Hypoxic hepatitis - epidemiology, pathophysiology and clinical management

[Monitoring of liver function in the critically ill]

Liver failure and hepatic dysfunction represent diagnostic and therapeutic challenges for the intensivist. Besides acute liver failure, hypoxic hepatitis, sepsis and (secondary) sclerosing cholangitis may lead to massive liver dysfunction with subsequent multiorgan dysfunction syndrome that limits survival. Among classical laboratory parameters (so-called static liver parameters) liver function tests may help with the diagnosis to allow early treatment or prevention of liver dysfunction. The aim of this article is to present the current aspects of liver function monitoring and to provide guidelines to the intensivist for diagnosing liver dysfunction in the intensive care setting.

Hepatotoxicity of halogenated inhalational anesthetics

Context:

Halogenated inhalational anesthetics are currently the most common drugs used for the induction and maintenance of general anesthesia. Postoperative hepatic injury has been reported after exposure to these agents. Based on much evidence, mechanism of liver toxicity is more likely to be immunoallergic. The objective of this review study was to assess available studies on hepatotoxicity of these anesthetics.

Evidence Acquisition:

We searched PubMed, Google Scholar, Scopus, Index Copernicus, EBSCO and the Cochrane Database using the following keywords: “inhalational Anesthetics” and “liver injury”; “inhalational anesthetics” and “hepatotoxicity”; “volatile anesthetics” and “liver injury”; “volatile anesthetics” and hepatotoxicity for the period of 1966 to 2013. Fifty two studies were included in this work.

Results:

All halogenated inhalational anesthetics are associated with liver injury. Halothane, enflurane, isoflurane and desflurane are metabolized through the metabolic pathway involving cytochrome P-450 2E1 (CYP2E1) and produce trifluoroacetylated components; some of which may be immunogenic. The severity of hepatotoxicity is associated with the degree by which they undergo hepatic metabolism by this cytochrome. However, liver toxicity is highly unlikely from sevoflurane as is not metabolized to trifluoroacetyl compounds.

Conclusions:

Hepatotoxicity of halogenated inhalational anesthetics has been well documented in available literature. Halothane-induced liver injury was extensively acknowledged; however, the next generation halogenated anesthetics have different molecular structures and associated with less hepatotoxicity. Although anesthesia-induced hepatitis is not a common occurrence, we must consider the association between this disorder and the use of halogenated anesthetics.

Preventive effects of dexmedetomidine on the liver in a rat model of acid-induced acute lung injury

The aim of this study was to examine whether dexmedetomidine improves acute liver injury in a rat model. Twenty-eight male Wistar albino rats weighing 300–350 g were allocated randomly to four groups. In group 1, normal saline (NS) was injected into the lungs and rats were allowed to breathe spontaneously. In group 2, rats received standard ventilation (SV) in addition to NS. In group 3, hydrochloric acid was injected into the lungs and rats received SV. In group 4, rats received SV and 100 µg/kg intraperitoneal dexmedetomidine before intratracheal HCl instillation. Blood samples and liver tissue specimens were examined by biochemical, histopathological, and immunohistochemical methods. Acute lung injury (ALI) was found to be associated with increased malondialdehyde (MDA), total oxidant activity (TOA), oxidative stress index (OSI), and decreased total antioxidant capacity (TAC). Significantly decreased MDA, TOA, and OSI levels and significantly increased TAC levels were found with dexmedetomidine injection in group 4 (P < 0.05). The highest histologic injury scores were detected in group 3. Enhanced hepatic vascular endothelial growth factor (VEGF) expression and reduced CD68 expression were found in dexmedetomidine group compared with the group 3. In conclusion, the presented data provide the first evidence that dexmedetomidine has a protective effect on experimental liver injury induced by ALI.

Statin therapy is associated with reduced incidence of hypoxic hepatitis in critically ill patients

BACKGROUND & AIMS

Hypoxic hepatitis (HH) is a frequent and life-threatening complication associated with states of oxygen depletion in critically ill patients. Ischemia and reperfusion contribute to liver injury in HH. Experimental data suggest beneficial effects of statins in hepatic ischemia/reperfusion injury. This study was conducted to investigate whether statin treatment prior to intensive care unit (ICU) admission affects incidence rates and severity of HH.

