Prognostic implications of hyperlactatemia, multiple organ failure, and systemic inflammatory response syndrome in patients with acetaminophen-induced acute liver failure

Prognostic models in acute liver failure-historic evolution and newer updates "prognostic models in acute liver failure"

Acute liver failure (ALF) is a rare and dynamic syndrome occurring as a sequela of severe acute liver injury (ALI). Its mortality ranges from 50% to 75% based on the aetiology, patients age and severity of encephalopathy at admission. With improvement in intensive care techniques, transplant-free survival in ALF has improved over time. Timely recognition of patients who are unlikely to survive with medical intervention alone is crucial since these individuals may rapidly develop multiorgan failure and render liver transplantation futile. Various predictive models, biomarkers and AI-based models are currently used in clinical practice, each with its fallacies. The King's College Hospital criteria (KCH) were initially established in 1989 to identify patients with acute liver failure (ALF) caused by paracetamol overdose or other causes who are unlikely to improve with conventional treatment and would benefit from a liver transplant. Since then, various models have been developed and validated worldwide. Most models include age, aetiology of liver disease, encephalopathy grade, and liver injury markers like INR, lactate, factor V level, factor VIII/V ratio and serum bilirubin. But none of the currently available models are dynamic and lack accuracy in predicting transplant free survival. There is an increasing interest in developing prognostic serum biomarkers that when used alone or in combination with clinical models enhance the accuracy of predicting outcomes in ALF. Genomics, transcriptomics, proteomics, and metabolomics as well as machine learning and artificial intelligence (AI) algorithms are areas of interest for developing higher-precision predictive models. Overall, the future of prognostic models in ALF is promising, with ongoing research paving the way for more accurate, personalized, and dynamic risk assessment tools that can potentially save lives in this challenging condition. This article summarizes the history of prognostic models in ALF and future trends.

Role of lactate and lactate metabolism in liver diseases (Review)

Lactate is a byproduct of glycolysis, and before the Warburg effect was revealed (in which glucose can be fermented in the presence of oxygen to produce lactate) it was considered a metabolic waste product. At present, lactate is not only recognized as a metabolic substrate that provides energy, but also as a signaling molecule that regulates cellular functions under pathophysiological conditions. Lactylation, a post‑translational modification, is involved in the development of various diseases, including inflammation and tumors. Liver disease is a major health challenge worldwide. In normal liver, there is a net lactate uptake caused by gluconeogenesis, exhibiting a higher net lactate clearance rate compared with any other organ. Therefore, abnormalities of lactate and lactate metabolism lead to the development of liver disease, and lactate and lactate metabolism‑related genes can be used for predicting the prognosis of liver disease. Targeting lactate production, regulating lactate transport and modulating lactylation may be potential treatment approaches for liver disease. However, currently there is not a systematic review that summarizes the role of lactate and lactate metabolism in liver diseases. In the present review, the role of lactate and lactate metabolism in liver diseases including liver fibrosis, non‑alcoholic fatty liver disease, acute liver failure and hepatocellular carcinoma was summarized with the aim to provide insights for future research.

Short-term outcomes of perioperative glucocorticoid administration in patients undergoing liver surgery: a systematic review and meta-analysis of randomised controlled trials

OBJECTIVE

The purpose of this systematic review and meta-analysis was to investigate whether glucocorticoid might be beneficial after hepatectomy.

DESIGN

Systematic review and meta-analysis.

DATA SOURCES

PubMed, Embase, Cochrane Library and Web of Science.

ELIGIBILITY CRITERIA

We included studies assessing the efficacy of perioperative glucocorticoid administration in patients undergoing liver surgery.

DATA EXTRACTION AND SYNTHESIS

Four data bases were retrieved for all randomised controlled trials. We considered postoperative complications, hospital stay and postoperative chemistry evaluations as outcomes. Pooled effects of dichotomic variables were expressed as relative risk (RR) with a 95% CI. The mean difference was used for continuous variables and an inverse variance statistical method was adopted.

RESULTS

Fourteen studies with 1205 patients were included. Lower risk of overall complications was associated with glucocorticoid (RR, 0.77; 95% CI 0.64 to 0.92), while no difference was found in hospital stay (RR, 0.02; 95% CI -0.47 to 0.51). There were also improvements in postoperative chemistry evaluations including interleukin 6 on day 1 and 3, C reactive protein on day 1, 2 and 3, international normalised ratio on day 2, total bilirubin on day 1, 2, 3 and 5, albumin on day 1.

CONCLUSION

Current evidence indicated that perioperative glucocorticoid administration for patients undergoing hepatectomy reduced the risk of overall complications with inhibited postoperative inflammatory response and improved postoperative liver function.

PROSPERO REGISTRATION NUMBER

CRD42022307533.

Tricarboxylic Acid Metabolite Imbalance in Rats with Acute Thioacetamide-Induced Hepatic Encephalopathy Indicates Incomplete Recovery

Exposure to the toxin thioacetamide (TAA) causes acute hepatic encephalopathy (HE), changes in the functioning of systemic organs, and an imbalance in a number of energy metabolites. The deferred effects after acute HE development are poorly understood. The study considers the balance of the tricarboxylic acid (TCA) cycle metabolites in the blood plasma, liver, kidneys, and brain tissues of rats in the post-rehabilitation period. The samples of the control (n = 3) and TAA-induced groups of rats (n = 13) were collected six days after the administration of a single intraperitoneal TAA injection at doses of 200, 400, and 600 mg/kg. Despite the complete physiological recovery of rats by this date, a residual imbalance of metabolites in all the vital organs was noted. The results obtained showed a trend of stabilizing processes in the main organs of the animals and permit the use of these data both for prognostic purposes and the choice of potential therapeutic agents.

The Role of Predictive Models in the Assessment of the Poor Outcomes in Pediatric Acute Liver Failure

OBJECTIVES

In children, acute liver failure (ALF) is a severe condition with high mortality. As some patients need liver transplantation (LT), it is essential to predict the fatal evolution and to refer them early for LT if needed. Our study aimed to evaluate the prognostic criteria and scores for assessing the outcome in children with ALF.

METHODS

Data of 161 children with ALF (54.66% female, mean age 7.66 ± 6.18 years) were analyzed based on final evolution (32.91% with fatal evolution or LT) and etiology. We calculated on the first day of hospitalization the PELD score (109 children), MELD, and MELD-Na score (52 children), and King's College Criteria (KCC) for all patients. The Nazer prognostic index and Wilson index for predicting mortality were calculated for nine patients with ALF in Wilson's disease (WD).

RESULTS

PELD, MELD, and MELD-Na scores were significantly higher in patients with fatal evolution (21.04 ± 13.28 vs. 13.99 ± 10.07, p = 0.0023; 36.20 ± 19.51 vs. 20.08 ± 8.57, p < 0.0001; and 33.07 ± 8.29 vs. 20.08 ± 8.47, p < 0.0001, respectively). Moreover, age, bilirubin, albumin, INR, and hemoglobin significantly differed in children with fatal evolution. Function to etiology, PELD, MELD, MELD-Na, and KCC accurately predicted fatal evolution in toxic ALF (25.33 vs. 9.90, p = 0.0032; 37.29 vs. 18.79, p < 0.0001; 34.29 vs. 19.24, p = 0.0002, respectively; with positive predicting value 100%, negative predicting value 88.52%, and accuracy 89.23% for King's College criteria). The Wilson index for predicting mortality had an excellent predictive strength (100% sensibility and specificity), better than the Nazer prognostic index.

CONCLUSIONS

Prognostic scores may be used to predict the fatal evolution of ALF in children in correlation with other parameters or criteria. Early estimation of the outcome of ALF is essential, mainly in countries where emergency LT is problematic, as the transfer to a specialized center could be delayed, affecting survival chances.

