Skeletal Muscle

Question 0

Most common and most serious form of MS

Answer 0

Duchenne’s MS

Question 1

broad range of inherited diseases that are characterized by progressive muscle damage and weakness

Answer 1

Muscular dystrophy

Question 2

Defective gene on the X chromosome that leads to an ability to produce one of the proteins in the skeletal muscle cell membrane

Answer 2

Duchenne’s MS

Question 3

protein in the skeletal muscle cell membrane not made in Duchenne’s

Answer 3

dystrophin

Question 4

Biopsy of late stage Duchenne’s shows

Answer 4

large areas of muscle almost entirely replaced by fat

Question 5

What is the hallmark of myasthenia gravis?

Answer 5

muscle weakness that worsens during periods of activity and improves after periods of rest

Question 6

Degeneration and atrophy of muscle fibers along with some muscle fiber regeneration and hypertrophy of remaining muscle fibers

Answer 6

Duchenne’s MS

Question 7

Myasthenia gravis pts have a strong association with what abnormalities?

Answer 7

Thymic abnormalities

Question 8

What thymic abnormalities are associated with which sex in myasthenia gravis?

Answer 8

women: thymic hyperplasia; men: thyoma (non-malignant tumor of the thymus)

Question 9

large collections of lymphocytes as well as necrotic muscle fibers that appear pale and atrophic

Answer 9

myasthenia gravis

Question 10

tumor originating from the epithelial cells of the thymus

Answer 10

Thyoma

Question 11

Found in 15% of myasthenia gravis pts

Answer 11

thyoma

Question 12

Diagnostic investigations of MG should usu include what 2 tests?

Answer 12

Testing for serum anti-acetylcholine receptor antibodies and repetitive nerve stimulation studies

Question 13

progressive muscle weakness, usu first noticed in the upper legs and upper arms

Answer 13

Lambert-Eaton syndrome

Question 14

60% of Lambert-Eaton syndrome cases are associated with what?

Answer 14

Small cell lung cancer

Question 15

Pts with Lambert-Eaton exhibit (greater/worsening) strength wit initial exertion and mild exercise and (greater/worsening) strength with prolonged exercise

Answer 15

greater; worsening

Question 16

What are antibodies directed against with Lambert-Eaton syndrome?

Answer 16

presynaptic calcium channels, which inhibits acetylcholine

Question 17

group of closely related, muscle-specific autoimmune dzs

Answer 17

inflammatory myopathy

Question 18

Most common forms of idiopathic inflammatory myopathies

Answer 18

dermatomyositis, polymyositis, inclusion body myositis

Question 19

These conditions occur as a result of immune mediated inflammation and vascular damage to striated muscle

Answer 19

dermatomyositis, polymyositis, and inclusion body myositis

Question 20

EMG reveal characteristic muscle tone abnormalities

Answer 20

idiopathic inflammatory myopathies

Question 21

connective-tissue dz that is characterized by inflammation of skeletal muscle and skin

Answer 21

dermatomyositis

Question 22

Up to 50% of dermatomyositis may be due to what?

Answer 22

Paraneoplastic syndrome

Question 23

A mixed B- and T- cell perivascular inflammatory infiltrate and perifascicular muscle fiber atrophy

Answer 23

classic microscopic findings of dermatomyositis

Question 24

Characteristic periorbital heliotrope rash is often seen preceding or accompanying muscle weakness

Answer 24

dermatomysitis

Question 25

characterized by a purple red papular rash over the dorsal aspect of the metacarpophalangeal and interphalangeal jts

Answer 25

Gottron’s sign

Question 26

symmetric proximal muscle weakness in the upper and lower extremeties with weakness of neck flexors

Answer 26

Polymyositis

Question 27

Skin involvement of dermatomyositis is (present/absent) in polymyositis

Answer 27

absent

Question 28

Polymyositis is a dz of (children/adults)

Answer 28

adults; very rare in persons under 20yo

Question 29

Dermatomyostis is primarily a dz of (children/adults)

Answer 29

adults; can be seen in children 5-14yo

Question 30

presenting with bilateral proximal muscle weakness, often noted in the upper legs while walking

Answer 30

polymyositis

Question 31

Focal areas of white blood cells and other inflammatory cells, the appearance of vacuoles in the muscle, deposits of amyloid-related proteins within the muscle cells and inclusions

Answer 31

inclusion body myositis

Question 32

Benign tumors of striated muscle

Answer 32

rhabdomyomas

Question 33

Round mass in the region of the neck

Answer 33

rhabdomyomas

Question 34

90% of rhabdomyomas are found where?

Answer 34

head and neck areas

Question 35

Malignancy that arises from embryonic mesenchymal cells that posses the potential to develop into skeletal muscle

Answer 35

Rhabdosarcoma

Question 36

Most common soft tissue tumor in children

Answer 36

rhabdomyosarcoma

Question 37

90% of all cases of rhabdosarcoma are dx in individuals in what age group?

Answer 37

Under 25yo

Question 38

Where is rhabdosarcoma most often found?

Answer 38

orbit, face, scalp, neck, extremities (1/3 of cases involve the orbit)