Marked Hypercapnia Secondary to Severe Metabolic Alkalosis

Abstract

A patient had alveolar hypoventilation secondary to chronic metabolic alkalosis. Severe hypercapnia occurred without any obstructive pulmonary disease or neuromuscular weakness. Cerebrospinal fluid showed marked cerebrospinal fluid alkalosis and a diminished cerebral blood flow. Recognition of hypercapnia as a sequel of chronic metabolic alkalosis allowed correction of the underlying alkalosis and avoided the risks of unnecessary mechanical ventilation. The mechanism of alveolar hypoventilation with metabolic alkalosis, the possible role played by azotemia, and the differential diagnosis of unexplained hypercapnia are discussed.