MSK/Dermatology Flashcards

1
Q
Physical exam signs for...
ACL injury
PCL injury
MCL injury
LCL injury
Medial meniscus tear
Lateral meniscus tear
A

Anterior drawer sign
Posterior drawer sign
Abnormal passive abduction (medial space widening)
Abnormal passive adduction (lateral space widening)
Pain, popping on external rotation
Pain, popping on internal rotation

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2
Q

Result of lateral force applied to planted leg - presents with acute knee pain and joint instability

A

UNHAPPY TRIAD

ACL
MCL
Medial meniscus

Note - Lateral meniscus damage is not classical but more common

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3
Q

Caused by excessive kneeling

A

Prepatellar bursitis

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4
Q

Popliteal fluid collection in gastrocnemius-semimembranosus bursa

A

BAKER CYST

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5
Q
Rotator cuff muscles and nerves...
Initial abduction
External rotation
Adduction and external rotation
Adduction and internal rotation
A

Supraspinatus - Suprascapular nerve
Infraspinatus - Suprascapular nerve
Teres minor - Axillary nerve
Subscapularis - Subscapular nerves

Note - All nerves primarily from C5-C6

Note - Supraspinatus most likely to be injured due to impingement between the humeral head and acromium

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6
Q

Caused by repetitive flexion (forehand)

A

Medial epicondylitis (Golfer’s elbow)

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7
Q

Caused by repetitive extension (backhand)

A

Lateral epicondylitis (Tennis elbow)

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8
Q

Wrist bones (lateral to medial; medial to lateral)

A

Scaphoid, Lunate, Triquetrum, Pisiform
Hamate, Capitate, Trapezoid, Trapezium

Note - Hook of hamate causes ulnar nerve injury

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9
Q

Risk factors for carpal tunnel

Note - Lunate fracture can cause acute carpal tunnel

A
Pregnancy
Rheumatoid arthritis
Hypothyroidism
Diabetes
Dialysis-related amyloidosis

Note - Sensation spared on palmar surface as palmar cutaneous branch is external to tunnel

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10
Q

Paresthesia, pain, and numbness in distribution of ulnar nerve in hand

A

GUYON CANAL SYNDROME

Typically seen in cyclists

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11
Q

Humeral neck fracture or anterior dislocation…

Flattened deltoid
Loss of abduction above 15 degrees
Loss of sensation over lateral arm

A

AXILLARY NERVE

C5-C6

Note - Runs along posterior circumflex artery

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12
Q

Upper trunk compression…

Loss of elbow (forearm) flexion
Loss of sensation over lateral forearm

A

MUSCULOCUTANEOUS NERVE

C5-C7

Note - Lateral cord

Note - Sensation over medial forearm is by medial antebrachial cutaneous nerve (medial cord - C8-T1)

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13
Q

Humeral midshaft fracture
Humeral anterolateral supracondylar fractures
Crutches
Saturday night palsy…

Wrist drop (extension)
Decreased grip strength
Loss of sensation over posterior arm and forearm, and dorsomedial hand
A

RADIAL NERVE

C5-T1 - Posterior cord gives rise to Axillary and Radial nerves

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14
Q

Humeral anteromedial supracondylar fracture…

“Ape hand” and “Pope’s blessing” when making fist
Loss of wrist flexion
Loss of 1st and 2nd lumbricals
Loss of sensation over dorsal and palmar lateral 3.5 fingers

A

PROXIMAL MEDIAN NERVE

C5-T1 - Combination of lateral and medial cords

Note - Distal median nerve lesion (e.g. wrist laceration) results in “median claw” on extension (more severe exaggeration)

Note - Runs with brachial artery in the humerus

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15
Q

Humeral medial epicondyle fracture (“funny bone”)…

“Ok sign” on making a fist
Radial wrist deviation on flexion
Loss of 3rd and 4th lumbricals
Loss of interossei (adduction, abduction)
Loss of sensation over dorsal and palmar medial 1.5 fingers

