Kidney

Spontaneous bacterial peritonitis

Hyperdynamic circulation

Kidney disease

Hepatorenal syndrome

Cardiology

Cirrhosis

Acute kidney injury

Terlipressin

Portal hypertension

Ascites

Internal medicine

Medicine

Gastroenterology

Renal function

Cardiorenal syndrome

Nature Reviews Disease Primers

Hepatorenal syndrome (HRS) is a form of kidney function impairment that characteristically occurs in cirrhosis. Recent changes in terminology have led to acute HRS being&nbsp;referred to as acute kidney injury (AKI)-HRS and chronic HRS as chronic kidney disease (CKD)-HRS. AKI-HRS is characterized by a severe impairment of kidney function owing to vasoconstriction of the renal arteries in the absence of substantial abnormalities in kidney histology. Pathogenetic mechanisms involve disturbances in circulatory function due to a marked splanchnic arterial vasodilation, which triggers the activation of vasoconstrictor factors. An&nbsp;intense systemic inflammatory reaction that is characteristic of advanced cirrhosis may also be involved. The main triggering factors of AKI-HRS are bacterial infections, particularly spontaneous bacterial peritonitis. The diagnosis of AKI-HRS is a challenge because of a lack of specific diagnostic tools and mainly involves the differential diagnosis from other forms of AKI, particularly acute tubular necrosis. The prognosis of patients with AKI-HRS is poor, with a median survival of ≤3 months. The ideal treatment for AKI-HRS is liver transplantation in patients without contraindications. Medical therapy consists of vasoconstrictor drugs to counteract splanchnic arterial vasodilation together with volume expansion with albumin. Effective measures to prevent AKI-HRS include early identification and treatment of bacterial infections and the administration of albumin in patients with spontaneous bacterial peritonitis. Hepatorenal syndrome (HRS) is defined as severe kidney functional impairment that occurs in patients with liver cirrhosis. This Primer discusses new diagnostic criteria of acute kidney injury in the context of HRS and also covers pathophysiology and management of this serious disorder.