Potassium Metabolism in Chronic Kidney Disease

Biff F. Palmer, Deborah J. Clegg

Research output: Chapter in Book/Report/Conference proceedingChapter

Abstract

Adaptive increases in renal and gastrointestinal excretion of K+ help to prevent hyperkalemia in patients with chronic kidney disease (CKD) as long as the glomerular filtration rate (GFR) remains >15-20mL/min. In these patients K+ balance is maintained by increased K+ secretion per functioning nephron, which is mediated in part by elevated plasma K+ concentration, aldosterone, increased flow rate, and enhanced Na+-K+-ATPase activity. Fecal losses of potassium also increase in CKD patients. These adaptive mechanisms are effective in preventing hyperkalemia, provided that urine output is in excess of 600mL/day. However, limits of adaptation render the CKD patient susceptible to hyperkalemia with even minor perturbations in these factors. Such is the case in patients with diabetes, where decreased mineralocorticoid activity is often an early finding caused by hyporeninemic hypoaldosteronism, or in patients primarily with renal tubular injury, as in tubulointerstitial renal disease. In these settings, hyperkalemia often develops with only mild or moderate reductions in GFR. Once the GFR falls to <15mL/min, an inflection point is reached whereby small incremental losses in renal function require progressively steeper rises in steady state S[K] to maintain total body K+ balance. Certain medications can impair potassium handling and excretion in CKD patients. At this level of renal function the impact of factors known to adversely affect K+ homeostasis is significantly magnified. In clinical practice hyperkalemia is usually the result of a combination of factors superimposed on renal dysfunction.

Original languageEnglish (US)
Title of host publicationChronic Renal Disease
PublisherElsevier
Pages643-659
Number of pages17
ISBN (Electronic)9780128158760
ISBN (Print)9780128158777
DOIs
StatePublished - Jan 1 2019

Keywords

  • Aldosterone
  • CKD
  • Glomerular filtration rate
  • Potassium
  • Urine flow

ASJC Scopus subject areas

  • Agricultural and Biological Sciences(all)
  • Biochemistry, Genetics and Molecular Biology(all)

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