A

PROXIMAL ULNAR NERVE

C8-T1 - Medial cord

Note - Distal ulnar nerve lesion (e.g. fractured hamate) results in “ulnar claw” on extension (more severe exaggeration)

Note - Ulnar claw looks like “Pope’s blessing,” while median claw looks like “ok sign”

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16
Q

Superficial laceration of palm…

“Ape hand”
Loss of thenar function
No loss of sensation

A

RECURRENT BRANCH OF MEDIAN NERVE

C5-T1

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17
Q

Cause of…
Abduction deficit
Lateral motion deficit
Flexion, supination deficit

A

ERB PALSY

Traction or tear of upper brachial trunk (C5-C6) - pulling on neck

Deltoid, Supraspinatus
Infraspinatus
Biceps

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18
Q

Cause of…
Total claw hand - no flexion of MCP or extension of any
DIP/PIP

A

KLUMPKE PALSY

Traction or tear of lower brachial trunk (C8-T1) - pulling on arm or thoracic outlet syndrome (e.g. pancoast tumor)

Intrinsic hand muscles (lumbricals, interossei, thenar, hypothenar)

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19
Q

Cause of…
Winged scapula
Cannot abduct arm above horizontal

A

WINGED SCAPULA

Lesion of long thoracic nerve (C5-C7) - From branchial roots. Innervates the serratus anterior which rotates the scapula upward allowing complete abduction the arm over the head

Note - Runs along lateral thoracic artery

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20
Q

Functions of dorsal and palmar interossei

A

Dorsal - Abduct

Palmar - Adduct

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21
Q

Pelvic surgery…

Decreased medial thigh sensation
Decreased thigh adduction

A

OBTURATOR

L2-L4

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22
Q

Pelvic fracture…

Decreased thigh flexion
Decreased leg extension

A

FEMORAL

L2-L4

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23
Q

Fibula neck fracture…

Loss of eversion and dorsiflexion - foot drop
Loss of sensation on dorsal foot

A

COMMON PERONEAL

L4-S2

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24
Q

Knee trauma, Baker’s cyst (proximal), or tarsal tunnel syndrome (distal)…

Inability to curl toes
Loss of inversion and plantarflexion (proximal) - can’t stand on tiptoes
Loss of sensation on plantar foot

A

TIBIAL

L4-S3

Note - Runs along popliteal to posterior tibial artery

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25
Q

IM injection to gluteal region…

Trendelenburg sign - Contralateral hip drop on standing
Gluteus lurch - Ipsilateral lean on walking

A

SUPERIOR GLUTEAL

L4-S1

Note - Choose superolateral gluteal quadrant

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26
Q

Posterior hip dislocation…

Loss of hip extension - Rising from seated position or climbing stairs

A

INFERIOR GLUTEAL

L5-S2

Note - Innervates gluteus maximus, while medius and minimus is by superior gluteal

Note - Gluteus maximus for hip extension, while medius and minimus for hip abduction

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27
Q

Weakness of knee extension

Decreased patellar reflex

A

L3/L4 RADICULOPATHY

Note - Disc herniation is usually posterolateral

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28
Q

Weakness of dorsiflexion

Difficulty in heel walking

A

L4/L5 RADICULOPATHY

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29
Q

Weakness of plantar flexion
Difficulty in toe walking
Decreased achilles reflex

A

L5/S1 RADICULOPATHY

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30
Q

Mechanism of skeletal muscle NMJ

Note - Skeletal NMJ is 1 T-tubule (plasma membrane) with 2 terminal cisternae (SR) making a triad, while cardiac NMJ is only a dyad

A

Neurotransmitter leads to motor end plate depolarization
Depolarization travels along muscle down T-tubule

Voltage-sensitive dihydropyridine receptor on T-tubule mechanically induces conformational change in RYR1 receptor on SR

Ca released from SR
Ca binds Troponin C
Tropomyosin released from actin filaments
Myosin binds actin filament
Myosin releases bound ADP and Pi - Power stroke
Binding of new ATP releases myosin
ATP hydrolysis to ADP “cocks” myosin

