Hepatorenal syndrome: a critical update

Acute kidney injury (AKI) is common in cirrhotic patients with ascites. Although not the primary etiology of AKI in cirrhotic patients, hepatorenal syndrome (HRS) is a unique form of AKI that develops only in cirrhotic patients. Intense renal vasoconstriction is the hallmark of HRS. Different mechanisms contribute to renal vasoconstriction, with splanchnic vasodilatation and reduced effective blood volume playing a central role. Diagnostic criteria for HRS have been developed and were recently modified, but diagnosing HRS and differentiating it from other causes of AKI in cirrhotic patients continues to be a difficult task in some patients. Given its overall dismal prognosis, strategies to prevent HRS have been developed and proved to be effective in reducing HRS prevalence among cirrhotic patients. Liver transplantation is the ultimate treatment, but more than one treatment modality can be utilized as a bridge to transplantation. This review provides an update on our current understanding of HRS with emphasis on the underlying pathophysiological mechanisms involved, difficulties in diagnosis, and different treatment modalities.