Acetylcysteine treatment for non-acetaminophen-induced acute liver failure

Dengue induced acute liver failure: A meta summary of case reports

BACKGROUND

Dengue fever is the most common cause of viral hemorrhagic fever, with more than 400 million cases being reported annually, worldwide. Even though hepatic involvement is common, acute liver failure (ALF) is a rare complication of dengue fever.

AIM

To analyze the demographic profile, symptomology, hospital course and outcomes of patients presenting with ALF secondary to dengue infection by reviewing the published case reports.

METHODS

A systematic search was performed from multiple databases including PubMed, Reference Citation Analysis, Science Direct, and Google Scholar. The search terms used were "dengue" OR "severe dengue" OR "dengue shock syndrome" OR "dengue haemorrhagic syndrome" OR "dengue fever" AND "acute liver failure" OR "hepatic failure" OR "liver injury". The inclusion criteria were: (1) Case reports or case series with individual patient details; (2) Reported acute liver failure secondary to dengue infection; and (3) Published in English language and on adult humans. The data were extracted for patient demographics, clinical symptomatology, clinical interventions, hospital and intensive care unit course, need for organ support and clinical outcomes.

RESULTS

Data from 19 case reports fulfilling the predefined inclusion criteria were included. The median age of patients was 38 years (inter quartile range: Q3-Q1 26.5 years) with a female preponderance (52.6%). The median days from diagnosis of dengue to development of ALF was 4.5 d. The increase in aspartate aminotransferase was higher than that in alanine aminotransferase (median 4625 U/L vs 3100 U/L). All the patients had one or more organ failure, with neurological failure present in 73.7% cases. 42.1% patients required vasopressor support and hepatic encephalopathy was the most reported complication in 13 (68.4%) cases. Most of the patients were managed conservatively and 2 patients were taken up for liver transplantation. Only 1 death was reported (5.3%).

CONCLUSION

Dengue infection may rarely lead to ALF. These patients may frequently require intensive care and organ support. Even though most of these patients may improve with supportive care, liver transplantation may be a therapeutic option in refractory cases.

Amanitin intoxication: effects of therapies on clinical outcomes - a review of 40 years of reported cases

BACKGROUND AND AIMS

Amanita phalloides poisoning causes severe liver damage which may be potentially fatal. Several treatments are available, but their effectiveness has not been systematically evaluated. We performed a systematic review to investigate the effect of the most commonly used therapies: N-acetylcysteine (NAC), benzylpenicillin (PEN), and silibinin (SIL) on patient outcomes. In addition, other factors contributing to patient outcomes are identified.

METHODS

We searched MEDLINE and Embase for case series and case reports that described patient outcomes after poisoning with amanitin-containing Amanita mushrooms. We extracted clinical characteristics, treatment details, and outcomes. We used the liver item from the Poisoning Severity Score (PSS) to categorize intoxication severity.

RESULTS

We included 131 publications describing a total of 877 unique cases. The overall survival rate of all patients was 84%. Patients receiving only supportive care had a survival rate of 59%. The use of SIL or PEN was associated with a 90% (OR 6.40 [3.14-13.04]) and 89% (OR 5.24 [2.87-9.56]) survival rate, respectively. NAC/SIL combination therapy was associated with 85% survival rate (OR 3.85 [2.04, 7.25]). NAC/PEN/SIL treatment group had a survival rate of 76% (OR 2.11 [1.25, 3.57]). Due to the limited number of cases, the use of NAC alone could not be evaluated. Additional analyses in 'proven cases' (amanitin detected), 'probable cases' (mushroom identified by mycologist), and 'possible cases' (neither amanitin detected nor mushroom identified) showed comparable results, but the results did not reach statistical significance. Transplantation-free survivors had significantly lower peak values of aspartate aminotransferase (AST), alanine aminotransferase (ALT), total serum bilirubin (TSB), and international normalized ratio (INR) compared to liver transplantation survivors and patients with fatal outcomes. Higher peak PSS was associated with increased mortality.

CONCLUSION

Based on data available, no statistical differences could be observed for the effects of NAC, PEN or SIL in proven poisonings with amanitin-containing mushrooms. However, monotherapy with SIL or PEN and combination therapy with NAC/SIL appear to be associated with higher survival rates compared to supportive care alone. AST, ALT, TSB, and INR values are possible predictors of potentially fatal outcomes.

N-acetylcysteine for non-acetaminophen induced acute liver failure: A review

The use of N-acetylcysteine (NAC) for non-acetaminophen-induced acute liver failure (NAI-ALF) has been increasing despite controversy in its efficacy. National guidelines are in disagreement for NAC use as standard of care; however, many healthcare centers continue to adopt the use of NAC outside of acetaminophen poisoning. While NAC may have multiple mechanisms of action in treatment of ALF, this has not translated to clinical benefit. Murine models have reported antioxidant and anti-inflammatory properties, as well as improvement in liver-specific microcirculation. Multiple case studies and series have reported positive outcomes of NAC treatment for ALF of various etiologies. While prospective studies suggested the benefit of NAC treatment, these studies have methodological and statistical shortcomings that affect the validity of the results. In this review, we aimed to summarize the existing literature on the efficacy of NAC for NAI-ALF including mechanism of action, case studies and series demonstrating outcomes, and prospective studies that have led to its current widespread use, along with the reported rate of adverse events.

Impact of Duration of N-Acetylcysteine in Non-Acetaminophen-Induced Acute Liver Failure

Supplemental Digital Content is available in the text.

OBJECTIVES:

Studies of the use of IV N-acetylcysteine in the management of non-acetaminophen-induced acute liver failure have evaluated various dosing regimens. The only randomized trial studying this application described a 72-hour regimen. However, observational studies have reported extended duration until normalization of international normalized ratio. This study seeks to compare differences in patient outcomes based on IV N-acetylcysteine duration.

DESIGN:

Retrospective cohort study.

SETTING:

Medical ICU at a large quaternary care academic medical institution and liver transplant center.

PATIENTS:

Adult patients admitted to the medical ICU who received IV N-acetylcysteine for the treatment of non-acetaminophen-induced acute liver failure.

INTERVENTIONS:

Patients were divided into cohorts based on duration; standard duration of IV N-acetylcysteine was considered 72 hours, whereas extended duration was defined as continuation beyond 72 hours.

