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Electrolyte Abnormalities

Electrolyte Abnormalities

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Electrolyte Abnormalities

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  1. Electrolyte Abnormalities 3 July 2008 Justin A. Glass, MD Emory Family Medicine

  2. Goals • Review of common electrolyte abnormalities • Normal ranges • Clinical manifestations of hypo- or hyper- states • Causes • Treatment options

  3. Goals • What will spend time on today… • Sodium • Potassium • Calcium • Magnesium • Phosphorus

  4. San Juan Mountains

  5. Hyponatremia • Sodium: Normal 135 – 145 mg / dl • Symptoms usually begin <120 mg /dl • Nausea • Lethargy • Muscle cramp • Psychosis • Seizure • Coma • Death

  6. Hyponatremia • Diagnosis based on assessment of serum osmolality and volume status

  7. Hyponatremia • Serum Osmolality • Osmolality (calculated) = 2 (Na) + Gluc / 18 + BUN /2.8

  8. Hyponatremia • Normal Osmolality (280 – 295 mOsm / kg) Isotonic pseudohyponatremia Hyperproteinemia (>10 mg / dl) Hyperlipidemia (severe)

  9. Hyponatremia • High Osmolality (>295 mosm / kg) Hypertonic hyponatremia Hyperglycemia Na: 2.4 mEq / liter decrease per 100 mg/dl increase in glucose Mannitol excess Glycerol therapy Am J Med 1999 Apr;106(4):399-403

  10. Hyponatremia • Low serum osmolality (<280 mOsm / kg) Hypotonic hyponatremia Need to assess volume status next in these patients.

  11. Hypotonic hyponatremia • Hypovolemia • GI losses • Renal losses plus excess water ingestion • Third space losses Tx: Isotonic saline

  12. Hypotonic Hyponatremia • Hypervolemia • CHF • Liver disease • Nephrotic syndrome • CKD Urine Na: < 20 mEq /liter except in CKD Tx: Salt restriction / water restriction / diuretics

  13. Hypotonic Hyponatremia • Isovolemia • Glucocorticoid insufficiency • Hypothyroidism • Psychogenic polydipsia • Medications (amitriptyline / cyclophosphamide / carbamazepine / morphine) • SIADH • Nausea / pain / emotional stress • Diuretic use with potassium depletion

  14. Isovolemic Hypotonic Hyponatremia • SIADH • Syndrome of inappropriate antidiuretic hormone • Hypotonic hyponatremia • Clinical euvolemia • Inappropriately elevated urine osmolality (>200) in face of low serum osmolality • Urine Na >20 mEq / liter • Normal renal function / TSH / cortisol

  15. SIADH • Acute tx • Severe hyponatremia (<110 mEq / liter) • IV lasix • NS with 20 – 40 mEq / liter KCL • Rarely 3% saline will be needed • Chronic tx • Mild hyponatremia • Water restriction to approx 1000 ml / day • Demeclocycline 300 mg PO bid if water restriction not working (contraindicated in liver disease)

  16. SIADH • Chronic treatment (cont) • Vasopressin receptor antagonists • Conivaptan (Vaprisol) IV prep • 20 mg infusion over 30 min, then gtt of 20 mg/24 hrs • Maximum dose 40 mg/24 hrs gtt • Maximum duration is 4 days

  17. Hyponatremia • How fast do we correct it?

  18. Hyponatremia • Treatment principles • Not too fast (pontine myelinolysis) • Symptomatic • Initial 1 - 2 mEq / L / hr x two hours, then • 0.5 mEq / L / hr • Asymptomatic • 0.5 mEq / L / hr • Max in 24 hours: 10 meq total rise • Max in 48 hours: 18 meq total rise Am J Med. 2007 Nov;120(11 Suppl 1):S1-21.

  19. Mountain Goats

  20. Hypernatremia • Sodium: Normal 135 – 145 mg / dl • Clinical manifestations • Tremors • Irritability • Ataxia • Spasticity • Mental confusion • Seizures • Coma • Death

  21. Hypernatremia • Cause: • Net sodium gain • Net water loss

  22. Hypernatremia • Volume expansion (net sodium gain) • Cause • Hypertonic saline / NaHCO3 administration • Primary hyperaldosteronism • Cushing’s syndrome Tx: Diuretics D5W to replace fluid loss after diuretics

  23. Hypernatremia • Water depletion • Hypotonic fluid losses

  24. Hypovolemic hypernatremia • Treatment • Calculate free water deficit • TBW (liters) = 0.6 x current total body weight (kg) • Desired TBW (liters) = Measured Na (mEq/l) x current TBW / Normal Na • Body water deficit (liters) = Desired TBW – current TBW

  25. Hypovolemic hypernatremia • If hemodynamic compromise, then replace initially with NS • Otherwise use ½ NS or D5W • Aim to decrease Na by 0.5 mEq / liter / hr • Correct one half of the water deficit in 24 hrs • Correct other half over next 24-48 hours

  26. Hypovolemic hypernatremia • Diabetes insipidus Sxs: Polyuria / Polydipsia / Low urine osm • Central • Tumor / Granuloma / Trauma / Surgery • Nephrogenic • Severe hypokalemia / hypercalcemia / CKD / Drugs (lithium / demeclocycline / amphotericin)

