MSK and CT Flashcards

1
Q

Osteogenesis imperfecta is due to mutations in what?

A

COL1A1 and COL1A2

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2
Q

What are the layers of the epidermis from surface to base?

A

Statum corneum (keratin), lucidum, granulosum, spinosum, basale

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3
Q

What is the role of integrins?

A

Maintain integrity of basolateral membrane of epithelial cells by binding to collagen and laminin in BM

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4
Q

What is the role of hemidesmosomes?

A

Connect keratin in basal cells to underlying BM.

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5
Q

What is the role of desmosomes?

A

Structural support via keratin interactions

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6
Q

What is the role of e-cadherin?

A

Part of adherens junction - below tight junction, forms “belt” connecting actin cytoskeletons of adjacent cells. Loss of e-cadherin promotes metastasis.

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7
Q

What is bullous pemphigoid?

A

Autoantibodies to hemidesmosomes

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8
Q

What is pemphigus vulgaris?

A

Autoantibodies to desmosomes

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9
Q

The rotator cuff muscles are innervated primarily by which spinal nerves?

A

C5-C6

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10
Q

What is does the supraspinatus do?

A

(suprascapular nerve) Abducts arm initially before the action of deltoid; most common rotator cuff injury

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11
Q

What is does the infraspinatus do?

A

(suprascapular nerve) Laterally rotates arm; pitching injury

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12
Q

What is does the teres minor do?

A

(axillary nerve) Adducts and laterally rotates arm

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13
Q

What is does the subscapularis do?

A

(subscapular nerve) Medially rotates and adducts arm

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14
Q

What are the four muscles of the rotator cuff?

A

Supraspinatus, infraspinatus, teres minor, subscapularis

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15
Q

Dislocation of which wrist bone may cause carpal tunnel syndrome?

A

Lunate

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16
Q

What is Guyon canal syndrome?

A

Compression of the ulnar nerve at the wrist or hand, classically seen in cyclists

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17
Q

Erb palsy (“waiter’s tip”) is due to injury of what?

A

Traction or tear of upper trunk: C5-C6 roots

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18
Q

What are the causes of Erb palsy?

A

Infants - Lateral traction on neck during delivery

Adults - Trauma

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19
Q

Klumpke palsy is due to injury of what?

A

Traction or tear of lower trunk (C8-T1)

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20
Q

What are the causes of Klumpke palsy?

A

Infants - Upward force of arm during delivery

Adults - Trauma (grabbing a tree branch when falling)

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21
Q

Thoracic outlet syndrome is due to injury of what?

A

Compression of lower trunk and subclavian vessels

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22
Q

What are the causes of thoracic outlet syndrome palsy?

A

Cervical rib injury; Pancoast tumor

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23
Q

Winged scapula is due to injury of what?

A

Lesion of long thoracic nerve

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24
Q

What are the causes of winged scapula?

A

Axillary node dissection after mastectomy, stab wounds

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25
Q

Describe Type 1 muscle

A

Slow twitch; red fibers

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26
Q

Describe Type 2 muscle

A

Fast twitch; white fibers - weight training results in hypertrophy of these

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27
Q

What is the difference between endochondral ossification and membranous ossification?

A

Endochondral ossification needs a cartilagenous model of bone made first. Membranous does not; calvarium and facial bones.

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28
Q

What is the function of PTH?

A

At low, intermittent levels, exerts anabolic effects. Chronic high PTH levels cause catabolic effects on bone.

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29
Q

Describe achondroplasia

A

Failure of endochondral ossification (only). Constitutive activation of fibroblast growth factor receptor (FGFR3) actually inhibits chondrocyte proliferation.

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30
Q

What is the inheritance pattern of achondroplasia?

A

Most mutations occur sporadically but condition also demonstrates autosomal dominance

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31
Q

What are treatment options for senile osteoporosis?

A

Bisphosphonates, PTH, SERMs, denosumab (monoclonal Ab against RANKL)

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32
Q

What is osteopetrosis?

A

Failure of normal bone resorption due to defective osteoclasts. Thickened, dense bones that are prone to fracture. Bones fill marrow space leading to pancytopenia and extramedullary hematopoiesis.

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33
Q

What is a treatment option for osteopetrosis?

A

Bone marrow transplant is potentially curative since osteoclasts are derived from monocytes

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34
Q

Describe Paget disease of bone (osteitis deformans)

A

Common, localized disorder of bone remodeling caused by increase in both osteoblastic and osteoclastic activity. Serum Ca, phosphorus, and PTH all normal. Increased ALP. Mosaic pattern of woven and lamellar bone; long bone chalk-stick fractures. Increased blood flow from increased arteriovenous shunts may cause high-output HF. Increased risk of osteogenic sarcoma.

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35
Q

What is the most common site of oseteonecrosis?

A

Femoral head - due to insufficiency of medial circumflex femoral artery

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36
Q

What is the most common benign tumor of bone?

A

Osteochondroma

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37
Q

What is the MOA of bisphosphatases?

A

Through bloodstream, attach to bone, then osteoclasts eat bisphosphonates and apoptosis is induced in the osteoclasts. Leads to relative increase in osteoblast activity.

38
Q

Osteomyelitis is seeded where in children and where in adults?

A

Metaphysis in kids, epiphysis in adults

39
Q

Where are osteomas usually found?

A

Surface of facial bones

40
Q

What are osteomas associated with?

A

Gardner syndrome

41
Q

Where do osteoid osteomas usually arise?

A

Cortex of long bones

42
Q

How does osteoid osteoma usually present?

43
Q

Where are giant cell tumors of bone found?