MEASUREMENTS AND MAIN RESULTS:

The primary outcome was time to normalization of international normalized ratio to less than 1.3 or less than 1.5; secondary outcomes included all-cause mortality and transplant-free survival at 3 weeks. In total, 53 patients were included: 40 in the standard duration cohort and 13 in the extended duration. There were no major differences in baseline characteristics. There was no significant difference in time to international normalized ratio normalization between cohorts. Transplant-free survival was higher with extended duration (76.9% extended vs 41.4% standard; p = 0.03). All-cause mortality at 3 weeks was numerically lower in the extended duration group (0% extended vs 24.1% standard; p = 0.08).

CONCLUSIONS:

Patients with non-acetaminophen-induced acute liver failure who received extended duration N-acetylcysteine were found to have significantly higher transplant-free survival than patients who received standard duration, although there was no significant difference in time to normalization of international normalized ratio or overall survival. Prospective, randomized, multicenter study is warranted to identify subpopulations of patients with non-acetaminophen-induced acute liver failure who could benefit from extended treatment duration as a bridge to transplant or spontaneous recovery.

Atypical Manifestations of Dengue Fever in Children

Objective The burden of dengue fever (DF) is increasing rapidly worldwide. Several atypical manifestations of DF are being increasingly reported but there are no clear guidelines on their definition and management. Their timely detection and appropriate management might improve outcomes. We describe here our experience in managing atypical manifestations of DF in children and their outcomes in a teaching hospital in South India.

Methods A retrospective chart review of children (1 month–18 years) hospitalized, between August 2017 and March 2018 with a diagnosis of DF (NS1 antigen or immunoglobulin M antibodies positivity), was done. The clinical details of the atypical manifestations are described.

Results During the study period, 925 children were hospitalized with DF, of which 94 (10.16%) had severe dengue and 2 (0.21%) died. Among the 925 children, 7 (0.75%) had cardiac, 5 (0.54%) had neurological, 5 (0.54%) had hepatic, and 31 (3.3%) had immunological (infection-associated immune dysregulation) manifestations.

Conclusion Most children with atypical manifestations of DF recover with supportive management. There is a need for a clear definition of atypical manifestations so that large prospective multicenter studies on incidence, optimum management, and outcomes can be done.

N-acetylcysteine for non-paracetamol (acetaminophen)-related acute liver failure

BACKGROUND

Acute liver failure is a rare and serious disease. Acute liver failure may be paracetamol-induced or non-paracetamol-induced. Acute liver failure not caused by paracetamol (acetaminophen) has a poor prognosis with limited treatment options. N-acetylcysteine has been successful in treating paracetamol-induced acute liver failure and reduces the risk of needing to undergo liver transplantation. Recent randomised clinical trials have explored whether the benefit can be extrapolated to treat non-paracetamol-related acute liver failure. The American Association for the Study of Liver Diseases (AASLD) 2011 guideline suggested that N-acetylcysteine could improve spontaneous survival when given during early encephalopathy stages for patients with non-paracetamol-related acute liver failure.

OBJECTIVES

To assess the benefits and harms of N-acetylcysteine compared with placebo or no N-acetylcysteine, as an adjunct to usual care, in people with non-paracetamol-related acute liver failure.

SEARCH METHODS

We searched the Cochrane Hepato-Biliary Group Controlled Trials Register (searched 25 June 2020), Cochrane Central Register of Controlled Trials (CENTRAL; 2020, Issue 6) in The Cochrane Library, MEDLINE Ovid (1946 to 25 June 2020), Embase Ovid (1974 to 25 June 2020), Latin American and Caribbean Health Science Information database (LILACS) (1982 to 25 June 2020), Science Citation Index Expanded (1900 to 25 June 2020), and Conference Proceedings Citation Index - Science (1990 to 25 June 2020).

SELECTION CRITERIA

We included randomised clinical trials that compared N-acetylcysteine at any dose or route with placebo or no intervention in participants with non-paracetamol-induced acute liver failure.

DATA COLLECTION AND ANALYSIS

We used standard methodological procedures as described in the Cochrane Handbook for Systematic Reviews of Interventions. We conducted meta-analyses and presented results using risk ratios (RR) with 95% confidence intervals (CIs). We quantified statistical heterogeneity by calculating I². We assessed bias using the Cochrane risk of bias tool and determined the certainty of the evidence using the GRADE approach.

MAIN RESULTS

We included two randomised clinical trials: one with 183 adults and one with 174 children (birth through age 17 years). We classified both trials at overall high risk of bias. One unregistered study in adults is awaiting classification while we are awaiting responses from study authors for details on trial methodology (e.g. randomisation processes). We did not meta-analyse all-cause mortality because of significant clinical heterogeneity in the two trials. For all-cause mortality at 21 days between adults receiving N-acetylcysteine versus placebo, there was inconclusive evidence of effect (N-acetylcysteine 24/81 (29.6%) versus placebo 31/92 (33.7%); RR 0.88, 95% CI 0.57 to 1.37; low certainty evidence). The certainty of the evidence was low due to risk of bias and imprecision. Similarly, for all-cause mortality at one year between children receiving N-acetylcysteine versus placebo, there was inconclusive evidence of effect (25/92 (27.2%) versus 17/92 (18.5%); RR 1.47, 95% CI 0.85 to 2.53; low certainty evidence). We downgraded the certainty of evidence due to very serious imprecision.  We did not meta-analyse serious adverse events and liver transplantation at one year due to incomplete reporting and clinical heterogeneity. For liver transplantation at 21 days in the trial with adults, there was inconclusive evidence of effect (RR 0.72, 95% CI 0.49 to 1.06; low certainty evidence). We downgraded the certainty of the evidence due to serious risk of bias and imprecision. For liver transplantation at one year in the trial with children, there was inconclusive evidence of effect (RR 1.23, 95% CI 0.84 to 1.81; low certainty of evidence). We downgraded the certainty of the evidence due to very serious imprecision.   There was inconclusive evidence of effect on serious adverse events in the trial with children (RR 1.25, 95% CI 0.35 to 4.51; low certainty evidence). We downgraded the certainty of the evidence due to very serious imprecision.  We did not meta-analyse non-serious adverse events due to clinical heterogeneity. There was inconclusive evidence of effect on non-serious adverse events in adults (RR 1.07, 95% CI 0.79 to 1.45; 173 participants; low certainty of evidence) and children (RR 1.19, 95% CI 0.62 to 2.16; 184 participants; low certainty of evidence). None of the trials reported outcomes of proportion of participants with resolution of encephalopathy and coagulopathy or health-related quality of life. The National Institute of Health in the United States funded both trials through grants. One of the trials received additional funding from two hospital foundations' grants. Pharmaceutical companies provided the study drug and matching placebo, but they did not have input into study design nor involvement in analysis.