Higher circulating natural killer cells and lower lactate levels at admission predict spontaneous survival in non-acetaminophen induced acute liver failure

Massive cellular necrosis in acute liver failure (ALF) is dominantly immune mediated and innate immune cells are major pathophysiological determinants in liver damage. In fifty ALF and fifteen healthy, immune cells phenotyping by flow-cytometry, DAMPs using ELISA were analysed and correlated with clinical and biochemical parameters. ALF patients (aged 27 ± 9 yr, 56% males, 78% viral aetiology) showed no difference in neutrophils and classical monocytes, but significantly increased intermediate monocytes (CD14⁺CD16⁺) (p < 0.01), decreased non-classical monocytes (CD14^-CD16⁺) and CD3^-veCD16⁺CD56⁺ NK cells compared to HC. ALF patients who survived, showed higher NK cells (9.28 vs. 5.1%, p < 0.001) among lymphocytes and lower serum lactate levels (6.1 vs. 28, Odds ratio 2.23, CI 1.27-3.94) than non- survivors had higher. Logistic regression model predicted the combination of lactate levels with NK cell percentage at admission for survival. In conclusion, Combination of NK cell frequency among lymphocytes and lactate levels at admission can reliably predict survival of ALF patients.

Liver transplantation in acute liver failure: Dilemmas and challenges

Acute liver failure (ALF) refers to a state of severe hepatic injury that leads to altered coagulation and sensorium in the absence of pre-existing liver disease. ALF has different causes, but the clinical characteristics are strikingly similar. In clinical practice, however, inconsistency in the definition of ALF worldwide and confusion regarding the existence of pre-existing liver disease raise diagnostic dilemmas. ALF mortality rates used to be over 80% in the past; however, survival rates on medical treatment have significantly improved in recent years due to a greater understanding of pathophysiology and advances in critical care management. The survival rates in acetaminophen-associated ALF have become close to the post-transplant survival rates. Given that liver transplantation (LT) is an expensive treatment that involves a major surgical operation in critically ill patients and lifelong immunosuppression, it is very important to select accurate patients who may benefit from it. Still, emergency LT remains a lifesaving procedure for many ALF patients. However, there is a lack of consistency in current prognostic models that hampers the selection of transplant candidates in a timely and precise manner. The other problems associated with LT in ALF are the shortage of graft, development of contraindications on the waiting list, vaguely defined delisting criteria, time constraints for pre-transplant evaluation, ethical concerns, and comparatively poor post-transplant outcomes in ALF. Therefore, there is a desperate need to establish accurate prognostic models and explore the roles of evolving adjunctive and alternative therapies, such as liver support systems, plasma exchange, stem cells, auxiliary LT, and so on, to enhance transplant-free survival and to fill the void created by the graft shortage.

Creatinine-lactate score predicts mortality in non-acetaminophen-induced acute liver failure in patients listed for liver transplantation

BACKGROUND

The aim of this study was to analyze prognostic indicators of in-hospital mortality among patients listed for urgent liver transplantation (LT) for non-acetaminophen (APAP)-induced acute liver failure (ALF).

METHODS

ALF patients listed for LT according to the King's College Criteria were retrospectively reviewed. Variables were recorded from medical records and electronic databases (HCMED and RedCap).

RESULTS

The study included 100 patients, of which 69 were subject to LT and 31 died while waiting for LT. Patients were 35.5 ± 14.73 years old, and 78% were females. The main etiologies were virus (17%), drug-induced (32%), autoimmune (15%), and indeterminate hepatitis (31%). The prioritization-to-LT time interval was 1.5 days (0-9). The non-LT patients showed higher lactate (8.71 ± 5.36 vs. 4.48 ± 3.33 mmol/L), creatinine (229 ± 207 vs. 137 ± 136 µm/L), MELD (44 ± 8 vs. 38 ± 8), and BiLE scores (15.8 ± 5.5 vs. 10.3 ± 4.1) compared to LT patients (p < 0.05). Multiple logistic regression analysis identified creatinine and lactate as independent prognostic factors, and a creatinine-lactate (CL) score was developed. ROC analysis showed that creatinine, lactate, MELD, BiLE, and CL scores had considerable specificity (71-88%), but only BiLE, lactate, and CL presented high sensitivities (70%, 80%, and 87% respectively). AUCs were 0.696 for creatinine, 0.763 for lactate, 0.697 for MELD, 0.814 for BiLE, and 0.835 for CL.

CONCLUSIONS

CL and BiLE scores predict mortality with more accuracy than MELD in patients with ALF during prioritization time. Creatinine and lactate are independent prognostic factors for mortality.

LR12 Promotes Liver Repair by Improving the Resolution of Inflammation and Liver Regeneration in Mice with Thioacetamide- (TAA-) Induced Acute Liver Failure

Background

Triggering receptor expressed on myeloid cells-1 (TREM-1) controls the mobilization of inflammatory cells in response to injury and consequently enhances liver damage. LR12 is a TREM-1 inhibitory peptide. However, the role of LR12 in acute liver failure (ALF) has remained elusive. This study was aimed at indicating whether LR12 could promote liver repair in mice with thioacetamide- (TAA-) induced ALF.

Methods

BALB/c mice were intraperitoneally injected with TAA, followed by intravenous injection of LR12. Damage and regeneration of the liver were assessed. LO2 cells and macrophages were used to assess the therapeutic effects of LR12.

Results

Mice treated with TAA for 24 h developed ALF, while liver inflammation was alleviated after LR12 treatment. Moreover, LR12 promoted hepatocyte regeneration in mice with TAA-induced ALF. In vitro, the supernatant from TAA+LR12-treated macrophages promoted the proliferation of LO2 cells. Cytokine protein microarray analysis suggested that LR12 promoted the secretion of C-C chemokine ligand 20 (CCL20) from macrophages. Besides, neutralization of CCL20 blocked the effects of LR12, thus inhibited the proliferation of LO2 cells in vitro, aggregated the liver inflammation, and restrained hepatocyte regeneration in ALF mice in vivo. Furthermore, we also found that LR12 activated the p38 mitogen-activated protein kinase (MAPK) pathway in hepatocytes through promoting the secretion of CCL20 from macrophages.

Conclusions

LR12 could improve the resolution of inflammation and liver regeneration in mice with TAA-induced ALF by promoting the secretion of CCL20 from macrophages and activating the p38 MAPK pathway. Therefore, LR12 could be an attractive therapeutic target for the treatment of ALF.

Applications of Nanobiomaterials in the Therapy and Imaging of Acute Liver Failure

This review focuses on the therapeutic mechanisms, targeting strategies of various nanomaterials in acute liver failure, and recent advances of diverse nanomaterials for acute liver failure therapy, diagnosis, and imaging. This review provides an outlook on the applications of nanomaterials, especially on the new horizons in acute liver failure therapy, and inspires broader interests across various disciplines. Acute liver failure (ALF), a fatal clinical disease featured with overwhelming hepatocyte necrosis, is a grand challenge in global health. However, a satisfactory therapeutic option for curing ALF is still absent, other than liver transplantation. Nanobiomaterials are currently being developed for the diagnosis and treatment of ALF. The liver can sequester most of nanoparticles from blood circulation, which becomes an intrinsic superiority for nanobiomaterials targeting hepatic diseases. Nanobiomaterials can enhance the bioavailability of free drugs, thereby significantly improving the therapeutic effects in ALF. Nanobiomaterials can also increase the liver accumulation of therapeutic agents and enable more effective targeting of the liver or specific liver cells. In addition, stimuli-responsive, optical, or magnetic nanomaterials exhibit great potential in the therapeutical, diagnostic, and imaging applications in ALF. Therefore, therapeutic agents in combination with nanobiomaterials increase the specificity of ALF therapy, diminish adverse systemic effects, and offer a multifunctional theranostic platform. Nanobiomaterial holds excellent significance and prospects in ALF theranostics. In this review, we summarize the therapeutic mechanisms and targeting strategies of various nanobiomaterials in ALF. We highlight recent developments of diverse nanomedicines for ALF therapy, diagnosis, and imaging. Furthermore, the challenges and future perspectives in the theranostics of ALF are also discussed.