METHODS

Eight hundred fifty-one patients admitted consecutively to three medical ICUs between December 2008 and December 2009 were prospectively screened for new occurrence of HH within 48 h following ICU admission. Statin treatment prior to ICU admission was assessed. 28-day-, 90-day-, and 1-year-survival as well as new-onset of complications in HH patients were prospectively documented.

RESULTS

Eighty-seven patients (10%) developed HH. Statin treatment prior to ICU admission was significantly associated with decreased incidence of HH within 48 h after ICU admission in the multivariate analysis (adjusted OR=0.42 (95% CI 0.19-0.95); p<0.05). Cardiogenic shock (p<0.001), septic shock (p<0.001) and active alcohol consumption (p<0.01) were identified as independent risk factors for development of HH. 28-day-, 90-day-, and 1-year-mortality rates in HH were 58%, 67%, and 74%, respectively. Statins were associated with improved 28-day-survival in the total study cohort (p<0.05), but did not affect 90-day- and 1-year-mortality, respectively.

CONCLUSIONS

Cardiogenic shock, septic shock, and active alcohol consumption were independent factors predisposing patients to new onset of HH. Statin treatment prior to ICU admission was the only protective factor regarding the new occurrence of HH in critically ill patients.

Advances in sepsis-associated liver dysfunction

Recent studies have revealed liver dysfunction as an early event in sepsis. Sepsis-associated liver dysfunction is mainly resulted from systemic or microcirculatory disturbances, spillovers of bacteria and endotoxin (lipopolysaccharide, LPS), and subsequent activation of inflammatory cytokines as well as mediators. Three main cell types of the liver which contribute to the hepatic response in sepsis are Kupffer cells (KCs), hepatocytes and liver sinusoidal endothelial cells (LSECs). In addition, activated neutrophils, which are also recruited to the liver and produce potentially destructive enzymes and oxygen-free radicals, may further enhance acute liver injury. The clinical manifestations of sepsis-associated liver dysfunction can roughly be divided into two categories: Hypoxic hepatitis and jaundice. The latter is much more frequent in the context of sepsis. Hepatic failure is traditionally considered as a late manifestation of sepsis-induced multiple organ dysfunction syndrome. To date, no specific therapeutics for sepsis-associated liver dysfunction are available. Treatment measure is mainly focused on eradication of the underlying infection and management for severe sepsis. A better understanding of the pathophysiology of liver response in sepsis may lead to further increase in survival rates.

Early diagnosis of sepsis-related hepatic dysfunction and its prognostic impact on survival: a prospective study with the LiMAx test

INTRODUCTION

Liver dysfunction can derive from severe sepsis and might be associated with poor prognosis. However, diagnosis of septic liver dysfunction is challenging due to a lack of appropriate tests. Measurement of maximal liver function capacity (LiMAx test) has been successfully evaluated as a new diagnostic test in liver resection and transplantation. The aim of this study was to evaluate the LiMAx test during sepsis in comparison to biochemical tests and the indocyanin green test (ICG-PDR).

METHODS

We prospectively investigated 28 patients (8 female and 20 male, age range 35 to 80 years) suffering from sepsis on a surgical ICU. All patients received routine resuscitation from septic shock (surgery, fluids, catecholamines, antibiotic drugs). The first LiMAx test and ICG-PDR were carried out within the first 24 hours after onset of septic symptoms, followed by day 2, 5 and 10. Other biochemical parameters and scores determining the severity of illness were measured daily. Clinical outcome parameters were examined after 90 days or at the end of treatment. The population was divided into 2 groups (group A: non-survivors or ICU length of stay (ICU-LOS) >30 days versus group B: survivors and ICU-LOS <30 days) for analysis.

RESULTS

Epidemiological baseline characteristics of both groups were similar. Group A patients had significant lower LiMAx and ICG-PDR values than patients in group B. Determination of ICG-PDR by finger probe failed in 14.3% of tests due to insufficient peripheral pulses. Respiratory, renal and hepatic dysfunction (LiMAx and ICG-PDR) were associated with prolonged ICU-LOS. Only LiMAx <100 μg/kg/h and respiratory dysfunction were associated with increased mortality. For LiMAx <100 μg/kg/h receiver operating characteristic-analysis revealed a 100% sensitivity and 77% specificity for death.

CONCLUSIONS

Sepsis-related hepatic dysfunction can be diagnosed early and effectively by the LiMAx test. The extent of LiMAx impairment is predictive for patient morbidity and mortality. The sensitivity and specificity of the LiMAx test was superior to that of ICG-PDR regarding the prediction of mortality.