A

Epiphyseal ends of long bones

44
Q

What is the age range of giant cell tumors of the bone?

45
Q

How do giant cell tumors of the bone appear on X ray?

A

“Soap bubbles”

46
Q

Osteochondromas are usually seen in whom?

47
Q

Where are osteosarcomas found?

A

Metaphysis of long bones, often around knee

48
Q

What is the age range of osteosarcomas?

A

Primary: 10-20 YO. Secondary: >65 YO

49
Q

What are predisposing factors of osteosarcoma?

A

Primary (10-20 YO): Familial RB, Li-Fraumeni, bone infarcts

Secondary (>65 YO): Paget disease of bone, radiation, bone infarcts

50
Q

How does osteosarcoma appear on X ray?

A

Codman triangle from elevation of periosteum, or sunburst pattern

51
Q

Ewing sarcoma is usually seen in whom?

52
Q

Where does Ewing sarcoma usually appear?

A

Diaphysis of long bones, pelvis, scapula, ribs

53
Q

What are the cells of Ewing sarcoma?

A

Poorly-differentiated cells from neuroectoderm

54
Q

Ewing sarcoma is associated with what translocation?

A

t(11;22) translocation

55
Q

Osteoblastoma is very similar to which other disease process?

A

Osteoid osteoma, except it does not respond to aspirin

56
Q

Chondromas usually arise where?

A

Small bones of hands and feet

57
Q

Chondrosarcomas usually arise where?

A

Pelvis or central skeleton

58
Q

Is giant cell tumor of the bone benign or malignant?

59
Q

What exactly is Rheumatoid Factor?

A

Anti-FcIgG IgM, associated with RA

60
Q

What is gout caused by?

A

Precipitation of monosodium urate (MSU) crystals in joints.

61
Q

Describe the birefringence of gout under polarized light

A

Negative birefringent (yellow under parallel light, blue under perpendicular light)

62
Q

Describe the birefringence of pseudogout under polarized light

A

Weakly positive birefringent, blue when parallel to light

63
Q

Sjogren syndrome patients have what kind of autoantibodies?

A

Antiribonucleoprotein Abs (Anti-SSA and anti-SSB)

64
Q

Sjogren syndrome patients are at risk for which malignancy?

A

B cell lymphoma

65
Q

Sjogren syndrome is what kind of hypersensitivity reaction?

66
Q

What are treatment options for gout?

A

NSAIDs (indomethacin), glucocorticoids, colchicine

67
Q

What is pseudogout?

A

Deposition of Calcium pyrophosphate crystals within joint space

68
Q

What are the symptoms of ankylosing spondylitis?

A

Ankylosis, uveitis, aortic regurgitation

69
Q

Describe sarcoidosis

A

Immune-mediated widespread noncaseating granulomas and elevated serum ACE levels

70
Q

What is polymyalgia rheumatica?

A

Pain and stiffness in shoulders and hips, often with fever, malaise, and weight loss; no muscular weakness

71
Q

What is polymyalgia rheumatica associated with?

A

Giant cell arteritis

72
Q

What kind of immune cells are seen in polymyositis?

A

CD8+ T cells

73
Q

What exactly is inflammed in polymyositis?

A

Endomysium

74
Q

What exactly is inflammed in dermatomyositis?

A

Perimysium

75
Q

What kind of immune cells are seen in dermatomyositis?

A

CD4+ T cells

76
Q

What is parakeratosis?

A

Hyperkeratosis (corneum) with retention of nuclei in stratum corneum

77
Q

What is spongiosis?

A

Epidermal accumulation of edematous fluid in intercellular spaces

78
Q

What is acantholysis?

A

Separation of epidermal cells

79
Q

What is acanthosis?

A

Epidermal hyperplasia (spinosum)

80
Q

What is melasma aka chloasma?

A

Hyperpigmentation associated with pregnancy or OCP use

81
Q

What is Leser-Trelat sign and what can it be associated with?

A

Sudden appearance of multiple seborrheic keratoses, indicating an underlying malignancy (GI, lymphoid)

82
Q

What is dermatitis herpetiformis?

A

IgA antibodies at tips of dermal papillae. Results in pruritic papules, vesicles, and bullae

83
Q

What is dermatitis herpetiformis associated with?

A

Celiac disease. Treating the Celiac disease will treat the dermatitis.

84
Q

Toxic epidermal necrolysis is the worst form of what?

A

Stevens-Johnson syndrome

85
Q

What are actinic keratoses?

A

Premalignant lesions caused by sun exposure. Small, rough, erythematous or brownish papules or plaques. Risk of SCC.

86
Q

What is erythema nodosum?

A

Painful inflammatory lesions of subcutaneous fat, usually on anterior shins. Usu idiopathic but can be associated with sarcoidosis, coccidioidomycosis, histoplasmosis, TB, streptococcal infections, leprosy, and Crohn disease

87
Q

What is Lichen Planus?

A

6 Ps: Pruritic, Purple, Polyganol Planar Papules and Plaques. Mucosal involvement manifests as Wickham striae (reticular white lines)

88
Q

What is Lichen Planus associated with?

89
Q

What does Lichen Planus look like on histology?

A

Sawtooth infiltrate of lymphocytes at dermal-epidermal junction.

90
Q

What is the most common cancer of the immunosuppressed?

A

Squamous cell carcinoma

91
Q

What is the tumor marker of melanoma?

92
Q

Metastatic or unresectable melanoma in patients with the BRAF V600E mutation may benefit from what treatment?

A

Vemurafenib, a BRAF kinase inhibitor