Evaluating lactate prognostic value in children suspected of acetaminophen-induced liver failure in Liberia

BACKGROUND

The prognostic significance of hyperlactatemia in young children with liver injury suspected to be attributed to repeated supratherapeutic doses of acetaminophen remain understudied.

METHODS

We conducted a retrospective medical chart review including children aged <5 years admitted with hepatocellular injury. The study was conducted in Bardnesville Junction Hospital operated by Médecins Sans Frontières in Monrovia, Liberia.

RESULTS

We analyzed 95 children with liver injury in whom a blood lactate measurement on admission was available. Eighty children (84%) were aged <2 years; 49 children (52%) died during hospitalization. The median acetaminophen concentration on admission was 20 mg/L with 60 (70%) children presenting concentrations exceeding 10 mg/L. Median lactate was significantly higher in children who died (10.7 mmol/L; interquartile range (IQR): 8.5-15.7) than those who survived (6.1 mmol/L; IQR: 4.1-8.5), P value < 0.001). The optimal threshold obtained was 7.2 mmol/L with a sensitivity of 84% and specificity 70% (area under curve = 0.80). The previously established thresholds of 3.5 and 4 mmol/L lactate had very low specificity identifying non-survival in children included in this study.

CONCLUSION

In this setting, young children with ALF possibly attributed to acetaminophen toxicity were unlikely to survive if the venous blood lactate concentration exceeded 7.2 mmol/L.

The Direct Contribution of Astrocytes and Microglia to the Pathogenesis of Hepatic Encephalopathy

Hepatic encephalopathy is a neurological complication resulting from loss of hepatic function and is associated with poor clinical outcomes. During acute liver failure over 20% of mortality can be associated with the development of hepatic encephalopathy. In patients with liver cirrhosis, 1-year survival for those that develop overt hepatic encephalopathy is under 50%. The pathogenesis of hepatic encephalopathy is complicated due to the multiple disruptions in homeostasis that occur following a reduction in liver function. Of these, elevations of ammonia and neuroinflammation have been shown to play a significant contributing role to the development of hepatic encephalopathy. Disruption of the urea cycle following liver dysfunction leads to elevations of circulating ammonia, which enter the brain and disrupt the functioning of astrocytes. This results in dysregulation of metabolic pathways in astrocytes, oxidative stress and cerebral edema. Besides ammonia, circulating chemokines and cytokines are increased following liver injury, leading to activation of microglia and a subsequent neuroinflammatory response. The combination of astrocyte dysfunction and microglia activation are significant contributing factors to the pathogenesis of hepatic encephalopathy.

Mesenchymal stem cells prolong survival and prevent lethal complications in a porcine model of fulminant liver failure

BACKGROUND

Fulminant liver failure (FLF) is a life-threatening disease.

METHODS

Lethal FLF was induced by ischemia-reperfusion (I-R) injury in mini-pigs, and MSCs were infused via splenic vein after reperfusion.

RESULTS

Accumulated survival within 28 days was significantly improved by MSCs (P = 0.0348). Notably, MSCs maintained blood-gas homeostasis in the first 24 hours and prevented FLF-induced elevation of prothrombin time, international normalized ratio, and creatinine and ammonia levels in the first 3 days. With MSCs, serum levels of liver enzymes gradually decreased after 3 days, and platelet count was back to normal at 1 week of FLF. MSCs promoted liver regeneration within 2 weeks and differentiated into functional hepatocytes at 2-4 weeks after transplantation, evidenced by increase in Ki67-positive cells, detectable human hepatocyte growth factor, human vascular endothelial growth factor, human hepatocyte-specific antigen, and human albumin-expressing cells in the liver at different time points. Reactive oxidative species (ROS) were accumulated after FLF and eliminated at 4 weeks after MSC transplantation.

CONCLUSIONS

Together, MSCs prolong the survival and prevent lethal sequelae of I-R injury-induced FLF by maintenance of liver-function homeostasis and rescue of ROS in the acute stage and by homing and differentiation into hepatocytes in the subacute stage.

The Role of Monocytes and Macrophages in Acute and Acute-on-Chronic Liver Failure

Acute and acute-on-chronic liver failure (ALF and ACLF), though distinct clinical entities, are considered syndromes of innate immune dysfunction. Patients with ALF and ACLF display evidence of a pro-inflammatory state with local liver inflammation, features of systemic inflammatory response syndrome (SIRS) and vascular endothelial dysfunction that drive progression to multi-organ failure. In an apparent paradox, these patients are concurrently immunosuppressed, exhibiting acquired immune defects that render them highly susceptible to infections. This paradigm of tissue injury succeeded by immunosuppression is seen in other inflammatory conditions such as sepsis, which share poor outcomes and infective complications that account for high morbidity and mortality. Monocyte and macrophage dysfunction are central to disease progression of ALF and ACLF. Activation of liver-resident macrophages (Kupffer cells) by pathogen and damage associated molecular patterns leads to the recruitment of innate effector cells to the injured liver. Early monocyte infiltration may contribute to local tissue destruction during the propagation phase and results in secretion of pro-inflammatory cytokines that drive SIRS. In the hepatic microenvironment, recruited monocytes mature into macrophages following local reprogramming so as to promote resolution responses in a drive to maintain tissue integrity. Intra-hepatic events may affect circulating monocytes through spill over of soluble mediators and exposure to apoptotic cell debris during passage through the liver. Hence, peripheral monocytes show numerous acquired defects in acute liver failure syndromes that impair their anti-microbial programmes and contribute to enhanced susceptibility to sepsis. This review will highlight the cellular and molecular mechanisms by which monocytes and macrophages contribute to the pathophysiology of ALF and ACLF, considering both hepatic inflammation and systemic immunosuppression. We identify areas for further research and potential targets for immune-based therapies to treat these devastating conditions.

Beyond KCH selection and options in acute liver failure

The King’s prognostic criteria for patients with acute liver failure (ALF) introduced in 1989 have been used worldwide. This distinguished for the first time cases with ‘hyper-acute’ course (characteristically paracetamol overdose) where there is a better chance of recovery with medical supportive care alone from those etiologies with a less acute course and paradoxically lower chances of ‘spontaneous’ recovery. Ongoing use showed the limited sensitivity of the criteria to constitute a significant practical limitation. Subsequent models including the MELD score and composite ones with markers of necrosis, an apoptotic liver cell death, proposed to improve sensitivity did not have the required high specificity. Two recent models utilizing new availability of web- and app-based computing delivering outcome predication through sophisticated algorithms are described. The first is a dynamic model described for paracetamol-induced ALF based upon admission findings and sequential variables over the first 2 days. The new model of the US Acute Liver Failure group was devised to cover all etiologies of ALF for predicting ‘transplant-free’ survival and accurately predicated spontaneous survival in two-thirds of cases. Improved survival results with medical management, particularly in hyper-acute cases, now approach those obtained with successful liver transplant and have raised the question of transplant benefit. Also considered in the review are new non-transplant approaches to treatment including the use of plasma exchange and based on successful results in acute-on-chronic liver failure, agents to modulate and improve hepatic regeneration.

Development of an organ failure score in acute liver failure for transplant selection and identification of patients at high risk of futility

INTRODUCTION

King's College Hospital criteria are currently used to select liver transplant candidates in acetaminophen-related acute liver failure (ALF). Although widely accepted, they show a poor sensitivity in predicting pre-transplant mortality and cannot predict the outcome after surgery. In this study we aimed to develop a new prognostic score that can allow patient selection for liver transplantation more appropriately and identify patients at high risk of futile transplantation.

