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Flashcards in Muscular Dystrophies Deck (26):
1

Muscular Dystrophies - Definition

Genetic disorders characterized by progressive muscle degeneration and weakness

2

How do MDs differ?

1. age of onset
2. distribution of weakness
3. Rate progression
4. +/- calf hypertrophy on CK levels
5. patterns of inheritence (male disease, females as carriers)

3

Duchene Muscular Dystrophy:
- pattern of inheritence
- age of onset
- pathogenesis
- life expectancy

- X-linked recessive gene mutation
- 3-5 yrs
- lack of dystrophin protein: leads to muscle fragility
- in the 30s (som into 40 and 50s)
*fastest progressing MD

4

DMD: first muscles affected, later muscles affected

muscles of the hip, pelvic area, thighs, and shoulder
later: skeletal muscles in the arms, legs, and trunk
by early teens: muscles of heart and respiration

5

DMD: unique signs/symptoms

1. gower's sign
2. calf hypertrophy (via fatty depositions)
3 loss of ambulation by 9-12yrs

6

Becker Muscular Dystrophy
- age of onset
- progression

less severe DMD
age of onset = >10yrs
slower progression than DMD, less predictable

7

Facioscapulohumeral Muscular Dystrophy (FSH, FSHD)
- pattern of inheritence
- definition
- age of onset
- life expectance
- CPK levels

- genetic: shorter segment of DNA on chromosome 4
- progressive muscular degeneration (slow) with increasing weakness and atrophy
- adult onset (20s) or infantile
- normal life expectancy
- normal CPK levels

8

Facioscapulohumeral Muscular Dystrophy (FSH, FSHD)
- muscles affected, early and late

Early: eyes and mouth, shoulder blades and upper arms
Later: abdominals, sometimes the hip muscles
*does NOT affect muscles of respiration

9

Myotonic Muscular Dystrophy: Characteristics

- weakness of voluntary muscles (varies by type of MMD and age)
- myotonia: inability to relax muscles at will (difficult to let go after shaking hands)
- Progression affects: heart, lungs, GI tract, genital system

10

Type 1 MMD

abnormally expanded section of gene on chromosome 19 (DMPK) - most common type

11

Type 2 MMD

Abnormally expanded section of gene on chromosome 3 (ZNF9)
- symptoms often mild and slow progressing
- rarely occurs in childhood

12

Types of Type 1 MMD based on age of onset

1. Adult onset: begins with weakness in muscles of face, neck, fingers, and ankles; slowly progressive for these and other muscles
2. Congenital-onset: requires ventilation, do not make it out of first year
3. Juvenile-Onset: can be very different from adult onset
*earlier onset = worse prognosis!

13

Diagnosis of MD

1. DNA analysis (genetic testing)
2. EMG (no neuro issues, # of recruited muscles low)
3. Muscle biopsy (degeneration and fatty deposition- if beckers no fatty deposition)

14

Treatment of MD

1. Corticosteroids (only for DMD)
2. Supportive managements- respiratory care
3. Orthopedic- scoliosis
4. rehab

15

Strengthening strategies with MD

prevent muscle damage! will be using the same muscles over and over to increase force and rate.
trying to maintain function
use low load
No eccentrics! (don't want to encourage muscle breakdown)
strengthen 3 or higher, brace when lower
NO SORENESS
never to exhaustion- only 60% HRmax

16

Most common site of contracture

PFs! hypertrophic calves (night splints)

17

Mitochondrial Myopathies: definition

mitochondria of the cells are effected; age of onset and progression vary

18

Mitochondrial encephalomyopathy

type of MM, causes both muscular and neurological problems (neuronal cells with lack of energy)

19

Common symptoms of the 9 types of MM

1. muscle weakness
2. exercise intolerance
3. hearing loss
4. trouble with balance and coordination
5. seizures
6. learning deficits

20

Mitochondrial Myopathies: cause

could be a spontaneous mutation, but many times there is a family history

21

MM: rehab management

1. teach energy conservation
2. compensations (no recovery; progressive disorder)
3. work on functional activities
*Treat the way they present!

22

Charcot Marie Tooth Disease: definition

most commonly inherited peripheral nerve disorder; slow progressive

23

CMT: Presentation

Distal weakness first! causes muscle weakness and atrophy with some loss in sensation (feet, lower legs, hands and the forearms)

24

6 types of CMT

CMT 1
CMT 2
CMT 4
CMT X
Congenital hypomyelinating neuropathy (CHN)

25

CMT Rehab management

1. know onset and progression
2. provide with orthotics (first sign is foot drop, maybe no push off)
3. strengthen everything that is not affected
4. aerobics: NOT to 80% max
5. only exercise >3/5 muscles
6. watch for overwork!

26

Other diseases under the DMD umbrella

1. ALS
2. SMA
3. Inherited endocrine myopathies
4. Metabolic disease of muscles