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Electric-Lytes

Electric-Lytes. Dr. Jeffrey P Schaefer General Internal Medicine. http://dr.schaeferville.com presentations. Download Slides @. Objectives. Case based approach to abnormal Sodium Potassium Calcium Magnesium Phosphate. Sodium. Warm Up Case. 81 yr old female presents to ER

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Electric-Lytes

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  1. Electric-Lytes Dr. Jeffrey P Schaefer General Internal Medicine

  2. http://dr.schaeferville.com presentations Download Slides @

  3. Objectives • Case based approach to abnormal • Sodium • Potassium • Calcium • Magnesium • Phosphate

  4. Sodium

  5. Warm Up Case • 81 yr old female presents to ER • recent viral illness • vomiting and diarrhea • Na  125 mmol/l

  6. What are the clinical features of hyponatremia?

  7. Hyponatremia • Neuromuscular Irritability • mild anorexia • headache • muscle cramps • irritability • delirium • coma • seizure • Rate of Reduction affects clinical severity

  8. What are the causes of hyponatremia?

  9. Common Causes • Volume Depletion diuretics (esp thiazide), vomiting, diarrhea • Edema • heart failure, nephrosis, cirrhosis • Water excess • SIADH, polydipsia, iatrogenesis • Salt loss • hypoadrenal, hypoT4, cerebral salt wasting • Shift (pseudohyponatremia) • hyperglycemia, hyperlipidemia

  10. Case • 81 yr old female presents to ER • malaise • recent viral illness • vomiting and diarrhea Na = 125 mmol/l

  11. How should this case be managed?

  12. Orders Solution? Volume? Rate(s)? Reassess?

  13. Orders Solution? Volume? Rate(s)? Reassess? • Normal Saline • 1 – 4 l according to clinical assessment • 250 – 500 / hr x 1 l, then 100 – 150 ml/hr • clinical reassess in 4 – 6 hours • recheck lab in 24 hours

  14. Sodium, Salt • What’s in Normal Saline? • NaCl 154 mmol/l • Na 154 mmol + Cl 154 / litre

  15. Sodium, Salt • What’s in Normal Saline? • NaCl 0.9% w/v • 0.9 grams solute per 100 grams solvent • 0.9 grams salt per 100 grams water • 9 grams salt per 1,000 grams water • 9 grams salt per 1,000 ml water • Normal Saline is NaCl 9 g / l • Implication for heart failure • Mw(NaCl) = 22.990 + 35.453 = 58.443 g/mol • Na accounts for (23/35) ~ 40% weight of salt • Low Salt Diet = 2 g of sodium = 1 tsp • Low Salt Diet = 2 g / 0.4 = 5 g NaCl • Low Salt Diet = 555 ml of normal saline

  16. What Other Flavors Do We Have?

  17. Sodium, Salt, Sugar Na+ mmol/l Dextrose in Water 0 ½ Normal Saline 77 Ringer’s Lactate* 130 Normal Saline 154 Hypertonic Saline 513 * Ringer’s Lactate: • Na+ 130 mmol, K+4 mmol, Ca++ 1.5 mmol, Cl− 109 mmol, lactate 28 mmol • electrolyte content is isotonic (273 mOsmol/liter) in relation to the extracellular fluid (approx. 280 mOsmol/liter).

  18. Case • 82 year old female in ER • HTN on thiazide • presents with seizure and coma • estimated weight 60 kg • Na = 105 mMol

  19. How should this case be managed?

  20. Sodium Deficit • Calculated sodium deficit *0.6 males x (weight in kg) x (desired sodium - actual sodium)*0.5 for females desired range is 105 mmol/l + 5 mmol/l = 110 mmol/l hypertonic saline has 513 mMol / l of Na

  21. Sodium Deficit *0.5 x (weight in kg) x (desired sodium - actual sodium)*0.5 for females 0.6 for males desired increase = 105 mmol/l + 5 mmol/l = 110 mmol/l 0.5 x 60 kg = 30 l 30 l x 5 mmol/l = 150 mmol hypertonic saline has 513 mMol / l of Na 150 / 514 = 300 ml 300 ml over 1 or 2 hours then reassess OR 100 ml bolus x 10 min, then another, then another... REASSESS CLINICALLY and BIOCHEMICALLY q 1-2h

  22. Rapid Correction of Hyponatremia • central pontine myelinolysis risk • risk is minimal if increase is 0.5 – 1.0 mmol/h

  23. Case • 30 year old female presents to ER • was hiking in the mountains • drank 10 liters of water per day on the advice of a well meaning friend • delirium with paranoia • Na = 110 mmol/l • ?