METHODS

We analysed consecutive patients admitted to the Royal Free and Beaujon Hospitals between 1990 and 2015. Clinical and laboratory data at admission were collected. Predictors of 3-month mortality in the non-transplanted patients admitted to the Royal Free Hospital were used to develop the new score, which was then validated against the Beaujon cohort. The Beaujon-transplanted group was also used to assess the ability of the new score in identifying patients at high risk of transplant futility.

RESULTS

152 patients were included of who 44 were transplanted. SOFA, CLIF-C OF and CLIF-ACLF scores were the best predictors of 3-month mortality among non-transplanted patients. CLIF-C OF score and high dosages of norepinephrine requirement were the only significant predictors of 3-month mortality in the non-transplanted patients, and therefore were included in the ALF-OFs score. In non-transplanted patients, ALF-OFs showed good performance in both exploratory (AUC = 0.89; sensitivity = 82.6%; specificity = 89.5%) and the validation cohort (AUC = 0.988; sensitivity = 100%; specificity = 92.3%). ALF-OFs score was also able to identify patients at high risk of transplant futility (AUC = 0.917; sensitivity = 100%; specificity = 79.2%).

CONCLUSION

ALF-OFs is a new prognostic score in acetaminophen-related ALF that can predict both the need for liver transplant and high risk of transplant futility, improving candidate selection for liver transplantation.

Increased Expression of Cytotoxic T-Lymphocyte-Associated Protein 4 by T Cells, Induced by B7 in Sera, Reduces Adaptive Immunity in Patients With Acute Liver Failure

BACKGROUND & AIMS

Patients with acute liver failure (ALF) have defects in innate immune responses to microbes (immune paresis) and are susceptible to sepsis. Cytotoxic T-lymphocyte-associated protein 4 (CTLA4), which interacts with the membrane receptor B7 (also called CD80 and CD86), is a negative regulator of T-cell activation. We collected T cells from patients with ALF and investigated whether inhibitory signals down-regulate adaptive immune responses in patients with ALF.

METHODS

We collected peripheral blood mononuclear cells from patients with ALF and controls from September 2013 through September 2015 (45 patients with ALF, 20 patients with acute-on-chronic liver failure, 15 patients with cirrhosis with no evidence of acute decompensation, 20 patients with septic shock but no cirrhosis or liver disease, and 20 healthy individuals). Circulating CD4⁺ T cells were isolated and analyzed by flow cytometry. CD4⁺ T cells were incubated with antigen, or agonist to CD3 and dendritic cells, with or without antibody against CTLA4; T-cell proliferation and protein expression were quantified. We measured levels of soluble B7 molecules in supernatants of isolated primary hepatocytes, hepatic sinusoidal endothelial cells, and biliary epithelial cells from healthy or diseased liver tissues. We also measured levels of soluble B7 serum samples from patients and controls, and mice with acetaminophen-induced liver injury using enzyme-linked immunosorbent assays.

RESULTS

Peripheral blood samples from patients with ALF had a higher proportion of CD4⁺ CTLA4⁺ T cells than controls; patients with infections had the highest proportions. CD4⁺ T cells from patients with ALF had a reduced proliferative response to antigen or CD3 stimulation compared to cells from controls; incubation of CD4⁺ T cells from patients with ALF with an antibody against CTLA4 increased their proliferative response to antigen and to CD3 stimulation, to the same levels as cells from controls. CD4⁺ T cells from controls up-regulated expression of CTLA4 after 24-48 hours culture with sera from patients with ALF; these sera were found to have increased concentrations of soluble B7 compared to sera from controls. Necrotic human primary hepatocytes exposed to acetaminophen, but not hepatic sinusoidal endothelial cells and biliary epithelial cells from patients with ALF, secreted high levels of soluble B7. Sera from mice with acetaminophen-induced liver injury contained high levels of soluble B7 compared to sera from mice without liver injury. Plasma exchange reduced circulating levels of soluble B7 in patients with ALF and expression of CTLA4 on T cells.

CONCLUSIONS

Peripheral CD4⁺ T cells from patients with ALF have increased expression of CTLA4 compared to individuals without ALF; these cells have a reduced response to antigen and CD3 stimulation. We found sera of patients with ALF and from mice with liver injury to have high concentrations of soluble B7, which up-regulates CTLA4 expression by T cells and reduces their response to antigen. Plasma exchange reduces levels of B7 in sera from patients with ALF and might be used to restore antimicrobial responses to patients.

EASL Clinical Practical Guidelines on the management of acute (fulminant) liver failure

The term acute liver failure (ALF) is frequently applied as a generic expression to describe patients presenting with or developing an acute episode of liver dysfunction. In the context of hepatological practice, however, ALF refers to a highly specific and rare syndrome, characterised by an acute abnormality of liver blood tests in an individual without underlying chronic liver disease. The disease process is associated with development of a coagulopathy of liver aetiology, and clinically apparent altered level of consciousness due to hepatic encephalopathy. Several important measures are immediately necessary when the patient presents for medical attention. These, as well as additional clinical procedures will be the subject of these clinical practice guidelines.

The value of blood lactate kinetics in critically ill patients: a systematic review

BACKGROUND

The time course of blood lactate levels could be helpful to assess a patient's response to therapy. Although the focus of published studies has been largely on septic patients, many other studies have reported serial blood lactate levels in different groups of acutely ill patients.

METHODS

We performed a systematic search of PubMed, Science Direct, and Embase until the end of February 2016 plus reference lists of relevant publications. We selected all observational and interventional studies that evaluated the capacity of serial blood lactate concentrations to predict outcome. There was no restriction based on language. We excluded studies in pediatric populations, experimental studies, and studies that did not report changes in lactate values or all-cause mortality rates. We separated studies according to the type of patients included. We collected data on the number of patients, timing of lactate measurements, minimum lactate level needed for inclusion if present, and suggested time interval for predictive use.

RESULTS

A total of 96 studies met our criteria: 14 in general ICU populations, five in general surgical ICU populations, five in patients post cardiac surgery, 14 in trauma patients, 39 in patients with sepsis, four in patients with cardiogenic shock, eight in patients after cardiac arrest, three in patients with respiratory failure, and four in other conditions. A decrease in lactate levels over time was consistently associated with lower mortality rates in all subgroups of patients. Most studies reported changes over 6, 12 or 24 hrs, fewer used shorter time intervals. Lactate kinetics did not appear very different in patients with sepsis and other types of patients. A few studies suggested that therapy could be guided by these measurements.

CONCLUSIONS

The observation of a better outcome associated with decreasing blood lactate concentrations was consistent throughout the clinical studies, and was not limited to septic patients. In all groups, the changes are relatively slow, so that lactate measurements every 1-2 hrs are probably sufficient in most acute conditions. The value of lactate kinetics appears to be valid regardless of the initial value.

Acute Liver Failure: Diagnosis and Management

Acute liver failure is life threatening liver injury with coagulopathy and hepatic encephalopathy within 26 weeks and generally, in the absence of preexisting liver disease. Fulminant liver failure occurs when hepatic encephalopathy occurs within 8 weeks of jaundice. The majority of patients with ALF are women with the median age of 38 years. In the United States, drug induced liver injury including acetaminophen causes the majority of ALF cases. The etiology of ALF should be determined, if possible, because many causes have a specific treatment. The mainstay for ALF is supportive care and liver transplantation, if necessary. There are multiple prognostic criteria available. Prognosis can be poor and patients should be referred to a liver transplantation center as soon as possible.

Acute liver failure in dogs and cats

OBJECTIVE

To define acute liver failure (ALF), review the human and veterinary literature, and discuss the etiologies and current concepts in diagnostic and treatment options for ALF in veterinary and human medicine.

ETIOLOGY

In veterinary medicine ALF is most commonly caused by hepatotoxin exposure, infectious agents, inflammatory diseases, trauma, and hypoxic injury.

