Pathophysiology
Clinical meaning
Hepatorenal syndrome (HRS) is a form of functional renal failure occurring in patients with advanced liver cirrhosis and portal hypertension, in which the kidneys are structurally normal but fail due to severe renal vasoconstriction. The pathophysiology begins with portal hypertension causing splanchnic arterial vasodilation (mediated by nitric oxide and other vasodilators), which reduces effective arterial blood volume and activates compensatory vasoconstrictive systems (renin-angiotensin-aldosterone, sympathetic nervous system, vasopressin). These vasoconstrictors preferentially constrict the renal vasculature, reducing renal blood flow and GFR while preserving perfusion to other vital organs. HRS-AKI (formerly type 1, creatinine doubling to >2.5 mg/dL within 2 weeks) carries a median survival of 2 weeks without treatment, while HRS-NAKI (formerly type 2, gradual creatinine rise with refractory ascites) progresses more slowly. The nurse monitors urine output hourly, assesses fluid balance meticulously, monitors serum creatinine and electrolytes, administers vasoconstrictors (terlipressin, norepinephrine, or midodrine plus octreotide) combined with albumin infusion as prescribed, avoids nephrotoxic agents, and coordinates liver transplant evaluation as the only definitive treatment.