High Aldosterone as a Cause of Metabolic Alkalosis
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   SECONDARY HYPERALDO may be due to:
   þ  volume, or  effective volume (e.g. in cirrhosis, CHF, nephrotic
     syndrome)
   þ  Cl- (perhaps the effector of decreased volume)
   All of these cause secondary  aldo (which causes sodium avidity in the
   distal tubule).

   PRIMARY HYPERALDO may be due to
   þ tumor,
   þ licorice,
   þ Bartter's syndrome.

   High aldo (along with  Na+ delivery to the distal aldo-sensitive areas of
   the tubule from diuretics or  HCO3- over what the proximal tubule can
   absorb) causes  Na+ reabsorbtion and obligate K+ or H+ excretion. Attempts
   to retain Na+/HCO3- by the distal tubule lead to secretion of H+ to permit
   recovery of the HCO3-; otherwise, a large amount of Na+ would be lost along
   with the HCO3-, resulting in volume depletion.