bone pathology Flashcards
What is ESR?
erythrocyte sedimentation rate, RBC aggegation causes increased sedimentation (falls faster in test tube)
why does elevated ESR indicate inflammation?
inflammatory products (fibrinogen) coat RBC and cause aggregation –> falls faster in test tube
increased ESR in lab could mean…
anemia infection, inflammation cancer pregnancy autoimmune(SLE)
SLE
systemic lupus erythematous autoimmune CT disease, chronic antigen / Ab complex (tyoe 3 hypersensitivity) malarbutterfly, discoid rash, oral ulcers, arthritis, raynauds , anemia, phenomenon childbearing aged women imitates many diseases! inflammation Not as damaging as RA. \+ ANA/anti-sdDNA/anti Sm
what disease/gene causes impaired cartilage proliferation in growth plate (short extremities and normal head and chest?
achondroplasia
activating mutation –> overexpression of FGFR3
what type of bone formation does achondroplasia affect?
endochondral bone formation!
intramembranous is unaffected
what disease gives you normal size head and chest but small extremities?
how are mental function, life span, and fertility
achondroplasia
osteogenesis imperfecta
congenital defect of bone formation–> weak bone
defect in collagen type 1 synthesis
features of osteogenesis imperfecta
weak bone
multiple fractures (can mimic child abuse)
blue sclera - thinning to see choroidal veins
hearing loss - middle ear factures easily
abnormal bone resorption
- -> abnormal thick heavy bone that fractures easily
- poor osteoclast [ ]
osteopetrosis
what mutation occurs in osteopetrosis?
carbonic anhydrase II mutation –>leads to loss of acidic microenvironment and bone cannot be resorbed by osteoclasts
osteopetrosis treatment?
marrow transplant
osteoclasts form from monocytes
clinical features of osteopetrosis
anemia/thrombocytopenia due to bony replacement of marrow
vision and hearing impaired - cranial nerve impingement
hydrocephalus due to narrowing of foramen magnum
renal tubular acidosis- lack of carbonic anhydrase –>decreased HCO3 resorbtion
osteoblasts –> bone?
osteoblasts form osteoid which is then mineralized w calcium and phosphate to form bone
low vit D results in low serum —- & —-?
calcium and phosphate
rickets and osteomalacia are diseases that…
defective mineralization of osteoid due to low vitamin D
vitaminD sources and activation
diet and sunlight;
activated in liver (25 hydroxylation) and proximal tubule cells of kidney (1 alpha hydoxylation)
what does ACTIVATED vit D do?
raises serum ca and phosphate by increasing reabsorption in intestine, kidney,and bone
rickets
low vit D in children leading to low bone mineralization
arises <1yo, pigeon breast deformity, frontal bossing (osteoid deposit in forehead), rachitic rosary, bowing of legs
osteomalacia
low vit D leading to low bone mineralization in adults
weak bone with increased risk of fracture
LAB: decreased serum ca and phosphate and increased PTH and alkaline phosphatase
Lab: decreased serum ca and phosphate, increased PTH and alkaline phosphatase
osteomalacia
reduction in trabecular bone mass resulting in porous bone
osteoporosis
RANKL - what does it do and what is it a sign of
increase osteoclast activity;
osteoporosis
risk of Osteoporosis
mostly senile and postmenopausal
rate based on peak bone mass (30 yo) and rate of bone loss after (normally 1% a yr)
bone loss is more rapid with lack of weight bearing exercise, poor diet, and decreased estrogen
treatment for osteoporosis
exercise, vit D, calcium, bisphosphonates
not glucocorticoids!!
what do bisphosphonates do?
induce apoptosis of osteoclasts
Lab for osteoporosis
ca, phosphotase, PTH, and allkaline phosphatase all NORMAL –> rules out osteomalacia
**measure bone density using DEXA
clinical features of osteoporosis
bone pain and fractures in weightbearing areas - vertebra, hip, distal radius
-lost of height from vertebra compression
paget disease
imbalance between osteoclast and osteoblast activity, in late adulthood
three stages - osteoclastic, mixed, and osteoblastic/sclerotic
results in thick, bone with lamellar cement lines (jig saw) that fractures easily due to rushed osteoblasts
does paget disease affect entire skeleton?
NO, just one or a few bones
-skull is common
clinical features of pagets disease?
bone pain (microfractures), increasing hat size, hearing loss (impinged cranial nerve), lion like facies,
Lab shows all normal except isolated elevated alkaline phosphotase
paget disease
treatment of pagets
calcitonin (inhibits osteoclasts)
bisphosphonates (osteoclast apoptosis)
two complications of pagets disease
osteosarcoma
AV shunts in bone –> cardiac failure
osteomyelitis
infection of marrow and bone, usually bacterial, hematogenous spread
kids>adults
pain with systemic signs of infection
lytic focus (abcess) surrounded by bone sclerosis (sequestrum surrounded by involucrum)
where does each form of osteomyelitis seed and in who?
transient bacteremia (kids) - metaphysis open wound bacteremia (adults) - epiphysis
most common cause of osteomyelitis (plus others)
**staph aureus - 90%
Ngonorrhoeae - sexually active young adults
salmonella - sickle cell
pseudomonas - diabetics or IV drug users
pasteurella - cat or dog bite
mycobacterium tuberculosis - involves vertebra
avascular aseptic necrosis vs osteomyelitis
similar presentation except aseptic necrosis is not caused by bactera
avascular aseptic necrosis
ischemic necrosis of bone and marrow
caused by trauma, fracture, steroids, sickle cell anemia, and caisson disease (N gas in blood)
whats a major complication of avascular necrosis?