Hypoxic liver injury and cholestasis in critically ill patients

PURPOSE OF REVIEW

Liver dysfunction frequently complicates the clinical picture of critical illness and leads to increased morbidity and mortality. The purpose of this review is to characterize the most frequent patterns of liver dysfunction at the intensive care unit, cholestasis and hypoxic liver injury (HLI), and to illustrate its clinical impact on outcome in critically ill patients.

RECENT FINDINGS

Liver dysfunction at the intensive care unit can be divided into two main patterns: cholestatic and HLI, also known as ischemic hepatitis or shock liver. Both hepatic dysfunctions occur frequently and early in critical illness. Major issues are the early recognition and subsequent initiation of therapeutic measures.

SUMMARY

Clinical awareness of the liver not only as a victim, but also as a trigger of multiorgan failure is of central clinical importance. Physicians have to identify the underlying factors that contribute to its development to initiate curative measures as early as possible.

A case of idiopathic anaphylaxis followed by acute liver injury

Idiopathic anaphylaxis is characterized by recurrent anaphylaxis without a known trigger. The coexistence of acute liver injury with idiopathic anaphylaxis is rare, even in cases of severe anaphylaxis such as shock. An unusual case involving repeated episodes of anaphylactic shock accompanied by acute liver injury is described here. A 36-year-old woman who experienced anaphylaxis due to an unknown cause was referred to our hospital because of marked elevations in her liver enzyme levels. After a thorough evaluation to determine the cause of the acute liver injury, viral infection, drug use, and autoimmune hepatitis were excluded. The episodes were accompanied by elevated liver enzymes, which suggested that this was a case of anaphylaxis followed by acute liver injury. The patient will have to use self-injectable epinephrine to prevent future hepatic failure.

Jaundice increases the rate of complications and one-year mortality in patients with hypoxic hepatitis

Hypoxic hepatitis (HH) is the most frequent cause of acute liver injury in critically ill patients. No clinical data exist about new onset of jaundice in patients with HH. This study aimed to evaluate the incidence and clinical effect of jaundice in critically ill patients with HH. Two hundred and six consecutive patients with HH were screened for the development of jaundice during the course of HH. Individuals with preexisting jaundice or liver cirrhosis at the time of admission (n = 31) were excluded from analysis. Jaundice was diagnosed in patients with plasma total bilirubin levels >3 mg/dL. One-year-survival, infections, and cardiopulmonary, gastrointestinal (GI), renal, and hepatic complications were prospectively documented. New onset of jaundice occurred in 63 of 175 patients with HH (36%). In patients who survived the acute event of HH, median duration of jaundice was 6 days (interquartile range, 3-8). Patients who developed jaundice (group 1) needed vasopressor treatment (P < 0.05), renal replacement therapy (P < 0.05), and mechanical ventilation (P < 0.05) more often and had a higher maximal administered dose of norepinephrine (P < 0.05), compared to patients without jaundice (group 2). One-year survival rate was significantly lower in group 1, compared to group 2 (8% versus 25%, respectively; P < 0.05). Occurrence of jaundice was associated with an increased frequency of complications during follow-up (54% in group 1 versus 35% in group 2; P < 0.05). In particular, infections as well as renal and GI complications occurred more frequently in group 1 during follow-up.

CONCLUSION

Jaundice is a common finding during the course of HH. It leads to an increased rate of complications and worse outcome in patients with HH.

Hypoxic hepatitis

Hypoxic hepatitis (HH), an acute liver injury also known as 'ischaemic hepatitis' or 'shock liver', is frequently observed in intensive care units. HH is heralded by a massive but transient rise in serum aminotransferase activities caused by anoxic necrosis of centrilobular liver cells. Cardiac failure, respiratory failure and toxic-septic shock are the main underlying conditions accounting for more than 90% of cases, but HH may also occur in other circumstances. Until recently, liver ischaemia, i.e. a drop in hepatic blood flow, was considered the leading, and even the sole, hemodynamic mechanism responsible for HH, and it was generally held that a shock state was required. In reality, other hemodynamic mechanisms of hypoxia, such as passive congestion of the liver, arterial hypoxaemia and dysoxia, play an important role while a shock state is observed in only 50% of cases. Accordingly, 'ischaemic hepatitis' and 'shock liver' are misnomers. Therapy of HH depends primarily on the nature of the underlying condition. The prognosis is poor, with more than half of patients dying during the hospital stay.