Note - Mechanical coupling induces resistance to CCBs which mostly affect Ca-induced-Ca release (smooth, cardiac)

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31
Q

Lengths of H, I, Z, and A bands during contraction

A
H zone (Myosin without Actin, near M line) - Shortens
I band (Actin without Myosin, near Z line) - Shortens
Z line (Sarcomere boundaries) - Shortens
A band (Entire Myosin) - Constant
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32
Q
Difference between type 1 and type 2 muscle fibers...
Speed
Contents
Contraction
Increased with

(“1 slow, red ox”)

A
Type 1:
Slow
Red (mitochondria, myoglobin)
Sustained
Endurance training
Type 2:
Fast
White (anaerobic glycolysis, glycogen)
Not-sustained
Resistance training
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33
Q

Mechanism of smooth muscle contraction/relaxation

A
L-type voltage gated Ca channels open
Ca-calmodulin complex forms
Myosin-light-chain kinase activated
Myosin + Actin converted to Myosin-P + Actin
Contraction

Parasympathetic (Ach, Bradykinin) on Guanyl Cyclase
Activates cGMP
cGMP/PKG activate Ca channels
NO synthase converts L-Arginine to NO
NO diffuses from endothelial cell into smooth muscle cell
NO converts CTP to cGMP
Activation of Myosin-light chain phosphatase
Myosin-P + Actin converted to Myosin + Actin
Relaxation

Note - No T-tubules

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34
Q

Difference between endochondral (axial, appendicular, skull base) and membranous (calvarium, facial) ossification

A

Endochondral:
Cartilaginous model of bone by Chondrocytes
Osteoclasts/Osteoblasts replace with woven bone
Woven bone remodeled to lamellar bone

Note - Increased woven bone in fractures and Paget (osteitis deformans)

Membranous:
Woven bone formed directly (no chondrocytes)
Woven bone remodeled to lamellar bone

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35
Q

Mechanism of osteoblast function

Note - At low intermittent levels PTH stimulates, but chronically high levels (hyperparathyroidism) results in catabolism

A

Mesenchymal origin:

Secretes collagen and catalyzes mineralization in alkaline environment via ALP

Response to to mechanical stress via signals from osteocytes

Note - Apoptosis inhibited by estrogen

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36
Q

Mechanism of osteoclast function

A

Monocyte/Macrophage origin - Secretes H and collagenase to break down bone

Note - Apoptosis induced by estrogen

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37
Q

Acute back pain
Loss of height
Kyphosis

Normal Ca
Normal PO4
Normal PTH
Normal ALP

A

VERTEBRAL COMPRESSION FRACTURE

Often secondary to osteoporosis - diagnosed with T-score < -2.5 or fragility fracture of hip/vertebrae

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38
Q
Fragility fractures
Generalized osteosclerosis
Pancytopenia/extramedullary hematopoiesis
Cranial nerve impingement
"Bone in bone" on XR

Normal or decreased Ca
Normal PO4
Normal PTH
Normal ALP

A

OSTEOPETROSIS

Carbonic anhydrase II mutation results in inability of osteoclasts to secrete H - No mature trabeculae (spongiosa filling medullary canals)

Treat with bone marrow transplant

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39
Q
Craniotabes (soft skull)
Bow legs
Epiphyseal widening
Metaphyseal cupping and fraying
Rachitic rosary at costochondral junction
Decreased vit D
Decreased Ca
Decreased PO4
Increased PTH
Increased ALP
A

RICKETS

In adults presents as osteomalacia - XR shows osteopenia and pseudofractures only

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40
Q

Long bone chalk-stick fractures
Increased hat size
Hearing loss

Normal Ca
Normal PO4
Normal PTH
Elevated ALP
Osteocytes with lacunae in chaotic juxtaposition - Mosaic pattern of woven and lamellar bone

Note - AV shunts may cause high output HF

A

PAGET (OSTEITIS DEFORMANS)

Presents in lytic (osteoclasts), mixed (osteoclasts + osteoblasts), scelrotic (osteoblasts), and quiescant stages