DIAGNOSIS

A patient may be deemed to be in ALF when there is a progression of acute liver injury with no known previous hepatic disease, the development of hepatic encephalopathy of any grade that occurs within 8 weeks after the onset of hyperbilirubinemia (defined as plasma bilirubin >50 μM/L [>2.9 mg/dL]), and the presence of a coagulopathy. Diagnostic testing to more specifically characterize liver dysfunction or pathology is usually required.

THERAPY

Supportive care to aid the failing liver and compensate for the lost functions of the liver remains the cornerstone of care of patients with ALF. Advanced therapeutic options such as extracorporeal liver assist devices and transplantation are currently available in human medicine.

PROGNOSIS

The prognosis for ALF depends upon the etiology, the degree of liver damage, and the response to therapy. In veterinary medicine, the prognosis is generally poor.

Assessment of preload and fluid responsiveness in intensive care unit. How good are we?

Early recognition and treatment of acute circulatory failure and tissue hypoperfusion are paramount for improving the odds of survival in critically ill patients. Fluid volume resuscitation is the mainstay intervention in redistributive and hypovolemic shock. Correct identification of a patient who would benefit from fluid administration allows optimization of hemodynamics and avoids ineffective or even deleterious volume expansion that may result in worsening of gas exchange and pulmonary edema in fluid unresponsive patients, in whom inotropic and/or vasopressor support should preferentially be used. The use of dynamic changes in central venous pressure, pulse pressure, and echocardiography for assessment of inferior vena cava diameter variations during respiration allows prediction of fluid volume responsiveness in hemodynamically unstable patients. The use of these bedside approaches and passive leg raising maneuver, which is a reversible and quick fluid volume challenge, allows timely formulation of treatment strategy in patients with shock.

Effects of antimicrobial prophylaxis and blood stream infections in patients with acute liver failure: a retrospective cohort study

BACKGROUND & AIMS

We investigated whether antimicrobial prophylaxis alters the incidence of bloodstream infection in patients with acute liver failure (ALF), and whether bloodstream infections affect overall mortality within 21 days after development of ALF.

METHODS

We performed a retrospective cohort analysis of 1551 patients with ALF enrolled by the US Acute Liver Failure Study Group from January 1998 through November 2009. We analyzed data on infections in the first 7 days after admission and the effects of prophylaxis with antimicrobial drugs on the development of bloodstream infections and 21-day mortality.

RESULTS

In our study population, 600 patients (39%) received antimicrobial prophylaxis and 226 patients (14.6%) developed at least 1 bloodstream infection. Exposure to antimicrobial drugs did not affect the proportion of patients who developed bloodstream infections (12.8% in patients with prophylaxis vs 15.7% in nonprophylaxed patients; P = .12), but a greater percentage of patients who received prophylaxis received liver transplants (28% vs 22%; P = .01). After adjusting for confounding factors, overall mortality within 21 days was associated independently with age (odds ratio [OR], 1.014), Model for End-stage Liver Disease score at admission (OR, 1.078), and vasopressor administration at admission (OR, 2.499). Low grade of coma (OR, 0.47) and liver transplantation (OR, 0.101) reduced mortality. Although bloodstream infection was associated significantly with 21-day mortality (P = .004), an interaction between bloodstream infection and etiology was detected: blood stream infection affected mortality to a greater extent in nonacetaminophen ALF patients (OR, 2.03) than in acetaminophen ALF patients (OR, 1.14).

CONCLUSIONS

Based on a large, observational study, antimicrobial prophylaxis does not reduce the incidence of bloodstream infection or mortality within 21 days of ALF. However, bloodstream infections were associated with increased 21-day mortality in patients with ALF-to a greater extent in patients without than with acetaminophen-associated ALF. Our findings do not support the routine use of antimicrobial prophylaxis in patients with ALF.

Effects of antimicrobial prophylaxis and blood stream infections in patients with acute liver failure: a retrospective cohort study

BACKGROUND & AIMS

We investigated whether antimicrobial prophylaxis alters the incidence of bloodstream infection in patients with acute liver failure (ALF), and whether bloodstream infections affect overall mortality within 21 days after development of ALF.

METHODS

We performed a retrospective cohort analysis of 1551 patients with ALF enrolled by the US Acute Liver Failure Study Group from January 1998 through November 2009. We analyzed data on infections in the first 7 days after admission and the effects of prophylaxis with antimicrobial drugs on the development of bloodstream infections and 21-day mortality.

RESULTS

In our study population, 600 patients (39%) received antimicrobial prophylaxis and 226 patients (14.6%) developed at least 1 bloodstream infection. Exposure to antimicrobial drugs did not affect the proportion of patients who developed bloodstream infections (12.8% in patients with prophylaxis vs 15.7% in nonprophylaxed patients; P = .12), but a greater percentage of patients who received prophylaxis received liver transplants (28% vs 22%; P = .01). After adjusting for confounding factors, overall mortality within 21 days was associated independently with age (odds ratio [OR], 1.014), Model for End-stage Liver Disease score at admission (OR, 1.078), and vasopressor administration at admission (OR, 2.499). Low grade of coma (OR, 0.47) and liver transplantation (OR, 0.101) reduced mortality. Although bloodstream infection was associated significantly with 21-day mortality (P = .004), an interaction between bloodstream infection and etiology was detected: blood stream infection affected mortality to a greater extent in nonacetaminophen ALF patients (OR, 2.03) than in acetaminophen ALF patients (OR, 1.14).

CONCLUSIONS

Based on a large, observational study, antimicrobial prophylaxis does not reduce the incidence of bloodstream infection or mortality within 21 days of ALF. However, bloodstream infections were associated with increased 21-day mortality in patients with ALF-to a greater extent in patients without than with acetaminophen-associated ALF. Our findings do not support the routine use of antimicrobial prophylaxis in patients with ALF.

Modulation of monocyte/macrophage function: a therapeutic strategy in the treatment of acute liver failure

Acute liver failure (ALF) is a condition with a high mortality and morbidity for which new treatments are desperately required. We contend that although the initial event in ALF is liver cell death, the clinical syndrome of ALF and its complications including multi-organ dysfunction and sepsis, are largely generated by the immune response to liver injury. Hepatic macrophages fulfil a diversity of roles in ALF, from pro-inflammatory to pro-resolution. Their inherent plasticity means the same macrophages may have a variety of functions depending on the local tissue environment at different stages of disease. A better understanding of the mechanisms that regulate macrophage plasticity during ALF will be an essential step towards realising the potential of immune-modulating therapies that re-orientate macrophages to promote the desirable functions of attenuating liver injury and promoting liver repair/regenerative responses. The key dynamics: temporal (early vs. late phase), regional (hepatic vs. systemic), and activation (pro-inflammatory vs. pro-resolution) are discussed and the potential for novel ALF therapies that modulate monocyte/macrophage function are described.

Thymosinβ4: a novel assessed biomarker of the prognosis of acute-on-chronic liver failure patient?

BACKGROUND AND AIM

In the previous study, we found serum thymosin β4 (Tβ4) levels were associated with mortality in liver failure patients. In this study, we try to evaluate the prognostic value of Tβ4 in acute-on-chronic liver failure (AoCLF) patients by comparing with the Child-Pugh (CTP) and Model for End-Stage Liver Disease (MELD) scores.

METHODS

Serum Tβ4 levels were measured by enzyme-linked immunosorbent assay (ELISA), and the CTP and MELD scores were calculated for each patient.

RESULTS

Serum Tβ4 levels of AoCLF patients [0.4120 (0.2447-0.7492)μg/mL] were lower than healthy controls [9.2710 (5.1660-13.2485)μg/mL] (P<0.001). AoCLF patients were divided into survival and death group. Compared to survivors, lower Tβ4 concentrations, higher CTP and MELD scores (P<0.001, respectively) were observed in AoCLF patients who died. There were negative correlations between Tβ4 levels and CTP scores (P<0.001), MELD scores (P<0.001). A CTP score of 11.5, a MELD score of 21.63 and a Tβ4 concentration of 0.3840μg/mL were identified as the cut-off values for the stratification of AoCLF patients. MELD≥21.63 combined with Tβ4<0.3840μg/mL can more exactly discriminate between the patients who would survive and die.

