BONE Flashcards
mutation in ACHONDROPLASIA
FGFR3- activates the receptor which inhibits cartilage proliferation
what location is affected in ACHONDROPLASIA
growth plate
clinical presentation of ACHONDROPLASIA
normal head and torso. small arms and legs.
*tibial bowing
ACHONDROPLASIA- genetics
AD
most lethal form of dwarfism | cause
thanatophoric dwarfism | GOF-FGFR3 mutation
clinical presentation in THANATOPHORIC DWARFISM
shortened limbs, small chest, bell shaped abdomen. LETHAL death from respiratory insufficiency
type 1 collagen synthesis defect leads to
osteogenesis imperfecta
genetics of osteogenesis imperfecta
AD
clinical features of osteogenesis imperfecta
blue sclera
deafness
pathologic fractures at birth
tx for osteogenesis imperfecta
bisphosphonates
which type of osteogenesis imperfecta is lethal?
TYPE 2 - AR
which type of osteogenesis imperfecta has normal sclerae?
TYPE 4
” too much bone” \ osteoclast defect
OSTEOPETROSIS
which enzyme is defective in osteopetrosis?
carbonic anhydrase 2 - cant acidify resorption pit
x-ray finding of osteopetrosis?
Erlenmeyer flask
genetics of osteopetrosis
AD- less severe - not seen until adolesence
AR- more severe
clinical features of osteopetrosis?
fractures
anemia
cranial nerve compression (visual/hearing loss)
MC metabolic bone disease | define it
osteoporosis | decreased organic bone matrix(osteoid) and mineralized bone leads to POROUS BONES AND REDUCED BONE MASS
types of primary osteoporosis
- idiopathic- MC in young
- type 1- postmenopausal
- type 2-senile (>70)
causes of secondary osteoporosis
- hypercortisolism*
- drugs - heparin
- space travel
- hypogonadism (hypopituitarism)
how does lack of estrogen(EGN) cause osteoporosis?
normally, EGN decreases cytokine release that cause increased osteoclast activity
LESS ESTROGEN-MORE OSTEOCLAST ACTIVTY
kyphosis seen in advanced osteoporosis
dowagers hump
low turnover vs high turnover osteoporosis
senile vs post menopausual
Paget disease aka
osteitis deformans
possible infection agent associated with OSTEITIS DEFORMANS
paramyxovirus
what is the morphological hallmark of PAGET DISEASE - describe the bone
mosaic pattern - larger than normal, but softer and porous- leading to fractures
stages of PAGET DISEASE
- osteoclast
2. then osteoblast
what serum marker is a key finding in PAGET DISEASE
increase ALK-PHOS with normal calcium and phosphorus
what is seen on radiographs/bone scan in PAGET DISEASE
increased thickness of bone \ HOT SPOTS**
complications of PAGET disease
osteogenic sarcoma
high output HF
rare anatomic change seen in sever hyperPTH involving bone
osteitis fibrosa cystica
what type of tumor is seen in hyperPTH
brown tumor - cysts formed from macrophages
describe von Recklinghausen disease of bone
aka osteitis fibrosa cystica
- hyperPTH leads to increased bone resorption
- bone loss leads to fractures and bleeding which causes peritrabecular fibrosis - and cyst like BROWN TUMOR
chronic renal disease leads to accumulation of what - that leads to what ?
phosphate - 2ndary hyperPTH
types of fractures
- bone is splintered
- communicates w/skin
- ends of bone are not aligned
- overlying tissue is intact
- comminuted
- compound
- displaced
- simple
TB osteomyelitis primarily targets which bone
vertebrae ** POTTS disease
saber shin
bone deposition on tibia
**skeletal syphilis
organisms for YAWS
treponema pertenue
osteoma MC location
face
osteoma - associated with?
FAP