R/O - Primary bone tumors Flashcards
what is the effect of PTH on the renal tubules?
increased resorption of calcium by renal tubules
what is the effect of PTH on vitamin D?
increased synthesis of vitamin D by kidneys - enhanced calcium reabsorption from gut
what are the skeletal changes in response to hyperparathyroidism?
abnormal osteoclastic activity - increased serum calcium and phosphate
bone cysts and brown tumors - diagnosis?
hyperPTH
“tunneling resorption” - diagnosis?
hyperPTH
what causes brown tumors of hyperPTH to be “brown”?
hemosiderin laden macrophages
renal osteodystrophy - HYPER or HYPO calcemia?
HYPO
what is the pathophysiology of renal osteodystrophy?
- renal failure: dysfunctional vitamin D activity - hypocalcemia - associated secondary hyperPTH
- increased PTH - increased osteoclastic activity - increased serum calcium and phosphate (bone cysts and brown tumors)
- metabolic acidosis, iron, and aluminum deposites in bone (derived from dialysis) - interfere further with matrix mineralization - osteomalacia
what is the effect of long term dialysis on bone?
osteomalacia - metabolic acidosis, iron, and aluminum deposites in bone - interfere with matrix mineralization
paget disease of bone is a disorder of bone _____________
maintenance
what is the pathophysiology of paget disease of bone? what are the early and late effects?
- aggressive osteoclast mediated bone resorption
- imperfect osteoblast mediated bone repair
- ACCELERATION OF BONE TURNOVER where bones are first degraded faster than they are built, then they recover, but in a ‘hectic’ strange and brittle way
- in early cases #1 overshadows #2, while the reverse is true in older cases
where are the hemorrhages located in vitamin C deficiency?
subperiosteal
what are the 3 distinct phases of fracture healing?
- organization of hematoma
- conversion of procallus to fibrocartilaginous callus
- replacement of mesenchymal cells by osseous callus
what are the inhibitory factors to fracture healing?
- infection
- non-union
- inadequate immobilization
- poor circulation: poor nutrition
- drugs
- underlying systemic abnormality
- overstressing healing fracture
definition: osteomyelitis
inflammation of bone and marrow caused by infection - most commonly by pyogenic agents or m. TB
what is the most common route of infection for osteomyelitis?
hematogenous
what is the main organism responsible for osteomyelitis in sickle cell disease patients?
salmonella
what is the main organism responsible for osteomyelitis in neonates?
group B strep
what is ‘sequestrum’ in the context of pyogenic osteomyelitis?
residual necrotic bone - may be resorbed or (if larger) surrounded by rim of reactice bone called involucrum
what is a brodie abscess?
walled off chronic osteomyelitis - when well-defined rim of sclerotic bone surrounds residual abscess - viable organisms may persist
what is the involucrum?
new woven bone surrounding drainage tract
what is Pott disease?
TB of vertebral bodies - vertebral deformity and collapse - neuro deficits
what are the most common sites of Pott disease?
- thoracic vertebrae
- lumbar vertebrae
