MSK, Skin and Connective Tissue Flashcards Preview

Step 1 > MSK, Skin and Connective Tissue > Flashcards

Flashcards in MSK, Skin and Connective Tissue Deck (117):
1

Unhappy triad

- Common injury in contact sport due to lateral force applied to a planted leg
- Classically consists of damage to ACL, MCL and medial meniscus (attached to MCL)
- However lateral meniscus injury is more common
- Presents with acute knee pain and signs of joint injury and instability

2

Prepatellar bursitis

- Inflammation of knee's largest sac of synovial fluid
- Can be caused by repeated trauma or pressure from excessive kneeling

3

Baker cyst

Popliteal fluid collection in gastrocnemius-semimembranous bursa commonly communicating with synovial space and related to chronic joint disease

4

Shoulder muscles that form the rotator cuff

Supraspinatus:
- Innervated by supraspinatus nerve
- Abducts arm initially (before the action of the deltoid)
- Most common rotator cuff injury (trauma or degeneration and impingement → tendinopathy or tear)
- Assessed by "empty/full can" test

Infraspinatus:
- Innervated by supraspinatus nerve
- Laterally rotates arm
- Pitching injury

teres minor:
- Innervated by axillary nerve
- Adducts and laterally rotates arm

Subscapularis:
- Upper and lower subscapular nerves
- Medially roates and adducts arm

"SItS"

5

Medial epicondylitis

- Golfer's elbow
- Repetitive flexion (forehand shots) or idiopathic → pain near medial epicondyle

6

Lateral epicondylitis

- Tennis elbow
- Repetitive extension (backhand shots) or idiopathic → pain near lateral epicondyle

7

Most commonly fractured carpal bone

- Scaphoid (palpated in anatomic snuff box)
- Typically from a fall on an outstretched hand
- Prone to avascular necrosis owing to retrograde blood supply

8

Dislocation may cause acute carpal tunnel syndrome

Lunate

9

Fall on outstretched hand that causes ulnar nerve injury

Hook of the hamate

10

Carpal tunnel syndrome is associated with

- Pregnancy
- Rheumatoid arthritis
- Hypothyroidism
- Diabetes
- Dialysis-related amyloidosis
- Repetitive use

11

Guyon canal syndrome

- Compression of ulnar nerve at wrist or hand
- Classically seen in cyclists due to pressure from handlebars

12

Muscle conduction to contraction structure in skeletal and cardiac muscle

Skeletal muscle → 1 T-tubule + 2 terminal cisternae = triad

Cardiac muscle → 1 T-tubule + 1 terminal cisterna = dyad

13

What is mechanically coupled to the ryanodine receptor on the sarcoplasmic reticulum

Depolarization of the voltage-sensitive dihydropyridine receptor, mechanically coupled to the ryanodine receptor on the SR induces a conformational change in both receptors, causing Ca2+ release from SR

14

Contraction changes length of which bands

Contraction results in shortening of H and I bands and between the Z lines (HIZ shrinkage) but the A band remains the same length (A band is Always the same length)

15

Endochondral ossification

- Bones of axial skeleton, appendicular skeleton and base of skull
- Cartilaginous model of bone is first made by chondrocytes
- Osteoclasts and osteoblasts later replace with woven bone and then remodel to lamellar bone
- In adults, woven bone occurs after fractures and in Paget disease
- Defective in achondroplasia

16

Membranous ossification

- Bones of calvarium and facial bones
- Woven bone formed directly without cartilage
- Later remodeled to lamellar bone

17

Osteoblast

- Builds bone by secreting collage and catalyzing mineralization in alkaline environment via ALP
- Differentiates from mesenchymal stem cells in periosteum

18

Osteoclast

- Dissolves bone by secreting H+ and collagenases
- Differentiates from a fusion of monocyte/macrophage lineage precursors

19

PTH

- Low, intermittent levels → anabolic effects (building bone) on osteoblasts and osteoclasts (indirect)
- Chronically ↑ PTH levels (primary hyperparathyroidism) → catabolic effects (osteitis fibrosa cystica)

20

Estrogen induces and inhibits apoptosis in which cells

Inhibits apoptosis in osteoblasts and induces apoptosis in osteoclasts

21

What inhibits chondrocyte proliferation in achondroplasia

Constitutive activation of fibroblast growth factor receptor (FGFR3) inhibits chondrocyte proliferation, therefore interfering with endochondral ossification

22

Causes of osteoporosis

- Most commonly due to ↑ resorption related to ↓ estrogen levels and old age
- Can be secondary to drugs (eg steroids, alcohol, anticonvulsants, anticoagulants, thyroid replacement therapy) or other medical conditions (hyperparathyroidism, hyperthyroidism, multiple myeloma, malabsorption syndromes)

23

What causes osteopetrosis

Failure of normal bone resorption due to defective osteoclasts. Mutations (eg carbonic anhydrase II) impair ability of osteoclast to generate acidic environment necessary.

