Quiz 8.20.21

Question 1

How do statins lead to myopathy?

Answer 1

Generally, HMG-CoA reductase converts HMG-CoA to mevalonic acid, which in turn produces Q10 (ubiquinone). Statin prevents production to mevalonic acid, leading to decreased Q10, decreased functioning of mito, decreased ATP availability.
Deregulation of mito may also cause calcium leak out of mito, uptake and overload by SR, then reexit by ryanadine.
Statins may also reduce cholesterol in muscles, making them less effective.
Statin may prevent functioning of GTP binding proteins, contributing to apoptotic signalling.

Question 2

How do quinolones cause myopathy

Answer 2

unknown.
Possible metalloproteins interfere w/ cell membranes.
Other theory = altered metabolism of tendon cells, leading to decreased collagen.

Question 3

Aims of Choosing Wisely

Answer 3

Decrease harm, reduce duplicate procedures, choose evidence based care, decide on necessary tests/procedures, promote communication between providers/pt

Question 4

Impact of Choosing Wisely.

Answer 4

May help providers and patients find sweet spot wrt care, costs, outcomes.

Question 5

4 steps to implement Choosing Wisely

Answer 5

1. Engage team (start conversations, identify barriers to starting, educate entire team)
2. Engage patients (talk about purpose of tests, risks, benefits, costs, provide accessible education materials)
3. Est. concrete, standardized plan.
4. Collect data that measures effectiveness of intervention.

Question 6

Recommended exercises for those w/ muscular diseases

Answer 6

Walking running (not downhill), resistance training (low load), balance, flexibility.

Question 7

Symptoms of FSHD

Answer 7

Muscle weakness in face, scapula fixators, humeral muscles, food flexors. May have difficulty manipulating mouth.

Question 8

Duchenne symptoms

Answer 8

Proximal muscle weakness, esp. at upper legs. 2-3 y/o @ onset. Often enlarged calves, death by 20 yo.

Question 9

Becker symptoms

Answer 9

Milder Duchene, onset in teens,

Question 10

Limb Girdle

Answer 10

Can start at any age, muscle weakness @ hips/ shoulders.

Question 11

Most common muscular dystrophies

Answer 11

Duchenne/Becker
Myotonic
FSHD
Limb Girdle
(all <15/100,000)

Question 12

Cell junctions of smooth, skeletal, and cardiac cells

Answer 12

Skeletal: None
Smooth: Gap junctions to coordinate function, but cells anchored in ECM.
Cardiac: Intercalated disks w/ electrical and ionic coupling. (Use desmosomes)

Question 13

What happens after Ach binding

Answer 13

Opening of sodium channels on sarcolemma causing an EPP, which downstream acts on DHRP, etc etc.

Question 14

Trigeminal Nerves (CN V1 - CN V3)

Answer 14

V1 - forehead, nose
V2 - upper jaw
V3 - lower jaw, ear

Question 15

Nerves to back of head-neck

Answer 15

C2-C4

Question 16

Nerves to arms

Answer 16

C5-T1

Question 17

Nerves to chest/abs

Answer 17

T2-L2

Question 18

Nerves to legs

Answer 18

L3-S1

Question 19

Nerves to groin

Answer 19

S1-S4

Question 20

Muscle Spindles mechanism of action

Answer 20

Sense overstretch, uses type 1a, and II, which contract the muscle and relax the antagonist to shorten muscle.

Question 21

Golgi tendon mechanism of action

Answer 21

Uses type 1b neurons, detects stretching of tendons which indicates overcontracting of muscle, causes muscle to relax and antagonist to contract.

Question 22

Inheritance patterns of Duschene, Limb-Girdle, FSHD, Becker’s and pathology.

Answer 22

FSHD: Autosomal dominant (shortened D4Z4), leads to rounding of muscle fibers, internal nuclei, scarring.
Beck, Duchenne: X-linked recessive. (exon deletion and frameshift mutation, respectively). Shortage/depletion of dystrophins.
Myotonic: Autosomal Dominant, repeat mutation @ DMPK gene. Clumping of RNA in muscle nuclei.

Question 23

Normal creatine Kinase

Answer 23

22-400, but up to 700 normal if African American.