1.4 Skeletal Muscle, NMJ, Soft Tissue Tumors Flashcards Preview

18 Musculoskeletal System > 1.4 Skeletal Muscle, NMJ, Soft Tissue Tumors > Flashcards

Flashcards in 1.4 Skeletal Muscle, NMJ, Soft Tissue Tumors Deck (29)
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1

how to differentiate dermatomyositis with polymyositis?

-Perimysial vs Endomysial inflammation
-dermatomyositis: perimysial ('closer to skin, so dermato-')

2

dermatomyositis
-clinical findings (3)
-which is considered classic hallmark symptoms?

1. "can't comb hair, can't climb stairs"--classic hallmark.
-proximal muscle weakness, distal later
2. heliotrope rash, malar rash
3. Gottron papules (red papules on elbows, knuckles, knees)

3

dermatomyositis
-lab findings (4)
-blood and biopsy

1. increased CK
2. + ANA (don't mistake for lupus)
3. anti-Jo-1 Ab (hallmark finding)
4. perimysial inflammation, leads to perifascicular atrophy (biopsy)

4

How does dermatomyositis present similarly to lupus, and how to differentiate in labs?

-both have malar rash and + ANA

-do more tests:
-lupus has anti-dsDNA Ab
-dermatomyositis has anti-Jo-1 Ab

5

Duchenne's muscular dystrophy (x-linked)
-mech/etiology
-clinical findings
-hallmark finding

-muscle turns into fat. muscle wasting
-defect in dystrophin gene (no dystrophin is produced), which anchors muscle to ECM.
-first presents as proximal muscle weakness at age 1, distal later
-Hallmark: Calf pseudohypertrophy--baby learning to walk has proximal muscle weakness so puts pressure on calf, which hypertrophies. Then, distal phase--calf turns into fat.

6

why does dystrophin get spontaneous mutations so often?

dystrophin is the biggest human gene.

7

Duchenne's muscular dystrophy (x-linked)
-what is abnormal on labs?

-increased CK

8

how do duchenne's muscular dystrophy kids die?

-Cardiac or respiratory failure.
-myocardium commonly involved

9

Becker's muscular dystrophy

-less severe version of Duchenne's
-mutated dystrophin, so reduced dystrophin is produced.
-as opposed to Duchenne's, where dystophin is not produced.

10

Myasthenia gravis vs Lambert-Eaton syndrome
-how do symptoms differ?

-MG: weakness gets worse with repeated use (contraction uses up presynaptic Ach)
-LE: weakness gets better with repeated use (contraction increases Ca+ gradient into presynaptic neuron)
-LE: proximal muscles weak. eyes usu spared.

-Tx: anticholinersterases do not work for LE

11

Lambert-Eaton syndrome
-mech
-etiology
-symptoms

-Ab against Ca+ channels on presynaptic terminal in NMJ
-blocked Ca+ channels block Ach release
-arises as paraneoplastic syndrome, usu small cell carcinoma of lung

-proximal muscles weak, improves with use. Eyes usu spared.

12

what disorders are myasthenia gravis associated with?

-thymic hyperplasia
-thymoma

13

most common benign soft tissue tumor in adults

lipoma

14

most common malignant soft tissue tumor in adults

liposarcoma

15

most common malignant soft tissue tumor in children

rhabdomyosarcoma

16

what is cardiac rhabdomyoma associated with?

tuberous sclerosis

17

rhabdomyosarcoma:
-classic sites

-common in head, neck
-vagina is classic site in young girls

18

Lambert-Eaton syndrome:
what disorder is it associated with?

-small cell lung cancer

19

Tx for dermatomyositis/polymyositis

steroids

20

"can't comb hair, can't climb stairs"

-inital presentation of dermatomyositis
-proximal muscle weakness, esp shoulder

21

Gottron's papules

-dermatomyositis
-red papules on elbows, knuckles, knees

22

heliotrope rash

-rash of upper eyelid.
-dermatomyositis

23

anti-Jo-1 antibody

-elevated in dermatomyositis
-use to differentiate from lupus

24

Sarcomas can be confused with these 2 things.

Pseudosarcomatous proliferations:
1. Nodular Fasciitis
2. Myositis ossificans--often in trauma

25

fibromatosis

-soft tissue tumors from fibroblasts
-malignant fibroblast tumor is a fibrosarcoma

26

most common neoplasm in women

uterine leiomyoma
-smooth m
-'uterine fibroids'

27

why are some leiomyosarcomas very dangerous?

-those that are in the retrperitoneum are often not noticed until very big. Also, they are difficult to reach and completely excise

28

rhabdomyosarcoma:
3 types

1. embyonal
2. alveolar (most have 1:13 or 2:13 translocation)
3. pleomorphic

29

synovial sarcoma
-what genetic etiology?

-X:18 translocation
-soft tissue sarcoma, usually around knee