Congestive hepatopathy and hypoxic hepatitis in heart failure: a cardiologist's point of view

In the setting of long-standing severe chronic heart failure, other organ systems are also involved. The liver is one of the organs that are very sensitive to haemodynamic changes. Differential diagnosis of the liver injury is extremely important in the cardiologist's clinical practice and calls for cardiologist's and hepatologist's collaboration because there are many other diseases that can affect the liver and mimic haemodynamic injury. In this article, liver injuries depending on cardiocirculatory dysfunction such as hypoxic hepatitis and congestive hepatopathy are analysed. The material in the article is presented in two aspects: the evaluation and treatment of heart failure in order to prevent pathologic processes in the liver, and the recognition of the liver injury, including diagnostic tests which are essential for differential diagnosis of different liver pathologies.

Short and long-term outcomes in patients with acute liver failure due to ischemic hepatitis

AIMS

The purpose of this study is to describe the incidence and presenting features of patients with acute liver failure (ALF) due to ischemic hepatitis and the prognostic factors associated with short (three-week) and long-term outcomes.

METHODS

Retrospective cohort analysis of adult patients enrolled in the Acute Liver Failure Study Group between 1998 and 2008 with ALF due to ischemic hepatitis. Predictors of adverse outcomes three weeks after presentation were identified by univariate and multivariate analysis.

RESULTS

Ischemic hepatitis accounted for 51 (4.4%) of the 1147 ALF patients enrolled. Mean age was 50 years, 63% were female, and only 31% had known heart disease before presentation. However, a cardiopulmonary precipitant of hepatic ischemia was identified in 69%. Three-week spontaneous survival was 71%, two patients (4%) underwent liver transplantation, and the remaining 13 patients (25%) died of multi-organ failure. Adverse outcomes were more frequent in subjects with higher admission phosphate levels (HR 1.3, 95% CI 1.1-1.6, P = 0.008) and in subjects with grade 3/4 encephalopathy at presentation (HR: 8.4, 95% CI 1.1-66.5, P = 0.04). Nineteen of the 28 short-term survivors (68%) were still alive at a median follow-up of 3.7 years whereas nine (32%) others had died at a median follow-up of 2 months.

CONCLUSIONS

A higher admission serum phosphate level and more advanced encephalopathy are associated with a lower likelihood of short-term survival of hospitalized patients with ALF due to ischemic hepatitis. Long-term outcomes are largely determined by underlying cardiovascular morbidity and mortality.

Hypoxic hepatitis: a challenging diagnosis

Hypoxic hepatitis (HH), one of the most common causes of acute liver injury, has a prevalence of up to 10% of admissions in intensive care units across the world. Inadequate oxygen uptake by the hepatocytes resulting in centrilobular necrosis associated with abnormally raised levels of the serum transaminases (ALT, AST) in patients with clinical history of cardiac, respiratory, or circulatory failures is the key feature of this condition. Abstracts, reviews, case reports, and research letters from various sources such as Pubmed, Proquest, Ovid, Google Scholar, and ISI Web of Knowledge dating from 1970 to 2011 were read and analyzed thoroughly. A study of 100 patients with HH, carried out from 2009 to 2010 at Tongji Hospital of Tongji University, Shanghai, People's Republic of China, is also documented. The contributing factors leading to HH are passive congestion, ischemia, and arterial hypoxemia of the liver. Ischemia/reperfusion injury also has a major role in HH. Some of its complications are spontaneous hypoglycemia, a high level of serum ammonia, and respiratory insufficiency due to hepatopulmonary syndrome. The therapy of HH lies mainly in the treatment of the main underlying causes, and this leads to the successful reversion of HH. The aim of this review is to present a simplified concept about the etiology, pathophysiology, mechanism, clinical manifestations, diagnosis, and treatment of HH.

Mitochondrial dysfunction and biogenesis: do ICU patients die from mitochondrial failure?

