Acute-on-chronic liver failure (ACLF) is an increasingly recognised entity encompassing an acute deterioration of liver function in patients with cirrhosis, which is usually associated with a precipitating event and results in the failure of one or more organs and high short term mortality. Prospective data to define this is lacking but there is a large body of circumstantial evidence suggesting that this condition is a distinct clinical entity. From the pathophysiologic perspective, altered host response to injury and infection play important roles in its development. This review focuses upon the current understanding of this syndrome from the clinical, prognostic and pathophysiologic perspectives and indicates potential biomarkers and therapeutic targets for intervention.

Bacterial infections are an important cause of mortality in cirrhosis but there is a paucity of multi-center studies. The aim was to define factors predisposing to infection-related mortality in hospitalized cirrhotic patients. Methods A prospective, cohort study of cirrhotic patients with infections was performed at eight North American tertiary-care hepatology centers. Data were collected on admission vitals, disease severity [MELD and sequential organ failure (SOFA)] scores], first infection site, type [community-acquired, health care-associated (HCA) or nosocomial], and second infection occurrence during hospitalization. The outcome was mortality within 30 days. A multi-variable logistic regression model predicting mortality was created. Results 207 patients (55 years, 60% men, MELD 20) were included. Most first infections were HCA (71%), then nosocomial (15%) and community-acquired (14%). Urinary tract infections (52%), spontaneous bacterial peritonitis (SBP, 23%) and spontaneous bacteremia (21%) formed the majority of the first infections. Second infections were seen in 50 (24%) patients and were largely preventable: respiratory, including aspiration (28%), urinary, including catheter-related (26%), fungal (14%) and C. difficile (12%) infections. Forty-nine patients (23.6%) who died within 30 days had higher admission MELD (25 vs 18, p<0.0001), lower serum albumin (2.4g.dL vs. 2.8g/dL, p=0.002), and second infections (49% vs. 16%, p<0.0001) but equivalent SOFA scores (9.2 vs. 9.9, p=0.86). Case fatality rate was highest for C. difficile (40%), respiratory (37.5%) and spontaneous bacteremia (37%), and lowest for SBP (17%) and urinary infections (15%). The model for mortality included admission MELD (OR: 1.12), heart rate (OR:1.03) albumin (OR:0.5) and second infection (OR:4.42) as significant variables. Conclusions Potentially preventable second infections are predictors of mortality independent of liver disease severity in this multi-center cirrhosis cohort.

Acute deterioration of patients with cirrhosis manifests as multiple organ failure requiring admission to an intensive care unit. Precipitating events may be viral hepatitis, typically in Asia, and drug or alcoholic hepatitis and variceal hemorrhage in the West. Patients with cirrhosis in the intensive care unit have a high mortality, and each admission is associated with a mean charge of US $116,200. Prognosis is determined by the number of organs failing (sequential organ failure assessment [SOFA] score), the presence of infection, and the degree of liver dysfunction (Child‐Turcotte‐Pugh or Model for End‐Stage Liver Disease scores). The most common organ failing is the kidney; sepsis is associated with further deterioration in liver function by compromise of the microcirculation. Care of these critically ill patients with impending multiple organ failure requires a team approach with expertise in both hepatology and critical care. Treatment is aimed at preventing further deterioration in liver function, reversing precipitating factors, and supporting failing organs. Liver transplantation is required in selected patients to improve survival and quality of life. Treatment is futile in some patients, but it is difficult to identify these patients a priori. Artificial and bioartificial liver support systems have thus far not demonstrated significant survival benefit in these patients. (HEPATOLOGY 2011)

Background Acute liver failure (ALF) is a rare syndrome of severe, rapid-onset hepatic dysfunction without prior advanced liver disease that is associated with high morbidity and mortality. Intensive care and liver transplantation provide support and rescue, respectively. Objective To determine whether changes in causes, disease severity, treatment, or 21-day outcomes have occurred in recent years among adult patients with ALF referred to U.S. tertiary care centers. Design Prospective observational cohort study. (ClinicalTrials.gov: NCT00518440) Setting 31 liver disease and transplant centers in the United States. Patients Consecutively enrolled patients–without prior advanced liver disease–with ALF (n = 2070). Measurements Clinical features, treatment, and 21-day outcomes were compared over time annually for trends and were also stratified into two 8-year periods (1998 to 2005 and 2006 to 2013). Results Overall clinical characteristics, disease severity, and distribution of causes remained similar throughout the study period. The 21-day survival rates increased between the two 8-year periods (overall, 67.1% vs. 75.3%; transplant-free survival [TFS], 45.1% vs. 56.2%; posttransplantation survival, 88.3% vs. 96.3% [P < 0.010 for each]). Reductions in red blood cell infusions (44.3% vs. 27.6%), plasma infusions (65.2% vs. 47.1%), mechanical ventilation (65.7% vs. 56.1%), and vasopressors (34.9% vs. 27.8%) were observed, as well as increased use of N-acetylcysteine (48.9% vs. 69.3% overall; 15.8% vs. 49.4% [P < 0.001] in patients with ALF not due to acetaminophen toxicity). When examined longitudinally, overall survival and TFS increased throughout the 16-year period. Limitations The duration of enrollment, the number of patients enrolled, and possibly the approaches to care varied among participating sites. The results may not be generalizable beyond such specialized centers. Conclusion Although characteristics and severity of ALF changed little over 16 years, overall survival and TFS improved significantly. The effects of specific changes in intensive care practice on survival warrant further study. Primary Funding Source National Institutes of Health.

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Acute-on-chronic liver failure may be a distinct clinical entity with a potential for reversibility when identified early and managed with aggressive critical care support.

In a large cohort of ALF patients, hyperammonemia was associated with high-grade HE and worse 21-day TFS. CRRT was associated with a reduction in serum ammonia level and improvement of 21-day TFS. (Hepatology 2017).

OBJECTIVES Acute liver failure (ALF) is classically defined by coagulopathy and hepatic encephalopathy (HE); however, acute liver injury (ALI), i.e., severe acute hepatocyte necrosis without HE, has not been carefully defined nor studied. Our aim is to describe the clinical course of specifically defined ALI, including the risk and clinical predictors of poor outcomes, namely progression to ALF, the need for liver transplantation (LT) and death. METHODS 386 subjects prospectively enrolled in the Acute Liver Failure Study Group registry between 1 September 2008 through 25 October 2013, met criteria for ALI: International Normalized Ratio (INR)≥2.0 and alanine aminotransferase (ALT)≥10× elevated (irrespective of bilirubin level) for acetaminophen (N-acetyl-p-aminophenol, APAP) ALI, or INR≥2.0, ALT≥10× elevated, and bilirubin≥3.0 mg/dl for non-APAP ALI, both groups without any discernible HE. Subjects who progressed to poor outcomes (ALF, death, LT) were compared, by univariate analysis, with those who recovered. A model to predict poor outcome was developed using the random forest (RF) procedure. RESULTS Progression to a poor outcome occurred in 90/386 (23%), primarily in non-APAP (71/179, 40%) vs. only 14/194 (7.2%) in APAP patients comprising 52% of all cases (13 cases did not have an etiology assigned; 5 of whom had a poor outcome). Of 82 variables entered into the RF procedure: etiology, bilirubin, INR, APAP level and duration of jaundice were the most predictive of progression to ALF, LT, or death. CONCLUSIONS A majority of ALI cases are due to APAP, 93% of whom will improve rapidly and fully recover, while non-APAP patients have a far greater risk of poor outcome and should be targeted for early referral to a liver transplant center.