Increased risk of osteogenic sarcoma (osteosarcoma) which has:

1) destruction of normal trabecular bone pattern
2) mixed radiodense and radiolucent areas
3) periosteal new bone formation
3) lifting of the cortex
4) codmans triange
5) sunburst pattern

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41
Q

Common causes of avascular necrosis of femoral head

Note - Medial circumflex femoral insufficiency

A
Corticosteroids --> crescent sign (subchondral collapse)
Trauma
Alcoholism
Legg-Calve-Perthes (insidious)
SCFE (acute)
SCD
Gaucher disease
Decompression disease
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42
Q
Mechanism of...
Hypercalcemia
Hyperphosphatemia
Decreased PTH
Normal ALP
A

HYPERVITAMINOSIS D

Caused by supplements of granulomatous disease (e.g. sarcoidosis)

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43
Q

Young male with…

Bony exostosis with cartilaginous cap

A

OSTEOCHONDROMA

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44
Q

Young adult with…
Soap-bubble on XR at epiphysis of long bones (knee)
Multinucleated giant cells

A

GIANT CELL TUMOR

Locally aggressive benign tumor

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45
Q

Teenager or elderly with…
Codman triangle - elevation of periosteum
Sunburst on XR at metaphysis of long bones (knee)

Note - Second most common bone malignancy after Multiple Myeloma

A

OSTEOSARCOMA

Aggressive - limb salvage and chemotherapy

Associated with...
Paget (osteitis deformans)
Ischemia
Radiation
Retinoblastoma
Li-Fraumeni p53 mutation (Sarcoma, Breast, Blood, Adrenal)
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46
Q

Teenage boy with…
Onion skin periosteal reaction
Diaphysis of long bones, pelvis, scapula, or ribs
Anaplastic small blue cell

A

EWING SARCOMA

t(11:22) translocation resulting in EWS-FL11 fusion protein

Extremely aggressive with early metastasis but responsive to chemotherapy

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47
Q
Joint findings associated with...
Weight bearing joints
DIP/PIP/CMC
Joint pain at the end of the day
"catching/locking" sensation
Asymmetric involvement
Bowleggedness (varus)

excess biomechanical stress and increased intraarticular metalloprotease activity results in degradation of type II collagen and proteoglycans within articular cartilage

A

OSTEOARTHRITIS

Osteophytes (bone spurs)
Joint space narrowing
Subchondral sclerosis and cysts
Slight synovial hypertrophy
Non-inflammatory synovial fluid (< 2000)
Associated with...
Elderly
Female
Obese
Prior trauma
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48
Q
Joint and immunologic findings associated with...
MCP, PIP, wrist - not DIP or CMC
Pain, swelling, and morning stiffness > 1 hr
Improvement with use
Symmetric involvement
Constitutional symptoms
Ulnar deviation
Subluxation
Swan neck
A

RHEUMATOID ARTHRITIS

immune complex deposition, neutrophil accumulation, perivascular inflammation, osteoclastic activity
Pannus (proliferative granulation tissue)
Bone and cartilage erosion
Increased synovial fluid
Juxtaarticular osteopenia
Inflammatory synovial fluid (> 2000)

HLA-DR4
Rheumatoid factor (anti-IgG)
Anti-cyclic citrullinated peptide (specific)

Associated with…
Female
Smoking
Silica

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49
Q

Extra-articular manifestations of rheumatoid arthritis

A
Skin nodules (fibrinoid necrosis with palisading histiocytes)
Lung nodules (Caplan's syndrome)
ILD
Pleuritis, Pericarditis
Felty syndrome (neutropenia, splenomegaly)
AA amyloidosis
Sjogren's syndrome
Scleritis
Carpal tunnel
50
Q
Needle shaped Monosodium urate crystals
Negatively birefringent under polarized light
Yellow under parallel light
Blue under perpendicular light
Numerous neutrophils
A

GOUT

Treat with NSAIDs, Glucocorticoids, Colchicine
Prevent with Xanthine oxidase inhibitors

why inflammation?

