Brainscape's Knowledge GenomeTM


Top Flashcards (Certified)
All Flashcards

Joe's Test Class > Ch 5 - EDX: Myopathies > Flashcards

Ch 5 - EDX: Myopathies Flashcards

1
Q

What is dystrophin?

A

Protein found in the sacrolemma of normal muscle that provides mechanical support and structural integrity for the muscle membrane cytoskeleton

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

What does mutation of dystrophin lead to?

A

Muscle fiber necrosis. Patients present with clinical symptoms of myalgias, fatigue, and weakness.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

What is myotonia?

A

Painless delayed relaxation of skeletal muscles following a voluntary contraction

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

What can exacerbate myotonia?

A

Cold
Dilantin
Procainamide
Calcium channel blockers

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

What is Arthrogryposis?

A

Fixed deformity of the extremities due to intrauterine hypomobility, myopathy, muscular dystophy or oligohydraminos

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

What is seen on NCS in myopathy?

A

SNAP: Normal
CMAP: Dec amp with significant muscle fiber atrophy. Normal latencies and conduction velocities

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

What is seen on EMG in myopathy?

A

Low amp
Short duration
Polyphasic MUAP with early recruitment
Resting activity depends on d/o

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

What is Quantitative EMG used for?

A

Detailed measurement of MUAPs and waveform duration using 20 MUAPs on screen set with a trigger and delay line

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

What causes short duration small amplitude (SDSA) MUAPs on EMG?

A

Classic polyphasic potentials are due to loss of muscle fibers

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

What causes long duration large amplitude (LDLA) MUAPs on EMG?

A

Polyphasic potentials are due to collateral sprouting

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

What causes long duration unstable MUAPs on EMG?

A

These variable amplitude potentials are due to blocking of immature NMJs, which are formed at the beginning of collateral sprouting

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

What can be demonstrated on single fiber EMG in myopathy?

A

Increased jitter, FD, and blocking

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

Which disorders have type I fiber atrophy on muscle biopsy?

A
  • Myotonic dystrophy
  • Nemaline rod myopathy
  • Fiber type disproportion
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

Which disorders have type II fiber atrophy on muscle biopsy?

A
  • Steroid myopathy
  • Myasthenia gravis
  • Deconditioning
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

What is the inheritance pattern of Duchenne Muscular Dystrophy?

A

X-linked recessive (xp21), spontaneous

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

What is the onset of Duchenne Muscular Dystrophy?

A

3 to 5 years old

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

What is the course of Duchenne Muscular Dystrophy?

A

Severely progressive (death by 20s)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

What is the clinical presentation of Duchenne Muscular Dystrophy?

A 
Proximal muscle weakness
Inc lumbar lordosis
Scoliosis
Calf pseudohypertrophy
Possible MR
Toe walking <5 years
Clumsy running <7 years
WC by 12 yo
Contractures: ITB first, Achilles tendon
Gower's sign
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

What is seen on muscle biopsy in Duchenne Muscular Dystrophy?

A

No dystrophin

Internal nuclei variation in fiber size

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

What are seen on labs in Duchenne Muscular Dystrophy?

A

Increased CPK and aldolase

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

When should surgery be done for scoliosis in Duchenne Muscular Dystrophy?

A

Before the vital

capacity is below 35% (usually due to a curve of >30°).

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

What is the inheritance pattern of Beck Muscular Dystrophy?

A

X-linked recessive

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

What is the onset of Becker Muscular Dystrophy?

A

Adulthood

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

What is the course of Becker Muscular Dystrophy?