AUTHORS' CONCLUSIONS

The available evidence is inconclusive regarding the effect of N-acetylcysteine compared with placebo or no N-acetylcysteine, as an adjunct to usual care, on mortality or transplant rate in non-paracetamol-induced acute liver failure. Current evidence does not support the guideline suggestion to use N-acetylcysteine in adults with non-paracetamol-related acute liver failure, nor the rising use observed in clinical practice. The uncertainty based on current scanty evidence warrants additional randomised clinical trials with non-paracetamol-related acute liver failure evaluating N-acetylcysteine versus placebo, as well as investigations to identify predictors of response and the optimal N-acetylcysteine dose and duration.

Acute liver failure and death predictors in patients with dengue-induced severe hepatitis

BACKGROUND

Liver injury in patients with dengue infection is common. Most patients have mild and transient hepatitis. Acute liver failure (ALF) in dengue infection is rare but results in an extremely poor prognosis.

AIM

To identify prognostic predictors of ALF and death in patients with dengue-induced severe hepatitis (DISH).

METHODS

We retrospectively reviewed 2311 serologically confirmed adolescent and adult dengue patients who were hospitalized during a 12-year study period (between 2007 and 2019) at the university hospital of King Chulalongkorn Memorial Hospital, Bangkok, Thailand. Patients with DISH [n = 134 (5.80%)], defined as a baseline transaminase > 10 times the normal reference cut-off level, and DISH with subsequent ALF as defined by the American Association for the Study of the Liver Diseases 2011 criteria [n = 17 (0.74%)], were included. Predictors of ALF and in-hospital death were identified using logistic regression analysis.

RESULTS

Of the 151 dengue-infected patients with severe liver injury or ALF, 51% were female, with a mean age of 27.9 ± 14.5 years. Capillary leakage syndrome (CLS) occurred in 68.2% (n = 103) of DISH and 100% of ALF patients. The mortality rate was low in DISH patients (0.8%) but was remarkably high if ALF developed (58.8%). In univariate analysis, age, sex, hematocrit, white blood count, atypical lymphocyte count, platelet count, international normalized ratio (INR), bilirubin, serum glutamate-oxaloacetate transaminase, serum glutamate-pyruvate transaminase, alkaline phosphatase, albumin, creatinine, Model for End-Stage Liver Disease (MELD) score, presence of liver comorbidity and presence of CLS were identified as potential prognostic parameters for ALF or death. In multivariate analysis, the MELD score remained the only predictor of ALF with an adjusted odds ratio (aOR) of 1.3 [95% confidence interval (CI): 1.1-1.5; P = < 0.001]. An initial MELD score ≥ 15 was associated with ALF from DISH with an area under the receiver operating characteristic (AUROC) of 0.91, 88.2% sensitivity and 87.3% specificity. Regarding mortality prediction, the deterioration of liver function to ALF was the most significant factor related to death in DISH patients (aOR 108.5, 95%CI: 5.5-2145.4, P = 0.002). Other independent factors associated with death included baseline INR (aOR 10.4, 95%CI: 2.6-40.5, P = 0.001). An INR ≥ 1.5 predicted death from DISH with an AUROC of 0.83 (81.8% sensitivity and 86.8% specificity).

CONCLUSION

The MELD score is the best predictor of ALF in DISH patients, a complication from dengue that is associated with high mortality. The presence of ALF and the baseline INR level are independent markers of death in DISH patients.

Possible role for acetylcysteine as a treatment for acute liver failure secondary to antitubercular medication use

PURPOSE

Drug-induced liver injury (DILI) that progresses to acute liver failure (ALF) has a high mortality rate, and therapeutic options are limited. Acetylcysteine has a labeled indication for use as an antidote for acetaminophen toxicity and has also been used with limited success in treatment of non-acetaminophen-induced liver injury, with small clinical trials indicating an increase in transplant-free survival. Recommendations for management of non-acetaminophen-induced DILI include withdrawal of the offending agent and supportive care. Treatment guidelines generally discourage a rechallenge with an offending medication, except in cases where there are no other therapeutic options for management of a serious disease, such as active tuberculosis (TB).

SUMMARY

This case report describes the reversal of ALF due to DILI in a patient receiving antitubercular agents for active TB. After withdrawal of initially prescribed antitubercular agents, the patient was switched to a less hepatotoxic anti-TB regimen and intravenous acetylcysteine pending results of antimicrobial susceptibility testing. After stabilization of the patient's liver enzyme levels, intravenous acetylcysteine was discontinued and oral acetylcysteine was continued for 5 days without an increase in hepatic enzyme levels or clinical deterioration. After 5 days, oral acetylcysteine was discontinued due to patient-reported nausea and vomiting.

CONCLUSION

Given the limited number of therapeutic interventions shown to be beneficial in ALF and data suggesting a protective effect against DILI with initiation of acetylcysteine at the start of treatment with anti-TB medications, acetylcysteine can be considered for patients with anti-TB - associated DILI.

Systematic comparison of routine laboratory measurements with in-hospital mortality: ICU-Labome, a large cohort study of critically ill patients

BACKGROUND

In intensive care unit (ICU) patients, many laboratory measurements can be deranged when compared with the standard reference interval (RI). The assumption that larger derangements are associated with worse outcome may not always be correct. The ICU-Labome study systematically evaluated the univariate association of routine laboratory measurements with outcome.

METHODS

We studied the 35 most frequent blood-based measurements in adults admitted ≥6 h to our ICU between 1992 and 2013. Measurements were from the first 14 ICU days and before ICU admission. Various metrics, including variability, were related with hospital survival. ICU- based RIs were derived from measurements obtained at ICU discharge in patients who were not readmitted to the ICU and survived for >1 year.

RESULTS

In 49,464 patients (cardiothoracic surgery 43%), we assessed >20·106 measurements. ICU readmissions, in-hospital and 1-year mortality were 13%, 14% and 19%, respectively. On ICU admission, lactate had the strongest relation with hospital mortality. Variability was independently related with hospital mortality in 30 of 35 measurements, and 16 of 35 measurements displayed a U-shaped outcome-relation. Medians of 14 of 35 ICU-based ranges were outside the standard RI. Remarkably, γ-glutamyltransferase (GGT) had a paradoxical relation with hospital mortality in the second ICU week because more abnormal GGT-levels were observed in hospital survivors.

