Hepatorenal Syndrome

OVERVIEW

• Hepatorenal Syndrome = profound oliguria and Na+ retention in the setting of severe liver dysfunction (cirrhosis or fulminant liver failure)
• usually fatal unless liver transplant performed.
• RRT can prevent advancement of condition

PATHOPHYSIOLOGY

• ?
• local production of intrarenal vasoconstrictors -> intrarenal vasoconstriction despite systemic vasodilation
• increased Q with reduced SVR and MAP
• hypovolaemia and raised intra-abdominal pressure may also be factors

Types

• I – rapidly progressive

1. acute deterioration (doubling of creatinine or halving of CrCl over 2 weeks) 2. absent renal parenchymal disease 3. absent proteinuria 4. no shock 5. no history of nephrotoxic drugs

• II – slower onset and progression

— renal failure in the context of end-stage liver disease that does not meet the criteria of type I

RISK FACTORS

• Na+ and H2O retention (urinary Na+ < 5mEq/L and dilutional hyponatraemia)
• low MAP
• poor nutrition
• reduced GFR
• high plasma renin activity
• oesophageal varices
• associated with infection, acute alcohol hepatitis, large volume paracentesis without albumin replacement

INVESTIGATIONS

• concentrated urine with low Na+ (<10mol/L)
• few granular casts (doesn’t improve with fluid replacement)
• no proteinuria
• normal kidneys on U/S

DIAGNOSTIC CRITERIA

• no other cause for renal failure
• Na+ and H2O retention

Major

• chronic or acute liver disease with advanced hepatic failure + portal hypertension
• low GFR (Cr > 130mmol/L or CrCl < 40ml/min)
• absence of shock, bacterial infection and recent treatment with nephrotoxic agents
• no sustained improvement in renal function post 1.5 of isotonic saline
• proteinuria < 0.5g/day
• no renal tract disease on U/S

Additional

• urine volume < 500mL/day
• urine Na+ < 10mmol/L -urine osmolality > plasma osmolality
• urine red blood count < 50 per high power field
• serum Na+ < 130mmol/L

MANAGEMENT

• diagnostic paracentesis (exclude SBP)
• albumin
• RRT
• transjugular intrahepatic portosystemic shunt (TIPS) – reduces blood pressure in portal vein
• liver dialysis (dialysis circuit with an albumin bound membrane to bind and remove toxins normally cleared by the liver)
• IV clonidine (improves GFR)
• terlipressin/octreotide – decrease portal vein pressure
• liver transplant