Acute kidney injury spectrum in patients with chronic liver disease: Where do we stand?

Table 1 Comparison of the definitions of acute-on-chronic liver failure from the Asian Pacific Association for the Study of Liver, American Association for the Study of Liver Diseases-European Association for the Study of the Liver, and World Gastroenterology Organization

Criteria	APSAL	AASLD-EASL	WGO
Preexisting or underlying chronic liver disease	Noncirrhotic chronic liver disease, compensated cirrhosis	Cirrhotic chronic liver disease, cirrhosis with prior decompensation	Noncirrhotic chronic liver disease, compensated cirrhosis, decompensated cirrhosis
Precipitating causes	Alcohol, drugs, hepatotropic viruses, surgery, trauma	Alcohol, drugs, hepatotropic viruses, surgery, trauma, variceal bleeding, infection/sepsis	Alcohol, drugs, hepatotropic viruses, surgery, trauma, variceal bleeding, infection/sepsis
Duration between acute liver injury and ACLF	4 wk	NA	NA
Organ failure	Hepatic failure	Extrahepatic organ failure	Hepatic failure, extrahepatic organ failure

APSAL: Asian Pacific Association for the Study of Liver; AASLD-EASL: American Association for the Study of Liver Diseases-European Association for the Study of the Liver; WGO: World Gastroenterology Organization; NA: Not available.

Table 2 The International Club of Ascites diagnostic criteria for hepatorenal syndrome

International Club of Ascites diagnostic criteria for hepatorenal syndrome
Diagnosis of cirrhosis and ascites
Diagnosis of acute kidney injury (AKI) according to ICA-AKI criteria (Table 3)
No response after 2 consecutive days of diuretic withdrawal and plasma volume expansion administration with albumin at 1 g/kg of body weight
Absence of shock
No current or recent use of nephrotoxic agents
No signs of structural kidney injuries, defined as the following:
Absence of proteinuria (> 500 mg/day or equivalent)
Absence of microscopic hematuria (> 50 red blood cells per high-power field)
Normal findings on renal ultrasonography

AKI: Acute kidney injury; ICA: Ascites diagnostic criteria.

Table 3 The proposed classification system of renal dysfunction in patients with cirrhosis proposed by the Acute Dialysis Quality Initiative and the International Club of Ascites work group[12]

Diagnosis	Definition
Acute kidney injury (AKI)	Rise in serum creatinine (SCr) of ≥ 50% from baseline or a rise in SCr by ≥ 0.3 mg/dL (26.5 μmol/L) in < 48 h. Hepatorenal syndrome (HRS) type 1 is a specific form of AKI
	Stage 1: Increase in serum creatinine (SCr) ≥ 0.3 mg/dL (26.5 μmol/L) or an increase in SCr 1.5-fold to 2-fold from baseline
	Stage 2: Increase in SCr > 2-fold to 3-fold from baseline
	Stage 3: Increase in SCr > 3-fold from baseline or an increase in 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
Chronic kidney disease (CKD)	Glomerular filtration rate (GFR) of < 60 mL/min for > 3 mo, calculated using the MDRD6 formula. HRS type 2 is a specific form of CKD
Acute-on-chronic kidney disease	Rise in SCr of ≥ 50% from baseline or a rise of SCr by ≥ 0.3 mg/dL (26.5 μmol/L) in < 48 h in a patient with cirrhosis whose GFR is < 60 mL/min for > 3 mo, calculated using the MDRD6 formula

MDRD: Modification in diet of renal disease; GFR: Glomerular filtration rate; CKD: Chronic kidney disease; AKI: Acute kidney injury; SCr: Serum creatinine.

Table 4 Comparison between the main mechanisms of the pathophysiology of hepatorenal syndrome–acute kidney injury and non-hepatorenal syndrome-acute kidney injury

Hepatorenal syndrome	Non-hepatorenal syndrome
Splanchnic vasodilatation	Acute-on-chronic liver failure
Inflammation	Inflammation
Adrenal insufficiency	Bacterial translocation
Cardiac dysfunction	Bile acid
	Worsening portal hypertension
	Worsening cardiac output