epidermis layers (external to internal)
corneum lucidum granulosum spinosum basale
tight jxn proteins
claudin and occludin
adherent jxn protein
cadherins
unhappy triad knee injury
tear of ACL, MCL, and meniscus (medial classically, but lateral more common)
landmarks for pudendal nerve block and lumbar puncture (separate)
pudendal block - ischial spine
LP - iliac crest
MC rotator cuff injury
supraspinatus
which rotator cuff muscle is injured in a pitching injury
infraspinatus
spinal level for innervation of rotator cuff muscles
C5-6
wrist bones
scaphoid, lunate, triquetrum, pisiform, trapezium, trapezoid, capitate, hamate
Some Lovers Try Positions That They Can’t Handle
which wrist bone is most prone to avascular necrosis?
scaphoid
which wrist bone has tendency to get dislocated and cause acute carpal tunnel syndrome?
lunate
Erb’s and Klumpke’s - where are the lesions
Erb - upper trunk (C5,6)
Klumpke - lower trunk (C8, T1)
winged scapula caused by lesion of what nerve? what muscle is affected?
long thoracic nerve
serratus anterior
radial nerve innervates (motor)
brachioradialis, extensors of wrist and fingers, supinator, triceps
lesion of median nerve causes what sign
papal benediction
muscles innervated by musculocutaneous nerve
biceps, brachialis, coracobrachialis
obturator nerve does what motor fn?
thigh adduction
femoral nerve motor fn
thigh flexion and leg extension
lesion of common peroneal nerve causes what motor deficit
foot drop and steppage gait
trendelenburg sign is from what nerve lesion?
superior gluteal
what does Ca do in muscle contraction?
binds to troponin C > conformational change that moves tropomyosin out of myosin binding groove on actin filaments
what corresponds with the power stroke in muscle contraction?
myosin release of ADP
type 1 vs type 2 muscle fibers
1 - slow twitch, red fibers
2 - fast twitch, white fibers
estrogen action on bone
inhibits apoptosis of osteoblasts / induces apoptosis in osteoclasts
type 1 vs 2 osteoporosis
1 - postmenopausal (dec estrogen)
2 - senile (>70)
osteopetrosis
inadequate osteoclast activity (can’t make env acidic enough) > thickened dense bones prone to fracture
drive bone marrow out > pancytopenia and extramedullary hematopoiesis
BMT potentially curative since osteoclasts are monocyte derivs
what are the bones like in osteomalacia/rickets?
soft, bow outwards
what is the cause of osteomalacia/rickets?
vit D def
Paget’s disease
inc remodeling of bone (osteoblast and clast activity inc). woven bone > more prone to fracture. inc alk phos and risk of osteogenic sarcoma
polyostotic fibrous dysplasia
bone replaced by fibroblasts, collagen, and irreg bony trabeculae
McCune Albright syndrome
polyostotic fibrous dysplasia + endocrine abnlmalities (precocious puberty) + cafe au lait spots
giant cell tumor (osteoclastoma)
20-40 yo
locally aggressive benign tumor, usually in distal femur/prox tibia
spindle shaped cells w/ multinucleated giant cells
“double bubble” or “soap bubble” appearance on x ray
giant cell tumor (osteoclastoma)
MC benign primary tumor of bone
osteochondroma
who does osteochondroma usually affect?
males <25 yo
2 MC primary malignant bone tumors
1 - multiple myeloma
2 - osteosarcoma
who tends to get osteosarcoma and where in their body?
male > female, 10-20 yo
knee
Codman’s triangle or sunburst pattern on xray
osteosarcoma
who gets Ewing’s sarcoma and where?
boys <15 yo
diaphysis of long bones, pelvis, scapula, ribs
properties of Ewing’s sarcoma
anaplastic small blue cell malignant tumor
very aggressive, but responsive to chemo
“onion skin” appearance in bone
Ewing sarcoma
translocation of Ewing Sarcoma
t(11;22)
who gets chondrosarcomas?
men 30-60 yo
joint findings in osteoarthritis
subchondral cysts, sclerosis, osteophytes, eburnation (polished appearance), Heberden’s and Bouchard’s nodes (DIP and PIP). NO MCP involvement
what type hypersensitivity is RA?
3
joint findings in RA
pannus formation (fluffiness), subq rheumatoid nodules, ulnar deviation in fingers, Baker’s cyst. NO DIP involvement
blood markers for RA
rheumatoid factor, anti-cyclic citrullinated peptide is more specific
Sjogren’s syndrome - cause, sx, who gets it
lymphocytic infiltration of exocrine glands
triad of xerophthalmia, xerostoma, arthritis
females 40-60 yo
antibodies involved in Sjogren’s syndrome
anti-SS-A and SS-B
what do gout crystal look like under microscope?
needle shaped
negatively birefringent - yellow crystals under parallel light
allopurinol drug class
xanthine oxidase inhibitors
pseudogout - what precipitates and what do the crystals look like
calcium pyrophosphate
rhomboid crystals, weakly pos birefringent, blue when parallel to light
causes of avascular necrosis
trauma, high dose corticosteroids, alcoholism, sickle cell
what is meant by “seronegative spondyloarthropathies”?
arthritis w/o rheumatoid factor
dactylitis with “pencil in cup” deformity on xray
psoriatic arthritis
reactive arthritis (Reiter’s) - triad of sx, what infxns does it occur after
“can’t see, can’t pee, cant climb a tree” - conjunctivitis, urethritis, arthritis
after GI or chlamydia infxns
Libman Sacks endocarditis
assoc w/ SLE
verrucous sterile vegetations on both sides of valve
antibodies assoc w/ SLE and which are useful for what?
