From the Guidelines
Diagnosing hepatorenal syndrome (HRS) requires a systematic approach based on specific diagnostic criteria, prioritizing the most recent and highest quality study, which is the 2022 study by the AGA Clinical Practice Update 1.
Diagnostic Criteria
The diagnosis is made by identifying acute kidney injury in patients with advanced liver disease after excluding other causes of kidney dysfunction.
- First, check for a serum creatinine increase of at least 0.3 mg/dL within 48 hours or a 50% increase from baseline.
- Ensure the patient has cirrhosis with ascites, as HRS typically occurs in this setting.
- Rule out other causes of kidney injury by checking for shock, infection, nephrotoxic medications, and performing urinalysis to exclude intrinsic kidney disease (minimal proteinuria, few cellular elements).
- Confirm that kidney function does not improve after 2-3 days of diuretic withdrawal and volume expansion with albumin (1 g/kg/day, maximum 100 g/day).
Classification and Treatment
HRS is classified as type 1 (rapid deterioration within 2 weeks) or type 2 (more gradual decline) 1.
- Prompt diagnosis is crucial as HRS carries high mortality, and early treatment with vasoconstrictors like terlipressin or norepinephrine plus albumin can improve outcomes while awaiting definitive treatment with liver transplantation.
- The use of a fixed threshold of serum creatinine at 1.5 mg/dL to define AKI in cirrhosis is problematic, and a dynamic definition referring to an acute increase of serum creatinine to ≥50% from baseline is preferred 1.
Key Considerations
- The removal of a fixed cut-off value of serum creatinine from the diagnostic criteria of HRS has important implications in the management of these patients, allowing for earlier treatment and potentially better outcomes 1.
- New urinary biomarkers, such as neutrophil gelatinase-associated lipocalin (NGAL), kidney injury molecule-1 (KIM-1), interleukin-18 (IL-18), and liver fatty acid-binding protein (L-FABP), may be useful in the differential diagnosis of AKI in patients with cirrhosis 1.
From the Research
Diagnosis of Hepatorenal Syndrome
To diagnose hepatorenal syndrome (HRS), the following criteria should be considered:
- Reduction in renal blood flow and glomerular filtration rate 2
- Absence of evidence of intrinsic kidney disease, such as hematuria, proteinuria, or abnormal kidney ultrasonography 2
- Functional changes in the renal circulation, which is potentially reversible with liver transplantation or vasoconstrictor drugs 2, 3
Types of Hepatorenal Syndrome
There are two forms of HRS, which are recognized depending on the acuity and progression of kidney injury:
- HRS-AKI (acute kidney injury): represents an acute impairment of kidney function 2
- HRS-CKD (chronic kidney disease): represents a more chronic kidney dysfunction 2
Diagnostic Approach
The diagnostic approach for HRS involves:
- Excluding other causes of acute kidney injury (AKI) 3
- Evaluating kidney function and sodium handling 4
- Assessing systemic hemodynamics and central blood volume 4
- Measuring hormonal markers 4
Challenges in Diagnosis
In some cases, the diagnostic criteria for HRS may not be completely fulfilled, making diagnosis challenging 5
- HRS may be superimposed on an organic nephropathy, which can complicate diagnosis 5