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12 Cards in this Set
- Front
- Back
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Vitamin-D- deficiency rickets is due to:
S/S? Biochemical hallmark? Other lab findings? |
lack of sunlight AND dietary Vitamin D - genetic absence of renal 1-A-hydroxylase (converts 25(OH)D --> 1,25(OH2)D
bowed legs, large and soft cranium, skeletal deformities low serum (OH)D low P, elevated Alk Phos, PTH, normal serum Ca++ |
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Explain how liver disease and anti-seizure meds affect vitamin D:
Deficiency in Vitamin-D resistant rickets, and lab findings: Tx for vit-D dependent and resistant rickets? |
decreased secretion of bile --> decreased ADEK absorption
decreased production, increased degradation of vitamin D defect in vit-D receptor - low serum Ca++, P, elevated P, 1,25(OH)2D (active form) dependent - vit D resistant - Ca++ IV, PO |
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Defect and Lab values for XL low P rickets:
Treatment? Complications? |
defect in PCT --> interferes with P absorption, vit D production
low serum P, high Alk Phos, normal Ca, PTH, 25(OH)D, 1,25(OH)2D, loss of phosphate in urine PO4, Vit D nephrocalcinosis, secondary hyper PTH |
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How is familial hypo-P rickets with calciuria different from XLH?
Tx? Effect of renal osteodystrophy on vit D, phosphate: Explain conection between secondary hyperPTH and renal osteodystrophy: |
serum 1,25(OH2)D is elevated, patient has hypercalciuria
phosphate decreased vit D production, PO4 clearance low vit D --> decreased Ca++ absorption from gut, high serum [P] |
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Major S/S of OI:
Most common iatrogenic OP: High risk of what fx? Tx? |
collagen I defect, recurrent fx, hearing loss, poor tooth growth, blue sclerae
steroid-induced - adults receiving long-term prednisone collapsed vertebrae, hip fx Ca, vit D, calcitonin, bisphosphonates |
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Function of bisphosphonates?
effective in what conditions? recombinant PTH, tx of OP, not approved for children: |
inhibits osteoclast action --> decreased bone resorption
hypercalcemia, post-menopause OP, Paget's, OI, steroid-induced osteopenia Teriparatide (Fortero) |
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serum level = body storage of vit D:
serum level = active metabolite of vit D: What promotes active vit D formation? What decreases production? |
25(OH)D - liver
1,25(OH)2D - kidney high PTH, low P high P, high Ca, decreased kidney tissue |
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Effect of low Ca, high P on PTH secretion:
High Ca, high 1,25(OH)2D effect: effect of serum Mg++: Connection between CaSR on tissues and PTH: |
increases
decreases mildly low Mg++ --> stimulates very low Mg++ --> suppresses CaSR senses low Ca++ --> stimulates PTH, high Ca++ --> inhibits PTH |
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Ca distribution in the serum:
pathology of tetany: Carpopedal spasm almost always occurs when serum Ca++ is below: |
45% albumin bound, 45% free, 10% complexed
decreased Ca++, Mg++ in fluids around neurons --> hyperexcitability total <5.0, ionized <2.5 |
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Eval for Ca++ disorders should include what serum tests?
What other diagnostic tests? |
serum total/ionized Ca++, albumin, pH, phosphorus, alk phos, creatinine, Mg, PTG, inactive/active vit D
urine Ca/creatinine ratio, tubular reabsorption of P, skeletal survey XR, renal U/S, PTHrP, calcitonin, Vitamin A |
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Tx of hypocalcemia:
Tx of hypercalcemia: Usual presentation, lab values of a kid with hypercalciuria: |
Ca++ IV/PO, vit D. check serum Mg
fluids, Lasix, steroids, calcitonin, bisphosphonates hematuria, dysuria, frequency wetting accidents, abd/back pain (most common cause of kidney stones) Lab - urine Ca > 4 mg/kg/24h |
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Tx of hypercalciuria:
Why TZ diuretics? Effect of K-citrate? |
low Na+/high K+ diet, fluid intake, RDA protein/Ca, TZ diuretics, K citrate
increase Ca reabsorption in DCT decreases Ca excretion, citrate pushes Ca to bones, increases Ca solubility in urine |
