Renal function, sodium and water homeostasis in patients with idiopathic extrahepatic portal vein thrombosis compared with normal healthy controls

Objectives. To determine whether portal hypertension in the absence of live r disease contributes to changes in renal function and renal sodium and wat er handling. Methods. Nine patients with extrahepatic portal vein thrombosis (PVT) with normal liver function and histology were compared with 9 matched healthy co ntrol subjects. All underwent standard measurements of glomerular filtratio n rate and effective renal blood flow using inulin and paraaminohippuric ac id (PAH) clearances, respectively. Sodium excretion and renin and aldostero ne levels were studied before, during and after an intravenous saline infus ion. Results. At baseline there were no difference in insulin clearance, PAH cle arance, fractional excretion of sodium and free water excretion. During and after the saline infusion both groups showed a significant increase in sod ium excretion with a reduction in water excretion, while the PAH and inulin clearances remained unchanged. Although aldosterone and renin levels both fell after the infusion, aldosterone levels were significant differences be tween the PVT and control groups. Conclusion. Renal function and odium and water handling were comparable in healthy controls and patients with PVT. It is unlikely that portal hyperten sion alone plays a significant role in the impaired ability to excrete sodi um and water in patients with liver cirrhosis.