Renal tubular acidosis following intestinal bypass: an etiological study

Nine cases of the distal type of renal tubular acidosis (RTA) following intestinal bypass were found. Diagnosis was based on inability to acidify the urine to pH values below 5.40 despite systemic acidosis. Acidosis, if not present, was induced by giving ammonium chloride 0.1 g/kg body weight. Patients were examined for diseases known to cause RTA but no already known etiological factor was found. Hyperoxaluria was found in eight of the nine cases with RTA, while not present in patients without RTA or in obese control patients. A causal relationship between hyperoxaluria and RTA is suggested though not proved. Cases reported in the literature of renal damage following bypass are summarized and discussed in relation to presence of hyperoxaluria and RTA.