Treatment of Hyperkalemia
The treatment of hyperkalemia should follow a stepwise approach based on severity, with calcium administration as the first intervention for severe hyperkalemia with ECG changes to stabilize cardiac membranes, followed by insulin with glucose and beta-agonists to shift potassium intracellularly, and finally potassium binders or dialysis to eliminate potassium from the body. 1
Classification of Hyperkalemia
Hyperkalemia is classified based on serum potassium levels:
- Mild: >5.0 to <5.5 mEq/L
- Moderate: 5.5 to 6.0 mEq/L
- Severe: >6.0 mEq/L 1
Assessment of Severity and Urgency
The need for urgent treatment depends on:
- Potassium level (especially >6.5 mmol/L)
- ECG changes (peaked T waves, flattened P waves, prolonged PR interval, widened QRS)
- Rate of rise in potassium levels
- Presence of symptoms (muscle weakness, paresthesia)
- Underlying conditions (renal failure, heart failure) 1
Treatment Algorithm
1. Cardiac Membrane Stabilization (Immediate)
- Calcium chloride (10%): 5-10 mL (500-1000 mg) IV over 2-5 minutes OR
- Calcium gluconate (10%): 15-30 mL IV over 2-5 minutes
- Onset: 1-3 minutes; Duration: 30-60 minutes
- Repeat ECG after administration; may repeat dose if ECG changes persist 1
2. Intracellular Shifting of Potassium (30-60 minutes)
- Insulin and glucose: 10 units regular insulin with 25g glucose (50 mL of D50W) IV over 15-30 minutes
- Monitor blood glucose closely to prevent hypoglycemia
- Nebulized albuterol: 10-20 mg nebulized over 15 minutes
- Can lower serum potassium by 0.5-1.0 mEq/L
- Use caution in patients with coronary artery disease
- Sodium bicarbonate: 50 mEq IV over 5 minutes (if metabolic acidosis present) 1
3. Elimination of Potassium (Hours)
- Loop diuretics: Furosemide 40-80 mg IV (if renal function adequate)
- Cation exchange resins:
- Sodium polystyrene sulfonate (Kayexalate): 15-50 g orally or rectally with sorbitol
- Important limitation: Not for emergency treatment due to delayed onset of action 2
- Newer potassium binders (patiromer, sodium zirconium cyclosilicate) when available
- Hemodialysis: Most effective method for severe hyperkalemia, especially in renal failure 1
Special Considerations
Causes of Hyperkalemia
Common causes to identify and address:
Decreased excretion:
- Renal failure (acute or chronic)
- Medications:
- RAAS inhibitors (ACE inhibitors, ARBs, MRAs)
- Potassium-sparing diuretics
- NSAIDs
- Beta-blockers
- Trimethoprim
- Calcineurin inhibitors 1
Increased intake/release:
- Potassium supplements
- Salt substitutes
- Stored blood products
- Tissue breakdown (rhabdomyolysis, tumor lysis)
- Metabolic acidosis 1
Pitfalls to Avoid
- Delayed recognition: ECG changes may be subtle initially
- Pseudo-hyperkalemia: Hemolysis during blood draw, thrombocytosis, leukocytosis
- Rebound hyperkalemia: Shifting therapies (insulin, albuterol) have temporary effects
- Overtreatment: Monitor for hypoglycemia with insulin therapy and hypocalcemia
- Inadequate monitoring: Repeat potassium measurements after interventions
- Medication interactions: Avoid concomitant use of sorbitol with sodium polystyrene sulfonate due to risk of intestinal necrosis 1, 2
Monitoring Response
- Repeat serum potassium 1-2 hours after treatment initiation
- Monitor ECG continuously in severe cases
- Follow glucose levels when insulin is administered
- Reassess acid-base status and renal function 1
Long-term Management
- Identify and treat underlying causes
- Dietary potassium restriction (<3g/day)
- Review and adjust medications
- Consider chronic potassium binders in recurrent hyperkalemia
- Regular monitoring of serum potassium in high-risk patients 1
Remember that severe hyperkalemia is a medical emergency requiring immediate intervention to prevent life-threatening cardiac arrhythmias and death. The treatment approach should prioritize cardiac membrane stabilization first, followed by shifting potassium intracellularly, and finally removing excess potassium from the body.