CONCLUSIONS

ICU-based RIs for may be more useful than standard RIs in identifying ICU patients at risk. The association of variability with outcome for most of the measurements suggests this is a consequence and not a cause of a worse ICU outcome. Late elevation of GGT may confer protection to ICU patients.

Acute Hepatitis in Infections Caused by Dengue Virus in Southern Punjab, Pakistan

Background

Dengue is the most common vector-borne disease worldwide. It poses a significant health burden in tropical and subtropical countries. Common clinical presentations include retro-orbital pain, fever, headache, nausea, vomiting and aches and pains in the body. A severe form of dengue fever is known as dengue hemorrhagic fever (DHF) that includes signs of hemorrhage. Besides the typical signs and symptoms, atypical presentations of dengue include myositis, hepatitis and encephalitis. Hepatic involvement in dengue has varied presentations. This study aims to highlight the importance of acute hepatitis, an atypical presentation in dengue patients.

Methods 

We conducted a descriptive, cross-sectional study in the Medical Unit-1 of Bahawal Victoria Hospital, Bahawalpur, a tertiary-care hospital serving the area of Southern Punjab, Pakistan. The relevant medical records of 63 patients admitted with dengue-associated hepatitis to the Medical Unit-1 of Bahawal Victoria Hospital, Bahawalpur, between January 1, 2015 and December 1, 2016, were reviewed. Informed consent was given. Information regarding demographic variables and disease course was collected and analyzed.

Results 

This study included 55 men (87.3%) and eight (12.7%) women. Fifty (79.3%) patients were diagnosed with dengue fever (DF). Thirteen patients were managed on the lines of DHF. Out of the total 63 patients, only six were locals. The common clinical presentations in these patients included high fever, retro-orbital pain, severe headache, rash, dark-colored urine, bleeding problems and hepatomegaly. Higher levels of aspartate aminotransferase (AST) were noted in comparison to alanine transferase (ALT). Despite the complicated clinical course in some patients, all patients were managed successfully and discharged, except one.

Conclusion

The frequency of acute hepatitis in dengue patients is high, especially in young men. Early diagnosis and prompt treatment are necessary for better prognosis. Although no specific treatment guidelines are available, supportive treatment in a timely fashion can prevent complications. Transfusion with packed cell volume (PCV) and N-acetyl cysteine (NAC) has produced promising results.

Series of 10 dengue fever cases with unusual presentations and complications in Sri Lanka: a single centre experience in 2016

Background

Dengue has global importance as a dreaded arboviral infection. It has 4 serotypes of epidemiological imporatnce. The classification denotes two clinical spectrums- dengue fever (DF) and dengue haemorragic fever (DHF). Most cases are stereotype and amenable to fluid resuscitation. However, unusual manifestations cause fatalities and often overlooked. This study describes 10 such dengue cases to fill the knowledge gaps.

Case presentation

All 10 patients presented to the Teaching Hospital, Peradeniya, Sri Lanka during mid-year epidemic of dengue in 2016. The mean age is 27 years (range 12-51 years) comprising 6 females and 4 males. The group had 7 DHF, 3 DF and 2 primary dengue infections who predominantly had severe bleeding into gut. Other potentially life threatening problems were acute severe hepatitis, severe septic shock, myocarditis, erratic rapid plasma leak, intracranial bleeding, diarrhoea and decompenstaed dengue shock due to 3rd space fluid leak. Blood transfusions and other empirical therapeutic methods were used apart from meticulous fluid management to suit issues of each patient. Bedside ultrasound scanning helped early detection of critical phase. All recovered fully.

Conclusions

Dengue is an extremely challenging infection to treat in the globe today. Above unusual presentation and complications could be fatal, if not detected early where therapeutic window period is very short. Clinicians need awareness of these problems which are not uncommon, but underreported and often overlooked. The clinical management of each patient was described for the purpose sharing the experiences.

The Role of Acetyl Cysteine in Cocaethylene (Non-Acetaminophen) Acute Liver Failure

Background

Acute liver failure can result from acetaminophen overdose, viral infection, toxins, and other disease conditions. Liver transplant is available in limited fashion and the criteria are strict as to who should get an available liver. N- Acetyl Cysteine (NAC) has been used in non-acetaminophen induced liver failure with success. Here we report a case of acute liver failure from cocaethylene that was reversed with NAC along with other medical therapy.

Case Presentation

A 50-year-old female patient presented to the Emergency Department (ED) with a two-day history of coffee ground vomiting and hematemesis. She reported occasional substance abuse and heavy alcoholism. She reported shortness of breath and chest pain from the recurrent forceful vomiting. The rest of the review of systems was unremarkable except a fall from intoxication. Physical examination revealed anicteric conjunctiva and nontender abdomen and her vital signs were within normal limits. Initial blood work revealed acute liver and renal failure. The patient was started with general medical management and liver transplant service rejected the case due to active substance abuse. She underwent brief hemodialysis and was started on NAC. Over the course of her hospital stay her liver function and kidney function improved significantly and patient was discharged to home.

Conclusion

In cases where liver transplant is not an option for various reasons including active substance abuse, a trial of N-Acetyl Cysteine may be beneficial and should be considered in the Emergency Department.

N-acetylcysteine ethyl ester as GSH enhancer in human primary endothelial cells: A comparative study with other drugs

Several drugs are currently in use as glutathione (GSH) enhancers in clinical, pre-clinical and experimental research. Here we compare the ability of N-acetylcysteine (NAC), 2-oxothiazolidine-4-carboxylic acid (OTC), glutathione ethyl ester (GSH-EE) and N-acetylcysteine ethyl ester (NACET) to increase the intracellular concentration of GSH using primary human umbilical vein endothelial cells (HUVEC) as in vitro model. Our experiments highlighted that NACET is largely the most efficient molecule in increasing the intracellular levels of GSH, cysteine, and γ-glutamylcysteine. This is because NACET is lipophilic and can freely cross plasma membrane but, inside the cell, it is de-esterified to the more hydrophilic NAC, which, in turn, is trapped into the cell and slowly transformed into cysteine. The higher availability of cysteine is matched by an increase in GSH synthesis, cysteine availability being the rate limiting step for this reaction. Surprisingly, the increase in GSH concentration was not linear but peaked at 0.5 mM NACET and gradually decreased when cells were treated with higher concentrations of NACET. We demonstrated that this puzzling ceiling effect was due to the fact that NAC released from NACET turned out to be a competitive inhibitor of the enzyme glutamate-cysteine ligase, with a Ki value of 3.2 mM. By using a cell culture medium lacking of cysteine and methionine, we could demonstrate that the slight increase in intracellular levels of cysteine and GSH induced by NAC in HUVEC grown in standard medium was due to the reduction of the cystine present in the medium itself there rather than to the action of NAC as Cys pro-drug. This fact may explain why NAC works well as GSH enhancer at very high concentrations in pre-clinical and in vitro studies, whereas it failed in most clinical trials.

