It's 3:40am and I can't think,,, so need clarification on something.....

Knicks

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Why, again, does hypercalcemia cause osteopenia and pathologic fractures? What happened to "drink milk [Ca2+] for strong bones"? :oops:
 

phospho

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(hopefully someone is here to answer)

Why, again, does hypercalcemia cause osteopenia and pathologic fractures? What happened to "drink milk [Ca2+] for strong bones"? :oops:
had the same question a few weeks ago, someone explained it to me and it made total sense... now, I can't remember it for the life in me...

it has something to do with lack of ca2+ receptors on osteoblasts or osteoclasts, not sure... or even maybe something to do with calcitonin or lack of vit D.

If you want another easier answer though, the pt probably has overactive PTH which is causing the hypercalcemia and osteopenia

sorry, been up for too long...
 

EBI831

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(hopefully someone is here to answer)

Why, again, does hypercalcemia cause osteopenia and pathologic fractures? What happened to "drink milk [Ca2+] for strong bones"? :oops:
hypercalcemia doesnt cause osteopenia and pathological fractures. it causes confusion/dehydration/mental status change and, in rare cases, pancreatitis. plus, it is hardly possible to drink enough milk to give yourself hypercalcemia. now perhaps if you take too many vitamin D pills (like waaaay too many) or too much tums (like waaaaaay too many) you can get hypercalcemia.

about the osteopenia and the resulting pathological fractures: this is due as mentioned above to hyperparathyrodism (most likely 2ndary...but eh up for debate). your body senses low [Ca] and as a result increases production of PTH which activates osteoclasts (actually works thru osteoblasts or something like that to stimulate osteoclasts via RANK and RANK-L receptors) which increase bone resorption ie take the Ca and P from your bones to increase the serum Ca. And what happens when you don't have as much Ca and P in your bones? Osteopenia or literally weak bones.

about the pathological fractures. actually, these hardly have to do with hyperparathyroidism unless it's in association with squamous cell carcinoma of the lungs as a paraneoplastic phenom secreting PTH-rp. Rather, it's due to mets to the bone (exclude the paraneoplastic syndromes) that cause weakening of bone to the point that just walking down stairs causes fractures. As expected, it's associated with hypercalcemia because to weaken bone you have to release Ca and P into serum.
 
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Knicks

Knicks

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hypercalcemia doesnt cause osteopenia and pathological fractures. it causes confusion/dehydration/mental status change and, in rare cases, pancreatitis. plus, it is hardly possible to drink enough milk to give yourself hypercalcemia. now perhaps if you take too many vitamin D pills (like waaaay too many) or too much tums (like waaaaaay too many) you can get hypercalcemia.

about the osteopenia and the resulting pathological fractures: this is due as mentioned above to hyperparathyrodism (most likely 2ndary...but eh up for debate). your body senses low [Ca] and as a result increases production of PTH which activates osteoclasts (actually works thru osteoblasts or something like that to stimulate osteoclasts via RANK and RANK-L receptors) which increase bone resorption ie take the Ca and P from your bones to increase the serum Ca. And what happens when you don't have as much Ca and P in your bones? Osteopenia or literally weak bones.

about the pathological fractures. actually, these hardly have to do with hyperparathyroidism unless it's in association with squamous cell carcinoma of the lungs as a paraneoplastic phenom secreting PTH-rp. Rather, it's due to mets to the bone (exclude the paraneoplastic syndromes) that cause weakening of bone to the point that just walking down stairs causes fractures. As expected, it's associated with hypercalcemia because to weaken bone you have to release Ca and P into serum.
Marvelous. :thumbup:


Why are you up at 3:40am? Get some sleep.
Went into overtime while burning the midnight oil. :D
 

J ROD

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hypercalcemia doesnt cause osteopenia and pathological fractures. it causes confusion/dehydration/mental status change and, in rare cases, pancreatitis. plus, it is hardly possible to drink enough milk to give yourself hypercalcemia. now perhaps if you take too many vitamin D pills (like waaaay too many) or too much tums (like waaaaaay too many) you can get hypercalcemia.

about the osteopenia and the resulting pathological fractures: this is due as mentioned above to hyperparathyrodism (most likely 2ndary...but eh up for debate). your body senses low [Ca] and as a result increases production of PTH which activates osteoclasts (actually works thru osteoblasts or something like that to stimulate osteoclasts via RANK and RANK-L receptors) which increase bone resorption ie take the Ca and P from your bones to increase the serum Ca. And what happens when you don't have as much Ca and P in your bones? Osteopenia or literally weak bones.

about the pathological fractures. actually, these hardly have to do with hyperparathyroidism unless it's in association with squamous cell carcinoma of the lungs as a paraneoplastic phenom secreting PTH-rp. Rather, it's due to mets to the bone (exclude the paraneoplastic syndromes) that cause weakening of bone to the point that just walking down stairs causes fractures. As expected, it's associated with hypercalcemia because to weaken bone you have to release Ca and P into serum.
Nice explanation! I just read something on this...and was about to attempt an answer....:laugh:
 

hrandani

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Now can anyone explain why women are more vulnerable to osteoporosis than men are despite a lifetime of this allegedly protective estrogen?
 

phospho

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Now can anyone explain why women are more vulnerable to osteoporosis than men are despite a lifetime of this allegedly protective estrogen?
I could be totally wrong, but from what I understand, testosterone enhances calcium reabsorption by the kidney.

so I guess you can say that testosterone in men acts the same way estrogen does in women (in terms of calcium)... men are like women, when they age, their testosterone drops (though not as dramatically as in women), and so they are also prone to osteoporosis (though not as much as women)... i think it's called andropause or something...

I know there's this whole debate about whether to give men testosterone replacement therapy when they get old...or if there's even a word called "andropause"...etc...
 

turkeyjerky

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Now can anyone explain why women are more vulnerable to osteoporosis than men are despite a lifetime of this allegedly protective estrogen?
testosterone does stimulate osteoblasts so that contributes (although estrogen is absolutely essential for both men and women). menopause does contribute to osteoporosis--the rate of bone loss is accelerated for about ten years before it calms back down. the biggest reason, though, is because men have a larger peak bone mass.