DISEASEOF THE MONTH Metabolic Alkalosis

Generation and Maintenance of Metabolic Alkalosis The pathogenesis of metabolic alkalosis involves both the generation and maintenance of this disorder ( 1 ). The generation of metabolic alkabosis refers to the addition of new HCO to the blood as a result of either loss of acid or gain of alkali. New HCO1 may be generated by either renal or extrarenal mechanisms. Because the kidneys have an enormous capacity to excrete HCO , even vigorous HCO generation may not be sufficient to produce sustained metabolic alkabosis. To maintam a metabolic alkabosis, the capacity of the kidney to correct the alkabosis must be impaired, or, equivalently, the capacity to reclaim HCO must be enhanced. On the other hand, increased capacity for HCO reclamation in the absence of generation is also insufficient to cause metabolic alkalosis. Thus, the two ingredients required for the pathogenesis of metabolic alkalosis are the generation of new HCO combined with an augmentation in the capacity of the kidney to reclaim the filtered HCO .