Lessons learnt from managing a case of dengue hemorrhagic fever complicated with acute liver failure and acute kidney injury: a case report

Background

Dengue is a common arboviral infection with a diverse spectrum of clinical manifestations. Dengue hemorrhagic fever is a more severe form of infection characterized by plasma leak and hemoconcentration. Although hepatic dysfunction is common in dengue illness, massive liver necrosis is rarely reported. Lactic acidosis is a poor prognostic marker in liver failure related to dengue. Management of acute renal injury in dengue hemorrhagic fever due to prolonged shock is challenging as the fluid reabsorption during the recovery phase expands the intravascular volume and precipitates heart failure and pulmonary edema.

Case presentation

We report the case of a 43-year-old Sri Lankan Sinhalese woman with serologically confirmed dengue fever presenting with evidence of plasma leakage developing acute liver failure evidenced by deranged liver functions, coagulopathy, and altered sensorium and acute kidney injury with anuria. She had elevated serum lactate levels. In addition to the “standard care,” she was managed with intravenously administered N-acetyl cysteine and blood transfusions, even in the absence of bleeding or dropping packed cell volume, targeting a higher packed cell volume anticipating a better oxygenation at tissue level. Continuous veno-venous hemodialysis was employed and continued for 138 hours removing the fluids reabsorbed during the recovery phase to prevent her from developing heart failure and pulmonary edema. She made full recovery with no sequelae.

Conclusions

N-acetyl cysteine and packed cell transfusion aiming at a higher packed cell volume to maintain adequate tissue perfusion during shock may be beneficial in acute liver failure due to dengue virus. The use of a continuous form of renal replacement such as continuous veno-venous hemodialysis is of paramount importance in managing fluid states in the recovery phase of dengue hemorrhagic fever in those with renal impairment. Interesting observations made in the fluid dynamics during the reabsorption phase need further studies preferably with an animal model.

Dengue hemorrhagic fever complicated with acute liver failure: a case report

Background

Dengue is a common arboviral infection with a clinically diverse spectrum of presentations. Although hepatic dysfunction is commonly identified in patients will dengue illness, acute liver failure is rare. The etiopathogenesis of hepatic dysfunction is multifactorial and related to direct viral invasion of hepatocytes, immunological factors and hypoxia particularly in cases of shock in dengue hemorrhagic fever. Ideal management of dengue-related hepatic dysfunction and acute liver failure is still debated.

Case presentation

We report a 53-year-old Sri Lankan Sinhalese male with serologically confirmed dengue fever presenting with evidence of plasma leakage developing acute liver failure evidenced by deranged liver functions, coagulopathy and altered sensorium. In addition to the ‘standard care’, the patient was managed with intravenous N-acetyl cysteine and blood transfusions even in the absence of bleeding or dropping packed cell volume (PCV), targeting a higher PCV in anticipation of better oxygenation at tissue level. He made a full recovery with no sequential infections.

Conclusion

N-acetyl cysteine and packed cell transfusion aiming at a higher PCV to maintain adequate tissue perfusion during shock may be beneficial in acute liver failure due to dengue virus. Large randomized trials should be carried out to establish the efficacy of these treatment strategies to support these observations and change the current practice.

Severe mushroom poisoning in one Macedonian family

BACKGROUND

Collecting and consuming wild mushrooms is a historical tradition in many European countries, including The Republic of Macedonia. This activity is predominantly performed in the period between June and October, when the weather is warm and humidity in the air and soil is at higher levels.The Amanita genus consists of 500 different species of mushrooms; among these, Amanita phaloides, Amanita virosa and Amanita verna are most commonly found in oak forests in our country. These species are highly poisonous and because they can be similar to some edible mushrooms, they have often been misidentified. Their consumption causes severe intoxication.

PURPOSE

The aim of this case series report is to demonstrate a severe poisoning with Amanita mushrooms (A. verna) that occurred in 8 patients, all from 1 Macedonian family.

RESULTS

We show the differences in the clinical appearance and status of these patients, the wide spectrum of symptoms as well as the treatment and outcome of this rare poisoning. One patient, an 8-month-old baby, was excluded from the study because the infant was immediately transferred to the pediatric clinic after admission to our clinic.

CONCLUSIONS

Despite modern therapy, poisoning due to ingestion of Amanita mushrooms is a serious clinical and health problem that may even be potentially lethal. The most efficient way for the general public to protect itself against potential poisoning is to avoid ingesting mushrooms that may not be edible.

Wild mushroom poisoning in north India: case series with review of literature

Mushroom is an important constituent of diet in many ethnic tribes in India. Ethnic Indian tribes are known to consume nearly 283 species of wild mushrooms out of 2000 species recorded world over. Although they are experts in distinguishing the poisonous from edible mushrooms, yet occasional cases of toxicity are reported due to accidental consumption of poisonous mushrooms. We report amanita like toxicity in a family after consumption of wild mushrooms resulting in fatal outcome.

Intravenous acetylcysteine for indications other than acetaminophen overdose

PURPOSE

The use of intravenous acetylcysteine for off-label indications, specifically non-acetaminophen-induced acute liver failure (NAI-ALF), severe alcoholic hepatitis, and contrast-induced nephropathy (CIN), is reviewed.