osteoarthritis and fracture
benign tumor of bone?
where do they arise mostly?
associated with?
osteoma
facial bones
gardner syndrome
osteoid osteoma
benign tumor of osteoblasts(that produce oteoid) surounded by rim of reactive bone
<2cm bony mass in duaphysis cortex (surface) of long bones (femur) with radiolucent core
-young adults
osteoid osteoma vs osteoblastoma
OO is 2cm, in vertebrae, and does NOT resolve w aspirin
osteochondroma
tumor of cone with an overlying cartilage cap; most common benign tumor of bone
arises from lateral projection of growth plate (metaphysis) and continuous w marrow
*rarely metastasis to osteosarcoma
malignant proliferation of osteoblasts, produces osteoid
osteosarcoma
demographics of osteosarcoma?
teens>elderly
where does osteosarcoma arise?
metaphysis of long bones in knee region (distal femur or proximal tibia)
risk factors for osteosarcoma?
familial retinoblastoma, paget disease, radiation exposure
three signs of osteosarcoma
bone pain with swelling or pathologic fracture
sunburst appearance
lifting of the periosteum (codman triangle)
codman triangle
lifting of the periosteum as tumor of bone protrudes through cortex
only tumor that grows in epiphysis?
giant cell tumor (epiphyses of long bones)
giant cell tumor
multinucleate giant cells and stromal cells, “soap bubble” on xray
-young adults, knee region, epiphysis
-aggressive, can recur
-
malignant proliferation of poorlydifferentiated cells from neuroectoderm, in diaphysis usually males <15
ewing sarcoma
onion skin appearance on xray
ewing sarcoma
where does ewing sarcoma develop?
diaphysis of long bone, usually in male kids <15
often metastasizes
biopsy of ewing sarcoma shows?
what genetic defect causes it?
small round blue cells that resemple lymphocytes
t(11,22) translocation
chondroma
benign tumor of cartilage
medulla of hands and feet
chondrosarcoma
malignant cartilage forming tumor
medulla of pelvis or central skeleton
metastatic tumors
more common than primary tumors –> result in osteolytic (punched out) lesions
BUT prostatic carcinoma results in osteoblastic lesions
osteoarthritis
progressive loss of articular cartilage due to wear and tear
stiffness in the morning that WORSENS during day
most common arthritis
osteoarthritis
risk factors for osteoarthritis
old age, obesity, trauma
osteoarthritis affects what joints?
hips, lumbar, knees, DIP AND PIP
what nodes develop at DIP and what at PIP?
DIP -> heberden nodes
PIP -> bouchard nodes
pathologic findings of osteoarthtritis?
disruption of articular surface (joint mice) eburnation (polishing) ofsubchondral bone after it is exposed osteophyte formation (reactive bony outgrowths) in DIP and PIP (heberden and bouchards)
osteophyte
reactive bony outgrowth
happens in osteoarthritis
rheumatoid arthritis
chronic, systemic, autoimmune
late bearing aged women
morning stiffness that IMROVES with activity
morning stiffness - gets worse in day or better….2 conditions?
worse –> osteoarthritis
better –> rheumatoid arthritis
disease associated with HLA-DR4?
rheumatoid arthritis
synovitis leading to pannus (inflamed granulation tissue)?
rheumatoid arthritis
what leads to joint space narrowing, loss of cartilage and destruction of joint, fusion (ankylosis)
rheumatoid arthritis
what is usually spared in RA?
DIP
symmetric involvement of PIP, wrists, elbows, ankles, and knees
Rheumatoid arthritis
clinical features of RA
rheumatoid nodules
vasculitis
baker cyst
pleural effusions
Lab findings of RA
IgM autoantibodies against FC portion of IGG
high neutrophils and high protein in synovial fluid
IgM autoantibodies against Fc portion of IgG
Rheumatoid arthritis
lack of rheumatoid factor
axial skeleton involvement
HLA-B27
seronegative spondyloarthropathies
HLA-B27 association
seronegative spondyloarthropathies
disease of vertebral column
seronegative spondyloarthropathies
ankylosing spondyloarthritis
involvement of sacroiliac joints and spine –> leads to fusion of vertebrae
young adults usually males
presents with low back pain
what can associate with uveitis and aoritis?
anklosing spondyloarthritis
reiter syndrome
arthritis, urethritis, and conjunctivitis
arises in young male adult weeks after GI infection
DIP of hands and feet are commonly affected (sausage fingers and toes)
psoriatic arthritis
psoriatic arthritis due to?
N gonorrhoeae - sexually active young adults
staph aureus - older children
usually involves a single joint, mostly knee
warm, erythematous limited ROM
psoriatic arthritis
gout
deposition of MSU crystals in tissues, especially the joints
due to hyperuricemia
hyperurimia and deposition of MSU crystals causes
gout
leukemia and MPDs
lesch nyhan syndrome
renal insufficiency
secondary gout
podagra
arthritis of big toe (acute gout)
chronic gout
tophi- uric acid crystals in soft tissue or joints
renal failure - uric acid deposition in tubules
yellow needle shaped crystals with negative birefringence under polarized light
chronic gout
pseudogout
resembles gout
deposition of calcium pyrophosphate
rhomboid shaped crystals with weak positive birefringence
gout vs pseudogout under polarized light
g- needle shaped, yellow, negative birefringence
ps- rhomboid, blue, positive birefringence
