r3enal-exam 1-calcium

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r3enal-exam 1-calcium
2010-03-03 09:30:56

exam 1
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  1. distribution of calcium
    primarily intracellular, huge reserve in bone
  2. Calcium RDA
    1000-1300 mg/d (elemental calcium)
  3. normal range (ECF) of calcium
    8.5-10.5 mg/dl, unbound is biologically active portion (45% is ionized)
  4. corrected calcium, when to use and equation
    use if alb level is <3.5 because measured value is falsely low, corrected calcium=(4-measured albumin) X 0.8 + measured calcium, if corrected calcium 8.5-10.5, assume ionized calcium WNL, if corrected calcium <8.5 assume decreased ionized calcium=hypocal
  5. effect of acidosis on ionized ca
    decreased protein binding, increase percent of ionized ca
  6. effect of alkalosis on ionized ca
    increased protein binding, decrease in ionized ca, can lead to symptomatic hypoca
  7. hypercalcemia
    >10.5 mg/dL
  8. severe hypercalcemia
    >13 mg/dL
  9. causes of hypercal
    hyperparathyroidsm(large contributor), immobiliation (primarily in children), malignancy(2nd), granulomatous disease, thyrotoxicosis, famillial, tumor secreates PTH like-substances and increases bone reabsorption or factor secreted at site of bone metastasis
  10. drugs that can cause hypercalc
    thiazides (more mild), Li, calcium supplement, excess antacids, vit D intox, Vit A toxicity, tamoxifen
  11. primary role of Vit D in regards to calcium homeostasis
    increases Ca absorption in sm int
  12. primary role of PTH in regards to ca homeostasis
    increase bone resorption and the release of Ca and phosphate
  13. signs and sx of hypercalcemia
    stones, bones, abd moans and psychic groans, sx usually seen when more than or equal to 13, with malignancy more severe sx
  14. renal stones
    nephrolithiasis, poluria, dehydration, acute renal failure (precipitation of ca and phos)
  15. NM "psychic groans"
    impaired conc and memory, confusion, stupor, coma, lethargy and fatigue, muscle weakness
  16. skeleton "bones"
    bone pain, joint pain
  17. CV-sx with hypercal
    HTN, shortened QT interval on ECG, bradarr, vascular calcification
  18. GI "abdominal moans"
    NV, anor, wt loss, consipation, abd pain, pancreatitis
  19. other sx of hypercalc
    itching keratitis, conjunctivitis
  20. backbone of treatment of hypercalcemia
    0.9% NaCl- 200-300 ml/hr IV inf, rapid onset, rehydration and dilutes Ca, increases excretion, AE: volume overload, decrease potassium, decrease Ca by 2-3 mg/dl within 24-48 hrs when used with a diuretic

    furosemide: 40-80 mg IV q 1-4 hrs, onset within 4 hrs, increased excretion, AE: vol deplation, decrease pot and mg, use only after rehydrated, prevents renal reabsorption of Calcium
  21. bisphosphonates for hypercalc
    zoledronate is more potent q 4-5 wks vs 30 days, 2nd choice for all, primary for malignacy, onset 24-48 hours
  22. calcitonin for hypercalc
    works faster than bis, but requires a test dose, tolerance can develop-rebound increase in ca
  23. GCs for hypercalc
    inhibitss vit D2 conv to D3(active) and decreases bone turnover, effective for hematologic malignancies and vit A and D toxicity
  24. plicamycin
    for hypercalc-used for pts refractory to other tx, need a central IV line, cytotoxic to osteoclasts, lots of AEs
  25. Mild hypercal <13 mg/dl, asymptomatic
    probably would not tx
  26. mild ca<13mg/dL, symptomatic hypercalc
    NS with loop diuretic
  27. severe hypercalc >=13 mg/dl with or w/out sx
    NS plus loop + bis(or other)
  28. monitoring of tx of hypercalc
    serum ca, UOP, EKG, VS
  29. hypocalcemia
    corrected calc <8.5 or ionized ca <4.0mg/dl
  30. increased loss of ca from ECF-hypocalc
    extravascular deposition-chronic hyperphosphatemia (CKD), acute pancreatitis, hungry bone syndrome, intravascular binding-IV phosphorus, foscarnet, hypercalciuria(loop diuretics)
  31. decreased entry of ca into ECF-hypocalc
    hypopara, decreased prod or action of vit D(nutritional, phenytoin, barbiturates, steroids), hypomg(decreased dPTH secretion or PTH resistance), Bisphos, calcitonin, cinacalcet
  32. acute neurologic presentations of hypocalc
    tetany, perioral paresthesias(numbness around mouth), carpopedal spasms, muscle spasms, cramps, pos chvostek's , pos trousseau's
  33. acute CV sx of hypocalc
    similar to ca channel blocker:prolonged QT interval, acute myocardial failure, HOTN, brady
  34. chronic CNS sx of hypocalc
    Irritabilitym memory loss, dep, conf, halluc, seizures
  35. chronic skin sx of hypocalc
    hair loss, brittle, grooved nails, eczema, psoriasis, hyperpig
  36. tx of acute symptomatic hypocalc (based on previous)
    ELEMENTAL calcium 100-300 mg slow IV(5-10 min) until tetany resolves, calc gluc -preferred-(4.65 mEq or about 93 mg elemental ca/gm OR calc chloride (13.6mEq or 273 mg elemental calc/gm

    followed by cont inf, in 1 L bag, of elemental calc at 0.5-2 mg/kg/hr

    monitor serum calcium q 4-6 hrs(should return to normal in 4-6) and adjust inf rate accordingly, target calcium is low end of normal
  37. tx for asymptomatic or chronic hypocalc
    oral calcium salts, carbonate requires acid(tk with meals-most common form, caution in elderly and if on PPIs or H2)only 30-40% absorbed, to increase abs: tk with food, divide into doses <=500mg, add vit D 200-800 IU/day, citrate does not req aicd
  38. hypocalcemia asociated with vit D deficiency
    vit D+ca supplementation
  39. ADRs of calcium supplementation
    constipation, potentially kidney stones
  40. rocaltrol, calcitrol
    already in active form-if underlying kidney fxn
  41. ergocalciferol and cholcalciferol
    most common forms of vit d