SUMMARY

I.V. acetylcysteine is most often used as an antidote for acetaminophen overdose due to its ability to increase levels of glutathione; however, it is also used to treat NAI-ALF and severe alcoholic hepatitis and to prevent CIN. Although the i.v. and oral formulations of acetylcysteine have been evaluated for these indications, most studies have examined the i.v. form. I.V. acetylcysteine is used in the treatment of NAI-ALF to improve oxygenation to the liver. One large randomized trial of 173 adults with NAI-ALF from any etiology and of any grade encephalopathy demonstrated overall improvement in transplant-free survival, particularly for patients with low-grade encephalopathy, though overall survival was not improved. When used to treat severe alcoholic hepatitis, i.v. acetylcysteine serves as an antioxidant and glutathione source. A trial of 174 patients with severe alcoholic hepatitis revealed that patients had 28-day survival benefit when treated with acetylcysteine; improvement in patients with hepatorenal syndrome was also noted. When used for the prevention of CIN, i.v. acetylcysteine provides antioxidants and vasodilation. The benefit for this indication is limited to surrogate markers such as serum creatinine and in patients with multiple risk factors for the development of CIN.

CONCLUSION

Data regarding the use of i.v. acetylcysteine for the treatment of NAI-ALF and severe alcoholic hepatitis and in the prevention of CIN are inconclusive, though some evidence supports its use in certain populations.

N-acetylcystein in dengue associated severe hepatitis

Although, N-acetylcystein (NAC) has shown benefit in non-acetaminophen related liver failure, it was not well studies in dengue associated severe hepatitis. We report a case of dengue hemorrhagic fever associated severe hepatitis (encephalopathy grade 2-drowsy and intermittent disorientation) treated with NAC resulted in good outcome without hepatic transplantation.

Intravenous N-acetylcysteine in pediatric patients with nonacetaminophen acute liver failure: a placebo-controlled clinical trial

N-acetylcysteine (NAC) was found to improve transplantation-free survival in only those adults with nonacetaminophen (non-APAP) acute liver failure (ALF) and grade 1-2 hepatic encephalopathy (HE). Because non-APAP ALF differs significantly between children and adults, the Pediatric Acute Liver Failure (PALF) Study Group evaluated NAC in non-APAP PALF. Children from birth through age 17 years with non-APAP ALF enrolled in the PALF registry were eligible to enter an adaptively allocated, doubly masked, placebo-controlled trial using a continuous intravenous infusion of NAC (150 mg/kg/day in 5% dextrose in water [D5W]) or placebo (D5W) for up to 7 days. The primary outcome was 1-year survival. Secondary outcomes included liver transplantation-free survival, liver transplantation (LTx), length of intensive care unit (ICU) and hospital stays, organ system failure, and maximum HE score. A total of 184 participants were enrolled in the trial with 92 in each arm. The 1-year survival did not differ significantly (P = 0.19) between the NAC (73%) and placebo (82%) treatment groups. The 1-year LTx-free survival was significantly lower (P = 0.03) in those who received NAC (35%) than those who received placebo (53%), particularly, but not significantly so, among those less than 2 years old with HE grade 0-1 (NAC 25%; placebo 60%; P = 0.0493). There were no significant differences between treatment arms for hospital or ICU length of stay, organ systems failing, or highest recorded grade of HE.

CONCLUSION

NAC did not improve 1-year survival in non-APAP PALF. One-year LTx-free survival was significantly lower with NAC, particularly among those <2 years old. These results do not support broad use of NAC in non-APAP PALF and emphasizes the importance of conducting controlled pediatric drug trials, regardless of results in adults.

[Acute liver failure after bariatric surgery. A case report and literature review]

Non-alcoholic fatty liver disease is common among morbidly obese people. Bariatric surgery is increasingly used in this population to control weight but is not free of risks. We present the case of a 28-year-old morbidly obese woman who underwent gastroplasty with intestinal resection and a gastro-jejunal anastomosis. Eleven months later, and with a weight reduction of 35%, the patient developed acute liver failure. A biopsy showed severe steatohepatitis and fibrosis. After prolonged hospital stay and management that consisted of support measures, nutritional assistance, N-acetyl cysteine, zinc and vitamin E, liver function was restored. A follow-up biopsy showed marked regression of the initial findings. Bariatric surgery has many beneficial effects. However, even with the most up-to-date techniques, complications can occur. Familiarity with these complications is important for their prevention and treatment.

N-acetylcysteine in children with dengue-associated liver failure: a case report

There is no specific treatment for dengue-associated fulminant liver failure. We report a child with dengue-associated fulminant liver failure who was treated successfully with intravenous N-acetylcysteine. A 6-year-old boy was diagnosed with dengue-associated fulminant liver failure. After administration of intravenous N-acetylcysteine, a rapid decrease in liver transaminases and normalization of coagulation profile was observed followed by clinical improvement and favourable outcome despite factors associated with poor prognosis. The use of intravenous N-acetylcysteine is safe and efficient in the treatment of dengue-associated fulminant liver failure, especially in centres when liver transplantation is not readily available.

Acute Liver Failure Caused by Amanita phalloides Poisoning

Mushroom poisoning is a relatively rare cause of acute liver failure (ALF). The present paper analyzes the pathogenesis, clinical features, prognostic indicators, and therapeutic strategies of ALF secondary to ingestion of Amanita phalloides, which represents the most common and deadly cause of mushroom poisoning. Liver damage from Amanita phalloides is related to the amanitins, powerful toxins that inhibit RNA polymerase II resulting in a deficient protein synthesis and cell necrosis. After an asymptomatic lag phase, the clinical picture is characterized by gastrointestinal symptoms, followed by the liver and kidney involvement. Amatoxin poisoning may progress into ALF and eventually death if liver transplantation is not performed. The mortality rate after Amanita phalloides poisoning ranges from 10 to 20%. The management of amatoxin poisoning consists of preliminary medical care, supportive measures, detoxification therapies, and orthotopic liver transplantation. The clinical efficacy of any modality of treatment is difficult to demonstrate since randomized, controlled clinical trials have not been reported. The use of extracorporeal liver assist devices as well as auxiliary liver transplantation may represent additional therapeutic options.

Acute liver failure: current practice and recent advances

ALF is an important cause of liver-related morbidity and mortality. Advances in the management of ICH and SIRS, and cardiorespiratory, metabolic, and renal support have improved the outlook of such patients. Early transfer to a liver transplant center is essential. Routine use of NAC is recommended for patients with early hepatic encephalopathy, irrespective of the etiology. The role of hypothermia remains to be determined. Liver transplantation plays a critical role, particularly for those with advanced encephalopathy. Several detoxification and BAL support systems have been developed to serve as a bridge to transplantation or to spontaneous recovery. However, such systems lack sufficient reliability and efficacy to be applied routinely in clinical practice. Hepatocyte and stem cell transplantation may provide valuable adjunctive therapy in the future.