CONCLUSIONS

Serum Tβ4 concentration has appreciable value to evaluate the short-term prognosis of AoCLF patients, although Tβ4 is not superior to MELD. The combination of Tβ4 and MELD scores are more effective in assessing the prognosis of AoCLF patients.

Timing and benefit of liver transplantation in acute liver failure

The case for using emergency liver transplantation in acute liver failure was made two decades ago by a series of single centre experiences. The development of models identifying a poor prognosis assisted the selection of patients for liver transplantation but none of these delivers both high sensitivity and specificity for prediction of death. Enhanced sensitivity favours the individual patient while enhanced specificity targets the pool of organs available at those who will derive greatest benefit. The non-transplant survival rates have improved considerably for certain cohorts of patients and these prognostic models have not been adjusted to reflect these changes. The presumption of transplant benefit can no longer be taken as established in paracetamol-related acute liver failure and a policy review is appropriate. In other scenarios, such as seronegative hepatitis and the phenotype of sub-acute liver failure, spontaneous survival rates remain low and the basis for liver transplantation remains sound. Outcomes after liver transplantation are improving but are not yet comparable to elective transplantation. The understanding of factors associated with failure after liver transplantation is improving but accurate definition of futility has not yet been attained.

Acute liver failure

Untreated acute liver failure (ALF) has a poor outcome and so rapid diagnosis and management is vital if the patient is to survive. ALF has such profound and widespread physiological consequences that whenever possible, patients with ALF should be managed in an intensive care unit. Management is to support the physiology and treat the underlying cause. Advice should be sought from a centre capable of performing liver transplantation. Should recovery seem unlikely, liver transplantation is a viable treatment option in some cases.

Role of toll-like receptor 4 in mediating multiorgan dysfunction in mice with acetaminophen induced acute liver failure

Strategies for the prevention of multiorgan dysfunction (MOD) in acetaminophen (APAP)-induced acute liver failure (ALF) are an unmet need. Our study tested the hypothesis that sterile inflammation induced by APAP in a mouse model would activate toll-like receptor 4 (TLR4) in the liver and extrahepatic organs and lead to the progression of ALF and MOD and that the administration of the novel TLR4 antagonist STM28 (a peptide formed of 17 amino-acids) would prevent liver injury and associated MOD. ALF and, subsequently, MOD were induced in TLR4-knockout (KO) mice (B6.B10ScN-Tlr4 (lpsdel) /JthJ) and wild-type (WT) mice (C57BL/6) with APAP (500 mg/kg). A second set of experiments was conducted to evaluate the effects of a pretreatment with a novel TLR4 antagonist, STM28, on APAP-induced MOD in CD1 mice. Animals were sacrificed at the coma stage, and plasma, peripheral blood cells, liver, kidneys, and brain were collected. Biochemistry values and cytokines were measured. Liver and kidneys were studied histologically and were stained for TLR4 and activated Kupffer cells, and the expression of nuclear factor kappa B-p65 was quantified with western blotting. Brain water was measured in the frontal cortex. After APAP administration, TLR4-KO (NFkBp65) mice were relatively protected from liver necrosis and end-organ dysfunction and had significantly better survival than WT controls (P < 0.01). STM28 attenuated liver injury and necrosis, reduced creatinine levels, and delayed the time to a coma significantly. The increases in cytokines in the plasma and liver, including TLR4 expression and the activation of Kupffer cells, after APAP administration were reduced significantly in the STM28-treated animals. The increased number of circulating myeloid cells was reduced significantly after STM28 treatment. In conclusion, these data provide evidence for an important role of the TLR4 antagonist in the prevention of the progression of APAP-induced ALF and MOD.

Fulminant viral hepatitis

Acute liver failure (ALF) is a condition wherein the previously healthy liver rapidly deteriorates, resulting in jaundice, encephalopathy, and coagulopathy. There are approximately 2000 cases per year of ALF in the United States. Viral causes (fulminant viral hepatitis [FVH]) are the predominant cause of ALF in developing countries. Given the ease of spread of viral hepatitis and the high morbidity and mortality associated with ALF, a systematic approach to the diagnosis and treatment of FVH is required. In this review, the authors describe the viral causes of ALF and review the intensive care unit management of patients with FVH.

Factors associated with outcome in acute liver failure in an intensive care unit

AIM

To study the factors associated with outcome in acute liver failure (ALF) in an intensive care unit (ICU).

METHODS

Consecutive patients with ALF admitted to the ICU from August 2003 to April 2010 were included. Factors associated with the primary outcome, death or survival, were compared.

RESULTS

Of 52 patients of median age 19 years (range 3-65), 35 (67 %) died. The etiology was viral hepatitis in 66 %, drug induced (anti-tubercular therapy) in 15 % and idiopathic in 15 %. Grades III+IV encephalopathy were found in 12 (70.6 %) survivors as against 33 (94.3 %) nonsurvivors (p = 0.019). The median admission sequential organ failure assessment (SOFA) score was eight in survivors vs. 12 in nonsurvivors (p < 0.001). Median admission prothrombin time (PT) was 42 s in survivors vs. 51 in nonsurvivors (p = 0.384); 16/17 (94.1 %) survivors had normal PT on day 4 as compared to 7/35 (20 %) nonsurvivors (p < 0.001). Median PT on day 4 was 18 s in survivors against 37 in nonsurvivors (p < 0.001). Serum bilirubin, alanine aminotransferase; and serum creatinine, sodium and phosphorus were similar in survivors and nonsurvivors. Mechanical ventilation, vasopressors and dialysis were used in 65 %, 30 %, and 12 % survivors as against 100 % (p < 0.001), 51 % and 26 % nonsurvivors. Sixteen patients had upper gastrointestinal (GI) bleed. Blood cultures were positive more often in nonsurvivors (p = 0.058). On multiple regression analysis, factors independently associated with outcome included admission SOFA score >9.5 and absolute value of PT on day 4.

CONCLUSIONS

Grades III and IV encephalopathy, higher SOFA score at admission and a prolonged PT which did not normalize by 4 days were associated with mortality in ALF.

Myocardial involvement during ischemia-induced acute liver failure in the pig

OBJECTIVE

The objective of this experimental study was to investigate a possible myocardial involvement in acute liver failure.

MATERIALS AND METHODS

A porcine model of acute liver failure induced by hepatic devascularization was used. Twenty animals were allocated to the Acute Liver Failure (ALF) or Control Group (CG). Serum cardiac troponin I (cTnI), MB isoenzyme of creatine kinase (CK-MB), and also hemodynamic variables were measured and compared before surgery (T1), at 4 hr (T2), and at 7 hr (T3) after the end of surgery.

RESULTS

Data from 10 pigs in the ALF and 7 in the CG were analyzed. In the ALF group, cTnI increased from 0.3 ± 0.055 to 0.35 ± 0.696 and 0.39 ± 0.06 ng/ml at T1, T2, and T3 time points, respectively (p < .001). In the CG, cTnI was not significantly changed from 0.29 ± 0.07, to 0.31 ± 0.01, and 0.31 ± 0.11 ng/ml at T1, T2, and T3 time points, respectively (p = .895). A statistically significant difference was found in cTnI between the groups at T3 (z = -2.93, p = .002). CK-MB increased significantly in both groups: in ALF group, CK-MB changed from 3.43 ± 0.53 to 4.33 ± 0.73 and 7.14 ± 1.12 ng/ml at T1, T2, and T3 time points, respectively (p < .001). In the CG, CK-MB changed from 3.6 ± 0.597 to 4.6 ± 1.07 and 6.2 ± 1.17 ng/ml at T1, T2, and T3 time points, respectively, (p = .001). Mean arterial pressure (MAP) was significantly reduced in the ALF group.

