Low Potassium or Low Chloride as Causes of Metabolic Alkalosis
        --------------------------------------------------------------


   LOW POTASSIUM may cause metabolic alkalosis by:

   þ causing obligatory H+ excretion, instead of K+ excretion, in exchange for
     Na+);

   þ also, K+ shifts out of cells, and H+ shifts into cells, causing alkalosis
     and  HCO3-.


   LOW CHLORIDE causes obligatory excretion of K+ and H+, and therefore
   retention of HCO3-, to reabsorb Na+ and therefore to maintain volume.