Treatment of Hyperkalemia and Hypernatremia
Critical Initial Assessment
When hyperkalemia and hypernatremia coexist, treat the hyperkalemia first as it poses the most immediate life-threatening risk for cardiac arrhythmias and sudden death. 1, 2
Hyperkalemia Takes Priority
- Severe hyperkalemia (K+ ≥6.5 mEq/L) or any ECG changes (peaked T waves, flattened P waves, prolonged PR interval, widened QRS) require immediate treatment regardless of sodium levels. 1, 2
- Hypernatremia correction can proceed more gradually once cardiac stability is achieved, as rapid sodium correction carries its own risks 3
- The combination of both electrolyte abnormalities suggests severe volume depletion, renal impairment, or medication effects that must be identified 4
Step 1: Immediate Hyperkalemia Management
Cardiac Membrane Stabilization (Within 1-3 Minutes)
- Administer calcium chloride 10%: 5-10 mL IV over 2-5 minutes (preferred over calcium gluconate for faster ionized calcium increase) 2
- Alternative: calcium gluconate 10%: 15-30 mL IV over 2-5 minutes 1, 2
- Effects last only 30-60 minutes and do not lower potassium—this buys time for definitive treatment 1, 2
- Use central line when possible to avoid tissue necrosis from extravasation 2
Shift Potassium Into Cells (Onset 15-30 Minutes, Duration 4-6 Hours)
- Insulin 10 units regular IV with 25g glucose (50 mL D50W) over 15-30 minutes 1, 2
- Nebulized albuterol 10-20 mg over 15 minutes as adjunctive therapy 1, 2
- Sodium bicarbonate 50 mEq IV over 5 minutes ONLY if concurrent metabolic acidosis present (pH <7.35, bicarbonate <22 mEq/L) 1, 2
- Monitor for rebound hyperkalemia after 2 hours as these are temporary measures 2
Eliminate Potassium From Body
- Loop diuretics (furosemide 40-80 mg IV) if adequate renal function present 1, 2
- Newer potassium binders are preferred: 1, 5
- Avoid sodium polystyrene sulfonate (Kayexalate) for chronic management due to risk of bowel necrosis 6, 5, 7
- Hemodialysis for severe hyperkalemia (K+ >6.5 mEq/L) unresponsive to medical management or with renal failure 1, 2
Step 2: Hypernatremia Management (After Cardiac Stabilization)
Classification and Assessment
- Determine volume status: hypovolemic, euvolemic, or hypervolemic hypernatremia 3
- Calculate free water deficit and correct slowly to avoid cerebral edema 3
- Chronic hypernatremia (>48 hours) should be corrected at ≤10-12 mEq/L per 24 hours 3
Treatment Based on Volume Status
Hypovolemic Hypernatremia (Most Common with Concurrent Hyperkalemia):
- Replace volume deficit first with isotonic saline (0.9% NaCl) to restore hemodynamic stability 3
- Once stable, switch to hypotonic fluids (0.45% NaCl or D5W) for gradual sodium correction 3
- Monitor sodium every 2-4 hours initially, then every 4-6 hours 3
Euvolemic Hypernatremia:
- Free water replacement with D5W or oral water if patient can drink 3
- Consider desmopressin if central diabetes insipidus suspected 3
Hypervolemic Hypernatremia:
- Loop diuretics with free water replacement 3
- May require dialysis if renal function severely impaired 3
Step 3: Address Underlying Causes
Medication Review (Critical for Both Disorders)
Hyperkalemia Contributors to Discontinue or Reduce: 6, 1
- NSAIDs
- Trimethoprim-sulfamethoxazole
- Heparin
- Potassium supplements and salt substitutes
- Beta-blockers (non-selective)
RAAS Inhibitors Require Special Consideration:
- Do NOT discontinue ACE inhibitors, ARBs, or MRAs if K+ 5.0-6.5 mEq/L—instead initiate potassium binder and maintain these life-saving medications 6, 1, 5
- Only reduce or temporarily discontinue RAAS inhibitors if K+ >6.5 mEq/L, then restart at lower dose once K+ <5.0 mEq/L 6, 5
Assess Renal Function
- Check creatinine, eGFR, and urinalysis 5
- The combination of hyperkalemia and hypernatremia strongly suggests acute kidney injury or chronic kidney disease 8, 4
Step 4: Monitoring Protocol
Hyperkalemia Monitoring
- Check potassium every 2-4 hours after initial treatment until <5.5 mEq/L 1
- Continuous ECG monitoring until K+ <6.0 mEq/L and ECG normalizes 1, 2
- Recheck potassium 7-10 days after any RAAS inhibitor dose adjustment 1
Hypernatremia Monitoring
- Monitor sodium every 2-4 hours initially during active correction 3
- Neurologic checks every 2 hours for altered mental status, seizures, or focal deficits 3
- Adjust fluid rate if sodium correcting too rapidly (>10-12 mEq/L per 24 hours) 3
Critical Pitfalls to Avoid
- Never use sodium bicarbonate for hyperkalemia without documented metabolic acidosis—it is ineffective and may worsen hypernatremia 1, 2
- Do not rely solely on ECG findings for hyperkalemia severity—they are variable and less sensitive than laboratory values 1
- Avoid discontinuing RAAS inhibitors prematurely—use potassium binders to maintain these mortality-reducing medications 6, 1, 5
- Never correct chronic hypernatremia rapidly—aim for ≤10-12 mEq/L decrease per 24 hours to prevent cerebral edema 3
- Remember that calcium, insulin, and beta-agonists only temporize hyperkalemia—definitive potassium removal is essential 1, 2
- Exclude pseudo-hyperkalemia from hemolysis or improper sampling before aggressive treatment 6, 2
Long-Term Prevention
For Recurrent Hyperkalemia
- Maintain potassium binder therapy (patiromer or SZC) rather than discontinuing beneficial RAAS inhibitors 6, 1, 5
- Optimize diuretic therapy with loop or thiazide diuretics 6, 1
- Dietary counseling focusing on reducing non-plant potassium sources rather than strict restriction 8
- Monitor potassium within 1 week of any medication changes 1