MSK/Derm III Flashcards
muscle components
Z disc - actin attachment M line - myosin attach A band - all myosin H band - myosin only I band - myosin only
sarcomere - Z disc to Z disc
smooth m contraction
nitric oxide - guanylate cyclase - increased cGMP
- de-P myosin
- relaxation
action potential - L-type Ca channel - increased Ca
-increased Ca/calmodulin complex > P of myosin
myosin-P bind actin and contraction occurs
endochondral ossification
cartilage bone - replaced by osteoclasts/blasts - into woven bone
remodeled to lamellar bone
woven bone - after fx and with pagets
membranous ossification
bones of calvarium and face
woven - without cartilage
later remodel to lamellar
osteoblast
from mesenchymal stem cell in periosteum
osteoclast
from monocyte/macrophage
PTH action
low - anabolic - build bone
chronic high - catabolic - osteitis fibrosa cystica
estrogen
inhibit apoptosis of osteoblasts
induce apoptosis osteoclasts
deficient - excess remodeling - osteoporosis
achondroplasia
fail long bone growth
- affect endochondral ossification
- membranous ossification unchanged
activation of FGFR3 - inhibit chondrocyte proliferation
auto dom - full penetrance
MCC dwarfism
primary osteoporosis
loss trabecular spongy bone and interconnections
with long term steroid use, anticonvulsant, antigcoag, thyroid replacement therapy
DEXA scan
T score
colles fx
distal radius
common with osteoporosis pt
type I osteoporosis
more resorption bc of low estrogen
post-menopause
type II osteoporosis
men and women >70yo
prophylaxis - Ca and vit D
tx - bisphosphonate, PTH analog, SERM
denosumab
mAb - RANKL
osteopetrosis
marble bone disease
failure resorption
-thick dense bones that fx
bone fills marrow space - pancytopenia
mutation of osteopetrosis
carbonic anhydrase II
-impair osteoclast ability generate acidic environment for bone resportion
bone in bone appearnce
get nerve impingement
tx osteopetrosis
bone marrow transplant
-curative
bc osteoclasts from monocytes
osteomalacia and rickets
Vit D deficient
defective calcification of osteoid - soft bones
low vit D, low serum Ca, igh PTH, low serum P
hyperactive osteoblast - elevated ALP
osteitis deformans
paget disease of bone
paget disease of bone
increased osteoblast and osteoclast activity
serum Ca, PTH, P - normal
elevated ALP
mosaic pattern of woven and lamellar bone
pagets stages
1 - lytic - osteoclast
2 - mixed - osteoclast/osteoblast
3 - sclerotic - osteoblast
4 - quiescent - minimal clast/blast activity
osteonecrosis
avascular
often femoral head - insufficient medial circumflex femoral a
with alcoholism, sickle cell, storage problem, pancreatitis, trauma, idiopathic, caisson
lab values osteoporosis
normal except low bone mass
osteopetrosis labs
possible low Ca
all else normal
dense brittle bone
low Ca if severe
paget disease of bone labs
high ALP
abnormal mosaic bone pattern
osteomalacia/rickets labs
low Ca
low P
high ALP
high PTH
soft bones
primary hyperPTH labs
high Ca
low P
high ALP
high PTH
secondary hyperPTH labs
low Ca
high P
high ALP
high PTH
compensation end stage renal disease - low P excretion and production of activated vit D
giant cell tumor
B9
in epiphysis
aka osteoclastoma
often around knee
soap bubble o X-ray
multinucleated giant cell
osteochondroma
B9 tumor
-often in kids
mature bone with cartilage cap
ostesarcoma
aka osteogenic sarcoma
-2nd MC primary malignant bone tumor - after MM
bimodal
risk fx osteosarcoma
paget bone infarct radiation Rb li fraumeni
location of osteosarcoma
metaphysis
see onion skin periosteal rxn of bone
codman triangle
elevation of periosteum - with osteosarcoma
also see sunbursy apttern
spread - hematogenous
ewing sarcoma
malignant tumor - boys
prognosis of ewing sarcoma
often in young kid
aggressive with early mets
-responsive to chemo
tumor of epiphysis
giant cell
tumor of metaphysis
osteosarcoma
osteochondroma
tumor of diaphysis
ewing
myeloma
osteoid osteoma - night pain with central nidus
fibrous dysplasia
t (11;22)
translpation fusion ESW-FLI 1
ewing sarcoma
-11 + 22 = 33 partic ewing jersey #
CD99 +
ewing sarcoma
