Hyperkalemia: Difference between revisions

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== Differential Diagnosis ==
== Differential Diagnosis ==
#Pseudohyperkalemia: hemolyzed specimen, prolonged tourniquet use prior to blood draw, thrombocytosis or leukocytosis  
#Pseudohyperkalemia: hemolyzed specimen, prolonged tourniquet use prior to blood draw, thrombocytosis or leukocytosis  
#Redistribution
#Redistribution (shift from intracellular to extracellular space)
##Acidemia (see [[Diabetic Ketoacidosis (DKA)|DKA]])
##Acidemia (see [[Diabetic Ketoacidosis (DKA)|DKA]])
##Cellular breakdown: see [[Rhabdomyolysis]]/[[Crush Injury]], hemolysis, see [[Tumor Lysis Syndrome]]  
##Cellular breakdown: see [[Rhabdomyolysis]]/[[Crush Injury]], hemolysis, see [[Tumor Lysis Syndrome]]  
#Increased total body potassium  
#Increased total body potassium  
##Inadequate excretion: Acute or chronic renal failure, hypoaldosteronemia
##Inadequate excretion: Acute/chronic renal failure, Addison's disease, type 4 RTA
##Drug-induced: potassium-sparing diuretic (spironolactone), angiotensin converting enzyme inhibitors (ACE-I), nonsteroidal anti-inflammatory drugs (NSAIDs)
##Drug-induced: potassium-sparing diuretic (spironolactone), angiotensin converting enzyme inhibitors (ACE-I), nonsteroidal anti-inflammatory drugs (NSAIDs)
##Excessive intake: diet, blood transfusion  
##Excessive intake: diet, blood transfusion  
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== Treatment ==
== Treatment ==
===Stabilize Cardiac Membranes: give if ECG changes, consider if K >7 mEq/L===
===Stabilize cardiac membranes===
#Intravenous calcium: only if QRS interval prolonged
#Indicated if there are any ECG changes or evidence of arrhythmias. Consider if K >7 mEq/L
#Intravenous calcium only if QRS interval is prolonged
#Can give as calcium gluconate or calcium chloride  
#Can give as calcium gluconate or calcium chloride  
##Calcium gluconate 2 - 3 grams IV
##Calcium gluconate: Give 10ml of a 10% solution over 10 mins
###Only 1/3 the calcium compared to calcium chloride  
###Only 1/3 the calcium compared to calcium chloride  
###Give over 10 minutes: can cause hypotension due to osmotic shift
###Can cause hypotension due to osmotic shift
##Calcium chloride 1 gram IV  
##Calcium chloride 1 gram IV  
###Give over 1 - 2 minutes  
###Give over 1 - 2 minutes  
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##Do serial [[EKG]]s to track progress: may need to give multiple doses
##Do serial [[EKG]]s to track progress: may need to give multiple doses


===Force Intracellular Shift===
===Shift K+ intracellularly===
#Intravenous insulin + dextrose  
#Intravenous insulin + dextrose  
##Give 10 units regular insulin intravenously with 25 to 50 grams (1 - 2 50 mL ampules) of 50% dextrose (D50)
##Give 10 units regular insulin intravenously with 25 to 50 grams (1 - 2 50 mL ampules) of 50% dextrose (D50)
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#Intravenous sodium bicarbonate 50 ml of 8.4% solution (1 ampoule) given over 5 minutes  
#Intravenous sodium bicarbonate 50 ml of 8.4% solution (1 ampoule) given over 5 minutes  
##Duration of effect: 1 - 2 hours
##Duration of effect: 1 - 2 hours
##More effective if patient is acidemic
##Generally not required, unless pH <7.1


===Remove from System===
===Remove K+ from system===
#Intravenous furosemide (Lasix) 40 - 80 mg
#Intravenous furosemide (Lasix) 40 - 80 mg
##Ensure adequate urine output first
#Sodium polystyrene sulfonate (Kayexylate): 30 gm oral or per rectum
#Sodium polystyrene sulfonate (Kayexylate): 30 gm oral or per rectum
##'''Controversial''', see: [[EBQ: Use of Kayexylate in Hyperkalemia]]
##'''Controversial''', see: [[EBQ: Use of Kayexylate in Hyperkalemia]]
#Intravenous normal saline solution for volume expansion if dehydrated, rhabdomyolysis, diabetic ketoacidosis or other acidosis  
#Intravenous normal saline solution for volume expansion if dehydrated, rhabdomyolysis, diabetic ketoacidosis or other acidosis  
#Definitive: hemodialysis
#Definitive treatment is hemodialysis


