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Electrolyte Disorders

  1. normal potassium levels
    3.5 -5.0 mEq/L
  2. clinical manifestation of moderate to severe hypokalemia (include AP)
    • weakness, myalgias, bradycardia
    • flattening of T wave and prominet U wave

    AP: lowers baseline, repoolarization faster, hyperpolarization?
  3. treatment for asymptomatic hypokalemia
    • oral potassium
    • increase potassium intake
    • maybe: K sparing diuretic (mild hypokalemai, but need diuretic)
  4. treatment for symptomatic hypokalemia
    IV 10-20 mEq/L K diluted in 100 mL NSS given over 1 hr
  5. monitoring for hypokalemia (severe and mild)
    • severe - monitor q4-6h with IV
    • mild - with oral every 2 weeks

    if no inc in K in 72 hrs, check Mg
  6. electrolyte disorder assoicated with Addison's disease
    hyperkalemia
  7. electrolyte disorder associated with adrenal insufficiency
    hyperkalemia
  8. drugs associated with hyperkalemia (7)
    • ACE/ARB
    • K-sparing (spironolacton, triamteren/amiloride)
    • NSAIDs
    • heparin
    • cyclosporin/tacrolimus
    • trimethoprim
    • pentamidine
  9. clinical manifestation of moderate to severe hyperkalemia (include AP)
    • more effect on the heart
    • peaked T waves
    • wider QRS
    • can lead to v. fib and asystole
  10. what happens to repol and hyperpol in hypokalemia
    • repol - quicker
    • hyperpol - slower
  11. what happens to repol and hyperpol in hyperkalemia
    • repol - slower
    • hyperpol - quicker
  12. treatment of moderate to severe hyperkalemia
    Ca slow push over 5 min, insulin/dextrose, furosemide 20-40 mg IV

    1. antagonize cardiac effects: 1 g Ca gluconate or chloride slow push over 5 min

    2. push K back into cell: insulin/dextrose (first line); albuterol (second line) [DON'T GIVE EPI]; sodium bicarbonate (3rd line)

    3. excrete excess K: furosemide 20-40 mg IV
  13. treatment for chronic hyperkalemia
    • dialysis
    • diuretics - oral furosemide
    • fludrocortisone - takes several days to work
  14. normal magnesium levels
    1.7 - 2.3 mg/dL
  15. alcoholism is associated with which electrolyte disorder?
    hypomagnesemia
  16. What is a positive Chvostek's indicative of?
    • hypoMg
    • hypoCa
  17. What is a positive Trousseau's indicative of?
    • hypoMg
    • hypoCa
  18. treatment for asymptomatic hypomagnesemia?
    • oral magnesium supplements
    • Mg oxide = most Mg
    • Mg gluconate = least Mg

    lactate and chloride = least diarrhea
  19. treatment for symptomatic hypomagnesemia
    Mg sulfate 2-4 g IV over 2-4 hrs [NO PUSH]
  20. clinical presentation of hypermagnesemia
    • loss of deep-tendon reflexes
    • CNS depression
    • resp muscle paralysis and dysrhythmias 
    • heart block b/c vents can't contract
  21. which electrolyte disorder is most common in renal failure?
    hypermagnesemia
  22. treatment of symptomatic hypermagnesemia
    • 1. Ca chloride or gluconate 1 g IV slow push over 5 min
    • 2. forced diuresis with normal saline and IV furosemide
    • can use shock and supportive care in life-threatening situations
  23. normal osmolality levels
    275-290 mOsm/kg
  24. normal sodium levels
    135-145 mEq/L
  25. what does ANP do? and when is it released?
    atrial natriuretic peptide - regulates Na excretion independent of water

