## Acute Symptomatic Hyperkalemia Management **Key Point:** Calcium gluconate is the first-line agent for acute symptomatic hyperkalemia with ECG changes (peaked T waves, prolonged PR interval, widened QRS). It acts within 1–3 minutes by stabilizing the cardiac membrane potential, reducing excitability without lowering serum potassium. ### Mechanism of Calcium Gluconate Calcium raises the threshold potential of cardiac myocytes, antagonizing the depolarizing effect of hyperkalaemia. This provides immediate cardiac protection and is the only agent that does NOT shift potassium intracellularly — it is purely cardioprotective. ### Comparison of Hyperkalemia Agents | Agent | Onset | Mechanism | Duration | Indication | |-------|-------|-----------|----------|------------| | **Calcium gluconate** | 1–3 min | Membrane stabilization | 30–60 min | Acute + ECG changes (FIRST-LINE) | | Insulin + dextrose | 10–20 min | Shift K⁺ intracellularly | 4–6 hrs | Acute without ECG changes; stable patients | | Sodium bicarbonate | 30–60 min | Shift K⁺ intracellularly | 2–4 hrs | Metabolic acidosis + hyperkalemia | | Beta-2 agonists (albuterol) | 30 min | Shift K⁺ intracellularly | 2–4 hrs | Adjunct; less effective alone | | Sodium polystyrene sulfonate | 4–24 hrs | GI K⁺ binding & excretion | 4–24 hrs | Chronic/mild hyperkalemia (NOT acute) | **High-Yield:** In this patient with **peaked T waves (ECG changes)**, calcium gluconate is mandatory as the first drug, regardless of whether other agents are added. ### Clinical Pearl Calcium gluconate does NOT lower serum K⁺ — it only protects the heart. Always follow with a K⁺-lowering agent (insulin + dextrose, bicarbonate, or diuretics) and definitive treatment (dialysis if CKD stage 4). **Tip:** Calcium gluconate is given IV over 2–5 minutes; repeat every 5 minutes if ECG changes persist. Avoid rapid infusion (risk of hypercalcemia and arrhythmias).
Sign up free to access AI-powered MCQ practice with detailed explanations and adaptive learning.