Normally urate crystals have a protective coating of APO E or B. When uric acid levels fluctuate or microtrauma occurs, bare urate crystals are shed and exposed to IgG antibodies. The subsequent antibody binding leads to neutrophil phagocytosis and release of inflammatory cytokines like IL-1

51
Q
Chondrocalcinosis on XR
Rhomboid crystals
Weakly positively birefringent
Blue under parallel light
Yellow under perpendicular light
A

CALCIUM PYROPHOSPHATE DEPOSITION (PSEUDOGOUT)

Treat with NSAIDs, Glucocorticoids, Colchicine
Prevent with Colchicine

52
Q
Inflammatory joint pain
Bilateral parotid enlargement
Keratoconjunctivitis
Xerostomia
Dental caries
Antiribonucleoprotein - SS-A (anti-Ro), SS-B (anti-La)

Note - ANA and RF may also be present

A

SJOGREN SYNDROME

Note - MALT may present as parotid enlargement

53
Q

Most common etiologies (3) of septic arthritis

A

S. aureus
Streptococcus
N. gonorrhoeae

Note - N. gonorrhoeae may present as polyarthralgia, tenosynovitis, and dermatitis instead if disseminated

54
Q

HLA associated with seronegative spondyloarthritis - no Rheumatoid factor (anti-IgG antibody)

Present as morning stiffness better with exercise and enthesitis

A

HLA-B27

Includes...
Psoriatic arthritis
Ankylosing spondylitis
IBD
Reactive arthritis
55
Q

“Pencil in cup” deformity on XR

A

Psoriatic arthritis

56
Q

Bamboo spine on XR
Uveitis
Aortic regurgitation

A

ANKYLOSING SPONDYLITIS

Symmetric involvement of spine and sacroiliac joint results in joint fusion (ankylosis)

57
Q
Etiologies associated with...
Urethritis
Enthesitis
Asymmetrical arthritis
Conjunctivitis
Occurs post...
Shigella
Salmonella
Yersinia
Campylobacter
Chlamydia
A

REACTIVE ARTHRITIS (REITER SYNDROME)
HLA B27
Deposition of immune complexes

Note: Not disseminated infection, joint aspirates are sterile

58
Q

Anti-histone antibodies

A

DRUG INDUCED LUPUS

Hydralazine
Procainamide

59
Q

False positive VDRL/RPR

Falsely prolonged aPTT

A

Anticardiolipin antibodies and Lupus anticoagulant

Note - APS also increases anti-b2 glycoproteins

60
Q

Speckled ANA

anti-U1 RNP antibodies

A

MIXED CONNECTIVE TISSUE DISEASE

Presents as mixture of…
SLE
Systemic sclerosis
Polymyositis

61
Q

Elevate CD4+/CD8+ ratio in bronchoalveolar lavage
Enlarged lymph nodes
Extensive hilar and mediastinal adenopathy
Elevated ACE

A

SARCOIDOSIS

Associated with...
ILD
Bell palsy
Erythema nodosum
Epithelioid granuloma (Schaumann and asteroid bodies)
Uveitis
Hypercalcemia
62
Q
Pain and stiffness in shoulders and hips
Normal strength
Constitutional signs
Elevated ESR
Elevated CRP
Normal CK
A

POLYMYALGIA RHEUMATICA

Treat with steroids - always investigate for giant cell (temporal) arteritis

63
Q
Elevated CK
ANA+
Anti-Jo-1+ (aminoacyl tRNA synthetase)
Anti-SRP+ (signal recognition particle)
Anti-Mi-2+ (helicase DNA binding protein)

Associated with…
ILD
Myocarditis

A

POLYMYOSITIS/DERMATOMYOSITIS

64
Q

Histology of…

Progressive symmetric muscle weakness

A

POLYMYOSITIS

Endomysial inflammation
CD8+ T cells

65
Q
Histology of...
Progressive symmetric muscle weakness
Gottron papules
Heliotrope (periorbital) rash
Shawl and face rash
A

