Natriuretic and aquaretic effects of intravenously infused calcium in preascitic human cirrhosis: physiopathological and clinical implications

Background: Preascitic cirrhosis is characterised by subtle renal sodium retention. Calcium inhibits Na+–K+–2Cl− cotransport in the Henle’s loop and could potentially correct sodium-handling abnormalities at that site. Aim: To investigate the effects of calcium infusion on sodium handling in 10 patients with preascitic cirrhosis and nine healthy controls after 1 week of sodium loading of 200 mmol sodium/day. Methods: All patients underwent a 3 h supine determination of inulin, para-aminohippurate, lithium and free-water clearances, absolute and fractional excretions of sodium, potassium and calcium and plasma concentrations of renin, aldosterone, norepinephrine and vasopressin. The same were repeated over a further 3 h supine period including 60 min intravenous infusion of 33 mg/min calcium gluconate. Results: After sodium loading, the 24 h urinary sodium excretion in patients with cirrhosis was lower than that in controls (p