CONCLUSIONS

In a porcine model of acute liver failure, a significant increase of cTnI serum levels was found, indicating that a subclinical myocardial damage may occur as a result of heart involvement in the multiple organ dysfunction.

Prediction of poor outcome in patients with acute liver failure-systematic review of prediction models

INTRODUCTION

Acute liver failure is a rare disease with high mortality and liver transplantation is the only life saving therapy. Accurate prognosis of ALF is crucial for proper intervention.

AIM

To identify and characterize newly developed prognostic models of mortality for ALF patients, assess study quality, identify important variables and provide recommendations for the development of improved models in the future.

METHODS

The online databases MEDLINE® (1950-2012) and EMBASE® (1980-2012) were searched for English-language articles that reported original data from clinical trials or observational studies on prognostic models in ALF patients. Studies were included if they developed a new model or modified existing prognostic models. The studies were evaluated based on an existing framework for scoring the methodological and reporting quality of prognostic models.

RESULTS

Twenty studies were included, of which 18 reported on newly developed models, 1 on modification of the Kings College Criteria (KCC) and 1 on the Model for End-Stage Liver Disease (MELD). Ten studies compared the newly developed models to previously existing models (e.g. KCC); they all reported that the new models were superior. In the 12-point methodological quality score, only one study scored full points. On the 38-point reporting score, no study scored full points. There was a general lack of reporting on missing values. In addition, none of the studies used performance measures for calibration and accuracy (e.g. Hosmer-Lemeshow statistics, Brier score), and only 5 studies used the AUC as a measure of discrimination.

CONCLUSIONS

There are many studies on prognostic models for ALF but they show methodological and reporting limitations. Future studies could be improved by better reporting and handling of missing data, the inclusion of model calibration aspects, use of absolute risk measures, explicit considerations for variable selection, the use of a more extensive set of reference models and more thorough validation.

Prediction of outcome and selection of the liver transplantat candidate in acute liver failure

Acute liver failure (ALF) is characterized by a sudden and severe deterioration of liver function, typically mirrored by a marked increase of the international normalized ratio (INR) and hepatic encephalopathy (HE). Due to various possible causes hepatocytes get damaged via either apoptotic or necrotic pathways. Anticipating the natural prognosis of a patient with ALF is one of the most challenging tasks in hepatology critical care. Important factors that influence the chance of spontaneous recovery are the underlying etiology of acute liver failure, the acuity of disease, and the severity of HE. Once an estimation of the prognosis in the individual patient has been made, this quickly has to be integrated in the discussion whether high-urgency liver transplantation is necessary and justifiable. This decision has to cover several medical, social, and organizational issues. Well organized liver transplantation programs around the world have achieved an impressive improvement of the 1 year survival rate in ALF from around 40% without transplantation up to nearly 80% with transplantation. The recent debate on whether severe acute alcoholic hepatitis could represent a new candidate eligible for high-urgency liver transplantation shows that the topic is still open for discussion.

Use of serial measurements of peritoneal fluid lactate concentration to identify strangulating intestinal lesions in referred horses with signs of colic

OBJECTIVE

To determine the value of serial measurements of peritoneal fluid lactate concentration (PFL) for detecting strangulating intestinal lesions (SLs) in referred horses with signs of colic.

DESIGN

Retrospective cohort study.

ANIMALS

94 horses with signs of colic.

PROCEDURES

Medical records of horses evaluated between September 2006 and February 2010 because of signs of colic were reviewed. All included horses had ≥ 2 peritoneal fluid samples collected, including one at admission and another within 1 to 6 hours after admission. Of the 94 horses, 26 were assigned to the SL group on the basis of findings at surgery or necropsy and 68 were assigned to the nonstrangulating intestinal lesion group because their signs of colic resolved with medical management. Peritoneal fluid lactate concentration was measured by use of a handheld lactate monitor. Data were analyzed by use of univariable and multivariable logistic regression analysis.

RESULTS

PFL at admission > 4 mmol/L, an increase in PFL over time, and especially an increase in PFL over time in horses with a PFL < 4 mmol/L at admission (OR, 62; sensitivity, 95%; specificity, 77%) were significant predictors of horses with an SL.

CONCLUSIONS AND CLINICAL RELEVANCE

Serially determined PFL was a strong predictor for differentiating horses with SLs from horses with nonstrangulating intestinal lesions. Given the high OR, sensitivity, and specificity of these tests, serially determined PFL may have potential as a screening test for identifying horses with SLs. Further evaluation of the clinical value of PFL for predicting SLs in a prospective, multicenter study is warranted.

Systematic review: acute liver failure - one disease, more than 40 definitions

BACKGROUND

Acute liver failure (ALF) is a clinical syndrome with very high mortality estimates ranging between 60% and 80%.

AIM

To investigate the explicitness and extent of variability in the used ALF definitions in the ALF prognostic literature.

METHODS

All studies that pertain to the prognosis of patients with ALF were electronically searched in MEDLINE (1950-2012) and EMBASE (1950-2012). Identified titles and abstracts were independently screened by three reviewers to determine eligibility for additional review. We included English articles that reported original data from clinical trials or observational studies on ALF patients.

RESULTS

A total of 103 studies were included. Of these studies 87 used 41 different ALF definitions and the remaining 16 studies did not report any explicit ALF definition. Four components underlying ALF definitions accounted for the differences: presence and/or grading of hepatic encephalopathy (HE); the interval between onset of disease and occurrence of HE; presence of coagulopathy and pre-existing liver disease.

CONCLUSIONS

The diversity in acute liver failure definitions hinders comparability and quantitative analysis among studies. There is room for improvement in the reporting of acute liver failure definitions in prognostic studies. The result of this review may be useful as a starting point to create a uniform acute liver failure definition.

Staggered overdose pattern and delay to hospital presentation are associated with adverse outcomes following paracetamol-induced hepatotoxicity

AIMS

Paracetamol (acetaminophen) poisoning remains the major cause of severe acute hepatotoxicity in the UK. In this large single centre cohort study we examined the clinical impact of staggered overdoses and delayed presentation following paracetamol overdose.

RESULTS

Between 1992 and 2008, 663 patients were admitted with paracetamol-induced severe liver injury, of whom 161 (24.3%) had taken a staggered overdose. Staggered overdose patients were significantly older and more likely to abuse alcohol than single time point overdose patients. Relief of pain (58.2%) was the commonest rationale for repeated supratherapeutic ingestion. Despite lower total ingested paracetamol doses and lower admission serum alanine aminotransferase concentrations, staggered overdose patients were more likely to be encephalopathic on admission, require renal replacement therapy or mechanical ventilation and had higher mortality rates compared with single time point overdoses (37.3% vs. 27.8%, P= 0.025), although this overdose pattern did not independently predict death. The King's College poor prognostic criteria had reduced sensitivity (77.6, 95% CI 70.8, 81.5) for this pattern of overdose. Of the 396/450 (88.0%) single time point overdoses in whom accurate timings could be obtained, 178 (44.9%) presented to medical services >24 h following overdose. Delayed presentation beyond 24 h post overdose was independently associated with death/liver transplantation (OR 2.25, 95% CI 1.23, 4.12, P= 0.009).

CONCLUSIONS

Both delayed presentation and staggered overdose pattern are associated with adverse outcomes following paracetamol overdose. These patients are at increased risk of developing multi-organ failure and should be considered for early transfer to specialist liver centres.

