Challenges and Management of Liver Cirrhosis: Pathophysiology of Renal Dysfunction in Cirrhosis

Kidney dysfunction is a common complication of patients with advanced cirrhosis and is associated with poor prognosis. Patients with advanced cirrhosis show circulatory dysfunction characterized by reduced systemic vascular resistance due to splanchnic arterial vasodilation, which is caused by portal hypertension. The progressive reduction in systemic vascular resistance leads to effective arterial hypovolemia. In order to maintain arterial pressure within normal limits in this setting, there is activation of systemic vasoconstrictor systems, including the renin-angiotensin-aldosterone system, sympathetic nervous system and, in late stages, nonosmotic hypersecretion of vasopressin. Although these systems have positive effects in maintaining arterial pressure, they have a negative influence on kidney function, leading to the retention of sodium and solute-free water, and in late stages of the disease an intense kidney vasoconstriction develops, leading to decrease of the glomerular filtration rate and the development of hepatorenal syndrome (HRS). Moreover, bacterial translocation and the existence of a systemic inflammatory state in patients with advanced cirrhosis may play a role in the impairment of circulatory function. HRS is a unique cause of kidney failure of functional origin that develops in patients with cirrhosis. However, besides HRS, patients with cirrhosis may develop kidney failure due to other causes, including bacterial infections, prerenal kidney failure, shock, use of nephrotoxic drugs or intrinsic kidney diseases. Considering the existence of circulatory dysfunction and some degree of kidney vasoconstriction, patients with advanced cirrhosis have fragile kidney function and are susceptible to easily developing kidney failure associated with other complications of the disease, particularly bacterial infections and gastrointestinal bleeding.