Muscular Dystrophy

Question 1

What is muscular dystrophy?

Answer 1

inherited X-linked recessive disorder

Question 2

Associated with most severe clinical symptoms?

Answer 2

Duchenne Muscular dystrophy (DMD)

Question 3

Later onset and a milder clinical course?

Answer 3

Becker Muscular dystrophy (BMD)

Question 4

Heart is primarily affected and skeletal muscle is spared

Answer 4

DMD-associated dilated cardiomyopathy

Question 5

Stabilizing component of glycoprotein complex?

Answer 5

dystrophin

Question 6

What happens when dystrophin is absent?

Answer 6

degradation of muscle fibers, leads to weakness and wasting

Question 7

What are the dystrophin levels in DMD?

Answer 7

reduced or absent

Question 8

What are dystrophin levels in BMD?

Answer 8

altered

Question 9

What is the primary symptom of muscular dystrophy?

Answer 9

WEAKNESS

Question 10

What age is muscular dystrophy diagnosed?

Answer 10

before age 5

Question 11

What is the presentation of a child with MD?

Answer 11

difficulty running, jumping, and walking up, gower’s sign, waddling gait, lumbar lordosis, calf enlargement, leg pain

Question 12

What is Gower’s sign?

Answer 12

using hands to push into an upright position when getting up from the floor

Question 13

What muscles are affected first in MD?

Answer 13

proximal before the distal limb, and lower before upper extremities

Question 14

What does DMD cause?

Answer 14

cardiomyopathy, conduction abnormalities, arrhythmia

Question 15

Cardiomyopathy is found in ALL of what age of DMD?

Answer 15

> 18yr

Question 16

When is DMD usually found?

Answer 16

late in the disease course, due to inability to exercise

Question 17

What type of injuries is seen in MD?

Answer 17

frequent arm and leg fractures (due to falling)

Question 18

What develops in all MD pts?

Answer 18

progressive scoliosis

Question 19

What causes the acute respiratory failure?

Answer 19

scolosis

Question 20

What reflexes is found in MD?

Answer 20

Hyporeflexia or areflexia

Question 21

What age are BMD pt usually ambulatory until?

Answer 21

15 yo

Question 22

What age does BMD pts die and why?

Answer 22

mid 40’s due to dilated cardiomyopathy

Question 23

Can rapidly progress to heart failure due to fibrosis of the heart muscle?

Answer 23

BMD

Question 24

How does DMD- w/ dilated cardiomyopathy present?

Answer 24

dilated cardiomyopathy and CHF

Question 25

Who can have rapid progression of disease to death?

Answer 25

men

Question 26

How long do women take to progress in DMD/w heart?

Answer 26

10 yrs

Question 27

What ways can a woman be tested for as a carrier?

Answer 27

prenatal- amniocentesis

Question 28

What is seen in symptomatic female carriers?

Answer 28

``` elevated serum CK (70%) muscle weakness (20%) ```

Question 29

What is considered a suspected diagnosis of MD?

Answer 29

increased serum CK Myopathic changes on electromyography + family hx suggesting X recessive inheritance

Question 30

DMD serum CK is?

Answer 30

10-20x the upper limit of normal

Question 31

BMD/ female carries serum CK is?

Answer 31

2-3xs normal

Question 32

Dystrophin blood samples show what in DMD and BMD?

Answer 32

DMD- complete or almost complete absence | BMD- abnormal molecular weight or reduced quantity

Question 33

What does a electromyography show?

Answer 33

myopathic changes WITHOUT nerve conduction abnormalities

Question 34

What does molecular genetic testing show?

Answer 34

elevated serum CK and dystrophinopathy

Question 35

When can elevated CK be tested?

Answer 35

early as 12wks gestation by chorionic vilius sampling and DNA analysis

Question 36

What does a muscle biopsy show?

Answer 36

isolated "opaque" hypertrophic fibers

Question 37

What is dystrophin replaced with?

Answer 37

muscle fat and connective tissue

Question 38

What is the 5 criteria according to European Neuromuscular Centre?

Answer 38

1. Onset of proximal weakness by age of 5 2. Loss of unassisted walking by 13 yrs 3. 10 fold > elevation of CK 4. Absent or almost no dystrophin on muscle biopsy 5. Duchenne type mutation in dystrophin gene

Question 39

When do DMD die and why?

Answer 39

late teens or twenties due to respiratory insufficiency or cardiomyopathy (few beyond 3rd decade)

Question 40

What age is DMD usually wheelchair bound?

Answer 40

age 12

Question 41

What is the txt for MD?

Answer 41

Predisone or prednisolone daily

Question 42

If ventricular dysfunction on cardiac imaging is seen what meds can be given?

Answer 42

ACE inhibitor and/or Beta blocker

Question 43

Txt overt heart failure?

Answer 43

diuretics

Question 44

Txt for heart transplant?

Answer 44

digoxin

Question 45

What is the screening for echocardiography or cardiac MRI for boys?

Answer 45

around age 10, OR symptom onset, repeat q 6-12mo

Question 46

What is the screening for echocardiography or cardiac MRI for female carriers?

Answer 46

start after teenage years

Question 47

Recommendation for pediatric pulmonology?

Answer 47

baseline @ yearly prior to wheelchair (5-6y) | twice yearly when wheelchair bound

Question 48

What age is ambulation lost?

Answer 48

9 yrs

Question 49

What age is a electric wheelchair dependent?

Answer 49

14 yrs

Question 50

What age is assistance need for eating and drinking

Answer 50

18 yrs

Question 51

What age is ventilation assistant needed?

Answer 51

19yrs

Question 52

What should all MD patients have?

Answer 52

advanced planning w/ palliative care and end of life issues guided by patient preference