hyperkalemia
Summary
Elevated serum potassium (>5.0-5.5 mEq/L) that impairs cardiac conduction and muscle function, potentially causing fatal arrhythmias. Requires urgent treatment based on etiology and severity.
Detail
Hyperkalemia impairs cellular repolarization, making myocardial cells hyperexcitable. Severe hyperkalemia causes peaked T waves, widened QRS, sine-wave pattern, and ventricular fibrillation. Etiologies include redistribution (acidosis, insulin deficiency, succinylcholine), impaired renal excretion (CKD, type IV RTA, ACE inhibitors, potassium-sparing diuretics), and increased intake. Management: calcium gluconate stabilizes the cardiac membrane; insulin + dextrose and albuterol shift K+ intracellularly; loop diuretics promote excretion; hemodialysis is definitive for refractory cases.
Sources
- First Aid for the USMLE Step 1
- Pathoma
- Harrison's Principles of Internal Medicine
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