Hepatorenal syndrome and type 1 and 2 cardiorenal syndromes: distinct competing medical therapies applied to a similar background of vasomotor reactive nephropathy

The authors summarize some current views regarding the pharmacologic therapies of hepatorenal and cardiorenal syndromes, respectively. A common pathogenetic background of the two edematous disorders is outlined, consisting in reduced effective blood arterial volume ‑ due to the splanchnic vasodilation in the hepatorenal syndrome (HRS) and to the fall in cardiac output and the rise in central venous pressure in cardiorenal syndrome (CRS). In both diseases, arterial underfilling elicits multiple water- and sodium- retentive mechanisms, by activating sympathetic nervous system and stimulating both rennin-angiotensin-aldosterone and vasopressin systems. These neurohormonal adjustments subsequently concur to a vasomotor nephropathy which originates - as a same kind of vasoconstrictor reflex renal response ‑ from the splanchnic vasodilation, in the case of liver cirrhosis, or from the fall in renal perfusion and filtration gradients in the case of cardiorenal syndrome. Despite these pathogenetic similarities, the renal insufficiency of HRS compared to that of CRS is treated using diametrically opposite approaches: actually withdrawal of diuretics and administration of vasoconstrictor agents is the first choice in the case of HRS, while CRS is tackled by forcing diuretic regimen and by continuing vasodilator treatment with ACE-inhibitors. The pros and cons of these strategies ‑ which are still matter of debate among the physicians and researchers ‑ are then succinctly presented and discussed.