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724: Medical Lectures > Myopathies > Flashcards

Flashcards in Myopathies Deck (39)
1

MUSCULAR DYSTROPHIES

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2

What are muscular dystrophies characterized by?

Progressive muscle weakness and wasting

3

What serum level is oftentimes elevated in muscular dystrophies?

creatine kinase

4

A genetic defect on the short arm of the X chromosome has been identified in _____ dystrophy

Duchenne

5

This genetic defect found in Duchenne's cdes for what protein? What is the affect?

dystrophin

Levels are markedly reduced or absent in the muscle of these patients

6

Are dystrophin levels affected in the Becker variety of muscular dystrophies?

No

7

What medication improves muscle strength and function in boys with Duchenne dystrophy?

Prednisone

8

What things must be avoided and what things are encouraged in these patients?

Bed rest is associated with a worsening of the disease

PT and orthopedic procedures may help counteract deformities or contractures

9

MYOTONIC DYSTROPHY

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10

Myotonic dystrophy is a slow, progressive, inherited disorder that manifests in the __ or __ decade of life

3rd or 4th

11

How many types of myotonic dystrophies have been determined?

2

12

What are 3 muscular symptoms of myotonia?

- muscle stiffness
- marked delay in muscle relaxation following contraction
- weakness and wasting of the facial, SCM, and distal limb muscles

13

What are 6 clinical features of myotonia?

- cataracts
- frontal baldness
- testicular atrophy
- diabetes mellitus
- cardiac abnormalities
- intellectual changes

14

What drug may be helpful when myotonia is disabling?

Sodium channel blockers such as...
- phenytoin
- procainamide
- mexiletine

15

True or False

Associated weakness and the course of myopathy are influenced by treatment

False

16

MYOTONIA CONGENITA

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17

Myotonia congenita is commonly inherited as a _____ trait

dominant

18

The responsible gene on chromosome 7 is responsible for what?

encoding a voltage-gated chloride channel

19

When do symptoms of myotonia congenita develop?

early childhood

20

What are the 2 signs and symptoms of myotonia?

- muscle stiffness that is enhanced by cold and inactivity
- muscle hypertrophy

21

What relieves muscle stiffness?

exercise

22

What durgs are used to treat myotonia congenita?

- procainaminde
- tocainide
- mexiletine
- phenytoin

23

INCLUSION BODY MYOSITIS

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24

Inclusion body myositis begins _____, usually after middle age

insidiously

25

What is the main characteristic of inclusion body myositis?

progressive proximal weakness of first the LEs and then the UEs

26

Where does muscle weakness often begin in inclusion body myositis? (LE and UE)

- the quadriceps femoris

- forearm flexors

27

What confirms the diagnosis of inclusion body myositis?

muscle biopsy

28

What drug therapy has been found to have a mild benefit on inclusion body myositis?

Intravenous immunoglobin (IVIG) therapy

29

MITOCHONDRIAL MYOPATHIES

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30

What can be seen on pathologic examination of skeletal muscle with the modified Gomori stain in patients with mitochondrial myopathies?

characteristic "ragged red fibers" containing accumulations of abnormal mitochondria

31

What 2 signs do patients with mitochondrial myopathies present with?

- progressive external ophthalmoplegia
- limb weakness that is exacerbated or induced by activity

32

Some patients with mitochondrial myopathies present with what type of dysfunction?

CNS (epilepsy, ragged red fiber syndrome, or MERRF)

33

What does the acronym MELAS stand for?

Myopathy
Encephalopathy
Lactic Acidosis
Stroke-like episodes

34

What type of patients do mitochondrial myopathies develop?

- AIDS patients receiving zidovudine
- HIV1 patients receiving HAART

35

ASSOCIATED MYOPATHIES

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36

What are some associated disorders myopathy may occur with?

- chronic hypokalemia
- endocrinopathy

37

Myopathy may develop in patients taking what drugs?

- corticosteroids
- chloroquine
- colchinice
- clofibrate
- emetine
- aminocaproic acid
- statin drugs
- bretylium tosylate

38

Weakness due to myopathy is mainly _____.

proximal

39

Preexisitng myotonia may be exacterbsated or unmasked by what drugs?

- depolarizing muscle relaxants
- beta-blockers
- fenoterol
- ritodrine
- diuretics