Myopathies Flashcards
1
Q
Neurologic Ddx of weakness
A
- UMN
- LMN
- NMJ
- muscle
2
Q
Three major groups of myopathies
A
1) muscular dystrophies
2) inflammatory myopathies
3) metabolic myopathies
3
Q
What are “dystrophic” features of muscles?
A
1) fiber splitting
2) increased CT
4
Q
Five major muscular dystrophies
A
1) Duchenne
2) Becker
3) FSH
4) Myotonic
5) Limb Girdle
5
Q
Two minor muscular dystrophies
A
1) Emery Dreifuss
2) Oculo-pharyngeal muscular dystrophy
6
Q
What are the inheritance patterns of the major muscular dystrophies?
A
Duchenne and Becker- XR
FSH and myotonic- AD
Limb Girdle- Can be AD vs AR on multiple chromosomes
7
Q
Duchenne/ Becker chromosome
A
21 deletion
8
Q
FSH assc chromosome?
Myotonic assc chromosome?
A
FSH- 4
Myotonic- 19
9
Q
When do the major muscular dystrophies onset?
A
Duchenne and Becker: early (5-10 years old)
Others: 10-30 years of age
10
Q
Where is primary weakness in Duchenne/ Beckers?
A
pelvic region first
11
Q
Where is primary weakness in Myotonic dystrophy?
A
-distal
12
Q
Which muscular dystrophies involve the face?
A
- FSH, myotonic
- Later in disease Duchenne, Becker
- None in limb girdle
13
Q
What EKG abnormality is seen in muscular dystrophies? Which major dystrophy is an exception?
A
Deep narrow Q waves in L precordial leads
except FSH which has normal EKG
14
Q
Which of the muscular dystrophies have elevated CK?
A
Duchenne, Becker, Limb Girdle
Normal in FSH, myotonic
15
Q
Duchenne:
- biopsy appearance
- specific gene involved
A
- macs invade necrotic muscle fibers, missing dystrophin on stain
- dystrophin out of frame mutation
16
Q
Contrast Duchenne mutation w/ Beckers
A
Duchenne: out of frame mutation
Beckers: in frame mutation
17
Q
Classic symptomatic features of DMD:
A
- waddling gait
- lumbar lordosis
- calf pseudohypertrophy
18
Q
Life threatening complications of DMD (2)
+ life expectancy
A
- cardiomyopathy
- intestinal pseudo-obstruction
(death by cardiorespiratory failure around age 20)
19
Q
Treatment for DMD
A
No cure, can prolong course with steroids if started at 4-7 years of age.
(stabilizes sarcolemma, increases muscle mass)
20
Q
Female DMD carrier symptoms
A
mild compared to diseased males
- risk CVD, weakness, cognitive/behavioral issues
- myalgia, ^^CK/ aldolase are are possible
21
Q
Beckers:
- life expectancy
- onset
A
- live beyond 30 (DMD death by 20)
- Does not onset until ~12 years
- less likely to have complications outside of weakness
22
Q
FSH:
- muscle groups involved
- life expectancy
A
- facial
- scapular
- humeral
- peroneal
-normal life expectancy
23
Q
Clues to FSH on exam
A
- down sloping shoulders
- winged scapula
- prominent clavicles
24
Q
Contrast Myotonic Dystrophy types 1 and 2
A
- Type 1: Distal weakness, common
- Type 2: Proximal, rare
25
Gene assc with MD1
CTG repeat at DMPK gene
| Cats Throw Goldfish) and (Dumb Mammals Punch Kids
26
MD1:
- personality
- assc findings (6)
-avoidant personality
- early cataracts
- hypersomnia
- hypogonad
- ID
- insulin resistance
- cardiac arrhythmia
27
What muscle groups are atrophied in MD?
- face
- neck
- finger
28
"Limb Girdle" refers to what part of the body?
hip and shoulders
29
What proteins are most common disordered in LGMD?
-sarcolemmal proteins
30
Typical course of LGMD
- slow
- symmetric
- proximal
31
What are the two types of LGMD?
- LGMD1 dominant
| - LGMD2 recessive
32
Emery Dreiffus Types 1 and 2:
| genetic defect
Type 1: Emerin mutation, Recessive
Type 2: Lamin A/C mutation, may be dominant or recessive
*alphabetic order (1 emerin --> 2 lamin)
33
What ED type is assc with contractures and cardiac abnormalities:?
-ED1
34
Oculopharyngeal Muscular Dystrophy:
| mutation
-AD mutation in PABN1 (GCG) or PABN1 (GCA)
**Gag Cough Gag or Gag Cough Aspirate
35
OPMD Clinical Features
- Ptosis
- EOM weakness
- Dysphagia
- Reduced Gag
36
Treatment OPMD
- oculoplasty
| - PEG
37
What are the three inflammatory myopathies?
- dematomyositis
- polymyositis
- inclusion body myositis
38
Which inflammatory myopathy is assc with rash and responds to steroids?
DERMATOmyositis
39
Distribution of weakness in Inflammatory myopathies:
- proximal in dermatomyositis and polymyositis
| - distal and proximal/ assymetric in inclusion body
40
Which of the three inflammatory myopathies has an unequal sex distribution?
- Inclusion body is more common in males
| - dermato and poly are either more common in female or equal (her slides are contradictory)
41
Which of the two inflammatory myopathies may be assc with cancer?
