endocrine and metabolic disorders
Hyperkalemia
Key Points
Common causes of hyperkalemia include potassium-retaining drugs, renal insufficiency, adrenal insufficiency, and disorders involving cellular breakdown (eg, rhabdomyolysis, burns, bleeding into soft tissue or the gastrointestinal tract). Hyperkalemia is usually asymptomatic until cardiac toxicity develops, although some patients have weakness. ECG changes begin with an increased PR interval, shortening of the QT interval, and tall, symmetric, peaked T waves; with potassium>6.5 mEq/L (> 6.5 mmol/L), QRS interval widens, and P wave disappears; ultimately, the QRS complex degenerates into a sine wave pattern, and ventricular fibrillation or asystole ensues. Givesodium polystyrene sulfonate,patiromer, orsodium zirconium cyclosilicatefor mild hyperkalemia. Give IVinsulin, glucose, and calcium, and possibly an inhaled beta 2-agonist for moderate to severe hyperkalemia. Use hemodialysis for patients with chronic kidney disease and those with significant ECG changes. 