Hepatorenal syndrome
Formal Definition
A form of acute kidney injury occurring in patients with advanced cirrhosis and ascites, characterized by vasodilation of the splanchnic circulation leading to reduced effective arterial blood volume, activation of the RAAS and sympathetic nervous system, and resulting in intense renal vasoconstriction and reduced GFR; diagnosed by excluding other causes of AKI and by demonstrating low urine sodium (<10 mEq/L) and preserved kidney histology; treated with vasoconstrictors (terlipressin + albumin or norepinephrine) and liver transplantation as definitive cure.
How It's Used on the Ward
"HRS" or "hepatorenal syndrome" — the kidneys are shutting down despite being structurally normal because the cirrhosis has caused the blood vessels to dilate so much that the kidneys are underperfused; the kidneys are responding to a systemic problem, not a primary kidney problem.
Example
""58-year-old male with alcoholic cirrhosis, ascites, MELD-Na score 28, now with rising creatinine (1.8 from baseline 0.9), BUN 48, urine sodium 4 mEq/L, urine sediment bland. No nephrotoxic medications, no contrast exposure, ultrasound shows no obstruction. Diagnosis: hepatorenal syndrome Type 1 (AKI criteria: creat rise >0.3 in 48h). Started albumin 1g/kg bolus then 20-40g/day maintenance, terlipressin 0.5mg IV q4h. Nephrology and transplant hepatology consulted for MELD score and transplant evaluation.""
Clinical Context
Type 1 HRS: rapidly progressive (doubling of creatinine to >2.5 mg/dL or 50% reduction in creatinine clearance over <2 weeks). Type 2 HRS: more stable but progressive renal failure in patients with refractory ascites. Diagnosis: requires cirrhosis + ascites + AKI (modified ICA criteria), no shock, no nephrotoxins, no structural cause (no proteinuria, no hematuria, normal ultrasound), FENa <10 mEq/L. Precipitants to identify and treat: SBP (most common trigger), large volume paracentesis without albumin, GI bleed, over-diuresis. Treatment: stop diuretics, give albumin, give vasoconstrictors (terlipressin + albumin is gold standard; midodrine + octreotide is alternative), consider TIPS for refractory ascites and HRS. Definitive: liver transplantation. Prognosis: Type 1 median survival ~2 weeks without transplant; Type 2 median survival ~6 months.