  24. Case • 78 year old female on general surgery • Post-op day 3 hemicolectomy for Duke B ca • Overnight developed delirium • Post-op IV order: ‘2/3 – 1/3 @ 125 ml/h’ • Na = 120 mMol

  25. Case • 19 year old man presents to ER • progressive weakness • anorexia and weight loss • nauseated • Na = 128 mMol, K = 6.5 mMol

  26. Case • 82 year old female in clinic • HTN on thiazide • feels well • Na = 125 mMol

  27. Case • 65 year old man on neurosurgery • post-op day 2 brain aneursym clip • Na = 129 mMol

  28. Case • 59 year old female • presents with pneumonia • day 4 feels strange • can eat and drink, likes tea • Na = 120 mMol

  29. water restriction is mainstay diuretics maybe vaptans... probably not yet SIADH

  30. ADH antagonist - Tolvaptan (Samsca, Otsuka) in Canada - 15 – 30 mg tablets..... $120 / day - black box warning re: hepatic toxicity Vaptans

  31. Warm Up Case • 81 year old female on stroke unit • doing poorly over last few days • now unconscious • Na = 176 mMol (normal 135-145 mMol)

  32. What are clinical features of hypernatremia?

  33. Clinical Features • Hypernatremia • lethargy • weakness • irritability • twitching • delirium • reduced level of consciousness • coma • seizures ‘neuromuscular irritability’

  34. What are the causes of hypernatremia?

  35. DDx – HyperNa+ • Not enough water! • no thirst • can’t act on thirst • can’t retain water • except for Normal Saline, not usually a salt issue

  36. Case • 81 year old female on stroke unit • doing poorly over last few days • now unconscious • Na = 176 mMol (normal 135-145 mMol) • estimated weight 60 kg

  37. Diagnosis? • Management? • Solution • Volume • Rate

  38. Solution Na+ mmol/l Dextrose in Water 0 ½ Normal Saline 77 Ringer’s Lactate* 130 Normal Saline 154 Hypertonic Saline 513 * Ringer’s Lactate: • Na+ 130 mmol, K+4 mmol, Ca++ 1.5 mmol, Cl− 109 mmol, lactate 28 mmol • electrolyte content is isotonic (273 mOsmol/liter) in relation to the extracellular fluid (approx. 280 mOsmol/liter).

  39. Rate of Correction Correct no faster than 0.5 – 1 mmol / hr Risk of cerebral edema • determine water deficit • determine duration of correction • rate = deficit / duration (index to hour) • consider ongoing losses • decide on re-assessment

  40. Volume Water Deficit (Na+ measured – 140 mmol/l) 0.6 x kg -------------------------------------- 140 mmol/l use 0.5 for females desired = 140 mMol

  41. Calculate Free Water Deficit Water Deficit (176 mmol / l – 140 mmol/l) 0.5 x 60 x -------------------------------------- 140 mmol/l 7,710 ml 36 mmol / 0.5 – 1.0 mmol/hr = 48 hr 160 ml/hr of ‘free water’ D5W or tube water at 160 ml/hr

  42. Advanced Case • 55 year old female • pituitary resection • post-op dilute polyuria • Na = 165 mMol

  43. DDAVP • IV / sq  1-2 ug q12 h • nasal  10 – 40 ug / day (divide bid / tid) • oral  0.1 – 1.2 mg / day (divide bid / tid) • give hypotonic IV while getting control • usually this is a planned event

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