Hyperkalemia: Symptoms and Treatment
Clinical Manifestations
Hyperkalemia is often asymptomatic or presents with nonspecific symptoms, and the first indicator may be peaked T waves on ECG rather than clinical symptoms. 1
Cardiac Manifestations
- ECG changes are the most critical findings and progress in a characteristic pattern as potassium rises 1:
Important caveat: ECG findings are highly variable and not as sensitive as laboratory testing in predicting hyperkalemia or its complications 1. The REVEAL-ED study demonstrated poor correlation between ECG changes and potassium levels 1.
Neuromuscular Symptoms
- Flaccid paralysis 1
- Paresthesias 1
- Depressed deep tendon reflexes 1
- Respiratory difficulties 1
- Muscle weakness (particularly in severe cases) 1
Severity Classification
- Mild: >5.0 to <5.5 mEq/L 2
- Moderate: 5.5 to 6.0 mEq/L 2
- Severe: >6.0 mEq/L (or >6.5 mEq/L by some definitions) 1, 2
Treatment Approach
Life-Threatening Hyperkalemia (>6.5 mEq/L or ECG Changes)
This is a medical emergency requiring immediate multi-pronged treatment with calcium for membrane stabilization, followed by agents to shift potassium intracellularly, and finally measures to remove potassium from the body. 1
Step 1: Stabilize Cardiac Membrane (Acts in 1-3 minutes)
- Calcium chloride 10%: 5-10 mL (500-1000 mg) IV over 2-5 minutes 1
Step 2: Shift Potassium Into Cells (Acts in 30 minutes)
These are temporary measures lasting 1-4 hours; rebound hyperkalemia can occur after 2 hours. 1
Insulin plus glucose (most reliable agent) 1, 3:
- Mix 25 g glucose (50 mL of D50) with 10 U regular insulin IV over 15-30 minutes 1
Nebulized albuterol: 10-20 mg over 15 minutes 1
- Can be used alone or to augment insulin effect 3
Sodium bicarbonate: 50 mEq IV over 5 minutes 1
Hypertonic saline (3-5%) if concurrent hyponatremia 1
Step 3: Remove Potassium From Body
Initiate early as shifting agents are only temporary. 1
Loop diuretics: Furosemide 40-80 mg IV 1
Hemodialysis: Most reliable method for potassium removal 1, 4
Potassium binders (subacute treatment):
Chronic/Recurrent Hyperkalemia Management
Do not discontinue RAAS inhibitors after a single elevated potassium measurement, as this offsets survival benefits. 2
Treatment Options
- Loop or thiazide diuretics to promote urinary potassium excretion 1
- Modify RAAS inhibitor dose rather than discontinue 1
- Remove other hyperkalemia-causing medications (NSAIDs, potassium-sparing diuretics) 1, 2
- Dietary potassium restriction: Limit fruits (bananas, melons, orange juice), vegetables (potatoes, tomatoes), dairy products, chocolate, and salt substitutes 2
- Newer potassium binders (patiromer, sodium zirconium cyclosilicate) for ongoing maintenance 1
- Fludrocortisone in aldosterone deficiency, though carries risk of fluid retention and hypertension 1
High-Risk Populations Requiring Close Monitoring
- Advanced chronic kidney disease (eGFR <15 mL/min/1.73 m²) - up to 73% risk 2
- Chronic heart failure - up to 40% risk 2
- Diabetes 2
- Elderly patients 2
- Patients on spironolactone or other RAAS inhibitors 2
Critical pitfall: Up to one-third of heart failure patients starting mineralocorticoid receptor antagonists develop hyperkalemia over 2 years, and 50% of cardiovascular disease patients with chronic kidney disease experience recurrent episodes within 1 year 2. Despite this, the clinical benefit of these medications persists even with modest potassium elevations 1.