Term
| How much of our dietary calcium intake is usually absorbed? |
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Definition
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Term
| Describe the distribution of serum calcium. |
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Definition
40% bound to albumin
15% complexed
45% free (ionized) |
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Term
| When would the total calcium measurement give a falsely low estimate, and how do you correct for this? |
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Definition
hypoalbuminemia or acidosis
add .8 to the total calcium value for each 1g/dl decrease in albumin below 4 |
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Term
| What are the functions of PTH? |
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Definition
increase renal Ca reabsorption and phosphate excretion
increase renal production of Vit D, which increase intestinal calcium and phosphate absorption
increase resorption of calcium and phosphate from bone |
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Term
| What are the measureable forms of vitamin D? |
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Definition
25-hydroxyvitamin D (calcidiol)- primary circulating form, best measure of body stores, but inactive
1,25-dihydroxyvitamin D(calcitriol): active form |
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Term
| What functions do vitamin D and PTH have in common? |
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Definition
increase renal calcium reabsorption
increase calcium and phosphate reabsorption from bone |
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Term
| What are the functions of vitamin D? |
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Definition
increase renal calcium reabsoption
inhibit PTH production and release
increase resorption of Ca and phosphate from bone |
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Term
| What are the symptoms of hypercalcemia? |
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Definition
| stones, bones, abd groans (PUD, pancreatitis, anorexia, constipation), and psychic moans (lethargy, depression, confusion, coma). also muscle weakness |
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Term
| What can hypercalcemia lead to? |
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Definition
| renal failure, nephrogenic diabetes insipidus, nephrolithiasis, shorterning of QT interval on EKG |
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