Iatrogenic Hyperkalemia: Definition, Causes, and Management
Iatrogenic hyperkalemia is elevated serum potassium (>5.0 mmol/L) caused by medications, medical interventions, or healthcare-related factors, often occurring in patients with cardiovascular disease, chronic kidney disease, diabetes, or advanced age. 1
Definition and Classification
- Hyperkalemia is defined as serum potassium >5.0 mmol/L, with severity classified as mild (>5.0 to <5.5 mEq/L), moderate (5.5 to 6.0 mEq/L), or severe (>6.0 mEq/L) 1, 2
- Iatrogenic hyperkalemia specifically refers to elevated potassium levels resulting from medical interventions, particularly medications 1
- The prevalence of iatrogenic hyperkalemia is approximately 2-4% in the general population but increases to 10-55% in hospitalized patients and up to 73% in those with advanced chronic kidney disease 1
Common Causes of Iatrogenic Hyperkalemia
Medications That Decrease Potassium Excretion
- Renin-angiotensin-aldosterone system inhibitors (RAASi): ACE inhibitors, angiotensin receptor blockers, mineralocorticoid receptor antagonists 1, 3
- Potassium-sparing diuretics (spironolactone, triamterene, amiloride) 1, 3
- Beta-blockers (reduce renin release) 1, 3
- Non-steroidal anti-inflammatory drugs (NSAIDs) 1, 3
- Calcineurin inhibitors (cyclosporine, tacrolimus) 1, 3
- Trimethoprim-sulfamethoxazole 1, 3
- Heparin (suppresses aldosterone production) 1, 3
- Digitalis 1
Medications That Increase Potassium Intake/Administration
- Potassium supplements 1, 3
- Salt substitutes containing potassium 1
- Stored blood products 1
- Certain herbal supplements (alfalfa, dandelion, horsetail) 1
Medications That Alter Transmembrane Potassium Movement
Risk Factors for Iatrogenic Hyperkalemia
- Decreased renal function (eGFR <50 ml/min) - the most significant risk factor, increasing risk fivefold 4
- Advanced age (especially >75 years) 5
- Comorbidities: chronic kidney disease, heart failure, diabetes mellitus 1, 6
- Combination therapy with multiple potassium-influencing medications 4
- Female gender (observed in some studies) 5
- Dehydration or acute illness 7
Clinical Presentation and Consequences
- Often asymptomatic, especially in chronic cases 1
- May present with muscle weakness, paresthesias, or cardiac arrhythmias 2
- ECG changes: peaked T waves, flattened P waves, prolonged PR interval, widened QRS complex 2
- Severe bradyarrhythmias and complete atrioventricular block may occur in severe cases 5
- Can lead to cardiac arrest and death if untreated 1
Diagnosis and Evaluation
- Confirm hyperkalemia with laboratory testing and rule out pseudohyperkalemia 1, 8
- Pseudohyperkalemia can result from hemolysis during sample collection, excessive fist clenching, or delayed specimen processing 8
- Obtain ECG to assess for cardiac effects 2
- Evaluate renal function (creatinine, eGFR) 4
- Review medication list for potential causative agents 2
- Measure urine potassium, creatinine, and osmolarity to determine the cause 7
Management
Acute Management of Severe Iatrogenic Hyperkalemia
- Calcium chloride or calcium gluconate for cardiac membrane stabilization 2
- Insulin with glucose or nebulized beta-2 agonists to shift potassium into cells 1, 2
- Sodium bicarbonate if metabolic acidosis is present 1
- Loop diuretics to increase renal potassium excretion 1
- Potassium binders (sodium polystyrene sulfonate, patiromer, sodium zirconium cyclosilicate) 1
- Hemodialysis for severe cases or when other measures fail 1
Management of Chronic Iatrogenic Hyperkalemia
- Identify and adjust causative medications 2
- Consider dose reduction rather than discontinuation of beneficial medications (especially RAASi) 2
- Dietary potassium restriction (<3 g/day) 2
- Regular monitoring of serum potassium levels 2, 6
- Consider newer potassium binders for long-term management 2
Prevention Strategies
- Regular monitoring of potassium levels in high-risk patients 6
- More frequent monitoring after starting or adjusting doses of potassium-influencing medications 2
- Particular caution with polypharmacy in elderly patients 5
- Assessment of renal function before and during treatment with RAASi 5
- Education about dietary potassium restriction when appropriate 9
Common Pitfalls to Avoid
- Failing to rule out pseudohyperkalemia before initiating treatment 8
- Permanently discontinuing beneficial RAASi medications instead of adjusting doses 2
- Delaying treatment of severe hyperkalemia while waiting for confirmation of repeat laboratory values 2
- Overlooking ECG changes in patients with hyperkalemia 2, 8
- Inadequate monitoring of high-risk patients on potassium-influencing medications 6