What are the criteria for managing patients with ascites (fluid accumulation in the abdomen) and Acute Kidney Injury (AKI)?

International Club of Ascites-Acute Kidney Injury (ICA-AKI) Criteria

The International Club of Ascites (ICA) defines AKI in cirrhotic patients with ascites as an increase in serum creatinine (sCr) by ≥0.3 mg/dL (26.5 μmol/L) within 48 hours or an increase in sCr ≥1.5 times baseline within 7 days. 1

Diagnostic Criteria for ICA-AKI

The ICA-AKI criteria combine elements from the KDIGO (Kidney Disease Improving Global Outcomes) criteria with conventional criteria for cirrhotic patients:

• Definition of AKI: Increase in sCr by ≥0.3 mg/dL (26.5 μmol/L) within 48 hours; OR increase in sCr to ≥1.5 times baseline, which is known or presumed to have occurred within the prior 7 days 1

• Baseline sCr: The last stable value of sCr within the last 3 months. If no previous sCr is available, the admission value can be used as baseline 1

• AKI Staging:

  • Stage 1: Increase in sCr ≥0.3 mg/dL (26.5 μmol/L) or an increase in sCr ≥1.5-fold to twofold from baseline 1
    • Stage 1A: Peak sCr <1.5 mg/dL (133 μmol/L)
    • Stage 1B: Peak sCr ≥1.5 mg/dL (133 μmol/L)
  • Stage 2: Increase in sCr >twofold to threefold from baseline 1
  • Stage 3: Increase in sCr >threefold from baseline or sCr ≥4.0 mg/dL (353.6 μmol/L) with an acute increase ≥0.3 mg/dL (26.5 μmol/L) or initiation of renal replacement therapy 1

• Response to Treatment:

  • No response: No regression of AKI 1
  • Partial response: Regression of AKI stage with a reduction of sCr to ≥0.3 mg/dL (26.5 μmol/L) above the baseline value 1
  • Full response: Return of sCr to a value within 0.3 mg/dL (26.5 μmol/L) of the baseline value 1

Management Algorithm for ICA-AKI

Stage 1 AKI

• Close monitoring 1
• Remove risk factors:
  • Review all medications (including OTC drugs) 1
  • Reduce or withdraw diuretic therapy 1
  • Withdraw nephrotoxic drugs, vasodilators, and NSAIDs 1
  • Treat infections when diagnosed 1
• Plasma volume expansion in case of hypovolemia (with crystalloids, albumin, or blood) 1

Stage 2 and 3 AKI

• Withdrawal of diuretics (if not already done) 1
• Volume expansion with albumin (1 g/kg) for 2 consecutive days 1
• If no response and meets criteria for HRS-AKI: vasoconstrictors and albumin 1
• If other AKI phenotypes identified: specific treatment for those conditions 1

Diagnostic Criteria for Hepatorenal Syndrome (HRS) Type of AKI

• Diagnosis of cirrhosis and ascites 1
• Diagnosis of AKI according to ICA-AKI criteria 1
• No response after 2 consecutive days of diuretic withdrawal and plasma volume expansion with albumin 1 g/kg bodyweight 1
• Absence of shock 1
• No current or recent use of nephrotoxic drugs (NSAIDs, aminoglycosides, iodinated contrast media, etc.) 1
• No macroscopic signs of structural kidney injury, defined as:
  • Absence of proteinuria (>500 mg/day) 1
  • Absence of microhematuria (>50 RBCs per high power field) 1
  • Normal findings on renal ultrasonography 1

Clinical Implications and Prognosis

• The cut-off value of sCr ≥1.5 mg/dL (133 μmol/L) is clinically significant for prognosis 1
• Patients with Stage 1A AKI (peak sCr <1.5 mg/dL) may have similar short-term mortality to those without AKI 1
• Patients with Stage 1B AKI (peak sCr ≥1.5 mg/dL) have higher short-term mortality than those without AKI 1
• Patients with AKI Stage 2 and 3 have the highest mortality 1, 2
• Even mild AKI (Stage 1) is associated with significantly increased 30-day mortality compared to patients without AKI 2

Important Considerations and Caveats

• The MDRD formula is inaccurate for estimating GFR in cirrhotic patients, particularly those with ascites, making imputed baseline creatinine values unreliable 1, 3
• Urinary biomarkers (NGAL, KIM-1, IL-18, L-FABP) may help in the differential diagnosis of AKI types in cirrhotic patients, but further studies are needed 1
• Bacterial infections are common precipitants of AKI in cirrhotic patients and require prompt recognition and treatment 1, 4
• The prevalence of un-precipitated AKI increases with ascites severity, suggesting the need for frequent monitoring of renal function in patients with severe ascites 5
• Liver transplantation remains the definitive treatment for patients with cirrhosis and AKI, especially HRS-AKI 6