Answer 71

toxic myopathy

Question 72

causes of toxic myopathies

Answer 72

``` cholesterol lowering drugs Herbicides anesthetics narcotics GCS ethanol ``` CHANGE your shit if you get toxic myopathy

Question 73

compound action potential becomes larger during fast stimulation rates

Answer 73

presynaptic disorders of neuromuscular transmission

Question 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.

Answer 74

myasthenia gravis

Question 75

etiology of myasthenia gravis

Answer 75

abs that bind and destroy Ach receptorts

Question 76

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

Answer 76

Edrophonium or Tensilon

Question 77

Tx for myasthenia gravis

Answer 77

``` Anticholinesterase immunosuppressants to dec Abs Plasma Exchange thymectomy corticosteriods ``` CAP IT

Question 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 ```

Answer 78

eaton lambert syndrome

Question 79

etiology of Eaton Lambert syndrome

Answer 79

Abs against pre-synaptic voltage gated Ca channels --> impairs release of Ach = affects both NICOTINIC and MUSCARINIC activity

Question 80

Therapy for eaton lambert syndrome

Answer 80

AchE inhibitors immunosuppressives phasmaphoresis corticosteropds

Question 81

muscle fiber vacuolization

Answer 81

toxic myopathy

Question 82

fluctuating muscle weakness that worsens with muscle activity

Answer 82

myasthenia gravis

Question 83

Transient improvement in muscle power following exercise

Answer 83

eaton lambert syndrome

Question 84

muscle pain during exercise

Answer 84

Mc Ardie's Dz

Question 85

+/- lung tumor

Answer 85

eaton lambert syndrome

Question 86

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

Answer 86

metabolic myopathies | Mc Ardies is an example

Question 87

muscle spasms not weakness

Answer 87

hypothyroidism

Question 88

dry mouth

Answer 88

eaton lambert syndrome

Question 89

difficulty relxing

Answer 89

myotonic dystrophy