DERMATOMYOSITIS

Perimysial inflammation
CD4+ T cells

Note - Increased risk of occult malignancy

66
Q

Proximal muscle weakness
Improves with use
Autonomic symptoms (dry mouth, impotence)

A

LAMBERT-EATON SYNDROME

Auto-antibodies against presynaptic Ca channel leads to decreased Ach release - AchE inhibitors have minimal effect

Treat by removal of possible SCLC

67
Q

Suspicious calcified mass at site of previous trauma

A

MYOSITIS OSSIFICANS

68
Q

Triad of…
Autoimmunity
Noninflammatory vasculopathy
Collagen deposition with fibrosis

A

SCLERODERMA (SYSTEMIC SCLEROSIS)

69
Q
Antibody associated with...
Widespread skin sclerosis
Rapid progression
Early visceral involvement
Mortality from PAH or ILD
A

DIFFUSE SCLERODERMA

Anti-Scl-70 (anti-DNA topoisomerase I)

70
Q
Antibody associated with...
Calcinosis
Raynaud
Esophageal dysmotility
Sclerodactyly
Telangiectasias
A

LIMITED SCLERODERMA (CREST)

Anti-centromere

71
Q

Color sequence and treatment of Raynaud’s disease (primary) or Raynaud’s syndrome (secondary)

Note - Secondary causes include SLE, CREST, and mixed connective tissue disease

A

White (ischemia)
Blue (hypoxia)
Red (reperfusion)

Treat with Ca channel blockers

Note - Only secondary results in digital ulceration (critical ischemia)

72
Q

Layers of epidermis (surface to base)

A
Stratum Corneum (keratin)
Stratum Lucidum
Stratum Granulosum
Stratum Spinosum (desmosomes)
Stratum Basale
73
Q

Structure and function of Tight Junctions (zona occludens)

A

Claudins and Occludins - Prevent paracellular movement of solutes

74
Q

Structure and function of Adherens Junctions (zonula adherens)

A

Connects adjacent cytoskeletons with E-Cadherins (Ca-dependent adhesion proteins, loss of Ca will cause loss of cell-cell adhesions)

Note - Loss results in metastasis

75
Q

Structure and function of Desmosomes (macula adherens)

A

Connection of adjacent Cadherins (Desmoglein, Desmocollin) allows for structural support

Note - Autoantibodies result in pemphigus vulgaris

76
Q

Structure of gap junctions

A

Connexons - located under desmosomes

Note - Allows for myocardial and uterine contractions

77
Q

Structure and function of Hemidesmosomes

A

Connects Keratin to underlying BM

Note - Autoantibodies results in bullous pemphigoid

78
Q

Structure and function of Integrins

A

Membrane proteins which connect intracellular microfilaments to ECM (Fibronectin, Collagen, Laminin)

79
Q

Mechanism of Albinism

A

Decreased Tyrosinase activity or defective tyrosine transport results in decreased melanin production - normal number of melanocytes

Note - Compare to vitiligo which is autoimmune destruction of melanocytes

80
Q

Hyperpigmentation associated with pregnancy or OCP use

A

MELASMA (CHLOASMA)

81
Q

Increased stratum corneum (hyperkeratosis)
Nuclei in stratum corneum (parakeratosis)
Increased stratum spinosum (acanthosis)
Decreased stratum granulosum
Clubbed Rete ridges
Microabscesses
Auspitz sign - Pinpoint bleeding from dermal papillae with scraping

A

PSORIASIS

Treat with Calcipotriol - Inhibits proliferation while inducing differentiation

Note - Associated with psoriatic arthritis, pitting nails, and uveitis

82
Q

Erythematous papules and pustules on face
Facial flushing
No comedones

A

ROSACEA

Phymatous Rosacea - bulbous deformation of nose

83
Q

Flat, greasy, pigmented plaque
Squamous epithelial proliferation
Keratin-filled cysts (horn cysts)
Looks “stuck on”

A

SEBORRHEIC KERATOSIS

Benign unless sudden eruption - Leser-Trelat sign

84
Q

Epidermal hyperplasia
Hyperkeratosis
Koilocytosis (large dark nuclei, peripheral halo)

