From the Guidelines
Diagnosing hepatorenal syndrome (HRS) requires a systematic approach based on the most recent diagnostic criteria, which involves establishing the presence of cirrhosis with ascites and acute kidney injury, defined as serum creatinine increase ≥0.3 mg/dL within 48 hours or ≥50% from baseline, as per the guidelines outlined by 1. To diagnose HRS, first establish the presence of cirrhosis with ascites and acute kidney injury. Then, rule out other causes of kidney dysfunction through:
- Urinalysis, which should show <500 mg/day proteinuria and <50 red blood cells per high power field
- Ultrasound, which should indicate normal kidney structure
- Medication review, which should involve discontinuing nephrotoxic drugs Volume expansion with albumin (1 g/kg, maximum 100 g/day for 2 days) should be attempted, with HRS suspected if kidney function doesn't improve, as suggested by 1 and further clarified by 1. Two types of HRS exist:
- HRS-AKI (formerly type 1) with rapid deterioration within 2 weeks
- HRS-CKD (formerly type 2) with more gradual decline Laboratory findings typically show elevated serum creatinine (>1.5 mg/dL), low urine sodium (<10 mEq/L), and low urine output. The diagnosis of HRS is essentially one of exclusion, requiring the elimination of prerenal causes (dehydration), intrinsic kidney disease, and post-renal obstruction, as emphasized by 1. The pathophysiology involves splanchnic vasodilation and systemic vasoconstriction leading to reduced renal perfusion despite preserved kidney structure, explaining why the diagnostic approach focuses on excluding structural kidney damage while confirming the presence of advanced liver disease. Given the most recent guidelines from 1, the diagnosis of HRS should be based on the updated criteria, which include an increase in serum creatinine 0.3 mg/dL within 48 hours, an increase in serum creatinine to 1.5-fold from baseline, or urine volume <0.5 mL/kg/h for 6 hours, and should take into account the patient's baseline renal function and the presence of cirrhosis with ascites.
From the Research
Diagnostic Criteria for Hepatorenal Syndrome
- Hepatorenal syndrome (HRS) is diagnosed when kidney function is reduced but evidence of intrinsic kidney disease, such as hematuria, proteinuria, or abnormal kidney ultrasonography, is absent 2
- The International Ascites Club recommended strict diagnostic criteria for HRS, which includes the presence of cirrhosis with ascites, serum creatinine > 1.5 mg/dL, and no improvement in serum creatinine after diuretic withdrawal and volume expansion with albumin 3
- Two forms of hepatorenal syndrome are recognized: HRS-AKI (acute kidney injury) and HRS-CKD (chronic kidney disease) 2, 4
Diagnostic Challenges
- The diagnosis of HRS can be challenging due to the lack of specific diagnostic tools and the need for differential diagnosis from other forms of acute kidney injury (AKI) 4
- In some cases, the diagnostic criteria for HRS may not be completely fulfilled, making diagnosis more difficult 3
Diagnostic Tools and Tests
- Serum creatinine levels are used to diagnose and monitor HRS, with a significant increase in serum creatinine indicating a poor prognosis 3, 5
- Abdominal imaging and laboratory assessments, such as urine analysis and kidney ultrasonography, may be used to rule out other causes of kidney disease 2, 5
- The current consensus definition of HRS-AKI includes proposed diagnostic criteria based on changes in serum creatinine levels, tailored for high sensitivity and rapid detection 5
Prognosis and Predictive Factors
- The prognosis of patients with HRS is poor, with a median survival of ≤3 months 4
- Age, bilirubin levels, and creatinine increase after diagnostic volume expansion are independent predictors of death in patients with HRS 3
- The severity of HRS, complex pathology, limited treatment options, and range of associated conditions pose significant challenges for both patients and care providers 5