[Non-lactic metabolic acidosis]

The definition of metabolic acidosis (MA) is a primary decrease in plasma bicarbonate concentration. The visceral consequences are largely dependent on the degree of acidosis and the rapidity of its onset; they have been studied mainly in animal studies and therefore, extrapolation to the clinical situation should be cautious. The MA can be classified in two groups according to whether the anionic serum gap is increased or normal (hyperchloremic acidosis). The etiologies of the first group are lactic acidosis, the cetoacidoses and renal failure. The hyperchloremic acidoses usually result from gastro-intestinal bicarbonate losses; the biochemical diagnosis of rarer causes of hyperchloremic acidosis is facilitated by measuring the serum potassium, urinary pH and the urinary anionic gap. Although all causes of MA must be treated, the use of bicarbonate should be discussed in each individual case.