24

How does osteopetrosis cause pancytopenia and extramedullary hematopoiesis

Bone fills marrow space

25

What is potentially curative of osteopetrosis

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

26

Presentation of osteomalacia/rickets

X rays show osteopenia and "looser zones" (pseudofractures) in osteomalacia, epiphyseal widening and metaphyseal cupping/fraying in rickets. Children with rickets have bow legs bead-like costochondral junctions (rachitic rosary), craniotabes (soft skull)

27

Stages of Paget disease

- Lytic → osteoclasts
- Mixed → osteoclasts + osteoblasts
- Sclerotic → osteoblasts
- Quiescent → minimal osteoclast/osteoblast activity

28

What type of fractures are seen with Paget disease

Long bone chalk-stick fractures

29

What causes heart failure in Paget disease

↑ blood flow from ↑ arteriovenous shunts may cause high-output heart failure

30

Causes of osteonecrosis

- Corticosteroids
- Alcoholism
- Sickle cell disease
- Trauma
- "the Bends" (caisson/decompression disease)
- LEgg-Calve-Perthes disease (idiopathic)
- Gaucher disease
- Slipped capital femoral epiphysis

"CAST Bent LEGS"

31

Lab values of osteoporosis

- Normal Ca2+, PO43-, ALP, PTH
- ↓ bone mass

32

Lab values of osteopetrosis

- Normal or ↓ Ca2+
- Normal PO43-, ALP, PTH

33

Lab values of Paget disease of bone

- Normal Ca2+, PO43-, PTH
- ↑ ALP
- Abnormal "mosaic" bone architecture

34

Osteitis fibrosa cystica - Primary hyperparathyroidism

- ↑ Ca2+
- ↓ PO43-
- ↑ ALP
- ↑ PTH
- "Brown tumors" due to fibrous replacement of bone, subperiosteal thinning
- Idiopathic or parathyroid hyperplasia, adenoma, carcinoma

35

Osteitis fibrosa cystica - Seondary hyperparathyroidism

- ↓ Ca2+
- ↑ PO43-
- ↑ ALP
- ↑ PTH
- Often as compensation for CKD

36

Osteomalacia/rickets

- ↓ Ca2+
- ↓ PO43-
- ↑ ALP
- ↑ PTH
- Soft bones
- Vitamin D deficiency also causes secondary hyperparathyroidism

37

Hypervitaminosis D

- ↑ Ca2+
- ↑ PO43-
- Normal ALP
- ↓ PTH
- Caused by oversupplementation or ganulomatous disease (eg sarcoidosis)

38

Osteochondroma

- Most common benign bone tumor
- Males

39

Giant cell tumor/ osteoclastoma

- 20-40 yo
- Epiphyseal end of long bones
- Often around knee
- Locally aggressive benign tumor
- "Soap bubble" appearance on x-ray
- Multinucleated giant cells

40

Osteosarcoma/ osteogenic sarcoma

- 2nd most common primary malignant bone tumor (after multiple myeloma)
- Bimodal distribution: 10-20 yo (primary), > 65 yo (secondary)
- Predisposing factor → Paget disease, bone infarcts, radiation, familial retinoblastoma, Li-fraumeni syndrome (germline p53 mutation)
- Metaphysis of long bones, often around knee
- Codman triangle (from elevation of periosteum)
- Sunburst pattern
- Aggressive
- Treat with surgical en bloc resection (with limb salvage) and chemotherapy

41

Ewing sarcoma

- Boys

42

Osteoid osteoma

- Diaphysis
- Nighttime pain
- Central nidus

43

Juvenile idiopathic arthritis

- Most common arthritis seen in pediatric patients
- Often presents as recurrent and relapsing fevers accompanied by polyarticular joint pain, an evanescent macular, salmon-pink rash (anywhere on body)
- Rheumatoid factor not usually present
- Also associated with chronic anterior uveitis and decreased growth rates
- 30-50% develop hemophagocytic syndrome
- In adults, JIA is known as "Still disease"

