In known or suspected hyperkalemia:

1. Initiate cardiac monitoring.
2. Obtain IV access.
3. Order an ECG and a lab re-draw.
4. If hyperkalemic emergency (defined below), initiate calcium, insulin and dextrose.

Hyperkalemia is defined as serum K⁺ >5.2 mmol/L

– Can provoke dangerous arrhythmias and ultimately cardiac arrest in severe cases.

Common causes of significant hyperkalemia include:

• Increased K⁺ release from cells (intracellular à extracellular shift.)
  • Pseudohyperkalemia (hemolyzed sample, extremely common.)
  • Metabolic acidosis via H⁺ exchange.
  • Insulin deficiency, hyperglycemia, hyperosmolality.
  • Increased tissue catabolism, exercise (e,g., rhabdomyolysis.)
• Decreased excretion.
  • AKI/CKD
  • Decreased aldosterone secretion or sensitivity (i.e., RAAS blockade via ACEs, ARBs.)
  • Reduced renal sodium and water delivery (i.e., effective arterial blood volume depletion.)

Signs and symptoms:

• Usually asymptomatic.
• If moderate to severe hyperkalemia, can variably see:
  • CVS: Arrhythmias
  • Neuromuscular: muscle cramps, generalized weakness, paresthesias, tetany, focal or global paralysis
  • GI: nausea, vomiting, diarrhea

ECG findings:

• Hyperkalemia can lead to nearly any cardiac arrhythmia.
• “Typical” findings are not sensitive or specific – can be absent in very high K⁺, or can be present in normal K⁺ for other reasons.
• Typical findings include:
  • Tall-peaked T waves
  • Wide PR interval
  • Shrinking and then loss of P waves
  • Widening of the QRS interval à Sinusoidal Wave

Approach to treatment in the ED:

1. Determine if hyperkalemic emergency:

– If any of the following, require rapidly acting therapy with calcium and insulin/glucose immediately, followed by K⁺ removal therapies.

• 1 clinical manifestation of hyperkalemia (muscle weakness or paralysis, cardiac conduction abnormalities or arrhythmias.)
• Serum K⁺ >6.5 mEq/L
• Serum K⁺ >5.5 mEq/L with both:
  • Significant kidney function impairment
  • Ongoing tissue breakdown (e.g., rhabdomyolysis, crush injury, tumour lysis syndrome) or ongoing K⁺ absorption (e.g., significant GI bleeding.)

2. If not hyperkalemic emergency but K⁺ >5.5 mEq/L and severe kidney function impairment, lower over 6 to 12 hours – rapid acting therapies not required.

• Patients with ESKD or oliguria: Dialysis if available or GI cation exchanger if not.
• Reversal of cause if known (e.g., d/c RAAS blockade.)
• If metabolic acidosis present, treat with bicarbonate.
• If hypervolemic, diurese.

3. If none of the above (K <5.5 mEq/L, or >5.5 mEq/L but preserved renal function) K⁺ can be lowered slowly (ex. dietary modification, diuretics, bicarbonate, reversal of causes (e.g, NSAIDS, hypovolemia) etc.)

Treatment modalities:

1. Myocardial stabilization

• Calcium gluconate 10 mL of 10% solution (1g of calcium) infused over 2-3 minutes. Repeat after 5 minutes if ECG changes persist on cardiac monitoring.
• • Duration of action is 30-60 minutes, can be repeated q30-60mins if non-resolving and not hypercalcemic.

2. Shift K⁺ to intracellular compartment

• Insulin/Dextrose: 10 units of rapid insulin bolused with 50mL of D50W over 5 minutes, then D10W at 50 – 75 mL/hr
• Can hold dextrose if glucose >13.9 mmol/L.
• Monitor glucose q1h x 6 hours to ensure no hypoglycemia
• Bicarbonate: 100mL of 8.4% HCO_3-
• Adjuvant therapy if concurrent metabolic acidosis
• Salbutamol: 0.5mg IV or 20mg albuterol nebulized
• Adjuvant therapy only

3. Eliminate K⁺ from body

Diuretics (if reasonable kidney function)

• Hypervolemia: furosemide 40mg IV q12h
• Euvolemic or hypovolemia: Achieve euvolemia with Lactated Ringers (see reference 5) first, then furosemide 40mg IV q12h + continuous LR to maintain volume status.

K+ binders (gastrointestinal cation exchanger)

• • Sodium zirconium cyclosilicate 10 g po or patiromer 8.4 g po can be given, especially in patients with severe kidney function impairment in whom hemodialysis cannot be quickly performed.
  • Do not use sodium polystyrene sulphonate (kayexalate) unless there are no other options due to risk of adverse events and lack of evidence for efficacy.

Dialysis

• Essential therapy in patients with ESKD or severe kidney function impairment.

• Patients with hyperkalemic emergency should be admitted to hospital.
• Any clinically unstable patient with hyperkalemia requires admission to ICU setting
• All moderate or severe hyperkalemia cases should be admitted as a monitored inpatient during and after treatment.

• In patients requiring dialysis, transfer may be necessary depending on availability of dialysis.

• Patients who receive insulin should undergo hourly glucose measurements for 6 hours to monitor for hypoglycemia.
• Patients with hyperkalemic emergency in the setting of ESKD should have urgent nephrology consult.

• Hyperkalemia resolved, etiology discovered and addressed, with follow up plans arranged as necessary.
• If on RAAS blockade, follow up with prescribing provider to adjust as necessary.

1. Hyperkalemia ECGs: https://litfl.com/hyperkalaemia-ecg-library/

   Lactated ringers in hyperkalemia: https://emcrit.org/pulmcrit/myth-busting-lactated-ringers-is-safe-in-hyperkalemia-and-is-superior-to-ns/

   Use of kayexalate: https://rebelem.com/kayexalate-useful-treatment-hyperkalemia-emergency-department

   
   

1. David M. Treatment and prevention of hyperkalemia in adult. In: UpToDate [Internet]. 2022. Available from: https://www.uptodate.com/contents/treatment-and-prevention-of-hyperkalemia-in-adults

   
   

2. Littmann L, Gibbs MA. Electrocardiographic manifestations of severe hyperkalemia. J Electrocardiol. 2018;51(5):814–7.

   
   

3. Long B, Warix JR, Koyfman A. Controversies in Management of Hyperkalemia. J Emerg Med. 2018 Aug;55(2):192–205.

   
   

4. Pfennig CL, Slovis CM. Chapter 125. Electrolyte Disorders. In: Marx JA et al. eds. Rosen’s Emergency Medicine, 8e. Philadelphia: Elsevier Saunders; 2014.

   
   

5. Farkas J. Myth-busting: Lactated Ringers is safe in hyperkalemia, and is superior to NS. [Internet]. EMCrit Project. 2014 [cited 2022 Dec 1]. Available from: https://emcrit.org/pulmcrit/myth-busting-lactated-ringers-is-safe-in-hyperkalemia-and-is-superior-to-ns/