Lactobacilli and acidosis in children with short small bowel.

Background: In patients with a short small bowel, D-lactic acidemia and D-lactic aciduria are caused by intestinal lactobacilli. The purpose of this study was to obtain a detailed picture of the metabolic acidosis in young children with short small bowel.

Methods: Feces, blood, and urine of children with short small bowel and acidosis were studied microbiologically and/or biochemically.

Results: Previous findings were confirmed that more than 60% of the fecal flora of patients with small short bowel, who are not receiving antibiotics, consists of lactic acid-producing lactobacilli. In blood, D-lactic acid was the most prominent metabolite: the highest serum D-lactate (15.5 mmol/l) was observed in a sample taken immediately after the onset of hyperventilation. The highest D-lactate excretion was in urine collected some hours after the onset of hyperventilation, and amounted to 59 mol/mol creatinine. Acidosis in the patients with short small bowel was related to strongly increased serum D-lactate and anion gap and to strongly decreased serum bicarbonate and pH.

Conclusion: In children with small short bowel and acidosis, the common intestinal flora of mainly lactobacilli abundantly produces D-lactic acid from easily fermentable carbohydrates. Thus, these bacteria directly cause shifts of bicarbonate, pH, and base excess and indirectly cause shifts of the anion gap, as well as hyperventilation. These kinetic parameters are strongly associated.