44

Which glycogen storage disease is associated with Gout

Overproduction of uric acid is seen in von Gierke disease

45

Calcium pyrophosphate deposition disease is associated with

- Idiopathic (most often)
- Hemochromatosis
- Hyperparathyroidism
- Joint trauma

46

In which disease where crystals are found in joints is distribution of disease between the sexes equal

Both sexes are affected equally in calcium pyrophosphate deposition disease where as gout is more common in males

47

Is underexcretion or overproduction of uric acid a more common cause of gout

Underexcretion of uric acid

48

Prophylactic treatment of gout vs calcium pyrophosphate deposition disease

Gout → xanthine oxidase inhibitors (eg allopurinol, febuxistat)

Calcium pyrophosphate deposition disease → colchicine (can be used for acute and chronic treatment)

49

Chondrocalcinosis is seen in

Chondrocalcinosis, cartilage calcification, is seen on x-ray in calcium pyrophosphate deposition disease

50

Findings in Sjogren syndrome

- Inflammatory joint pain
- Keratoconjunctivits sicca (↓ tear production and subsequent corneal damage)
- Xerostomia (↓ saliva production)
- Presence of antinuclear antibodies: SS-A (anti-Ro) and/or SS-B (anti-La)
- Bilateral parotid enlargement

51

Complications of Sjogren syndrome

- Dental caries
- Mucosa associated lymphoid tissue (MALT) lymphoma → may present as parotid enlargement

52

Gonococcal arthritis

STI that presents as either purulent arthritis (eg knee) or triad of polyarthralgias, tenosynovitis (eg hand), dermatitis (eg pustules)

53

Enthesitis

- Inflamed insertion sites of tendons
- Associated with seronegative spondyloarthritis

54

Dactylitis and "pencil-in-cup" deformity of DIP on x-ray are associated with

Psoriatic arthritis

55

Ankylosis (joint fusion), uveitis and aortic regurgitation are associated with

Ankylosing spondylitis

56

Causes of reactive arthritis/ Reiter syndrome

- Post-GI → Shigella, Salmonella, Yersinia, Campylobacter
- Chlamydia

57

Common causes of death in SLE

- Cardiovascular disease
- Infections
- Renal disease

58

What does "RASH OR PAIN" stand for with regards to SLE

- Rash (malar or discoid)
- Arthritis (nonerosive)
- Serositis
- Hematologic disorders (eg cytopenias)
- Oral/nasopharyngeal ulcers
- Renal disease
- Photosensitivity
- Antinuclear antibodies
- Immunologic disorder (anti-DNA, anti-Sm, antiphospholipid)
- Neurologic disorders (eg seizures, psychosis)

59

Antihistone antibodies are sensitive for

Drug-induced lupus (eg hydralazine, procainamide)

60

Antinuclear antibodies and SLE

Sensitive but not specific

61

Anti-dsDNA antibodies

Specific and indicates poor prognosis (renal disease)

62

Anti-Smith antibodies

- Directed against snRNPs
- Specific but not prognostic

63

Which complement components are decreased in serum in SLE

↓ C3, C4, and CH50 due to immune complex formation

64

Treatment of SLE

- NSAIDs
- Steroids
- Immunosuppressants
- Hydroxychloroquine (traditionally, anti-malarial)

65

Antiphospholipid syndrome

- Primary or secondary autoimmune disorder (most commonly SLE)
- Diagnose based on clinical criteria including history of thrombosis (arterial or venous) or spontaneous abortion along with laboratory findings of lupus anticoagulant, anticardiolipin, anti-β2 glycoprotein antibodies
- Anticardiolipin and lupus anticoagulant can cause false positive VDRL/RPR and PROLONGED PTT
- Not corrected with 1:1 fresh frozen plasma
- Treat with systemic anticoagulation

66

Mixed connective tissue disease

- Features of SLE, systemic sclerosis, and/or polymyositis
- Associated with anti-U1 RNP antibodies (speckled ANA)
- U1 RNP = U1 snRNP → also associated with splicesome

67

Sarcoidosis is associated with

- Restrictive lung disease (interstitial fibrosis)
- Erythema nodosum
- Lupus pernio (skin lesions on face resembling lupus)
- Bell palsy
- Epithelioid granulomas containing microscopic Schaumann and asteroid bodies
- Uveitis
- Hypercalcemia

