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Hepatorenal Syndrome

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Overview

Hepatorenal syndrome (HRS) is a potentially fatal complication of end-stage liver disease and is diagnosed by excluding other causes of renal failure.

There are two types of HRS and their presentations vary. Both types are associated with a poor prognosis.

Pathophysiology

Its mechanism is not fully understood; however, it is thought that the damaged liver causes vasodilation in the arteries supplying the intestines which then leads to reduced blood pressure to the kidneys. The juxtaglomerular apparatus of the kidneys sense this reduced blood pressure and activates the renin-angiotensin-aldosterone system, which leads to renal vasoconstriction which is not sufficient to cope with the decreased blood pressure sensed by the juxtaglomerular apparatus. This leads to persistent underfilling of the kidney, which leads to further worsening kidney vasoconstriction and eventually failure.

Risk Factors

Presentation and Types

Hepatorenal syndrome should be suspected in patients with signs and symptoms of severe liver disease who develop renal failure, such as increasing creatinine levels or oliguria.

The types of HRS are based on the rate of progression:

  • Type 1 HRS – rapidly progressing decline (up to 2 weeks):
    • Doubling of creatinine to >221 μmol/L in <2 weeks
    • eGFR is typically very low (often <20 ml/minute)
    • There is usually a precipitating event (e.g. spontaneous bacterial peritonitis or bleeding varices)
  • Type 2 HRS – progression is more gradual:
    • Progression is much slower
    • Associated with refractory ascites
    • There is not usually a precipitating event

Diagnosis

  • The diagnosis of HRS is based on ruling out other potential causes of kidney dysfunction.

Management

Overview

Liver transplantation is the only definitive option for management. Vasopressin analogues and transjugular intrahepatic portosystemic shunting can buy time while waiting for a transplant.

Prognosis

  • The prognosis for HRS is very poor. The median survival time for type 1 HRS is 2 weeks and for type 2 HRS is 6 months.

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