secondary hyperparathyroidism---vit d def vs crf - got2study2pass

[ArchivalUser]

im confused....from step 1 i got this concept:

in vit d deficiency u have decreased calcium---->increased PTH-----decreased Phosphate

in renal failure u have decreased calcium---->increased PTH----but since kidneys are failed...u have INCREASED PHOSPHATE.....


i am looking at videos and they say that you are having decreased phosphate, and not increased phosphate....which is confusing me....

can you guys help me on this.

[ArchivalUser]

i think serum phosphate should be looked at based on the cause of hyperpara. In case of renal failure, serum phosphate is high dure to renal insufficiency. but in case of vit-D deficiency in a healthy kidney, serum phosphate would be low.

there's one more thing. osteomalacia can also develop in CRF, about 10%, the most common form of renal osteodystrophy is osteitis fibrosa cystica. I'm not sure what serum phosphate would be in this case, case of osteomalacia in CRF, probably high though because of lost kidney function.

[ArchivalUser]

ok but that guy in the video says that serum phosphate is low even in renal failure...