Critical care management of patients before liver transplantation

The critical care management of patients before liver transplantation is aimed at optimizing hepatic and extrahepatic organ function before the transplant operation, with a goal to favorably influence perioperative and postoperative graft and patient outcomes. Critical illness in liver disease can present in the context of acute liver failure or acute on chronic liver failure. The differing pathophysiologic processes underlying these 2 types of liver failure necessitate specific approaches to their intensive care management. In their extreme presentations, both types of liver failure present as multiorgan system failure; and therefore, the critical care management of these entities requires a systematic multiorgan system approach to address hepatic and extrahepatic organ dysfunction. This review provides a multiorgan system-based description of critical care management of acute liver failure and acute on chronic liver failure before liver transplantation.

N-acetylcysteine attenuates cerebral complications of non-acetaminophen-induced acute liver failure in mice: antioxidant and anti-inflammatory mechanisms

N-acetylcysteine (NAC) is an effective antidote to treat acetaminophen (APAP)-induced acute liver failure (ALF). NAC is hepatoprotective and prevents the neurological complications of ALF, namely hepatic encephalopathy and brain edema. The protective effect of NAC and its mechanisms of action in ALF due to other toxins, however, are still controversial. In the present study, we investigated the effects of NAC in relation to liver pathology, hepatic and cerebral glutathione, plasma ammonia concentrations, progression of encephalopathy, cerebral edema, and plasma proinflammatory cytokines in mice with ALF resulting from azoxymethane (AOM) hepatotoxicity, a well characterized model of toxic liver injury. Male C57BL/6 mice were treated with AOM (100 microg/g; i.p.) or saline and sacrificed at coma stage of encephalopathy in parallel with AOM mice administered NAC (1.2 g/kg; i.p.). AOM administration led to hepatic damage, significant increase in plasma transaminase activity, decreased hepatic glutathione levels and brain GSH/GSSG ratios as well as increased expression of plasma proinflammatory cytokines. NAC treatment of AOM mice led to reduced hepatic damage and improvement in neurological function, normalization of brain and hepatic glutathione levels as well as selective attenuation in expression of plasma proinflammatory cytokines. These findings demonstrate that the beneficial effects of NAC in experimental non-APAP-induced ALF involves both antioxidant and anti-inflammatory mechanisms.

Effect of N-acetylcysteine on the accuracy of the prothrombin time assay of plasma coagulation factor II+VII+X activity in subjects infused with the drug. Influence of time and temperature

OBJECTIVES

The prothrombin time (PT) assay of factor II+VII+X activity is an important predictor of liver damage in paracetamol poisoned patients. It complicates interpretation of results that the antidote, acetylcysteine (NAC) depresses this activity. The aim was to investigate if NAC influences the accuracy of the plasma PT assay.

MATERIALS AND METHODS

The accuracy of Nycotest PT was studied using plasma added NAC in vitro and plasma from subjects infused with NAC. The latter results were compared with those obtained by analysis of PT by CoaguChek S.

RESULTS

Therapeutic NAC concentrations added to plasma in vitro decreased factor II+VII+X activity at 37 degrees C in a time-dependent manner. This effect was quenched at temperatures <24 degrees C. Activity lost at 37 degrees C could partly be recovered by subsequent incubation at 5 or 20 degrees C. Incubation at 37 degrees C prior to assay led to a significant additional depression of factor II+VII+X activity in plasma from subjects infused with NAC during the first 3h of infusion indicating that it contained reactive NAC. The risk that this NAC interfered with the accuracy of the PT assay was considered minimal with samples stored below 24 degrees C. This was supported by similarity of results obtained by analysis of appropriately stored plasma and simultaneously drawn blood by CoaguChek S.

CONCLUSIONS

Residual reactive NAC does not interfere with the accuracy of the PT assay of plasma stored below 24 degrees C, but NAC-induced loss in activity at 37 degrees C may be partly recovered during subsequent storage below 24 degrees C.

Intravenous N-acetylcysteine improves transplant-free survival in early stage non-acetaminophen acute liver failure

BACKGROUND & AIMS

N-acetylcysteine (NAC), an antidote for acetaminophen poisoning, might benefit patients with non-acetaminophen-related acute liver failure.

METHODS

In a prospective, double-blind trial, acute liver failure patients without clinical or historical evidence of acetaminophen overdose were stratified by site and coma grade and assigned randomly to groups that were given NAC or placebo (dextrose) infusion for 72 hours. The primary outcome was overall survival at 3 weeks. Secondary outcomes included transplant-free survival and rate of transplantation.

RESULTS

A total of 173 patients received NAC (n = 81) or placebo (n = 92). Overall survival at 3 weeks was 70% for patients given NAC and 66% for patients given placebo (1-sided P = .283). Transplant-free survival was significantly better for NAC patients (40%) than for those given placebo (27%; 1-sided P = .043). The benefits of transplant-free survival were confined to the 114 patients with coma grades I-II who received NAC (52% compared with 30% for placebo; 1-sided P = .010); transplant-free survival for the 59 patients with coma grades III-IV was 9% in those given NAC and 22% in those given placebo (1-sided P = .912). The transplantation rate was lower in the NAC group but was not significantly different between groups (32% vs 45%; P = .093). Intravenous NAC generally was well tolerated; only nausea and vomiting occurred significantly more frequently in the NAC group (14% vs 4%; P = .031).

CONCLUSIONS

Intravenous NAC improves transplant-free survival in patients with early stage non-acetaminophen-related acute liver failure. Patients with advanced coma grades do not benefit from NAC and typically require emergency liver transplantation.

7 Leverfalen

De lever vervult tal van essentiële functies in het menselijk lichaam, waaronder ontgifting van het bloed en aanmaak van diverse eiwitten en hormonen. Tevens speelt de lever een rol in het afweersysteem. Leverfalen kan omschreven worden als een situatie van onvoldoende werking van de lever bij deze processen. Dit beeld ontstaat wanneer door het verlies van functionele cellen het totale effectieve levervolume beneden een kritische grens komt. In dit hoofdstuk wordt ingegaan op diverse vormen van leverfalen en twee specifieke bij leverfalen voorkomende problemen, namelijk hepatische encefalopathie en verhoogde bloedingsneiging.

