Why does hyperkalemia occur in CKD, and what are some treatment steps?

• A. Increased potassium excretion; treat with potassium supplementation.
• B. Potassium retention due to increased aldosterone; treat with aldosterone antagonists only.
• C. Impaired potassium excretion; treatment includes dietary restriction, diuretics, insulin with glucose, calcium gluconate for membrane stabilization, and dialysis if needed.
• D. Hyperkalemia due to excessive intake only; treat with vomiting.

Answer: (C)

Hyperkalemia in CKD happens because the damaged kidneys can’t excrete potassium effectively as the glomerular filtration rate falls. With fewer functioning nephrons, potassium that would normally be eliminated builds up in the blood. Metabolic acidosis, common in CKD, also pushes potassium out of cells, making the problem worse.

Treatments target both lowering the serum potassium and protecting the heart while the body clears the excess. Start with dietary restriction of potassium to limit intake. If there is still some urine output, diuretics can help promote potassium excretion. For a rapid reduction, insulin given with glucose drives potassium back into cells, lowering serum levels quickly. If there are signs of potential cardiac issues or if potassium remains high, calcium gluconate stabilizes the cardiac membranes to reduce the risk of dangerous arrhythmias, though it doesn’t reduce the potassium level itself. When potassium remains dangerously high or cannot be controlled by these measures, dialysis is used to remove potassium directly from the blood.