From the Guidelines
Diagnosing hepatorenal syndrome (HRS) requires identifying acute kidney injury in patients with advanced liver disease, using the revised International Club of Ascites criteria, which includes a serum creatinine increase of ≥0.3 mg/dL within 48 hours or ≥50% from baseline, as stated in the 2021 guidelines 1. The diagnostic criteria for HRS have been revised to include two types: HRS-AKI (acute kidney injury) and HRS-NAKI (non-acute kidney injury). HRS-AKI is characterized by a rapid reduction in renal function, with a serum creatinine increase of ≥0.3 mg/dL within 48 hours or ≥50% from baseline, without necessitating a final cut-off value of 1.5 mg/dL, as per the 2021 guidelines 1. Key diagnostic criteria include:
- Advanced liver disease with portal hypertension
- Serum creatinine increase of ≥0.3 mg/dL within 48 hours or ≥50% from baseline
- Absence of shock, ongoing bacterial infection, recent treatment with nephrotoxic drugs, or massive gastrointestinal or renal fluid losses
- No sustained improvement in renal function following diuretic withdrawal and expansion of plasma volume with 1.5 L of isotonic saline
- Less than 500 mg/dL proteinuria and no ultrasonographic evidence of obstructive uropathy or parenchymal kidney disease, as outlined in the 2004 study 1. The revised criteria allow for earlier treatment initiation, and the mainstay of treatment for HRS-AKI involves vasoconstrictors, particularly terlipressin, in combination with albumin, as shown in recent RCTs 1. Diagnostic workup should include urinalysis, urine electrolytes, urine osmolality, renal ultrasound, and assessment of response to volume expansion. Early diagnosis is crucial, as HRS carries high mortality, and prompt treatment can improve outcomes while awaiting definitive management with liver transplantation.
From the Research
Diagnostic Criteria for Hepatorenal Syndrome (HRS)
The diagnostic criteria for HRS have been defined by various studies, including those published in 2, 3, 4, 5, 6. The key criteria include:
- Severe cirrhosis
- Glomerular hypofiltration
- No other functional or organic causes of renal failure
- Failure of plasma volume expansion
- No proteinuria
- Serum creatinine changes, rather than a fixed high value, are used to diagnose HRS 2 Some studies also differentiate between two types of HRS:
- Type 1 HRS: characterized by a rapid reduction of renal function, with a serum creatinine level increasing by more than 50% of the baseline value to above 133 micromol/L 4
- Type 2 HRS: characterized by a slowly progressive reduction of renal function
Additional Diagnostic Considerations
Other factors that may be considered in the diagnosis of HRS include:
- Urinary biomarkers, such as neutrophil gelatinase-associated lipocalin, to identify patients with acute tubular necrosis 2
- The absence of hematuria or proteinuria 3
- The presence of ascites and severe liver disease 6 It is important to note that the diagnosis of HRS can be challenging, and other types of acute renal failure may need to be ruled out, such as ischemic or toxic tubular necrosis or sepsis 4.