A

Slowly progressive

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
What is the clinical presentation of Becker Muscular Dystrophy?
* Proximal weakness * Calf pseudohypertrophy * Cardiomyopathy * Less mental retardation than DMD
26
What is seen on muscle biopsy of Becker Muscular Dystrophy?
Decreased dystrophin | 15% to 85%
27
What is seen in labwork in Becker Muscular Dystrophy?
Increased CPK
28
What is the inheritance pattern of Myotonic dystrophy?
Autosomal dominant
29
What is the onset of Myotonic dystrophy?
Infancy
30
What is the clinical presentation of Myotonic dystrophy?
``` Distal > proximal myotonia with sustained grip Hatchet face Frontal balding Poor vision/Ptosis Hypertrichosis Impotence MR Cardiac/Endocrine ABN ```
31
Describe the appearance of hatchet face.
Wasting of the temporalis and | masseter
32
What are clinical features specific to Congenital myotonic dystrophy?
“Shark mouth” appearance Facial diplegia Possible club foot
33
What is seen on muscle biopsy in Myotonic Dystrophy?
Type I fiber atrophy Type II hypertrophy No dystrophin involvement
34
What medications can be used in treatment of Myotonic Dystrophy?
Procainamide Dilantin Quinine (PDQ)
35
What is inheritance pattern and onset of Central Core Disease?
Autosomal dominant | Infancy
36
What is clinical presentation of Central Core Disease?
* Floppy infant/hypotonia * Proximal weakness * Congenital hip dislocation * Delayed milestones * Associated with malignant hyperthermia
37
What is seen on muscle biopsy in Central Core Disease?
Central cores in Type I fibers | Absent mitochondria
38
What is the inheritance pattern and onset of Nemaline Rod Myopathy?
Autosomal dominant/ Recessive | Infancy
39
What is clinical presentation of Nemaline Rod Myopathy?
* Floppy infant/hypotonia * Diffuse weakness * Facial involvement * Narrowed long face * High arched palate * Foot drop
40
What is the typical cause of death in Nemaline Rod Myopathy?
Respiratory failure
41
What is seen on muscle biopsy in Nemaline Rod Myopathy?
Rod-shaped bodies on Gomori trichrome stain
42
What is the inheritance pattern and onset of Centronuclear myotubular myopathy?
X-linked recessive | Infancy
43
What is the clinical presentation of Centronuclear myotubular myopathy?
``` Floppy infant/hypotonia • Ptosis • Extra ocular muscle involvement • Facial diplegia • Dysphagia • Respiratory insufficiency ```
44
What is seen on muscle biopsy in Centronuclear myotubular myopathy?
Central location of fiber nuclei, forming chains
45
What is the inheritance pattern and onset of Fiber Type Disproportion?
Variable inheritance | Infancy
46
What is the clinical presentation of Fiber Type Disproportion?
* Floppy infant/hypotonia * Hip contractures * Hip dislocations
47
What is seen on muscle biopsy in Fiber Type Disproportion?
Numerous small Type I and normal to large Type II fibers
48
What is the etiology of Polymyositis/ Dermatomyositis?
Autoimmune Connective tissue disorder Infection Cancer
49
What is the clinical presentation of both Polymyositis/ Dermatomyositis?
* Symmetrical proximal weakness: Hips followed by shoulders * Neck flexion weakness * Myalgias, dysphagia, dysphonia
50
What is the clinical presentation specific to Dermatomyositis?
Periorbital violet rash and edema Gottron’s sign: Red-purple patches over the knuckles, elbows, knees
51
What is seen in lab work of Polymyositis/ Dermatomyositis?
Increased CPK, ESR, aldolase, SGOT, SGPT, LDH
52
What is seen on muscle biopsy in Polymyositis/ Dermatomyositis?
Necrosis of the Type I and II fibers. Perifascicular atrophy
53
What is the inheritance pattern of Inclusion Body Myositis?
Unknown
54
What is the clinical presentation of Inclusion Body Myositis?
Asymmetric, slowly progressive, painless weakness in proximal and distal muscles
55
What is associated with Inclusion Body Myositis?
Polyneuropathy
56
What is the age distribution of Inclusion Body Myositis?
Adults 45 to 55 years and peaks at 70 years
57
What is seen in lab work of Inclusion Body Myositis?
Increase in CK muscle
58
What is seen on muscle biopsy in Inclusion Body Myositis?