== See Also ==
== See Also ==

Revision as of 00:17, 9 February 2015

Background

  • Defined as >6.0 mEq/L
  • Consider pseudohyperkalemia (e.g. from hemolysis)
  • Potassium secretion is proportional to flow rate and sodium delivery through distal nephron
    • This is how loop & thiazide diuretics cause hypokalemia

Diagnosis

ECG

Changes NOT always predictable and sequential

  • 6.5 - 7.5 mEq/L: peaked T waves, prolonged PR interval, shortened QT interval
  • 7.5 - 8.0 mEq/L: widened QRS interval, flattened P waves
  • 10 - 12 mEq/L: sine wave, ventricular fibrillation, heart block

Differential Diagnosis

  1. Pseudohyperkalemia: hemolyzed specimen, prolonged tourniquet use prior to blood draw, thrombocytosis or leukocytosis
  2. Redistribution (shift from intracellular to extracellular space)
    1. Acidemia (see DKA)
    2. Cellular breakdown: see Rhabdomyolysis/Crush Injury, hemolysis, see Tumor Lysis Syndrome
  3. Increased total body potassium
    1. Inadequate excretion: Acute/chronic renal failure, Addison's disease, type 4 RTA
    2. Drug-induced: potassium-sparing diuretic (spironolactone), angiotensin converting enzyme inhibitors (ACE-I), nonsteroidal anti-inflammatory drugs (NSAIDs)
    3. Excessive intake: diet, blood transfusion
  4. Other causes: succinylcholine, digitalis, beta-blockers

Treatment

Stabilize cardiac membranes

  1. Indicated if there are any ECG changes or evidence of arrhythmias. Consider if K >7 mEq/L
  2. Intravenous calcium only if QRS interval is prolonged
  3. Can give as calcium gluconate or calcium chloride
    1. Calcium gluconate: Give 10ml of a 10% solution over 10 mins
      1. Only 1/3 the calcium compared to calcium chloride
      2. Can cause hypotension due to osmotic shift
    2. Calcium chloride 1 gram IV
      1. Give over 1 - 2 minutes
      2. Extravasation is bad: use a good IV
      3. Usually given in code situations
    3. Duration of action: 30 - 60 minutes
    4. Use caution in patients taking Digoxin although risk of Stone Heart may be unsubstantiated [1]
    5. Do serial EKGs to track progress: may need to give multiple doses

Shift K+ intracellularly

  1. Intravenous insulin + dextrose
    1. Give 10 units regular insulin intravenously with 25 to 50 grams (1 - 2 50 mL ampules) of 50% dextrose (D50)
      1. May withhold dextrose if blood sugar >300 mg/dl (>17 mmol/L)
      2. Duration of effect: 4 - 6 hours
  2. Nebulized albuterol 5 - 20 mg
    1. Response is dose-dependent
    2. Peak effect: 30 minutes
    3. Duration of effect: 2 hours
  3. Intravenous sodium bicarbonate 50 ml of 8.4% solution (1 ampoule) given over 5 minutes
    1. Duration of effect: 1 - 2 hours
    2. Generally not required, unless pH <7.1

Remove K+ from system

  1. Intravenous furosemide (Lasix) 40 - 80 mg
    1. Ensure adequate urine output first
  2. Sodium polystyrene sulfonate (Kayexylate): 30 gm oral or per rectum
    1. Controversial, see: EBQ: Use of Kayexylate in Hyperkalemia
  3. Intravenous normal saline solution for volume expansion if dehydrated, rhabdomyolysis, diabetic ketoacidosis or other acidosis
  4. Definitive treatment is hemodialysis

See Also

External Links

Source

Tintinalli Management Severe Hyperkalemia. Crit Care Med, 2008, 36:12 EMCrit Podcast #32

  1. ↑ Erickson CP, Olson KR. Case files of the medical toxicology fellowship of the California poison control system-San Francisco: calcium plus digoxin-more taboo than toxic? J Med Toxicol. 2008 Mar;4(1):33-9
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