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22 Cards in this Set
- Front
- Back
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osteopenia
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- low absolue amount of bone
- osteoporosis and osteomalacia |
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low turnover osteoporosis
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- normal number of BMUs
- impaired blast recruitment - age-related kind |
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how exactly does PTH increase bone resorption?
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- directly stimulates blasts
- the basts then do the clast activating factor - so high turnover osteoporosis - subperiosteal bone resorption and w/ cystic lesions, or brown tumors |
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what is going on w/ Ca and P in 1o hyperPT
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- high serum Ca, low serum P
- Ca taken from bone - P excretion increased - Ca excretion increased from big filtered load |
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what are the Sx of hyper PT?
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- stones (Ca kidney stones)
- bones (bone pain from more resorption and lesions) - groans (general malise) |
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hypoPT
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- usually no skeletal abnormalities
- from removal of thyroid - decreased Ca and increased P |
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pseudohypPT
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- PTH resistance
- PTH is high, but it isn't doing anything - low Ca, high P |
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Albright hereditary osteodystrophy
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- from pseudohypPT
- short stature - round facies - shortened ring fingers |
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Causes of 1,25-D deficiency
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- poor diet
- GI malabsorption - renal failure (no 2o OH) - lack of sun (rare) |
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what happens when the Ca P product is less than 30?
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osteomalacia (there is no mineralization)
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looser zones
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- from ricketts
- pseudofractures that are radiolucent lines perpendicular to the bone cortex |
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renal osteodystrophy
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- at first, it cant get rid of P, and it can't make 1,25-D so PTH is stiumlated (2o hyperPT)
- so P is really high, but Ca is really low, so product less than 30 and osteomalacia - when GFR gets below 25%, P even higher, so product more than 30, and osteoscleorsis - combo of 2o hyperPT, osteomalacia, and osteosclerosis |
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2 categories of 1o osteoporosis
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- juvenile (v. rare)
- involutional (type 1 and type 2) |
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type 1 involutional osteoporosis
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- women 5-20 yrs post-menopause
- greater loss of trabecular bone - high turnover - vertebral and colles fractures |
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type 2 involutional osteoporosis
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- low turnover
- men and women - vertebral and prox femur fractures |
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steroid-induced osteoporosis
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- high turnover
- 2o hyperPT from low Ca gut absorption and renal resorption |
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hyperthyroid osteoporosis
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- high turnover
- HT initiates blasts, which then initiates clasts |
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muchopolysaccharidosis
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1o defect in blast function, so abnormal extracellular glycoproteins
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osteogenesis imperfecta type 1 and 2
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- inability to make type I collagen
- AD most common, mildest - type II more severe, die as prenates |
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osteopetrosis does what to the immune system?
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it decreases it b/c the marrow cavity is narrowed
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paget disease
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- AD, or viral factor
- LOTS of bone turnover, usually localized - bone is mixture of immature, women and matrue, lamellar - AP is way up - Ca and P are normal |
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Acromegaly and bone
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- too much GH
- high turnover osteopenia - but it also stiumates the periosteium - one of the few diseases where the periosteium is big in adults |
