SUPERStudy: Hepatorenal Syndrome (HRS)

By usmlevideoss

SUPERStudy: Hepatorenal Syndrome (HRS)

Introduction

Hepatorenal syndrome (HRS) is a functional renal failure occurring in patients with severe liver disease, such as cirrhosis, advanced liver failure, or fulminant hepatic failure. It is characterized by renal vasoconstriction and impaired renal function without intrinsic kidney disease.

Etiology

  • Primary Causes:
    • Advanced liver cirrhosis.
    • Acute liver failure.
  • Triggers:
    • Spontaneous bacterial peritonitis (SBP).
    • Gastrointestinal bleeding.
    • Large-volume paracentesis without albumin replacement.
    • Severe infections like sepsis.
  • Key Factor:
    • Splanchnic vasodilation and systemic hypoperfusion.

Epidemiology

  • Occurs in 10–20% of patients with advanced cirrhosis.
  • More common in men.
  • Typically presents in hospitalized patients with decompensated liver disease.

Pathophysiology

  • Severe liver disease causes splanchnic vasodilation (due to nitric oxide release) → reduced effective circulatory volume.
  • Activation of the renin-angiotensin-aldosterone system (RAAS) and sympathetic nervous system → renal vasoconstriction.
  • Glomerular filtration rate (GFR) decreases due to poor renal perfusion despite normal renal parenchyma.

 

Clinical Manifestations

  1. Type 1 HRS:
    • Rapidly progressive renal failure (doubling of serum creatinine within 2 weeks).
    • Final serum creatinine ≥2.5 mg/dL (233 μmol/L).
  2. Type 2 HRS:
    • Gradual renal failure with refractory ascites.
    • Less severe and more slowly progressive renal insufficiency.
  3. Common Symptoms:
    • Oliguria.
    • Low urine sodium concentration (<10 mEq/L).
    • Hyponatremia.
    • Azotemia.

Diagnosis

  1. Major Criteria: 
    • Advanced liver disease with portal hypertension.
    • Serum creatinine >1.5 mg/dL.
    • No improvement in renal function after volume expansion with albumin.
    • Absence of shock, nephrotoxic drugs, or intrinsic kidney disease.
  2. Exclusion Criteria: 
    • Proteinuria >500 mg/day.
    • Hematuria >50 RBCs/HPF.

Treatment

  1. Initial Measures: 
    • Volume expansion with albumin.
    • Vasoconstrictors:
      • Terlipressin.
      • Norepinephrine.
  2. Definitive Therapy: 
    • Liver transplantation (curative).
    • Dialysis as a bridge to transplant.
  3. Supportive Care: 
    • Manage complications of cirrhosis.
    • Avoid nephrotoxic agents.

Prognosis

  • Type 1 HRS:
    • Very poor prognosis without liver transplantation (median survival ~2 weeks).
  • Type 2 HRS:
    • Slightly better prognosis (~4–6 months survival).
  • Liver transplantation significantly improves survival.

SUPERPoint

Hepatorenal syndrome is a potentially reversible cause of renal failure in cirrhotic patients, highlighting the importance of early diagnosis and management to improve outcomes.

SUPERFormula

Cirrhosis + Advanced liver disease + Portal hypertension + Serum creatinine >1.5 mg/dL +  Renal vasoconstriction + Nitric oxide-driven splanchnic vasodilation + Poor renal perfusion = Hepatorenal Syndrome.

References: 

Wong F. Hepatorenal Syndrome. In: Lerma EV, Rosner MH, Perazella MA. eds.CURRENT Diagnosis & Treatment: Nephrology & Hypertension, 2e. McGraw-Hill Education; 2017. 

Mukhtar NA, Khalili M. Liver Disease. In: Hammer GD, McPhee SJ. eds.Pathophysiology of Disease: An Introduction to Clinical Medicine, 8e. McGraw-Hill Education; 2019

O’Mara SR, Wiesner L. Hepatic Disorders. In: Tintinalli JE, Ma O, Yealy DM, Meckler GD, Stapczynski J, Cline DM, Thomas SH. eds. Tintinalli’s Emergency Medicine: A Comprehensive Study Guide, 9e. McGraw-Hill Education; 2020.