-dermato vs poly myositis
42
Three tests for inflammatory myopathies:
- CK
- EMG
- Biopsy
43
CK findings in the three inflammatory myopathies
- ^^ in dermato/polymyositis
| - may or may not be elevated in inclusion body myositis
44
EMG/ NCS findings in inflammatory myopathies
- myopathic in all three
| - also neuropathic in inclusion body
45
Biopsy findings for:
- dematomyositis
- polymyositis
- inclusion body myositis
- dermatomyositis: perifasicular atrophy
- polymyositis: inflammatory (endomysial inflammation) v normal
- inclusion bodies: bodies + rimmed vacuoles
46
Which of the inflammatory myopathies may be seen in children?
-dermatomyositis
(also seen in 40+)
-poly in adults
-inclusion body in elderly
dermato --> poly --> inclusion body
47
What is a sign of proximal muscle weakness?
difficult standing from seated position or trouble lifting arms above head
48
Polymyositis treatment
-immunosuppression
49
Why might dermatomyositis be more common in women?
assc with breast and gyne cancers
| also lung
50
Describe dermatomyositis rash
- Grottons sign (rash at hands)
- helipotrope (rash at eyes)
- also cape like distribution rash
51
In addition to weakness and rash, what are features of dermatomyositis?
-cardiorespiratory involvement
52
Inclusion Body Myositis:
| muscle groups involved
finger and wrist flexors
| quads
53
Treatment Inclusion Body Myositis
Poor response to steroids/ immunosuppression
54
What systems are altered in metabolic myopathies? What is the typical inheritance pattern?
glycogen metabolism
lipid metabolism
electrolyte imbalance
mitochondria
AR
55
What are the four glycogenoses + their assc enzymes
- McArdles (=myophosphorylase)
- Pompes (=acid maltase)
- Tauri (= PFK Def)
- Cori-Forbes (debrancher deficiency)
56
Two lipidoses leading to myopathies
- carnitine deficiency
| - carnitine palmitoyl transferase deficiency
57
Four Channelopathies leading to myopathies
1) hyperkalemic perioidic paralysis
2) hypokalemic PP
3) Myotonia congenita
4) Paramyotonia congenita
58
Three mitochondrial myopathies
- Kearns Sayre
- MERRF
- MELAS
59
Characteristic of weakness in glycogenoses/ lipidoses
exercise intolerance
60
Diagnoses of glycogenoses/ lipidoses?
- myoglobinuria following exercise
- elevated CK
- EMG myopathies featuers
- biopsy (biochemical analysis)
61
What are types II, III, V, VII glycogen storage diseases?
II- Pompes
III- Cori/Forbes
V- McArdles
VII- Tauri
PLEASE CUT MY TAG! = 2 3 5 6
62
Pompes (II, acid maltase) 2 characteristics
1) fixed proximal weakness
| 2) early cardiorespiratory insufficiency (Pompes effects the pump-heart)
63
Cori-Forbes (III, debrancher) 2 features
1) distal weakness
| 2) cardiomyopathy
64
McArdles (V, myophosphorylase) 3 features
1) cramps
2) myoglobinuria
3) second wind phenomenon
65
Tauri Disease (VII, PFK Def) 2 characteristics
1) exercise intolerance
2) myoglobinuria
(true of most glycogen storage diseases....)
66
Lipid Storage disease:
- when are symptoms worst?
- biopsy findings?
- flares with fasting
| - lipid storage vacuoles
67
Four features of lipid storage disease?
- proximal weakness
- swollen muscles w/ exercise
- high CK
- myoglobinuria
68
Channels involved in hypokalemic and hyperkalemic periodic paralyses
- hypo: L type Ca Channel
| - hyper: SCN4A (Na) Channel
69
Contrast weakness in hyper/hypokalemic PP:
- hypo: lasts hours- days
- hyper: relieved quickly by eating or exercise
both occur after rest following carb load or exercise
70
Channels involved in myotonia congenital/ paramyotonia congenital
- myotonia: CLCN1- hypertrophy
| - paramyotonia: CLCN1 or SCN4A
71
What triggers paramyotonia congenital?
- exercise
| - cold
72
Mitohondrial myopathies:
- deficiency of ____
- two organ systems most effected
- inheritance pattern
- ATP
- brain, muscle
- maternal
73
Biopsy findings in mitochondrial myopathies
ragged red fibers
74
Provoked necrotizing polymyopathy is also known as?
-rhabdomyolsis with myoglobinuria
75
Cause of provoked necrotizing polymyopathy
crush injury
| extreme exertion
76
Who is most susceptible to necrotizing polymyopathy?
glycogen disorders
77
Defect in phosphodiesterase makes patient susceptible to?
Malignant hyperthermia
78
What anesthetics should be avoided in RYR1 mutation?
- halothane
| - succinylcholine
79
What are four systemic illnesses that may lead to myopathy?
- hypothyroid
- critical illness
- acromegaly
- cushings
80
Muscle biopsy findings in critical illness myopathy
loss of myosin
81
Acromegaly/ Cushings:
| distribution of weakness
- proximal
| * Cushings mainly of lower extremities
82
Common feature of hypothyroid + critical illness myopathy
-loss of DTRs
83
EMG findings in myopathies
1) low amplitude
2) short duration
3) polyphasic + rapid recruitment
84
Six meds that cause myopathy
1) steroids
2) statins
3) AZT
4) colchicine
5) chloroquine
6) rifampin
(Some Sucky Asians Cant Cook Rice)
++ alcohol
85
Why do statins lead to myopathy?
-inhibit synthesis of mevalonic acid = no coenzyme Q needed for ATP production
86
Myopathy type assc with AZT
mitochondrial
