Medusin
Forum Elite
Topics: 17
Posts: 279
|
Can somebody explain to me what is the relationship between calcium and phosphate? Apparently they are inversely related, meaning that when phosphate is high calcium is low and viceversa, but how is this so? What is the physiology?
I was reading about how patients with chronic renal failure develop secondary hyperparathyroidism.
Pathophysiology:
1. alfa 1 hydroxylase defiency, leads to less hydroxilation of vitamin D into its active form, calicum absorption in the intestine is impaired so ionized calcium is diminished and therefore PTH is increased.
2. hyerphosphatemia develops because of impaired renal function, leading to hypocalcemia which in turn activates PTH secretion. But how does this work?
___________________
What Starts Here Changes The World
|
| new_n_lost
Politically InCorrect
Topics: 650
Posts: 6,058
|
Plz Go Thru this Link N tell me if helps u it not then ask us again n i m sure atleast i will definitely respond.
http://www.prep4usmle.com/forum/thread/51734
___________________
FORUM RULES-- Those who believe in telekinesis, raise my hand. I get enough exercise just by pushing my luck --P4U World.." The pure and simple truth is rarely pure and never simple."
|
| Medusin
Forum Elite
Topics: 17
Posts: 279
|
No im sorry but I dont quite get it. Could you explain it to me please?
Why is there excess phosphate and low calcium? If phosphate is retained because of kidney impairment, why isnt calcium also retained?
___________________
What Starts Here Changes The World
|
| new_n_lost
Politically InCorrect
Topics: 650
Posts: 6,058
|
Major sites of regulation of phosphate excretion are the early proximal renal tubule and the distal convoluted tubule. In the proximal tubule, phosphate reabsorption by type 2 sodium phosphate cotransporters is regulated by dietary phosphate, PTH, and vitamin D. High dietary phosphate intake and elevated PTH levels decrease proximal renal tubule phosphate absorption, thus enhancing renal excretion.
Hyperphosphatemia causes hypocalcemia by precipitating calcium, decreasing vitamin D production, and interfering with parathyroid hormone-mediated bone resorption. Severe life-threatening hypocalcemia may result. Signs and symptoms of acute hyperphosphatemia are due to the effects of hypocalcemia.
___________________
FORUM RULES-- Those who believe in telekinesis, raise my hand. I get enough exercise just by pushing my luck --P4U World.." The pure and simple truth is rarely pure and never simple."
|
| Medusin
Forum Elite
Topics: 17
Posts: 279
|
Thanks. I think i got it.
___________________
What Starts Here Changes The World
|
|
| |
| | | | | |
