Hyperkalemia

Revision as of 16:06, 20 March 2026 by Danbot (talk | contribs) (Convert medication dosing to MedicationDose templates for SMW integration (8 medications: calcium gluconate, calcium chloride, insulin, albuterol, sodium bicarbonate, furosemide, kayexalate, lokelma))

Background

  • Defined as >5.5 mEq/L
  • Potassium secretion is proportional to flow rate and sodium delivery through distal nephron
    • Thus, loop & thiazide diuretics cause hypokalmia
  • Most common cause is hemolysis from blood draw (pseudohyperkalemia)

Medication Causes

Alter transmembrane potassium movement

  • β blockers
  • Digoxin
  • Potassium-containing drugs
  • Potassium supplements
  • Salt substitutes
  • Hyperosmolar solutions (mannitol, glucose)
  • Suxamethonium
  • Intravenous cationic amino acids
  • Stored red blood cells (haemolysis releases potassium)
  • Herbal medicines (such as alfalfa, dandelion, horsetail, milkweed, and nettle)

Reduce aldosterone secretion

Block aldosterone binding to mineralocorticoid receptors

Clinical Features

Typically non-specific

Differential Diagnosis

Hyperkalemia

  • Pseudohyperkalemia: hemolyzed specimen, prolonged tourniquet use prior to blood draw, thrombocytosis or leukocytosis
  • Redistribution (shift from intracellular to extracellular space)
  • Increased total body potassium
    • 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)
    • Excessive intake: diet, blood transfusion
  • Other causes: succinylcholine, digitalis, beta-blockers

Peaked T-waves

Wide-complex tachycardia

Assume any wide-complex tachycardia is ventricular tachycardia until proven otherwise (it is safer to incorrectly assume a ventricular dysrhythmia than supraventricular tachycardia with abberancy)

^Fixed or rate-related

Evaluation

Diagrammatic representation of ECG changes with increasing hyperkalemia
ECG in hyperkalemia with peaked T waves and small P waves
ECG with widened QRS complex and tall broad T waves
ECG showing sine wave pattern

Workup

  • ECG
  • Chem 10 (including potassium, magnesium, and phosphorus)
    • Consider point-of-care lab testing for more rapid result
  • Consider ABG/VBG to evaluate pH

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

Diagnosis

  • Based on lab testing (>5.5 mEq/L), although ECG may provide earlier information
  • Consider pseudohyperkalemia (e.g. from hemolysis)

Management

Stabilize cardiac membranes

Indicated if there are any ECG changes or evidence of arrhythmias. Consider if K >7 mEq/L

  • Either one of the following:
    • Calcium gluconate 10mL of 10% solution (1 gram) IV over 5-10 min; in severe cases may start with 3 grams (30 mL), repeat doses up to 9-15 grams total IV (onset 15-30 min, duration 30-60 min) — Only 1/3 elemental calcium vs calcium chloride; can cause hypotension
    • Calcium chloride 1 gram IV over 1-2 min IV (onset 15-30 min, duration 30-60 min) — Extravasation risk: use a good IV; usually given in code situations
  • Do serial ECGs to track progress: may need to give multiple doses
  • (If given for hyperkalemic cardiac arrest, need to continue resuscitation for at least 30 minutes)
  • Use caution in patients taking Digoxin although risk of Stone heart may be unsubstantiated [1]

Shift K+ intracellularly

  • Insulin 10 units regular insulin IV with 25-50g of D50 (1-2 ampules) IV (duration 4-6 hours) — May withhold dextrose if blood sugar >300 mg/dL; consider 5 units if glucose <150, AKI/CKD, no DM, weight <60kg, or female
      • Consider mixing in 10 cc NS syringe to ensure small volume of 10 units insulin fully administered via stopcock[2]
      • Follow glucose levels q30-60 min and supplement dextrose to avoid hypoglycemia (occurs in ~75% of patients)[3]
  • Albuterol 15-20 mg nebulized Nebulized (onset 30 min (peak), duration 2 hours) — Response is dose-dependent
  • Sodium bicarbonate 3 amps in 1L D5W (isotonic bicarbonate drip) IV drip — Generally not considered unless pH <7.1; pushing ampules of hypertonic bicarb ineffective in RCTs
    • For normovolemic or hypovolemic patients with metabolic acidosis

Remove K+ from body

  • Furosemide (Lasix) 40-80 mg IV IV — Ensure adequate urine output first
    • Decreases potassium by dilution, shifting into muscle cells, and promoting renal excretion via alkalosis[4]
  • Kayexalate (SPS) 30 g PO or PR PO/PR — Very controversial; high risk of bowel perforation
  • Lokelma (SZC) 10 g PO TID x48 hours, then 10-15 g PO daily maintenance PO — Similar to Kayexalate but without bowel perforation risk[5]
  • Intravenous lactated ringers solution for volume expansion if dehydrated, rhabdomyolysis, diabetic ketoacidosis or other acidosis (avoid NS, causes hyperchloremic acidosis which shifts potassium out of cells increasing level)
    • Consider isotonic bicarbonate if significant acidosis (D5W with 3 amps of bicarb per liter) [6]
  • Hydrocortisone if suspicious for adrenal insufficiency
  • Definitive treatment is hemodialysis

IV Fluid Choice

  • LR is preferred over NS, even in renal failure[7]
  • The small amount of 4 mEq/L of potassium in lactated ringers does not contribute to worsening hyperkalemia
  • Hyperkalemia worsens with metabolic acidosis, and large volume normal saline administration increases risk of hyperchloremic non-anion gap metabolic acidosis

Disposition

  • Consideration for ICU for frequent electrolyte checks and close cardiac monitoring

See Also

External Links

References

  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
  2. ↑ Sterns R, Grieff M, Bernstein P (2016). Treatment of hyperkalemia: Something old, something new. Kidney International, 89(3), 546-554.
  3. ↑ Apel J, Reutrakul S, Baldwin D. Hypoglycemia in the Treatment of Hyperkalemia With Insulin in Patients With End-Stage Renal Disease. Clin Kidney J. 2014;7(3):248-250
  4. ↑ IBCC Hyperkalemia Chapter
  5. ↑ Beccari, Mario V, and Calvin J Meaney. "Clinical utility of patiromer, sodium zirconium cyclosilicate, and sodium polystyrene sulfonate for the treatment of hyperkalemia: an evidence-based review." Core evidence vol. 12 11-24. 23 Mar. 2017, doi:10.2147/CE.S129555
  6. ↑ https://emcrit.org/pulmcrit/fluid-selection-using-ph-guided-resuscitation
  7. ↑ O'Malley CM, Frumento RJ, Hardy MA, Benvenisty AI, Brentjens TE, Mercer JS, Bennett-Guerrero E. A randomized, double-blind comparison of lactated Ringer's solution and 0.9% NaCl during renal transplantation. Anesth. Analg. 2005 May;100(5):1518-24.
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