Hyperkalemia in the ED: Gone Bananas 

-Case-
A 68-year-old woman with ESRD misses dialysis for two sessions and presents with generalized weakness and palpitations. Her ECG shows peaked T waves and a wide QRS complex. Labs confirm a potassium level of 7.2 mEq/L. 

-Evaluation-
Hyperkalemia is defined as serum potassium >5.0 mEq/L and can rapidly become life-threatening due to its effects on cardiac conduction.

  • Causes:
    • Renal failure (most common)
    • Medications (ACE inhibitors, ARBs, spironolactone, NSAIDs)
    • Hemolysis, rhabdomyolysis
    • Metabolic acidosis
    • Tumor lysis syndrome
  • Symptoms:
    • Often vague: weakness, fatigue, palpitations
    • Can rarely be asymptomatic until cardiac arrest!
  • ECG canges (in order of what is classically seen early to late):
    • Peaked T waves
    • Flattened P waves
    • Prolonged PR interval
    • Widened QRS
    • Sine wave pattern → cardiac arrest

Diagnosis in the ED:

  • Confirm with serum potassium level, and always repeat if hemolysis suspected!
  • Assess ECG for cardiac instability
  • Check renal function and acid-base status

-Management-

  1. Stabilize the myocardium:
    • Calcium gluconate
    • Keep in mind – this medications protects heart, but does not lower K!
  2. Shift K intracellularly:
    • Insulin +/- D50 (depending on blood sugar)
    • Albuterol nebulizer
    • Sodium bicarbonate only if profoundly acidotic
  3. Remove K from the body:
    • Furosemide (if urine output is adequate/patient still makes urine)
    • Sodium polystyrene sulfonate (Kayexalate) – slow effect; will typically not acutely help in the ED
    • Hemodialysis: most definitive in ESRD or severe/refractory cases, often reserved for symptomatic patients requiring emergent HD

-Fast Facts-

  • ECG is not always reliable – don’t wait for changes if K is critically high!
  • Calcium = heart protector; insulin = fastest potassium shifter
  • Albuterol works but requires high doses; keep in mind, this med can cause significant tachycardia, too!
  • Dialysis is the definitive treatment in unstable or ESRD patients
  • Recheck potassium and ECG frequently after treatment

This case of missed dialysis is a classic hyperkalemic storm. The ECG gives you the heads-up, but the potassium level seals the deal. In the ED, treating hyperkalemia means acting quickly and in three phases: stabilize, shift, and eliminate. When the heart’s on the line, every second counts!

Want to learn more? Read our in-depth study guide on this topic!

Cheers,

Tamir Zitelny, MD

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-References-

  1. Palmer BF, Clegg DJ. Hyperkalemia across the continuum of kidney function. Clin J Am Soc Nephrol. 2018;13(1):155–157. doi:10.2215/CJN.11761117
  2. Montford JR, Linas S. How dangerous is hyperkalemia? J Am Soc Nephrol. 2017;28(11):3155–3165. doi:10.1681/ASN.2016121344
  3. Einhorn LM, Zhan M, Hsu VD, et al. The frequency of hyperkalemia and its significance in chronic kidney disease. Arch Intern Med. 2009;169(12):1156–1162. doi:10.1001/archinternmed.2009.132
  4. Acker CG, Johnson JP, Palevsky PM, Greenberg A. Hyperkalemia in hospitalized patients: causes, adequacy of treatment, and results of an attempt to improve physician compliance with published therapy guidelines. Arch Intern Med. 1998;158(8):917–924. doi:10.1001/archinte.158.8.917
  5. Weiner ID, Wingo CS. Hyperkalemia: a potential silent killer. J Am Soc Nephrol. 1998;9(8):1535–1543. doi:10.1681/ASN.V981535
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