A

VERRUCAE (CONDYLOMA ACUMINATUM)

Note - Condyloma lata is smooth, not cauliflower

85
Q

Skin cancer associated with radiation and chronic postmastectomy lymphedema

A

ANGIOSARCOMA

86
Q

AIDS patient with…
Benign capillary skin papule
Neutrophilic infiltrate

A

BACILLARY ANGIOMATOSIS

Bartonella henselae

87
Q

Hemangioma that does not regress - frequency increases with age

A

CHERRY HEMANGIOMA

88
Q

Cavernous lymphangioma of the neck - associated with Turner syndrome

A

CYSTIC HYGROMA

89
Q

Painful, red-blue benign tumor under fingernails

A

GLOMUS TUMOR

Modified smooth muscle cells of thermoregulatory glomus body (shunts blood away in cold temp to prevent heat loss and shunt blood towards fingers when hot to promote heat loss)

90
Q

Aids patient with…
Cutaneous or GI tract maculopapular lesion or hemorrhagic polypoid lesion
Spindle shaped tumor cells with vessel proliferation

A

KAPOSI SARCOMA

HHV-8

Note - Endothelial malignancy

91
Q

Polyploid lobulated capillary hemangioma

May ulcerate and bleed

A

PYOGENIC GRANULOMA

Associated with trauma and pregnancy

92
Q

Etiology of impetigo

A

S. aureus (especially bullous)

S. pyogenes

93
Q

Infection of upper dermis and superficial lymphatics - clear demarcation

A

ERYSIPELAS

S. pyogenes

Note - Cellulitis is infection of deeper dermis and SQ tissues (S. aureus, S. pyogenes)

94
Q

Purple skin
Bullae
Crepitus (methane, CO2)

A

NECROTIZING FASCIITIS

S. pyogenes
Anaerobes

95
Q
Child or adult with renal insufficiency...
Fever
Generalized erythematous rash
Sloughing of upper epidermis
Nikolsky sign
Heals completely
A

STAPHYLOCOCCAL SCALDED SKIN SYNDROME

S. aureus exfoliative exotoxin destroys keratinocyte attachments in Stratum Granulosum only

96
Q

Irregular, white, painless plaques on lateral tongue that cannot be scraped off

A

HAIRY LEUKOPLAKIA

EBV in HIV patients and organ transplant patients

Note - Thrush is scrapable, and leukoplakia (precancerous) is on top of tongue

97
Q

Flaccid intraepidermal bullae
Involves oral mucosa
Nikolsky sign
Stratum Spinosum acantholysis (separation of epidermal cells)
IF shows antibodies around epidermal cells in reticular pattern

A

PEMPHIGUS VULGARIS

IgG against Desmoglein in Desmosomes - desmosomes hold stratum Spinosum Keratinocytes together

98
Q

Tense blisters containing eosinophils
Spares oral mucosa
No Nikolsky sign
IF shows linear pattern at epidermal-dermal junction

A

BULLOUS PEMPHIGUS

IgG against Hemidesmosomes

99
Q

Pruritic papules, vesicles, bullae at elbows
IgA at tip of dermal papillae
subepidermal blisters

cross reactivity of anti-gliadin IgA antibodies with transglutaminase at the dermal basement membrane

A

DERMATITIS HERPETIFORMIS

Associated with Celiac

Treat with…
Dapsone
Gluten-free diet

100
Q

Fever
Bullae and necrosis
Sloughing at dermal-epidermal junction
Involves 2 mucous membranes

A

STEVENS-JOHNSON SYNDROME

> 30% involvement - Toxic Epidermal Necrolysis

101
Q

Small, sandpaper, erythematous papules or plaques
Hyperkeratosis
Parakeratosis

A

ACTINIC KERATOSIS

Associated with sun exposure - may develop into SCC

102
Q

Pruritic, purple, polygonal planar papules and plaques
Increased Stratum Granulosum (hypergranulosis)