Rimmed or cytoplasmic/ basophilic vacuoles Eosinophilic inclusion bodies
59
What is the inheritance pattern of McArdle disease (Type V metabolic myopathy)?
Autosomal recessive | Myophosphorylase deficiency
60
What is the onset of McArdle disease (Type V metabolic myopathy)?
<15 years of age
61
What is the clinical presentation of McArdle disease (Type V metabolic myopathy)?
* Exercise intolerance * Easy fatigability * Muscle stiffness * Cramping * Second-wind phenomenon
62
What can happen with exercise in McArdle disease (Type V metabolic myopathy)?
Strenuous exercise can precipitate myolysis (possibly cause renal failure and death)
63
What is the inheritance pattern of Pompe's disease (Type III metabolic myopathy)?
Autosomal recessive | Acid maltase deficiency
64
What is the onset of Pompe's disease (Type III metabolic myopathy)?
Infant to adult
65
What is the clinical presentation of Pompe's disease (Type III metabolic myopathy)?
* Hypotonia * Tongue enlargement * Cardiomegaly * Hepatomegaly * Respiratory insufficiency * Death by 2 years of age * A milder form may affect adults
66
What is the inheritance pattern of Hyperkalemic Periodic Paralysis?
Autosomal dominant | Multiple secondary causes
67
What is the onset of Hyperkalemic Periodic Paralysis?
Childhood–second decade
68
What is the clinical presentation of Hyperkalemic Periodic Paralysis?
* Proximal muscle weakness * Paresthesias of the lips and lower limbs * Myotonia * Attacks last 10 to 60 min * May be aborted with exercise * Exacerbated with cold exposure and rest following exercise
69
What is seen on labwork of Hyperkalemic Periodic Paralysis?
High K+ during the attack
70
What is the treatment of Hyperkalemic Periodic Paralysis?
High carbohydrate diet
71
What is the inheritance pattern of Hypokalemic Periodic Paralysis?
Autosomal dominant | Multiple secondary causes
72
What is the onset of Hypokalemic Periodic Paralysis?
Starts in early second decade
73
What is the clinical presentation of Hypokalemic Periodic Paralysis?
* Weakness starts in the legs and spreads proximally * Attacks last 12 to 24 hours * Myotonia seen in the eyelids * Exacerbated with rest after exercise, stress, and a high carbohydrate diet
74
What is seen on labwork of Hypokalemic Periodic Paralysis?
Low potassium | Muscle biopsy normal
75
What is the treatment of Hypokalemic Periodic Paralysis?
K+ supplement
76
What are different names for Myotonia Congenita?
Thomsen's disease | Little Hercules
77
What is the inheritance pattern and onset of Myotonia Congenita?
Autosomal dominant | Birth–adulthood
78
What is the clinical presentation of Myotonia Congenita?
* Severe spasms exacerbated by the cold * Improves with warmth and exercise * Muscle hypertrophy * Myotonia * No weakness
79
What are treatments for Myotonia Congenita?
Procainamide | Dilantin, quinine (PDQ)
80
What is the inheritance pattern and onset of Paramyotonia congenita (Eulenburg)?
Autosomal dominant | Birth–adulthood
81
What is the clinical presentation of Paramyotonia congenita (Eulenburg)?
* Stiffness * Weakness * Fatigue * Myotonia * Exacerbated with cold and exercise
82
What is the treatment of Paramyotonia congenita (Eulenburg)?
Warm extremities
83
What is the etiology of steroid myopathy?
Corticosteroid proteolysis effect
84
What is the clinical presentation of steroid myopathy?
* Proximal muscle weakness * Risk is increased if on 30 mg / day * Preferentially affects the hip girdle muscles
85
What is seen on muscle biopsy of steroid myopathy?
Type II atrophy
86
What is the clinical presentation of statin myopathy?
* Proximal weakness and pain * Worse with exercise * Lipophilic statins are more likely to produce muscular effects, than are relatively hydrophilic agents
87
What are lipophilic statins?
Simvastatin Atorvastatin Lovastatin
88
What are hydrophilic statins?
Pravastatin Rosuvastatin Fluvastatin
89
What are treatments of statin myopathy?
Stop statins, or stop medications that | interfere with Cy-P450: macrolide antibiotics, verapamil, diltiazem, cimetidine, etc.

Joe's Test Class (91 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2025 Bold Learning Solutions. Terms and Conditions