Latent distal renal tubular acidosis (dRTA) in primary biliary cirrhosis (PBC) and chronic autoimmune hepatitis (CAH).

In an attempt to evaluate the latent distal renal tubular acidosis (dRTA7) in patients with primary biliary cirrhosis (PBC), and chronic autoimmune hepatitis (CAH), and differences between them in relation to the sodium urinary excretion ([Na]u), thirty four patients divided in two groups were studied. Group A: 17 patients who fulfilled criteria for PBC diagnosis (clinical and humoral evidence antimitochondrial antibody titles of 1/80 or above by indirect immunofluorescence technique, and liver biopsy). Group B: 17 patients who fulfilled criteria for CAH diagnosis (clinical and humoral evidence, antinuclear and smooth muscle antibody titles of 1/80 or above and liver biopsy). Patients with ascitis and/or edema were excluded from the study. Ability to acidify urine was evaluated by gradient between pC02 in urine and blood (U-BpC02) after alkali infusion. Five patients in Group A (29.4%7) and six in Group B(35.2%) had dRTA, (p = 0.49). When analyzing patients with dRTA in both groups, the mean [Na]u in Group A was 152.2 +/- 33.8, versus 50.8 +/- 8.1 mEq/l, in Group B. (p = 0.00016). We concluded that the prevalence of dRTA was similar in patients with PBC and CAH but the urinary acidifications impairment of the former did not correlate with [Na]u, as it did with the latter.