[Changes in antidiuretic hormone (ADH) in liver cirrhosis with resistant ascites]

The pathogenetic role of ADH in determining hyponatremia in patients with liver cirrhosis is still much debated. Osmotic stimuli are not able to inhibit secretion of ADH in refractory ascites and under such conditions the reduction in effective plasma volume has been put forward as the main cause. Twenty patients with liver cirrhosis and refractory ascites were studied before and during extraction-concentration-reinfusion (ECR) of ascitic fluid by means of Rhodiascit. ADH, renin, aldosterone, blood and urine osmolarity, plasma and urinary concentration of sodium, potassium, chlorine, and the clearance of free water were evaluated. All patients presented high renin values (15.4 +/- 11.7 ng/ml), aldosterone (341 +/- 172 ng/ml), ADH (6.3 +/- 5.2 pg/ml). During ECR, a significant drop was observed in renin (p less than 0.001), aldosterone (p less than 0.001) urinary osmolarity (p less than 0.001) and an equality significant increase in diuresis (p less than 0.001), natriuria (p less than 0.005), kaliuria (p less than 0.001) while ADH presented an irregular course: in 11 cases it remained unchanged, in 3 it fell and in 6 it presented a constant increase. To conclude, data suggest that the diminished filtrate reaching the distal tubule constitutes the greatest cause of the inability to dilute urine in many patients with cirrhosis and that ADH is a permissive rather than a primary factor.