MSK, Skin, and Connective Tissue Flashcards
Epidermis layers
Corneum, lucidum, granulosum, spinosum, basale
Erb palsy
Upper (C5-C6 roots).
=”waiter’s tip”
Klumpke palsy
Lower (C8-T1 roots)
=claw hand
Musculocutaneous n.
C5-C7
Upper trunk compression
Loss of forearm flexion and supination.
sensation over lateral forearm.
Radial n.
C5-T1
Wrist drop, decreased grip strength
LOS over posterior arm/forearm and dorsal hand.
Midshaft fracture of humerous,
Compression at axilla (crutches)
Median n.
C5-T1
loss of wrist and lateral finger flexion, thumb opposition, lumbricals of 2nd and 3rd digits.
LOS thenar eminence and lateral 3.5 fingers.
Tinel sign.
Supracondylar fracture of humerus
Carpal tunnel syndrome.
Ulnar n.
C8-T1
Radial deviation of wrist upon flexion.
Loss of flexion of wrist and medial fingers, abduction, and adduction of fingers.
LOS medial 1.5 fingers, hypothenar eminence.
Fracture of medial epicondyle of humerus or hook of hamate.
Recurrent branch of median n.
C5-T1
loss of thenar muscle group; opposition, abduction, and flexion of thumb.
No LOS.
Superficial laceration.
Interossei
Dorsals abduct
Palmars adduct
Peroneal n.
Peroneal everts and dorsiflexes.
Injury (near fibular neck) –> foot droPED
Dorsum of foot sensation.
Tibial n.
Tibial inverts and plantarflexes
Injury (popliteal fossa) –> can’t walk on TIPtoes.
Plantar of foot sensation.
Type 1/2 muscles
1: slow twitch, aerobic, red.
2: fast twitch, anaerobic, white.
Osteoblast
markers/stimulated by
alkaline phosphatase
Stimulated by:
- Transforming growth factor beta
- IGF-1
- FGF
Osteoclasts
markers/stimulated by
Urinary deoxypyridinoline (best)
Tartrate-resistant acid phosphatase
Urinary hydroxyproline
Stimulated by:
- M-CSF
- RANK-L
Ewing sarcoma genetics
t(11;22)
Onion skin
Anaplastic small blue cell tumor
Osteosarcoma
The young and old
Risks: paget’s, bone infarcts, radiation, Rb, LiFraumeni
Codman triangle, sunburst
Bone tumor locations
giant cell tumor: epiphysis
Osteosarcoma: metaphysis (near knee).
Ewing sarcoma: diaphysis.
Crystal types
Gout: monosodium urate
Pseudogout: calcium pyrophosphate
Sarcoidosis
elevated serum ACE levels.
Associated with:
-Restrictive lung disease (interstitial fibrosis)
-Erythema nodosum
-Bell palsy
-Uveitis
-Hypercalcemia (2/2 increases 1 alpha hydroxylase outside of kidney in macrophages, which activates vitamin D).
Polymyalgia rheumatica
Pain and stiffness in shoulders and hips
Often fever, malaise, weight loss. No weakness.
Associated with temporal arteritis.
labs: increased ESR/ CRP, normal CK.
Tx: low dose steroids.
Polymyositis
progressive symmetric proximal muscle weakness. Most often = shoulders.
Endomysial inflammation with CD8+ cells.
Labs: increased CK, ANA+, anti-Jo-I, anti-SRP, anti-Mi-2
Tx: steroids.
Dermatomyositis
Polymyositis + malar rash, heliotrope rash, shawl and face rash, mechanic’s hands, increased risk occult malignancy.
Perimysial inflammation and atrophy with CD4+.
Labs: increased CK, ANA+, anti-Jo-I, anti-SRP, anti-Mi-2
Tx: steroids.
Scleroderma
Excessive fibrosis and collagen deposition. Commonly sclerosis of skin, renal, pulmonary, cardiovascular, and GI.
Diffuse:
- widespread, rapid, early visceral invovlemnt.
- Anti-Scl-70 = anti-DNA topoisomerase I
Limited (fingers/face; more benign) = CREST:
- Calcinosis
- Raynaud phenomenon
- Esophageal dysmotility
- Sclerodactyly
- Telangiectasia
- Anti-Centromere.
Osler-Weber-Rendu
=hereditary hemorrhagic telancectasia.
Autosomal dominant.
Telangectasia of skin and mucous membrane, lips, oropharynx, respiratory tract, GI, urinary.
–> epistaxis, GI bleed, hematuria.
Leser-Trelat sign
Sudden appearance of multiple seorrheic keratoses, indicating an underlying malignancy.
=Flat, greasy, pigmented, squamous epithelial proliferation with keratin-filled cysts. Looking “suck on.”
Psoriasis Tx
Topical Vitamin D analogues = calcipotriene, calcitriol, tacalcitol
Cyclosporin
Methotrexate
Etancerept = TNF receptor
Ustekinumab = IL-12, IL-23 antibody (downregs Th1)
Ecthyma gangrenosum
Cutaneous necrosis associated with P. aeruginosa bacteremia and it’s released toxins (elastase, exotoxin A, etc.).
Pemphigus vulgaris
Nikolsky sign (separation with touch).
Immunofluorescence shows antibodies around epidermal cell sin reticular pattern.
+oral mucosa.
IgG against desmoglein (of desmosomes).
Bullous pemphigoid
IgG against hemidesmosomes.
=Tense blisters contianing eosinophils of skin, not oral.
Pityriasis rosea
“herald patch” followed days later by “christmas tree” distribution.
Plaques will collarette scale.
Self-resolving in 6-8 weeks.
Basal cell carcinoma
Most common.
Locally invasive but no mets.
Pink, pearly nodules, commonly with telangiectasias, rolled borders, central crusting or ulceration or as non-healing ulcers or scaling plaque.
Histo: basal cell palisading nuclei with nests of basaloid cells in dermis.
Squamous cell carcinoma
Second most common skin cancer.
Locally invasive, rare mets.
Ulcerative red lesions with frequent scale.
Associated with chronic training sinuses.
Actinic keratosis = scaly plaque and precursor to SCC.
Keratoacanthoma: a rapidly growing variant that may regress spontaneously.
Melanoma
S-100 tumor marker.
BRAF V600E mutation common. May benefit from vemurafenib (BRAF kinase inhibitor).
Types: superficial spreading, nodular, lentigo maligna, acrolentiginous.
LTB4
neutrophil chemotaxis
-Blocked by colchicine (via MT stabilization)
LTC4, LTD3, LTE4
Increase bronchial tone
-blocked by zafirlukast, montelukast.
Corticosteroids
Block phospholipase A2 (membrane lipids to arachidonic acid)
Plock protein synthesis for COX-2
Probenecid
Inhibits reabsorption of uric acid in PCT. Don’t give if risk of nephrolithiasis.
Acute gout drugs
NSAIDs,
Glucocorticoids,
Colchicine (AEs = N/abd pain/diarrhea).
