RT Book, Section
A1 Mount, David B.
A2 Jameson, J. Larry
A2 Fauci, Anthony S.
A2 Kasper, Dennis L.
A2 Hauser, Stephen L.
A2 Longo, Dan L.
A2 Loscalzo, Joseph
SR Print(0)
ID 1178487194
T1 Hypokalemia
T2 Harrison's Principles of Internal Medicine, 20e
YR 2018
FD 2018
PB McGraw-Hill Education
PP New York, NY
SN 9781259644016
LK accesspharmacy.mhmedical.com/content.aspx?aid=1178487194
RD 2024/04/18
AB Homeostatic  mechanisms  maintain  plasma  K+  concentration  between  3.5  and  5.0  mM,  despite  marked  variation  in  dietary  K+  intake.  In  a  healthy  individual  at  steady  state,  the  entire  daily  intake  of  potassium  is  excreted,  ~90%  in  the  urine  and  10%  in  the  stool;  thus,  the  kidney  plays  a  dominant  role  in  potassium  homeostasis.  However,  >98%  of  total-body  potassium  is  intracellular,  chiefly  in  muscle;  buffering  of  extracellular  K+  by  this  large  intracellular  pool  plays  a  crucial  role  in  the  regulation  of  plasma  K+  concentration.  Changes  in  the  exchange  and  distribution  of  intra-  and  extracellular  K+  can  thus  lead  to  marked  hypo-  or  hyperkalemia.  A  corollary  is  that  massive  necrosis  and  the  attendant  release  of  tissue  K+  can  cause  severe  hyperkalemia,  particularly  in  the  setting  of  acute  kidney  injury  and  reduced  excretion  of  K+.