Comparison of the sequential organ failure assessment score with the King's College Hospital criteria and the model for end-stage liver disease score for the prognosis of acetaminophen-induced acute liver failure

Acetaminophen-induced acute liver failure (ALF) is a complex multiorgan illness. An assessment of the prognosis is essential for the accurate identification of patients for whom survival without liver transplantation (LT) is unlikely. The aims of this study were the comparison of prognostic models [King's College Hospital (KCH), Model for End-Stage Liver Disease, Sequential Organ Failure Assessment (SOFA), and Acute Physiology and Chronic Health Evaluation II (APACHE II)] and the identification of independent prognostic indicators of outcome. We evaluated consecutive patients with severe acetaminophen-induced ALF who were admitted to the intensive care unit. At admission, demographic, clinical, and laboratory parameters were recorded. The discriminative ability of each prognostic score at the baseline was evaluated with the area under the receiver operating characteristic curve (AUC). In addition, using a multiple logistic regression, we assessed independent factors associated with outcome. In all, 125 consecutive patients with acetaminophen-induced ALF were evaluated: 67 patients (54%) survived with conservative medical management (group 1), and 58 patients (46%) either died without LT (28%) or underwent LT (18%; group 2). Group 1 patients had significantly lower median APACHE II (10 versus 14) and SOFA scores (9 versus 12) than group 2 patients (P < 0.001). The independent indicators associated with death or LT were a longer prothrombin time (P = 0.007), the inspiratory oxygen concentration (P = 0.005), and the lactate level at 12 hours (P < 0.001). The KCH criteria had the highest specificity (83%) but the lowest sensitivity (47%), and the SOFA score had the best discriminative ability (AUC = 0.79). In conclusion, for patients with acetaminophen-induced ALF, the SOFA score performed better than the other prognostic scores, and this reflected the presence of multiorgan dysfunction. A further evaluation of SOFA with the KCH criteria is warranted.

The sequential organ failure assessment (SOFA) score is prognostically superior to the model for end-stage liver disease (MELD) and MELD variants following paracetamol (acetaminophen) overdose

BACKGROUND

The prognostic value of the model for end-stage liver disease (MELD) and sodium-based MELD variants in predicting survival following paracetamol overdose remains unclear.

AIM

To examine the prognostic accuracy of sodium-based MELD variants in paracetamol-induced acute liver injury compared with the sequential organ failure assessment (SOFA) score.

METHODS

Retrospective analysis of 138 single time point paracetamol overdoses admitted to a tertiary liver centre. Individual laboratory samples were correlated with the corresponding clinical parameters in relation to time post-overdose, and the daily MELD, MELD-Na, MELDNa, MESO, iMELD, UKELD, updated MELD and SOFA scores were calculated.

RESULTS

Sixty-six (47.8%) patients developed hepatic encephalopathy, of whom 7 were transplanted and 21 died without liver transplantation. SOFA had a significantly greater area under the receiver operator characteristic for the prediction of spontaneous survival compared with MELD at both 72 (P = 0.024) and 96 (P = 0.017) h post-overdose. None of the sodium-based MELD variants improved the prognostic accuracy of MELD. A SOFA score >6 by 72 h or >7 by 96 h, post-overdose predicted death/transplantation with a negative predictive value of 96.9 (95% CI 90.2-99.4) and 98.8 (95% CI 93.6-99.9) respectively. SOFA and MELD had similar accuracy for predicting the development of hepatic encephalopathy (P = 0.493).

CONCLUSIONS

The SOFA score is superior to MELD in predicting spontaneous survival following paracetamol-induced acute liver injury. Modification of the MELD score to include serum sodium does not improve prognostic accuracy in this setting. SOFA may have potential as a quantitative triage marker following paracetamol overdose.

Liver transplantation for acute liver failure

Liver transplantation is now an integral part of the management of acute liver failure. The challenge for clinicians is to select the appropriate candidates with a combination of need and high likelihood of benefiting from the transplant. This is achieved through a combination of prognostic modelling and ongoing clinical evaluation. Although the outcomes after liver transplantation are good the survival rates do not quite match those achieved after elective transplantation.

Acute liver failure in neonates, infants and children

Acute liver failure (ALF) is a rare but devastating syndrome. ALF in children differs from that observed in adults in both the etiologic spectrum and the clinical picture. Specific therapy to promote liver recovery is often not available and the underlying cause of the liver failure is often not determined. Management requires a multidisciplinary approach and should focus on preventing or treating complications and arranging for early referral to a transplant center. Although liver transplantation has increased the chance of survival, children who have ALF still face an increased risk of death, both while on the waiting list and after emergency liver transplantation. This article will review the current knowledge of the epidemiology, pathobiology and treatment of ALF in neonates, infants and children, and discuss some recent controversies.

Brain energy metabolism and mitochondrial dysfunction in acute and chronic hepatic encephalopathy

One proposed mechanism for acute and chronic hepatic encephalopathy (HE) is a disturbance in cerebral energy metabolism. It also reviews the current status of this mechanism in both acute and chronic HE, as well as in other hyperammonemic disorders. It also reviews abnormalities in glycolysis, lactate metabolism, citric acid cycle, and oxidative phosphorylation as well as associated energy impairment. Additionally, the role of mitochondrial permeability transition (mPT), a recently established factor in the pathogenesis of HE and hyperammonemia, is emphasized. Energy failure appears to be an important pathogenetic component of both acute and chronic HE and a potential target for therapy.

Acute liver failure

PURPOSE OF REVIEW

Acute liver failure (ALF) results in a multitude of serious complications that often lead to multi-organ failure. This brief review focuses on the pathophysiological processes in ALF and how to manage these.

RECENT FINDINGS

The clinical presentation in ALF ranges from slightly altered conscious level with profound coagulopathy to coma with a catastrophic failure of multiple organs, including uncontrollable cerebral edema and brain death, which is rarely seen in decompensated cirrhosis. Interestingly, ALF patients who recover as the liver is regenerating, usually do not suffer from hepatic or extrahepatic sequelae. In contrast patients surviving acute-on-chronic liver failure will return to a state with incompensated cirrhosis, and eventually need transplantation for survival.In the management of ALF, the use of noradrenalin in combination with continuous high-dose renal replacement therapy, terlipressin, hypertonic sodium chloride, and mannitol can ameliorate systemic vasodilation and attenuate brain edema. Furthermore, liver assist devices seem to improve extrahepatic organ dysfunction and survival.

SUMMARY

Insight into the of pathopysiological mechanisms of ALF that lead to cardiovascular instability, brain edema and development of multiorgan failure has advanced and resulted in improved survival. The role of liver assisting is still unknown but preliminary results indicate a positive effect on survival.

The systemic inflammatory response syndrome and sequential organ failure assessment scores are effective triage markers following paracetamol (acetaminophen) overdose

BACKGROUND

The systemic inflammatory response syndrome (SIRS) and sequential organ failure assessment (SOFA) scores are widely used as prognostic markers in critical care settings and could improve triage of high-risk paracetamol (acetaminophen) overdose patients.

AIM

To evaluate the prognostic accuracy of the SIRS and SOFA scores following single time point paracetamol overdose.

METHODS

Analysis of 100 single time point paracetamol overdoses admitted to a tertiary liver centre, with subsequent prospective validation of identified thresholds. Individual laboratory samples were correlated with the corresponding clinical parameters in relation to time post-overdose, and the daily SOFA and SIRS scores calculated.

RESULTS

A total of 74 (74%) patients developed the SIRS, which occurred significantly earlier in patients who died (n=21) compared with spontaneous survivors (n=53, P=0.05). The SIRS occurred in 70 (70%) patients by 96h post-overdose, with a 30% mortality rate; compared with 0% mortality in the 30 non-SIRS patients (P=0.001). Median SOFA scores were significantly higher in nonsurvivors at 48 (P=0.009), 72 (P<0.001), and 96h (P<0.001). A SOFA score >7 during the first 96h post-overdose predicted death/transplantation with a sensitivity of 95.0 (95% CI 78.5-99.1) and specificity of 70.5 (95% CI 66.3-71.6). A validation cohort of 38 single time point paracetamol overdoses confirmed the extremely high negative predictive value of both the SIRS and SOFA thresholds.

CONCLUSIONS

The absence of either a SOFA score >7 or a SIRS response during the first 96 h following paracetamol overdose could improve triage and reduce transfers of lower risk patients to tertiary liver centres.