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Hyperkalemia

Mengyao Tang and Amanda Morrison


Background

  • Causes:

    • Cellular shifts: Acidemia, Rhabdomyolysis, TLS, beta blockade

    • Aldosterone deficient states: T4 RTA, Primary adrenal insufficiency

    • Decreased distal tubular delivery: Volume depletion

    • Decreased clearance: AKI, CKD, ESRD

    • Excessive intake

    • Medication-related: ACEi, ARB, MRA, NSAIDs, TMP/SMX, digoxin, heparin

  • Pseudo-Hyperkalemia: hemolysis, severe leukocytosis

  • Symptoms are rare, but usually manifest as cardiac dysrhythmias

Evaluation

  • Confirm hyperkalemia with repeat BMP

  • Check EKG for hyperkalemic changes (sensitivity for EKG findings in hyper K is poor)

    • K+ 5.5-6.5: peaked T waves, prolonged PR interval

    • K+ 6.5-8: prolonged QRS, loss of P wave, ST elevation, ectopic beats

    • K+ >8: sine wave pattern, asystole, PEA, VF

Management

  • If EKG changes or signs of instability

    • Calcium gluconate 1g IV (effective within 3-5 min)

      • Stabilizes cardiac membrane for ~60mins

      • SHOULD BE REPEATED HOURLY while hyperkalemic

  • Shift K+ (temporizing measures)

    • D50 w/ regular insulin 10 units (can order using Adult Hyperkalemia order set in epic)

      • Use 5 units if there is renal impairment

      • Lasts for 4-6hrs (can be longer in renal impairment)

  • Correct acidosis- Consider using isotonic bicarb

  • Beta Agonists (e.g. high-dose albuterol nebulizer); lasts 2-4 hrs

    • Note that typical albuterol nebulizer is 2.5mg, need 10-20mg to have an effect
  • Increase K+ Excretion

    • Loop diuretic- if the kidneys work, use them

      • If there is AKI or a volume deficit can administer with IVF
    • Volume expansion with IVF: Increases distal Na delivery and K excretion. NS and LR are likely equally effective.

    • GI cation exchangers

      • Kayexalate (Polystyrene sulfonate)- only effective if having BMs. 60g PO q2h until bowel movement (If using oral, ensure patient is having bowel movements and is not obstructed, could cause bowel injury/ necrosis). PO can take up to 6hrs to work. Consider per rectal administration for faster action but DO NOT GIVE WITH SORBITOL per rectum

      • Lokelma (Sodium-zirconium-cyclosilicate) 10 g PO TID for 48 H. Actively exchanges K for other cations within the small bowel and works within 2 hours. Remember to stop once the K is normal since can cause hypokalemia. Also keep in mind the high Na content of Lokelma (400mg/5g dose of lokelma)

        • Needs approval from Nephrology
  • Hemodialysis: Consult nephrology early if severe hyper K+