Renal function with respect to water clearance and renal hemodynamics was studied in 15 patients with
obstructive jaundice due to
cholangiocarcinoma. The results were compared with those of the control normal subjects. There was no change in renal function in the patients with mild to moderate
jaundice, with total serum
bilirubin from 8.0 to 15.1 mg/dl. Increased urinary
sodium excretion and decreased free water and negative water clearances were observed in the patients with severe
jaundice with total serum
bilirubin from 27.0 to 40.4 mg/dl and normal
serum albumin. Renal blood flow was normal, but
creatinine clearance was decreased. In severely jaundiced patients with serum
bilirubin from 30.5 to 40.1 mg/dl and
hypoalbuminemia urinary
sodium excretion, free water clearance, negative water clearance, renal blood flow and
creatinine clearance were decreased. There was
salt and water retention in this group. The findings suggest that in severe
jaundice there is inhibition of
sodium chloride reabsorption in the thick ascending limb of Henle's loop. ADH and increased hydraulic conductivity of the collecting tubules possibly contribute to decreased free water clearance. In severely jaundiced patients with
hypoalbuminemia this
salt losing effect is converted to
salt retention by increased proximal tubular reabsorption of
sodium.