Bile salts and hypokalemia
Last week, I saw a 53 y old man admitted with end stage liver disease due to chronic alcoholism. He was admitted for altered mental status, acute kidney injury with rise in creatinine from 0.8 about two months ago to 3.4 at the time of admission. However, his serum potassium was 2.4 with transtubular potassium gradient (TTKG ) of 13 (indicates renal wasting). His total bilirubin was 32.
Bile acids are known to cause this low aldosterone and salt retentive states by inhibiting 11 beta hydroxy steroid dehydrogenase enzyme. This enzyme normally converts cortisol into cortisone. When inhibited, as in the above example, it allows normal cortisol to drive sodium absorption and renal potassium wasting in the distal tubules.