Potassium and renal failure.

Hyperkalemia caused by decreased renal K+ secretion may be seen in patients with mild, moderate, or severe ARF or CRF. Decreased K+ secretion by the distal tubule may be due primarily to a decrease in tubular fluid flow rate, as in ARF, or it may be due to diminished circulating aldosterone concentrations, as in patients with hyporeninemic hypoaldosteronism. Patients with CRF adapt to K+ loads by increasing K+ excretion per nephron as well as by transferring K+ more rapidly into cells. However, an increased K+ load may still produce hyperkalemia in the CRF patient because of limitations in the adaptive responses. Hyperkalemia may present a true medical emergency in the patient with renal failure. Although the serum K+concentration can usually be controlled by the administration of calcium, glucose and insulin, sodium bicarbonate, diuretics, and/or the use of K+ exchange resins, dialysis may be necessary. Hyperkalemia complicating acute or chronic renal failure is an important, common problem requiring the use of peritoneal dialysis or hemodialysis.