| Clinical features |
| Signs and symptoms are uncommon and tend to occur only when serum potassium is >7.0 meq/L; can include muscle weakness and ventricular arrhythmias. |
| There are two major mechanisms of hyperkalemia: |
| Increased potassium release from cells (eg, severe hyperglycemia, rhabdomyolysis). |
| Reduced potassium excretion in urine (eg, hypoaldosteronism, kidney failure). |
| Pseudohyperkalemia is a common cause of a reported elevation in serum potassium and must be excluded. It does not reflect true hyperkalemia and does not produce ECG changes. |
| ECG manifestations |
| The relationship between the degree of serum potassium elevation and ECG changes varies from patient to patient, and changes are more common with acute-onset hyperkalemia. |
| ECG findings that are commonly observed with more severe elevation of the serum potassium include: |
| Tall peaked T waves. |
| Shrinking and then loss of P waves. |
| Widening of the QRS interval and then "sine wave," ventricular arrhythmia, and asystole. |
| Early management |
| Exclude pseudohyperkalemia. |
| Obtain ECG and place patients with hyperkalemic emergency on continuous cardiac monitoring. Patients with hyperkalemic emergency include: |
| Those with clinical manifestations or ECG changes. |
| Those with serum potassium of >6.5 meq/L. |
| Those with serum potassium of >5.5 meq/L plus kidney function impairment and ongoing tissue breakdown or potassium absorption. |
| In patients with a hyperkalemic emergency: |
| If ECG changes present and/or serum potassium >6.5 meq/L: Give calcium gluconate 1000 mg (10 mL of 10% solution) or calcium chloride 500 to 1000 mg IV over two to three minutes to stabilize cardiac membranes. |
| For ALL hyperkalemic emergencies: Give insulin and glucose to shift K+ intracellularly (only give glucose if serum glucose is <250 mg/dL [13.9 mmol/L]). A common regimen consists of a bolus injection of 10 units of regular insulin, followed immediately by 50 mL of 50% dextrose (25 g of glucose) over 5 minutes. We subsequently infuse 10% dextrose at 50 to 75 mL/hour and closely monitor blood glucose levels every hour for five to six hours. |
| Give therapy to remove potassium from the body (refer below). |
| Remove potassium from the body |
| Hemodialysis should be performed in patients with ESKD or severe kidney function impairment. |
| Loop diuretics (in hypervolemic patients) or saline infusion with IV loop diuretics can be administered (eg, 40 mg of furosemide every 12 hours) to nonoliguric patients without severe kidney function impairment. |
| A gastrointestinal cation exchanger (eg, sodium zirconium cyclosilicate 10 g orally or patiromer 8.4 g orally) can be given, especially in patients with severe kidney function impairment in whom hemodialysis cannot be swiftly performed. Sodium polystyrene sulfonate (15 to 30 g orally) should not be given unless there are no other options to effectively remove potassium from the body in a timely fashion. |
