Week 8 Muscular Dystrophy

Question 1

what is Duchenne’s MD

Answer 1

DMD, the most common childhood MD. untreated, can cause death. survival into adulthood with treatment.

Question 2

what is the leading cause of death with DMD

Answer 2

respiratory insufficiency in late and early teens, and dilated cardiac myopathy

Question 3

what is DMD caused by

Answer 3

a mutation in the dystrophin gene on the X chromosome at Xp21. severe reduction or absence of dystrophin in skeletal and cardiac muscles.

Question 4

what does dystrophin loss disrupt

Answer 4

the linkage between the intracellular cytoskeleton and the extracellular matrix, leading to sarcolemma instability.

Question 5

what do you need dystrophin for

Answer 5

essential for force transduction between contracting muscle fibers

Question 6

what causes the mental retardation in 1/3 of DMD cases

Answer 6

the iso forms expressed in the brain

Question 7

what are the 5 variations of MD

Answer 7

1. dystrophinopathies
2. limb-girdle MD
3. facioscapulohumeral MS
4. myotonic dystrophy
5. distal myopathy

Question 8

what is dystrophinopathies

Answer 8

severe DMD and beckers MD, absence of dystrophin (DMD0 or partially functioning forms of dystrophin

Question 9

what is limb girdle MD

Answer 9

pelvic or shoulder girdle muscles predominantly involved

Question 10

what is facioscapulohumeral MD

Answer 10

one of the most common inherited myopathies

Question 11

what is DM (myotonic dystrophy)

Answer 11

adult onset, disorder affecting many organs, the brain, peripheral nerves and immune system

Question 12

what is distal myopathy

Answer 12

Welander distal myopathy (WDM). progressive and progressive beginning in the hands or feet, late adult onset

Question 13

what is the motor presentation of MD

Answer 13

abnormal gait, toe walking and waddling gait, with frequent falls. calf hypertrophy, not posture abnormalities and difficulty running and rising from the floor. loss of ambulation and WC dependent by 9.5 years.

Question 14

what is the non motor presentation of MD

Answer 14

developmental delay, and learning disabilities like autism, failure to thrive, and liver daises, serum creatine kinase (CK) is elevated

Question 15

what are the respiratory complications of MD

Answer 15

teen years, decrease in respiratory reserve and sleep hypoventilation. respiratory muscle weakness, REM sleep and hypoxic dips and apnea. leads to drowsiness decreased appetite, HA, nausea, fatigue, poor concentration, failure to thrive, coughing ability decreased.

Question 16

in patients that are untreated and become hypercapnic, survival rate is

Answer 16

less than 1 year.

Question 17

what is non invasive ventilation (NIV)

Answer 17

night breathing is augmented by breaths of a portable breathing things with facial mask, nose mask. can extend serval into the 20s and 30s.

Question 18

a good indicator for NIV is when forced vital capacity is less than

Answer 18

50%

Question 19

what are the cardiac complications of MD

Answer 19

dilated cardiomyopathy usually over 18 years old. percent of deaths is going to increase (because NIV is taking away some respiratory related deaths). treated with ACE inhibitors, beta blockers, diuretics

Question 20

what are the 4 things we can treat MD with (meds)

Answer 20

1. glucocorticoid corticosteroids (most affective): gain weight and vertebral fx.
2. prednisone (stabilized strength and function) MOST USED. prolongs walking ability, and respiratory function, less cardiomyopathy.
3. alternating of 1 and 2
4. supplements like calcium and vit. D