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19 Cards in this Set
- Front
- Back
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What is the defect in achondroplasia? |
Failure of longitudinal bone growth (endochondral ossification) d/t constitutive activation of the fibroblast growth receptor (FGFR3) --> inhibits chondrocyte proliferation.
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What type of bone loss occurs in osteoporosis? What do labs look like? Why does this happen in postmenopausal women?
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Trabecular (spongy) bone. NORMAL LABS. Increased calcium reabsorption d/t decreased estrogen levels.
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What is the best treatment for osteoporosis? MOA?
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Bisphosphanates -- "-dronate"s. Inhibit osteoclasts. May cause corrosive esophagitis and osteonecrosis of the jaw.
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What is the defect in osteopetrosis? What are the labs? X-ray?
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No bone reabsorption --> thick, dense bones. Abnormal function of osteoclasts. LABS ARE NORMAL. Decreased marrow space causes aplastic anemia. "Erlenmeyer flask" on x-ray.
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What is the defect in osteomalacia and rickets? What do the labs look like?
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Defective mineralization/calcification of osteoid. Vit D deficiency --> Decreased calcium levels --> increased PTH --> decreased phosphate.
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What happens to the bone in polyostotic fibrous dysplasia?
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Bone is replaced with fibroblasts, collagen, and irregular bony trabeculae.
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What disease is associated with polyostotic fibrous dysplasia? What are the sx?
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McCune-Albright: polyostotic fibrous dysplasia leading to multiple unilateral bone lesions, endocrine abnormalities (precocious puberty), and cafè-au-lait spots.
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What is the origin of osteoclasts? Osteoblasts?
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Monocyte lineage. Osteoprogenitor cells.
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What type of bone formation occurs in longitudinal bone growth? What about flat bone growth?
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Endochondral ossification. Membranous ossification.
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In what area of the body does a DEXA scan need to be performed to best assess bones for osteoporosis?
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Hip, lumbar spine.
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How effective is Raloxifene (SERM) in treating osteoporosis?
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Decreased vertebral fx by 40%. No effect on non-vertebral fx risk. Reduces risk of breast cancer.
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What can cause osteitis fibrosa cystic (von Recklinghausen disease of bone)?
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This is a bony manifestation of an endocrine disorder. Caused by hyperparathyroidism or pseudohypoparathyroidism (PTH resistance at renal tubules). This high PTH --> excess osteoclastic activity --> "BROWN TUMORS" in bone which are cystic spaces lines by osteoclasts filled with stroma and blood. Labs: Increased Calicum, Decreased phosphate, increased ALP, increased PTH.
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What enzyme deficiency is seen in Osteopetrosis?
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Carbonic anhydrase II.
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In which bone disease does excessive osteoclastic and osteoblastic activity result in disorganized bony architecture? What are the lab values?
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Paget Disease. Normal calcium, phosphate, and PTH levels, INCREASED ALP.
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Paget disease can lead to what type of cancer?
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Osteogenic sarcoma.
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How does the bone appear in Ewing's sarcoma? What is the chromosomal mutation? Who gets this?
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"Onion skin" appearance to the bone. 11;22 translocation. Boys < 15yrs.
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You have a 28 y/o patient with pain in his leg. On x-ray you see a "double bubble" or "soap bubble" appearance at the distal femur. Biopsy of the nodule shows spindle-shaped cells with multinucleated giant cells. Diagnosis?
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Giant cell tumor / Osteoclastoma.
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What is the most common malignant primary bone tumor of children? Adults?
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Osteosarcoma. Multiple myeloma.
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What is the most common benign bone tumor? What might this actually be?
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Osteochondroma. Hamartoma!
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