R/O - Primary bone tumors

Question 1

what is the effect of PTH on the renal tubules?

Answer 1

increased resorption of calcium by renal tubules

Question 2

what is the effect of PTH on vitamin D?

Answer 2

increased synthesis of vitamin D by kidneys - enhanced calcium reabsorption from gut

Question 3

what are the skeletal changes in response to hyperparathyroidism?

Answer 3

abnormal osteoclastic activity - increased serum calcium and phosphate

Question 4

bone cysts and brown tumors - diagnosis?

Answer 4

hyperPTH

Question 5

“tunneling resorption” - diagnosis?

Answer 5

hyperPTH

Question 6

what causes brown tumors of hyperPTH to be “brown”?

Answer 6

hemosiderin laden macrophages

Question 7

renal osteodystrophy - HYPER or HYPO calcemia?

Answer 7

HYPO

Question 8

what is the pathophysiology of renal osteodystrophy?

Answer 8

1. renal failure: dysfunctional vitamin D activity - hypocalcemia - associated secondary hyperPTH
2. increased PTH - increased osteoclastic activity - increased serum calcium and phosphate (bone cysts and brown tumors)
3. metabolic acidosis, iron, and aluminum deposites in bone (derived from dialysis) - interfere further with matrix mineralization - osteomalacia

Question 9

what is the effect of long term dialysis on bone?

Answer 9

osteomalacia - metabolic acidosis, iron, and aluminum deposites in bone - interfere with matrix mineralization

Question 10

paget disease of bone is a disorder of bone _____________

Answer 10

maintenance

Question 11

what is the pathophysiology of paget disease of bone? what are the early and late effects?

Answer 11

1. aggressive osteoclast mediated bone resorption
2. imperfect osteoblast mediated bone repair
3. 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

Question 12

where are the hemorrhages located in vitamin C deficiency?

Answer 12

subperiosteal

Question 13

what are the 3 distinct phases of fracture healing?

Answer 13

1. organization of hematoma
2. conversion of procallus to fibrocartilaginous callus
3. replacement of mesenchymal cells by osseous callus

Question 14

what are the inhibitory factors to fracture healing?

Answer 14

• infection
• non-union
• inadequate immobilization
• poor circulation: poor nutrition
• drugs
• underlying systemic abnormality
• overstressing healing fracture

Question 15

definition: osteomyelitis

Answer 15

inflammation of bone and marrow caused by infection - most commonly by pyogenic agents or m. TB

Question 16

what is the most common route of infection for osteomyelitis?

Answer 16

hematogenous

Question 17

what is the main organism responsible for osteomyelitis in sickle cell disease patients?

Answer 17

salmonella

Question 18

what is the main organism responsible for osteomyelitis in neonates?

Answer 18

group B strep

Question 19

what is ‘sequestrum’ in the context of pyogenic osteomyelitis?

Answer 19

residual necrotic bone - may be resorbed or (if larger) surrounded by rim of reactice bone called involucrum

Question 20

what is a brodie abscess?

Answer 20

walled off chronic osteomyelitis - when well-defined rim of sclerotic bone surrounds residual abscess - viable organisms may persist

Question 21

what is the involucrum?

Answer 21

new woven bone surrounding drainage tract

Question 22

what is Pott disease?

Answer 22

TB of vertebral bodies - vertebral deformity and collapse - neuro deficits

Question 23

what are the most common sites of Pott disease?

Answer 23

• thoracic vertebrae

- lumbar vertebrae