Hypercalcemia pathophysiology: Difference between revisions
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==Pathophysiology== | ==Pathophysiology== | ||
===Mineral Homeostasis=== | ===Mineral Homeostasis=== | ||
Effect of [[Mineral|minerals]] and [[vitamin D]] on [[parathyroid hormone]]:<ref name="pmid14184232">{{cite journal |vauthors=HARRISON MT |title=INTERRELATIONSHIPS OF VITAMIN D AND PARATHYROID HORMONE IN CALCIUM HOMEOSTASIS |journal=Postgrad Med J |volume=40 |issue= |pages=497–505 |year=1964 |pmid=14184232 |pmc=2482768 |doi= |url=}}</ref><ref>{{cite book | last = Nussey | first = Stephen | title = Endocrinology : an integrated approach | publisher = Bios NCBI | location = Oxford, UK Bethesda, Md | year = 2001 | isbn = 1-85996-252-1 }}</ref> | |||
*Decrease in serum [[calcium]] concentration stimulates [[parathyroid hormone]]. | *Decrease in serum [[calcium]] concentration stimulates [[parathyroid hormone]]. | ||
*[[Calcium]] provides [[negative feedback]] on [[parathyroid hormone]]. | *[[Calcium]] provides [[negative feedback]] on [[parathyroid hormone]]. | ||
*[[Magnesium]] provides [[negative feedback]] on [[parathyroid hormone]]. | *[[Magnesium]] provides [[negative feedback]] on [[parathyroid hormone]]. | ||
*[[Vitamin D]] decreases the concentration of [[parathyroid hormone]]. | *[[Vitamin D]] decreases the concentration of [[parathyroid hormone]]. | ||
The effect of [[parathyroid hormone]] on [[mineral]] [[metabolism]] is as follows: | |||
*Effect on [[parathyroid hormone]] on [[calcium]] [[metabolism]]: | *Effect on [[parathyroid hormone]] on [[calcium]] [[metabolism]]: | ||
**Direct effect: | **Direct effect: | ||
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Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]; Associate Editor(s)-in-Chief:
Overview
Pathophysiology
Mineral Homeostasis
Effect of minerals and vitamin D on parathyroid hormone:[1][2]
- Decrease in serum calcium concentration stimulates parathyroid hormone.
- Calcium provides negative feedback on parathyroid hormone.
- Magnesium provides negative feedback on parathyroid hormone.
- Vitamin D decreases the concentration of parathyroid hormone.
The effect of parathyroid hormone on mineral metabolism is as follows:
- Effect on parathyroid hormone on calcium metabolism:
- Direct effect:
- Increased resorption of bones.
- Decreases excretion from kidney.
- Indirect effect:
- Increases conversion of inactive 25-hydroxy vitamin D to the active 1,25-dihydroxy vitamin D which increases absorption of calcium from gut. Decreased phosphate concentration also increases this conversion process. Vitamin D shows synergism with parathyroid hormone action on bone.
- Decreased serum inorganic phosphate concentration prevents precipitation of calcium phosphate in bones.
- Both these direct and indirect mechanism results in an increased serum calcium concentration.
- Direct effect:
- Effect of parathyroid hormone on inorganic phosphate metabolism:
- Increases excretion of inorganic phosphate from kidney resulting in decreased serum concentration of phosphate.
- Effect of parathyroid hormone on magnesium concentration:
The Sequence of Events in Mineral Homeostasis
| Parathyroid hormone | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| Kidney | Bone | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| Decreased excretion of magnesium | Increasead conversion of inactive 25-hydroyx vitamin D to the active 1,25-dihydroy xvitamin D | Increase excretion of inorganic phosphate | Decrease excretion of calcium | Increased resorption of bone | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| Increased serum concentration of magnesium | Increased absorption of calcium from gut | Decreased serum concentration of inorganic phosphate | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| Prevents precipitation of calcium phosphate in bones | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| Increased serum concentration of calcium | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
References
- ↑ HARRISON MT (1964). "INTERRELATIONSHIPS OF VITAMIN D AND PARATHYROID HORMONE IN CALCIUM HOMEOSTASIS". Postgrad Med J. 40: 497–505. PMC 2482768. PMID 14184232.
- ↑ Nussey, Stephen (2001). Endocrinology : an integrated approach. Oxford, UK Bethesda, Md: Bios NCBI. ISBN 1-85996-252-1.