Hepatorenal syndrome and its treatment today.

The pathogenesis of ascites, a severe and the most frequent complication during cirrhosis, is still not completely understood, but present evidence indicates that portal hypertension principally triggers renal sodium and water retention. Ascites is associated with profound disturbances of splanchnic and systemic haemodynamics, which in turn may influence renal function. Within the kidney the balance between vasoconstricting and vasodilating factors is critical for the maintenance of renal function. As the disease progresses, vasoconstricting factors (mainly angiotensin II, catecholamines, thromboxane, leucotrienes and endothelins) prevail, probably due to the exhaustion of the vasodilating renal autacoid system (mainly prostaglandins). In this setting, vasoconstriction of the intrarenal vascular system induces marked and often irreversible sodium and water retention, leading to refractory ascites, a progressive rise in plasma creatinine levels and reduction of renal clearances (hepatorenal syndrome, HRS). This persistent renal hypoxia may also favour the occurrence of tubular damage due to several causes. A careful therapeutic approach is first based on sequential diuretic treatment (and the addition of adequate plasma expansion with human albumin for patients with diuretic resistant ascites), which may lead to control of ascites for years. However, when HRS occurs, all the proposed treatments (such as paracentesis, administration of renal vasodilators, systemic vasoconstrictors, calcium channel antagonists, TIPS, surgical portosystemic shunts) have been shown to moderately or temporarily improve renal function only, leaving liver transplantation as the only choice of treatment for patients.