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Flashcards in MSK Random Facts Deck (86):
1

Baker cyst

Popliteal fluid collection commonly related to chronic joint disease

2

Most commonly involved ligament in an ankle sprain

Anterior talofibular

3

What innervates the teres minor?

Ancillary nerve

4

Injury classically seen in cyclists

Guyon canal injury to ulnar nerve

5

What supplies sensation to the lateral forearm?

Musculocutaneous nerve (C5-7)

6

What can you get with a superficial laceration of the Palm?

Injury to the recurrent branch of the median nerve, loss of thenar muscle group, no loss of sensation

7

Klumpke palsy

Lower trunk damage (C8-T1), loss of the intrinsic muscles of the hand, total claw hand-lumbricals normally flex MCP joints and extend DIP and PIP joints

8

Thoracic outlet syndrome

Compression of lower trunk and subclavian vessels

9

What do the interossei do

Dorsal interossei-abduct the fingers, Palmer interossei- adduct the fingers

10

What can cause an inferior gluteal nerve injury?

Posterior hip dislocation, nerve is L5-S1

11

What's in the anterior compartment?

Anterior tibial artery and deep peroneal nerve

12

What occurs during the power stroke?

Myosin releases bound ADP and PO4 causing displacement of the myosin and actin filament

13

What is ATP used for in the muscle contraction?

Myosin releasing actin

14

What is a type 1 muse fiber?

Slow twitch, red fiber, increased mitochondria and myoglobin concentration, used for sustained contraction

15

What is a type 2 muscle fiber?

Fast twitch fiber, white fiber, more anaerobic glycolysis, weight training results in hypertrophic of fast-twitch muscle fibers

16

McMurray test

External rotation and extension causing pain->medial meniscal tear; internal rotation and extension->lateral meniscal tear

17

How is contraction stimulated in smooth muscle?

AP opens L-type voltage gated Ca channel-> increased Ca in the cell binds to calmodulin-> Ca-calmodulin complex enhances myosin-light chain kinase, which phosphorylates myosin and leads to contraction

18

What do osteoblasts come from?

Differentiate from mesenchymal stem cells in the periosteum

19

What do osteoclasts come from and how do they work?

Differentiate from monocytes, macrophages. Multinucleated cells that dissolve bone by secreting acid and collagenases

20

Estrogens effects on bone

Estrogen inhibits apoptosis in bone-forming osteoblasts and induces apoptosis in bone-resorbing osteoclasts

21

Genetics of achondroplasia

Autosomal dominant (but >85% are sporadic), constitutive activation of fibroblast growth factor receptor (FGFR3) inhibits chondrocyte proliferation

22

Osteoporosis histo and labs

Trabecular (spongy) bone loses mass and interconnections despite NORMAL mineralization and lab values

23

What is denosumab?

Monoclonal antibody against RANK-L

24

MOA of osteopetrosis

Mutations (eg, carbonic anhydrase II) impair ability of osteoclast to generate acidic environment necessary for bone resorption. Leads to thickened, dense bones that are prone to fracture. Pancytopenia and extramedullary hematopoeisis

25

What's wrong in rickets/osteomalacia?

Defective mineralization/calcification of osteoid

26

Lab values in rickets

Low vit D, low Ca, high PTH, low phos

27

Lab values in Pagets

Normal Ca, phos, and PTH. Elevated ALP.

28

Histo of pagets

Mosaic pattern of woven and lamellar bone

29

What are rheumatoid nodules

Fibrinous necrosis

30

"Soap bubble appearance"

Giant cell tumor. Epiphyseal end of long bones. Locally aggressive benign tumor

31

Osteochondroma

Mature bone with a cartilagenous cap

32

Codman triangle

Osteosarcoma

33

Sunburst pattern

Osteosarcoma

34

Predisposing factors for osteosarcoma

Paget disease, bone infarcts, radiation, familial retinoblastoma, Li-Fraumenti syndrome (germline p53 mutation)

35

Where does an osteosarcoma most commonly occur?

Metaphysis of long bones, often around the knee

36

Onion skin periosteal reaction

Ewing sarcoma

37

Genetics of Ewing srcoma

t(11;22) translocation causing fusion protein EWS-FLI 1

38

Where does Ewing sarcoma occur?

Diaphysis of long bones

39

Histology of Ewing sarcoma?

Anapestic small blue cell malignant tumor

40

What do you see with osteoid osteomas?

Nighttime pain, central nidus, in the diaphysis

41

Antibodies in Sjogrens

SS-A (anti-Ro) and/or SS-B (anti-La)

42

Complications of Sjogrens

Dental caries, mucosa-associated lymphoid tissue (MALT) lymphoma (may present as parotid enlargement)

43

What drugs can precipitate a gout attack

Niacin, hydrochlorothiazide, cyclosporine, and pyrazinamide

44

What are the crystals in pseudo gout?

Calcium pyrophosphate

45

How do you monitor disease progression in anklyosing spondylitis?

Chest expansion

46

What do you see with ankylosing spondylitis?

Ankylosis, uveitis, aortic regurgitation

47

Triad of reactive arthritis

Conjunctivits, arthritis, urethritis (post-GI: shigella, salmonella, yersinia, campylobacter or chlamydia infections)

48

What dermal findings might you see in reactive arthritis?

