HRS Diagnostic Criteria
The diagnosis of hepatorenal syndrome requires serum creatinine >1.5 mg/dL (133 μmol/L) in a patient with advanced liver disease and ascites, after excluding shock, hypovolemia, nephrotoxic drugs, and parenchymal renal disease. 1
Essential Diagnostic Criteria
All of the following must be present to diagnose HRS 1:
Serum creatinine >1.5 mg/dL (133 μmol/L) 1
Absence of shock 1
Absence of hypovolemia, defined as no sustained improvement in renal function (creatinine failing to decrease to <133 μmol/L) following at least 2 days of diuretic withdrawal (if on diuretics) AND volume expansion with albumin at 1 g/kg/day up to a maximum of 100 g/day 1
No current or recent treatment with nephrotoxic drugs 1
Absence of parenchymal renal disease, defined by:
HRS Classification
Type 1 HRS (HRS-AKI) is characterized by rapid and progressive impairment in renal function with an increase in serum creatinine ≥100% compared to baseline to a level >2.5 mg/dL in less than 2 weeks 1, 2
Type 2 HRS shows stable or less progressive impairment in renal function and is commonly associated with refractory ascites 1
Clinical Context
HRS occurs in patients with advanced liver disease, most commonly cirrhosis with portal hypertension and ascites 1. The diagnosis is essentially one of exclusion of other causes of renal failure 1. The condition represents functional renal failure without structural kidney damage, as evidenced by histologically normal kidneys on postmortem examination 3.
Key Diagnostic Pitfalls
The distinction between HRS-AKI and acute tubular necrosis remains challenging with currently available clinical tools, yet this distinction has direct management implications since treatment differs between these conditions 4. The albumin challenge (1 g/kg/day for 2 days) is critical to exclude volume-responsive AKI before diagnosing HRS 1. Failure to withdraw diuretics and adequately volume expand before making the diagnosis is a common error that can lead to misclassification of prerenal azotemia as HRS 1.