    released when it is stretch b/c of too much blood volume in the atria
  26. Steps to approaching sodium disorders
    • 1. Check serum Na concentration (-natremic)
    • 2. Check serum osmolality (-tonic)
    • 3. Check fluid status (-volemic)
    • 4. Check urine sodium and urine osmolaltiy (to determine cause of Na disorder)
  27. Lab abnormalities present in hypovolemia
    • increased BUN:Scr ratio ( >20:1)
    • increased hematocit
  28. correcting hyponatremia too quickly will cause:
    osmotic demyelination syndrome
  29. hyponatremia is usually associated with:
    impaired water excretion
  30. excessive sodium loss is usually because of:
    thiazide diuretics in elderly women
  31. which electrolyte disorder is technically not possible?
    isotonic hyponatremia
  32. what is hypertonic hyponatremia caused by?
    increased number of solutes other than Na in the ECF
  33. What are the risk factors for hypovolemic hypotonic hyponatremia
    • elderly
    • woman
    • low body mass (dec in TBW)
    • concurrent meds that impair water excretion
  34. SIADH can cause what electrolyte disorder?
    isovolemic hypotonic hyponatremia
  35. clinical presentation of hyponatremia
    mental status changes
  36. treatment of symptomatic hypovolemic hypotonic hyponatremia?
    0.9% saline
  37. treatment of symptomatic hypervolemic hypotonic hyponatremia?
    • 3% saline
    • furosemide IV
  38. treament asymptomatic hypervolemic hypotonic hyponatremia?
    • restrict fluid intake
    • inc Na intake
  39. rate of saline infusion in acute symptomatic hyponatremia
    1.5 - 2 mEq/L/hr (12 mEq/L/day)
  40. rate of saline infusion in chronic symptomatic hyponatremia?
    1 mEq/L/hr (12 mEq/L/day)
  41. rate of saline infusion in chronic asymptomatic hyponatremia?
    0.5 mEq/L/hr
  42. treatment for symptomatic isovolemic hypotonic hyponatremia?
    • 3% saline
    • ADH antagonist - conivaptan or tolvaptan (LD: 20 mg IV infused over 30 min; MD: 20-40 mg IV infusion over 24 hrs for 1-3 days)
  43. treatment for asymptomatic isovolemic hypotonic hyponatremia?
    water restiction

    • demecocycline (chronic SIADH) - slow onset
    • initially: 900-1200 mg, then dec: 600-900 mg qd
  44. what is demecocycline used for?
    isovolemic hypotonic hyponatremia (SIADH)
  45. What is SIADH associated with?
    isovolemic hypotonic hyponatremia
  46. What condition is a counterpart of SIADH? What medications can cause this?
    Nephrogenic diabetes insipidus

    lithium, demeclocycline, cidofovir, foscarnet
  47. Which diuretics can cause hypovolemic hypernatremia?
    osmotic diuretics
  48. What can cause hyperolemic hypernatremia?
    • sodium overload
    • mineralcorticoid excess
  49. what electrolyte disorder is diabetes insipidus associated with? And what are the two types?
    isovolemic hypernatremia

    • central diabetes insipidus
    • nephrogenic diabetes insipidus
  50. What is central DI associated with?
    a lack of ADH secretion due to head trauma, surgy, or cancer
  51. what is nephrogenic DI associated with?
    lack of sensitivity of ADH (opposite of SIADH) caused by drugs such as demeclocycline which is used to treat SIADH
  52. what electrolyte disorders can cause SIADH?
    • hyperCa
    • hyopK
  53. when do you see the onset of polyuria in DI?
    • central - sudden onset
    • nephrogenic - gradual onset
  54. how do you decide what kind of DI it is?
    • water deprivation test:
    • 1. restrict water for 8-12 hours
    • 2. give desmopressin
    • 3. measure the osm before and after dDAVP given

    • if central will see a dec in urine outpus
    • if nephrogenic will not see a change
  55. How do yo treat hypovolemic hypernatremia?
    • 0.9% saline
    • D5W

    • replace 50% of water deficit in 24 hrs
    • replace rest of 50% deficit over next 1-2 days
  56. how do you treat central DI?
    • dDAVP (desmopressin) 10 mcg intranasally QD - BID
    • chlorpropamide 125 - 250 mg PO QD
    • carbamazepin 100 mg - 300 mg PO QD
    • clofibrate 500 po QID
  57. how do you treat nephrogenic DI?
    • sodium restriction
    • HCTZ 25 mg po q12-24h
    • amiloride 5-10 mg po qd (for Li induced)
    • NSAIDs: 
    • --indomethacin 50 mg q8-12h
    • --tometin 150 mg q6-8h
  58. how do you treat hypervolemic hypernatremia?
    • IV furosemide 20-40 mg
    • D5W
Author
jcu1
ID
187885
Card Set
Electrolyte Disorders
Description
Schonder
Updated

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