Sawtooth lymphocytic infiltrate at dermal-epidermal junction

A

LICHEN PLANUS

Associated with HCV

103
Q

Herald patch

Followed by scaly erythematous plaques in christmas tree distribution

A

PITYRIASIS ROSEA

Self-resolving

104
Q

Associations with…
UVA
UVB

A

Tanning, photoaging

Sunburn

105
Q

Pink, pearly nodules with rolled borders
Telangiectasias
Palisading nuclei

Nonhealing ulcer with infiltrating growth or scaling plaque

A

BASAL CELL CARCINOMA

106
Q

Face, lips, ears, hands
Ulcerative lesion with frequent scale
Chronic draining sinuses
Intercellular bridges and Keratin pearls

A

SQUAMOUS CELL CARCINOMA

Keratoacanthoma - Variant that grows rapidly and then regresses spontaneously over months

107
Q

Marker and mutation for Melanoma

A

S-100 marker (neural crest)
V600E BRAF mutation

Note - Can treat with IL-2

108
Q

Mechanism of Endoperoxide synthesis

A

Phospholipase A2 converts membrane phospholipids to Arachidonic acid

COX-1/2 convert Arachidonic acid to Cyclic endoperoxides

Note - Corticosteroids inhibit Phospholipase A2 and NF-kB which induces COX2

109
Q

Mechanism of Leukotriene synthesis

A

5-Lipoxygenase converts Arachidonic acid to 5-HPETE

5-HPTE forms Leukotrienes

110
Q

Actions of Endoperoxides (Prostacyclin, Prostaglandins, Thromboxane)

A

PGI2/Prostacyclin - Decreases platelet aggregation, Vasodilation

PGE2/D2 - Increased vascular permeability, Vasodilation

TXA2/Thromboxane - Increases platelet aggregation, Vasoconstriction

Note PGI2 made by endothelium (COX1/2), TXA2 made by platelets (COX1)

111
Q

Action of Leukotrienes

A

LTC4, LTD4, LTE4 - Vasoconstriction, Increased vascular permeability, Bronchospasm

LTB4/5-HETE - Neutrophil chemotaxis

Lipoxin A4/B4 - Decreased leukocyte recruitment

112
Q

Mechanism of glands…
Salivary and Sweat
Mammary
Sebaceous and Meibomian

A

Merocrine (exocytosis)
Apocrine (vesicles)
Holocrine (lysis)

113
Q

Photosensitivity
Hyperpigmentation
Atrophy
SCC

A

XERODERMA PIGMENTOSUM

Defect in nucleotide excision repair (endonuclease)

114
Q

Mechanism of photoaging (UVA)

A
Epidermal atrophy
Rete ridge flattening
Decreased collagen fibril production
Increased collagen cross-linking
Increased collagen/elastin degradation
115
Q

Most common cause of ankle sprain - Inversion

A

Talofibular ligament injury

116
Q

Arterial injury responsible for avascular necrosis after a fracture of the femoral head

A

Medial femoral circumflex

117
Q

Most common site of LE compartment syndrome

A

ANTERIOR COMPARTMENT

Contains…
Deep peroneal nerve
Anterior tibial vessels

Note - Deep posterior compartment contains Tibial nerve, Posterior tibial vessels, and Peroneal vessels

118
Q

What is at risk of injury with knee dislocation

A

popliteal artery
tibial nerve
common peroneal nerve

in post/ant dislocations, the popliteal artery is high risk because deep within popliteal fossa and tightly fixed by the adductor magnus and soleus muscles

119
Q

Sensation to medial leg and foot

A

saphenous nerve

120
Q

What is at risk of injury via penetrating trauma to the popliteal fossa

A

Tibial nerve because more superficial than popliteal artery

121
Q
cramping pain that gradually worsens in leg
worse when walks
occasionally present at rest
worst at night 
better in chair

history of DM, smoking, HTN, hypercholesterolemia

A

peripheral arterial disease

arterial atherosclerosis

122
Q

composed of lipoblasts

non membrane bound cytoplasmic lipid that shifts periodically causing scalloping of the nuclear membrane

A

liposarcoma