68

Polymyalgia rheumatica

- Pain and stiffness in shoulders and hips, often with fever, malaise, and weight loss
- Does NOT cause muscular weakness
- More common in women > 50 years old
- Associated with giant cell (temporal) arteritis
- ↑ ESR, ↑ CRP, normal CK
- Rapid response to low-dose corticosteroids

69

Fibromyalgia

- Most commonly seen in females 20-50 years old
- Chronic, widespread musculoskeletal pain associated with stiffness, paresthesias, poor sleep, fatigue, cognitive disturbance ("fibro fog")
- Treatment: regular exercise, antidepressants (TCAs, SNRIs), anticonvulsants

70

Antibodies seen in polymyositis and dermatomyositis

- ↑ CK
- ANA +
- Anti-Jo-1 + → histidyl tRNA synthase
- Anti-SRP + → signal recognition particle, universally conserved ribonucleoprotein that recognizes and targets specific proteins to the endoplasmic reticulum in eukaryotes and plasma membrane in prokaryotes
- Anti-Mi-2 +

71

Compare polymyositis and dermatomyositis

Polymyositis:
- Progressive symmetric proximal muscle weakness, characterized by endomysial inflammation with CD8+ T cells
- Most often involves the shoulders

Dermatomyositis:
- Similar to polymyositis
- Malar rash (similar to SLE)
- Grotton papules
- Heliotrope (erythematous periorbital) rash
- "Shawl and face" rash
- "Mechanic's hands"
- ↑ risk of occult malignancy
- Perimysial inflammation and atrophy with CD4+ T cells

72

Dermatomyositis - endomysial or perimysial inflammation

Perimysial inflammation and atrophy with CD4+ T cells

73

Polymyositis - endomysial or perimysial inflammation

Endomysial inflammation with CD8+ T cells

74

Compare the presentation of myasthenia gravis and Lambert-Eaton myasthenic syndrome

Myasthenia gravis → ptosis, diplopia, weakness; worsens with muscle use

Lambert-Eaton → proximal muscle weakness, autonomic symptoms (dry mouth, impotence); improves with muscle use

75

Myositis ossificans

- Heterotropic ossification of skeletal muscle following muscular trauma
- Most often seen in upper or lower extremity
- May present as suspicious mass at site of known trauma or as incidental finding on radiography

76

Scleroderma/ systemic sclerosis

- Triad → autoimmunity, noninflammatory vasculopathy and collagen deposition with fibrosis
- Commonly sclerosis of skin, manifesting as puffy, taut skin without wrinkles, fingertip pitting
- Also sclerosis of renal, pulmonary (most common cause of death), cardiovascular, GI systems
- 2 major types → diffuse and limited

77

Most common cause of death in scleroderma

Sclerosis of pulmonary system

78

Diffuse scleroderma

- Widespread skin involvement
- Rapid progression
- Early visceral involvement
- Associated with anti-Scl-70 antibody (anti-DNA topoisomerase I antibody)

79

Limited scleroderma

- Limited skin involvement confined to fingers and face
- Also with CREST syndrome
- Calcinosis
- Raynaud phenomenon
- Esophageal dysmotility
- Sclerodactyly
- Telangiectasia
- More benign clinical course than diffuse scleroderma
- Associated with anti-Centromere antibody

80

Tight junction

- Zonula occludens
- Prevents paracellular movement of solutes
- Composed of claudins and occludins

81

Adherens junction

- Belt desmosome, zonula adherens
- Below tight junction, forms "belt" connecting actin cytoskeletons of adjacent cells with CADhereins (Ca+ dependent adhesions proteins)
- Loss of E-cadherin promotes metastasis

82

Desmosomes

- Spot desmosome, macula adherens
- Structural support via intermediate filament interactions
- Autoantibodies → pemphigus vulgaris

83

Gap junctions

Channel proteins called connexons permit electrical and chemical communication between cells

84

Integrins

Membrane proteins that maintain the integrity of basolateral membrane by binding to collagen and laminin in basement membrane

85

Hemidesmosome

- Connects keratin in basal cells to underlying basement membrane
- Autoantibodies → bullous pemphigoid

86

Compare the presentation of intradermal and junctional nevi

Intradermal nevi → papular
Junctional nevi → macule

87

What layers of the epidermis are increased and decreased in psoriasis

- ↑ stratum spinosum (a part of acanthosis)
- ↓ stratum granulosum

Also seen is acanthosis with parakeratotic scaling (nuclei still in stratum corneum)