ANA - sensitive but not specific
anti-dsDNA - very specific, poor prognosis
anti-Smith - very specific, but not prognostic
anti-histone - more sensitive for drug induced lupus
2 hallmarks of sarcoidosis
noncaseating granulomas all over
elevated serum ACE levels
how does sarcoidosis often present?
asymptomatic w/ bilat hilar LAN
polymyalgia rheumatica
pain and stiffness in shoulder and hips, fever, malaise, wt loss. older women. assoc w/ giant cell (temporal) arteritis
responds well to low dose steroids
type of inflammatory cells involved in polymyositis vs dermatomyositis
polymyo - CD8 T cells
dermatomyo - CD4 T cells
antibody assoc w/ polymyositis and dermatomyositis
anti-Jo-1
myasthenia gravis assoc w/ what other conditions
thymoma / thymic hyperplasia
differences in pathophys and clinical features of myasthenia gravis vs lambert eaton syndrome
MG - ab to post synaptic ACh receptor, weakness worsens w/ muscle use
lambert eaton - ab to presynaptic Ca channel > less ACh released. improves w/ muscle use
myositis ossificans
metaplasia of skeletal muscle to bone following trauma
general path process of scleroderma
excessive fibrosis and collagen deposition throughout body
diffuse scleroderma vs CREST syndrome - assoc abs
diffuse - anti-Scl-70 (anti DNA topoisomerase I)
CREST - anti-centromere
CREST syndrome - presentation/course
type of scleroderma with more benign, limited course Calcinosis Raynaud's phenomenon Esophageal dysmotility Sclerodactyly Telangiectasia
macule vs papule
macule is flat, papule is elevated
acanthosis definition
epidermal hyperplasia (inc spinosum)
melasma
hyperpigmentation (usu on face) assoc w/ pregnancy and OCP use
ephelis is
a freckle
where does atopic dermatitis tend to appear?
face in infancy and antecubital fossa afterward
skin flexures
papules and plaques w/ silvery scaling
psoriasis
Auspitz sign
assoc w/ psoriasis
pinpoint bleeding spots from exposure of dermal papillae when scales are scraped off
flat, greasy, pigmented squamous epithelial prolif w/ keratin filled cysts that look “stuck on”
seborrheic keratosis
Leser-Trelat sign
sudden appearance of multiple seborrheic keratoses indicating underlying malignancy
pemphigus vulgaris - what is wrong, what does it look like
anti-desmoglein 3 - attacks desmosomes
acantholysis - intraepidermal bullae causing flaccid blisters. involves oral mucosa too
Nikolsky’s sign
separation of epidermis on stroking of skin seen in pemphigus vulgaris
bullous pemphigoid - what is wrong, what does it look like
antibody against hemidesmosomes
eosinophils w/ in tense blisters, spares oral mucosa
dermatitis herpetiformis
pruritic papules, vesicles, bullae caused by deposits of IgA. assoc w/ celiac dz
erythema multiforme
multiple types of lesions assoc w/ infections, drugs, cancers and autoimmune disease
stevens johnson syndrome - presentation
fever, bulla formation, necrosis, sloughing of skin, high mortality rate. lesions may appear like targets
toxic epidermal necrolysis
more severe form of Stevens Johnson syndrome
acanthosis nigricans - what is it assoc w/
hyperinsulinemia and visceral malignancy
actinic keratosis
premalignant lesions from sun
small rough erythematous or brownish papules/plaques
what is erythema nodosum assoc w/
sarcoidosis, cocci, histo, TB, strep, leprosy, Crohn’s
lichen planus - what does it look like, assoc w/
pruritic, purple, polygonal planar papules/plaques
Hep C
“herald patch” followed by “christmas tree distribution” of plaques. self resolving
pityriasis rosea
which UV type causes tanning/photoaging and which causes sunburn?
A - tanning/photoaging
B - sunBurn
2 MC skin cancers
1 - basal cell
2 - squamous cell
basal cell CA - behavior and appearance
locally invasive but almost never metastasizes
pink pearly nodules, rolled borders, central crusting/ulceration, “palisading nuclei”
precursor to SCC of skin
actinic keratosis
appearance of SCC of skin
ulcerative red lesions w/ frequent scale. on histo, “keratin pearls”
tumor marker for melanoma
S-100
gene mutation assoc w/ melanoma
BRAF kinase (activating mutation)
arachidonic acid goes through the ____ pathway to make leukotrienes
lipoxygenase
effects of leukotrienes
LTB4 - neutrophil chemotactic factor
LTC4, D4, E4 - bronchoconstriction, vasoconstriction, contraction of smooth muscle, inc vasc permeability
celecoxib - mech, adv/disadv
reversible COX2 inhib (unlike NSAIDs which are COX1 and 2). spares gastric mucosa and platelet fn, but inc risk of thrombosis and sulfa allergy
acetaminophen is toxic in overdose b/c it depletes _____. antidote is ____
glutathione
n-acetylcysteine
bisphosphonates - mech and tox
bind hydroxyapatite in bone, inhib osteoclast activity
tox - corrosive esophagitis and osteonecrosis of jaw
febuxostat
another xanthine oxidase inhibitor
drugs c/i with allopurinol
AZA and 6-MP - increases their conc
salicylates - depress uric acid clearance
probenecid
inhibits reabs of uric acid in PCT - used for chronic gout
colchicine mech
inhibits MT polymerization impairing leukocyte chemotaxis and degranulation
TNF alpha inhibitors
etanercept - soluble receptor
infliximab and adalimumab - monoclonal ab