  27. Hypovolemic hypernatremia • DI • Differentiation of central and nephrogenic • Trial of water deprivation • Failure to concentrate urine confirms DI • Subsequently given arginine vasopressin • Central DI (urine concentration increases) • Nephrogenic DI (no increase)

  28. Hypovolemic hypernatremia • DI • Treatment • Central • DDAVPP 5-10 mcg intranasally q day / bid • Nephrogenic • Correction of underlying cause if possible • Thiazide diuretic / salt restriction can help

  29. Columbine Pass

  30. Hypokalemia • Normal K level: 3.5 – 5.0 • Clinical manifestations • Fatigue • Cramps • Constipation • Weakness / Paralysis • Parasthesias • Arrhythmias

  31. Hypokalemia • EKG abnormalites • Flattened T waves • ST depressions • Prominent U waves

  32. EKG Changes in Hypokalemia http://www.merck.com/media/mmpe/figures/MMPE_12END_156_02_eps.gif

  33. Hypokalemia • Causes • GI losses • Renal losses • Acid-base shifts

  34. Hypokalemia Treatment • Oral therapy • Mild hypokalemia • Ability to tolerate oral replacement • Increase dietary intake • Potatoes / Bananas • KCl preps (i.e. KDur) • Preps can be used in range 8 – 20 mEq • Monitor K level and adjust dose as needed • Correct cause

  35. Hypokalemia Treatment • IV repletion • Severe hypokalemia • Inability to tolerate oral repletion Max Concentration: 60 mEq / liter Note pain is common at > 40 mEq /liter Rate: 10 mEq / hr (20 mEq / hr with tele) Monitor response and decrease conc / rate as appropriate.

  36. Hyperkalemia • Potassium Normal 3.5 – 5.0 • Elevated potassium level should be evaluated as to the following: • What is the cause? • Is the cause an acute or chronic issue? • Are there accompanying EKG changes?

  37. Hyperkalemia • Symptoms • Usually asymptomatic • Muscle weakness / paralysis • EKG abnormalities • Peaked T waves • ST depression • 1st degree AVB • QRS widening • “Sine wave sign”

  38. Hyperkalemia • EKG changes

  39. Hyperkalemia • Think about the cause • 1. Too much total potassium • Renal disease • Intake increased (rare outside of renal disease) • 2. Shift of potassium from intracellular space to extracellular space • DKA

  40. Hyperkalemia • Does the potassium level make sense in the patient? Pseudohyperkalemia

  41. Hyperkalemia • When do we treat • Patient assessment • Cause • Chronicity • Degree of potassium elevation • <6.0 Does not need acute invasive tx • >6.0- 6.5 Kayexalate +/- other modalities • >6.5 Consider more acute modalities

  42. Hyperkalemia • Treatment options • Calcium gluconate • NaHCO3 • Regular insulin • Albuterol nebulizer treatment • Kayexalate • Dialysis

  43. Hyperkalemia • Calcium gluconate • IV formulation is 1000 mg / 10 ml (10% soln) • Dose: 10 ml over 2-5 minutes IV with EKG monitoring • Action: Stabilization of cardiac cells. Does not lower potassium. Used for hyperkalemia with EKG changes. • If EKG changes do not immediately resolve, dose can be repeated in 5 minutes.

  44. Hyperkalemia • Calcium gluconate • Precautions • Do not infuse with bicarbonate (precipitation of calcium carbonate) • Do not use routinely with digitalis as hypercalcemia can augment digitalis toxicity. Limit use to patients with widened QRS.

  45. Hyperkalemia • Beta agonist • Albuterol nebulizer treatment • 2-4 ml of 0.5% soln (10-20 mg dose) • Note a usual nebulizer tx for RAD is 2.5 mg • Peak effect in 90 minutes • Epinephrine IV infusion • 0.05 mcg / kg / min IV infusion • Peak effect in 30 minutes • I would be hesitant to use this when an albuterol neb is easy and less risky.

  46. Hyperkalemia • Insulin • Regular insulin 10 units IV plus one D50 Amp over 5 minutes. This will give patient 25 grams of glucose. • Follow this with a D 5 containing IV maintenance fluid for several hours. • Effect within 15 minutes. Peak effect 60 min. Duration 3-4 hours.

  47. Hyperkalemia • NaHCO3 • 1 Amp (44.6 meq) IV over 5 minutes. • Onset: 30 minutes • Duration: 60-120 minutes

  48. Hyperkalemia • Alternate approach to NaHCO3 / Insulin: • Put 2 Amps NaHCO3 in 1 liter D10 W. • Give 300 ml over first 30 minutes, then change to 250 ml / hr until finished. • Give Regular insulin 25 units SQ with starting the IVF.

  49. Hyperkalemia • Kayexalate (Na – K exchange resin) • PO dosing: 15 -30 gram • Can be used as a dry powder • Can be mixed with 60-120 ml of a 20% sorbitol soln to avoid constipation • PR dosing: 50 grams • Mix with 50 ml of 70% sorbitol and 100 ml tap H20 • Retain in rectum x 30 minutes minimum but ideally 2+ hours

  50. Needles Peaks