88

What changes are seen in the epidermis of verrucae

Epidermal hyperplasia, hyperkeratosis (↑ thickness of stratum corneum), koilocytosis

89

What are characteristic findings of utricaria

Superficial dermal edema and lymphatic channel dilation

90

Hyperkeratosis

- ↑ thickness of stratum corneum
- Psoriasis, calluses

91

Parakeratosis

- Hyperkeratosis with retention of nuclei in stratum corneum
- Psoriasis

92

Hypergranulosis

- ↑ thickness of stratum granulosum
- Lichen planus

93

Spongiosis

- Epidermal accumulation of edematous fluid in intercellular spaces
- Eczematous dermatitis (utricaria)

94

Acantholysis

- Separation of epidermal cells
- Pemphigus vulgaris

95

Acanthosis

- Epidermal hyperplasia (↑ spinosum)
- Acanthosis nigricans

96

Angiosarcoma

- Rare blood vessel malignancy typically occuring in the head, neck and breast areas
- Usually in elderly, on sun-exposed areas
- Associated with radiation therapy and chronic postmastectomy lymphedema
- Hepatic angiosarcoma → associated with vinyl chloride and arsenic exposures
- Very aggressive and difficult to resect due to delay in diagnosis

97

Cystic hygroma

Cavernous lymphangioma of the neck. Associated with Turner syndrome.

98

Glomus tumor

Benign, painful, red-blue tumor, commonly under fingernails. Arises from modified smooth muscle cells of the thermoregulatory glomus body.

99

Pyogenic granuloma

Polyploid lobulated capillary hemangioma that can ulcerate and bleed. Associated with trauma and pregnancy.

100

Differentiate bacillary angiomatosis and Kaposi sarcoma

Bacillary angiomatosis → benign capillary skin papules found in AIDS patients; caused by Bartonella henselae infections; has neutrophilic infiltrate

Kaposi sarcoma → endothelial malignancy most commonly of the skin, but also mouth, GI tract, and respiratory tract; associated with HHV-8 and HIV; has lymphocytic infiltrate

101

Compare Staphylococcal scalded skin syndrome and TEN

Exotoxin of S aureus destroys keratinocyte attachments in stratum granulosum only, vs TEN which destroys dermal-epidermal junction

102

Staphylococcal scalded skin syndrome is seen in

Newborns, children and adults with renal insufficiency

103

Acantholysis is characteristic of

- Pemphigus vulgaris
- Acantholysis = keratinocytes in stratum spinosum are connected by desmosomes

104

Tense blisters of bullous pemphigoid contain

Eosinophils

105

Pemphigus vulgaris and bullous pemphigoid - which involves oral mucosa

Pemphigus vulgaris involves oral mucosa

106

Dermatitis herpetiforms

- Pruritic papules, vesicles, and bullae (often found on elbows)
- Deposits of IgA at tips of dermal papillae
- Associated with celiac disease
- Treatment → dapsone, gluten free diet

107

Erythema multiforme is associated with

- Infections (eg Mycoplasma pneumoniae, HSV)
- Drugs (eg sulfa drugs, beta lactams, phenytoin)
- Cancers
- Autoimmune disease

108

How many mucous membranes are usually involved with Stevens-Johnson syndrome

2

109

When is erythema multiforme/ Stevens-Johnson syndrome categorized as toxic epidermal necrolysis

> 30% of body surface involved

110

With actinic keratosis, the risk of SCC is proportional to

Degree of epithelial dysplasia

111

Erythema nodosum is associated with

- Sarcoidosis
- Coccidiomycosis
- Histoplasmosis
- TB
- Streptococcal infections
- Leprosy
- Inflammatory bowel disease

112

Lichen planus is associated with

Hepatitis C

113

Describe microscopic findings of lichen planus

Sawtooth infiltrate of lymphocytes at dermal-epidermal junction

114

Which skin cancer is associated with palisading nuclei

BCC

115

Which skin cancer is associated with chronic draining sinuses

SCC

116

Name 4 types of melanoma

- Superficial spreading
- Nodular
- Lentigo maligna
- Acral lentiginous

117

Vemurafenib benefits which patients

Patients with BRAF V600E mutations and metastatic or unresectable melanoma. Vemurafenib is a BRAF kinase inhibitor.