Acute liver failure including acetaminophen overdose

Acute liver failure (ALF) is a dramatic, highly unpredictable clinical syndrome defined by the sudden onset of coagulopathy and encephalopathy. Acetaminophen overdose, the leading cause of ALF in the United States, has a 66% chance of recovery with early N-acetylcysteine treatment and supportive care. Cerebral edema and infectious complications are difficult to detect and treat in these patients and may cause irreversible brain damage and multiorgan failure. One-year survival after emergency liver transplantation is 70%, but 20% of listed patients die, highlighting the importance of early referral of patients who have ALF with a poor prognosis to a transplant center.

N-acetylcysteine -- passe-partout or much ado about nothing?

In experimental studies, the old mucolytic agent N-acetylcysteine (NAC) has had beneficial effects in disorders supposedly linked to oxidative stress. Numerous, mainly small clinical trials with variable doses have yielded inconsistent results in a wide variety of diseases. NAC added to the conventional therapy of human immunodeficiency virus infection might be of benefit; in respect of chronic obstructive pulmonary disease, systematic reviews and meta-analyses suggested that prolonged treatment with NAC is efficacious, but a recent multicentre study has questioned this. In a large intervention trial on cancer recurrence, NAC was ineffective. NAC infusions have been widely used in acute hepatic failure but convincing evidence of its benefits is lacking. A preliminary study reported that NAC is effective in preventing radiocontrast-induced nephropathy but thereafter highly mixed results have been published, and even meta-analyses disagree on its efficacy. In intensive care NAC has mostly been a disappointment but recently it has 'given promises' in surgery with cardiopulmonary bypass. NAC therapy is routine only in paracetamol intoxication.

Influence of acetaminophen at therapeutic doses on surrogate markers of severity of acute viral hepatitis

OBJECTIVES

Data on the influence of acetaminophen intake on acute viral hepatitis is scarce, but it could play a role in the worsening of this disease. The aim of this study was to determine whether the intake of acetaminophen at therapeutic doses affects the severity of acute viral hepatitis.

METHODS

This was a prospective study concerning 37 consecutive patients hospitalized for acute viral hepatitis. Acetaminophen consumption and time since last intake were assessed by a questionnaire. Parameters of severity were studied in comparison to time related serum concentrations of acetaminophen.

RESULTS

Patients hospitalized for acute viral hepatitis (18 male, 19 female patients) had a mean age of 29.2 +/- 11.5 years. The causal virus was HAV (n=23), HBV (n=7) and other viruses (n=8). The mean cumulated dose of acetaminophen was 7.7 +/- 5.65 g. The daily dose did not exceed the therapeutic dosage and the mean was 1.95 +/- 0.81 g (1-3 g). Patients who received 7.5 g of acetaminophen or more had a lower prothrombin index 52.4 +/- 30.3% vs 74.2 +/- 17.2% (P=0.039), and a lower factor V 54.7 +/- 33.2% vs 83.3 +/- 19.6% (P=0.033). Prothrombin index and bilirubinemia were negatively correlated with time related plasma acetaminophen concentrations.

CONCLUSIONS

The use of acetaminophen at therapeutic doses was associated with greater alterations of surrogate markers of the severity of acute viral hepatitis especially hepatitis A. This was related to cumulated dosages and correlated to the time related acetaminophen plasma concentrations. Acetaminophen use should be interrupted when acute hepatitis is suspected.

Metabolic insights into the hepatoprotective role of N-acetylcysteine in mouse liver

The hepatoprotective mechanisms of N-acetylcysteine (NAC) in non-acetaminophen-induced liver injury have not been studied in detail. We investigated the possibility that NAC could affect key pathways of hepatocellular metabolism with or without changes in glutathione (GSH) synthesis. Hepatocellular metabolites and high-energy phosphates were quantified from mouse liver extracts by 1H- and 31P-NMR (nuclear magnetic resonance) spectroscopy. 13C-NMR-isotopomer analysis was used to measure [U-13C]glucose metabolism through pyruvate dehydrogenase (PDH) and pyruvate carboxylase (PC). NAC (150-1,200 mg/kg) increased liver concentrations of GSH from 8.60 +/- 0.48 to a maximum of 12.95 +/- 1.03 micromol/g ww, whereas hypotaurine (HTau) concentrations increased from 0.05 +/- 0.02 to 9.95 +/- 1.12 micromol/g ww. The limited capacity of NAC to increase GSH synthesis was attributed to impaired glucose metabolism through PC. However, 300 mg/kg NAC significantly increased the fractional 13C-enrichment in Glu (from 2.08% +/- 0.26% to 4.00% +/- 0.44%) synthesized through PDH, a key enzyme for mitochondrial energy metabolism. This effect could be uncoupled from GSH synthesis and was associated with the prevention of liver injury induced by tert-butylhydroperoxide and 3-nitropropionic acid. In conclusion, NAC (1) has a limited capacity to elevate GSH synthesis; (2) increases HTau formation linearly; and (3) improves mitochondrial tricarboxylic acid (TCA) cycle metabolism by stimulation of carbon flux through PDH. This latter effect is independent of the capacity of NAC to replete GSH stores. These metabolic actions, among other yet unknown effects, are critical for NAC's therapeutic value and should be taken into account when deciding on a wider use of NAC.

Drug-induced liver disease 2004

PURPOSE OF REVIEW

To summarize the salient reviews, studies and case reports and series that dealt with clinical, pathological, methodological, and epidemiological descriptions of drug-induced liver disease in the calendar year 2004.

RECENT FINDINGS

While no new causes of drug-induced liver injury were reported for 2004, several new reports of previously recognized hepatotoxins, including herbal products, were published. These include the antiretroviral drugs for HIV and agents to manage tuberculosis. Acetaminophen (APAP) retained its preeminent position as the leading cause of drug-induced acute liver failure, currently accounting for nearly 50% of cases according to the latest figures from the U.S. Acute Liver Failure Study Group. Not surprisingly, APAP also heads the list of drugs and toxins leading to liver transplantation for acute hepatic failure. Efforts to reduce the number of cases of intentional APAP poisonings by restricting the number of tablets sold at any one time in the UK are ongoing, but the success of the program may be lessening, as was pointed out this year. The use of potentially hepatotoxic medications in patients with underlying liver disease was examined with the statins, and they emerged as a safe class for use in this setting.

SUMMARY

Given the apparent increasing incidence of acute liver failure attributable to APAP in the US, additional efforts are still needed to better define the risks associated with its use and to further reduce the incidence of severe liver injury from this widely used agent.