Keratoderma blennorrhagicum (hyperkeratotic vesicles on the palms and soles) or circinate balanitis (serpiginous annular dermatitis of the glans penis)

49

What causes lupus nephritis?

Type III hypersensitivity reaction (nephritic: diffuse proliferative glomerulonephritis; nephrotic: membranous glomerulonephritis)

50

What causes the cytopenia in lupus?

Type II hypersensitivity reaction

51

Drugs indicated for drug-induced lupus

Procainamide, hydralazine, isoniazid, minocycline, TNF-alpha inhibitors

52

Which patients may be more likely to get drug-induced lupus?

Slow acetylators

53

What would you see in labs in sarcoid

Elevated ACE levels, elevated CD4/CD8 ratio

54

What causes the hypercalcemia in sarcoid

Increased 1-alpha-hydroxylase-mediated vitamin D activation in macrophages

55

What might you see in acute sarcoid?

Fever, parotid enlargement, anterior uveitis, and facial nerve palsy (Heerfordt-Waldenstrom syndrome)

56

Antibodies in polymyositis/dermatomyositis

anti-Jo-1 (anti-histidyl-tRNA synthetase), anti-SRP, anti-Mi-2 antibodies

57

What causes the inflammation in polymyositis and dermatomyositis?

Poly- endomysial inflammation with CD8 cells. Dermato-perimysial inflammation with CD4 cells

58

What is myositis ossificans?

Metaplasia of skeletal muscle into bone following muscular trauma

59

Zonula occludens

Tight junction, composed of claudins and occludins

60

Zonula adherens

Adherents junction, forms belt connecting actin cytoskeletons of adjacent cells with CADherins (Ca dependent adhesion proteins). Loss of E-cadherin promotes metastasis

61

Macula adherins

Desmosome- structural support via keratin interactions

62

What is spongiosis

Epidermal accumulation of edematous fluid in intercellular spaces, seen in eczematous dermatitis

63

What is acantholysis?

Separation of epidermal cells, seen in pemphigus vulgaris

64

What causes lack of pigment in albinism vs vitiligo?

Albinism- normal melanocyte number with decreased melanin production due to decreased tyrosinase activity or defective tyrosine transport. Can also be caused by failure of neural crest cell migration during development. Vitiligo is due to autoimmune destruction of melanocytes

65

Merocrine glands

Cells secrete via exocytosis. Ex. salivary, eccrine sweat, apocrine sweat

66

Apocrine glands

Cells secrete via membrane-bound vesicles. Ex. mammary glands

67

Holocrine glands

Cell lysis releases entire contents of the cytoplasm and cell membrane. Ex. sebaceous glands, meibomian glands

68

What is rhinopehyma?

Bulbous deformation of the nose from chronic inflammatory changes in rosacea

69

Difference between cellulitis and erysipelas?

Cellulitis is an infection of the deeper dermis and subcutaneous tissues (usually s. pyogenes or s. aureus), erysipelas is an infection involving upper dermis and superficial lymphatics (usually s. pyogenes)

70

Staphylococcal scaled skin syndrome

Exotoxin destroys keratinocyte attachements in stratum granulosum only (vs TEN which destroys dermal-epidermal junction)

71

Erythema migrans vs. multiforme vs. nodosum

Migrans- lyme; multiforme- dusky circles (often HSV but can be others); nodosum- subcutaneous nodules (sarcoid, coccidioidomycosis, hystoplasmosis, TB, strep, leprosy, Crohn)

72

Sawtooth infiltrate of lymphocytes at dermal-epidermal junction

Lichen planus

73

What is lichen planus associated with?

Hep C

74

Which UV light is dominant in sunburn

UVB (UVA dominant in tanning and photoaging)

75

What is melanoma often driven by?

Activation mutation in BRAF kinase. Patients with BRAF V600E mutation may benefit from vemurafenib, a BRAF kinase inhibitor)

76

Which COX is platelet function dependent on?

COX-1 (produces TXA2)

77

MOA of bisphosphonates

Pyrophosphate analogs; binds hyroxyapatite in bone, inhibiting osteoclast activity

78

SE of bisphosphonates

Corrosive esophagitis (patients are advised to take with water and remain upright for 30 min); osteonecrosis of the jaw

79

MOA of teriparatide

Recombinant PTH analog given subcutaneously daily. Increases osteoblastic activity. Causes increased bone growth compared to antiresorptive therapies

80

What are topical vitamin D analogs used for?

Psoriasis (bind to and activate the vit D receptor, a nuclear transcription factor that causes inhibition of keratinocyte proliferation and stimulation of keratinocyte differentiation

81

What drugs have their concentrations increased if administered with allopurinol?

Azathioprine and 6-MP

82

MOA of Febuxostat

Inhibits xanthine oxidase

83

MOA of Pegloticase

Recombinant uricase that catalyze metabolism of uric acid to allantoin (a more water soluble product)

84

MOA of probenecid

Inhibits reabsorption of uric acid in proximal convoluted tubule (also inhibits secretion of penicillin)

85

What should you not give in an acute gout attack?

Salicylates. All but the highest doses depress uric acid clearance

86

Wickham striae (reticular white lines)

Mucosal involvement of lichen planus