Hepatorenal syndrome

• related: GI
• tags: #note

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Pathophysiology

• important complication of end stage liver disease
• liver: cirrhosis => increased intrahepatic vascular resistance => portal HTN => increase NO, vasodilators => splanchnic arterial dilation (celiac, superior mesenteric, and inferior mesenteric arteries) => hypotension
• kidney: decrease in renal perfusion => activates RAAS/vasopressin => renal vasoconstriction with decreased perfusion and glomerular filtration.

Triggers:

• Decreased perfusion/volume:
  • GI bleed, sepsis, vomiting, diuretic use, NSAID use
  • ascites
  • too much lactulose
• SBP

Diagnosis

• decreased renal perfusion (decrease in GFR) without another clear cause
  • Cr > 1.5
  • BUN:Cr elevated > 20:1
• no tubular injury: no RBC, protein, granular casts in urine
  • protein excretion < 500 mg/d
• no obstruction: US benign
• Hyponatremia (dilutional hyponatremia)
  • low Na excretion in urine (<10 mmol/L)
• lack of improvement with volume resuscitation (BUN:Cr could be high in either prerenal or hepatorenal)
• look for triggers: paracentesis if has ascites

Treatment

• Goal: increase MAP > 82 (raise map by 10)
• Address triggers (hypovolemia, anemia, infection)
• Limit diuretics, beta blocker
• Plasma expander albumin
  • IV bolus (1g/kg per day, up to 100g max) on 1st day
  • followed by 25-50g/day until midodrine/octreotide discontinued
  • continue 2-3 days
• Splanchnic vasoconstrictors
  • midodrine (alpha agonist): 7.5 mg, titrate q8h up to 15 mg TID
  • octreotide (inhibits vasodilation): gtt 50 mcg/hr or 100-200 mcg SQ q8h
  • norepinephrine
• Increase urine output to at least 200 cc/4 hours
• TIPS
• discontinue therapy if no response after 4 days
• dialysis/transplant is next option
• Liver transplant
• Dialysis may be attempted to help bridge to liver transplantation.