Mitochondrial functions include production of energy, activation of programmed cell death, and a number of cell specific tasks, e.g., cell signaling, control of Ca²⁺ metabolism, and synthesis of a number of important biomolecules. As proper mitochondrial function is critical for normal performance and survival of cells, mitochondrial dysfunction often leads to pathological conditions resulting in various human diseases. Recently mitochondrial dysfunction has been linked to multiple organ failure (MOF) often leading to the death of critical care patients. However, there are two main reasons why this insight did not generate an adequate resonance in clinical settings. First, most data regarding mitochondrial dysfunction in organs susceptible to failure in critical care diseases (liver, kidney, heart, lung, intestine, brain) were collected using animal models. Second, there is no clear therapeutic strategy how acquired mitochondrial dysfunction can be improved. Only the benefit of such therapies will confirm the critical role of mitochondrial dysfunction in clinical settings. Here we summarized data on mitochondrial dysfunction obtained in diverse experimental systems, which are related to conditions seen in intensive care unit (ICU) patients. Particular attention is given to mechanisms that cause cell death and organ dysfunction and to prospective therapeutic strategies, directed to recover mitochondrial function. Collectively the data discussed in this review suggest that appropriate diagnosis and specific treatment of mitochondrial dysfunction in ICU patients may significantly improve the clinical outcome.

Extracorporeal artificial liver support in hypoxic liver injury

The incidence of hypoxic liver injury, most commonly referred to as hypoxic hepatitis (HH), is up to 10% in critically ill patients. In the majority of cases, HH occurs as a consequence of haemodynamic impairment following cardiogenic or septic shock. A marked, dramatic increase in the aminotransferase levels in a setting of cardiocirculatory failure is the key characteristic of HH. HH may contribute to several complications such as hepatopulmonary syndrome and hypoglycaemia. The overall mortality after the onset of HH is approximately 50-60% within 1 month. We report a case of severe HH that was successfully bridged using the Molecular Adsorbent Recirculating System. In addition to the possible effects of extracorporeal liver support devices, the recognition of HH and therapy of the underlying disease that led to the occurrence of HH is of central importance.

Impact of hypoxic hepatitis on mortality in the intensive care unit

PURPOSE

Hypoxic hepatitis (HH) is a form of hepatic injury following arterial hypoxemia, ischemia, and passive congestion of the liver. We investigated the incidence and the prognostic implications of HH in the medical intensive care unit (ICU).

METHODS

A total of 1,066 consecutive ICU admissions at three medical ICUs of a university hospital were included in this prospective cohort study. All patients were screened prospectively for the presence of HH according to established criteria. Independent risk factors of mortality in this cohort of critically ill patients were identified by a multivariate Poisson regression model.

RESULTS

A total of 118 admissions (11%) had HH during their ICU stay. These patients had different baseline characteristics, longer median ICU stay (8 vs. 6 days, p < 0.001), and decreased ICU survival (43 vs. 83%, p < 0.001). The crude mortality rate ratio of admissions with HH was 4.62 (95% CI 3.63-5.86, p < 0.001). Regression analysis demonstrated strong mortality risk for admissions with HH requiring vasopressor therapy (adjusted rate ratio 4.91; 95% CI 2.51-9.60, p < 0.001), whereas HH was not significantly associated with mortality in admissions without vasopressor therapy (adjusted rate ratio 1.79, 95% CI 0.52-6.23, p = 0.359).

CONCLUSIONS

Hypoxic hepatitis (HH) occurs frequently in the medical ICU. The presence of HH is a strong risk factor for mortality in the ICU in patients requiring vasopressor therapy.

Acetaminophen hepatotoxicity and HIF-1α induction in acetaminophen toxicity in mice occurs without hypoxia

HIF-1α is a nuclear factor important in the transcription of genes controlling angiogenesis including vascular endothelial growth factor (VEGF). Both hypoxia and oxidative stress are known mechanisms for the induction of HIF-1α. Oxidative stress and mitochondrial permeability transition (MPT) are mechanistically important in acetaminophen (APAP) toxicity in the mouse. MPT may occur as a result of oxidative stress and leads to a large increase in oxidative stress. We previously reported the induction of HIF-1α in mice with APAP toxicity and have shown that VEGF is important in hepatocyte regeneration following APAP toxicity. The following study was performed to examine the relative contribution of hypoxia versus oxidative stress to the induction of HIF-1α in APAP toxicity in the mouse. Time course studies using the hypoxia marker pimonidazole showed no staining for pimonidazole at 1 or 2h in B6C3F1 mice treated with APAP. Staining for pimonidazole was present in the midzonal to periportal regions at 4, 8, 24 and 48h and no staining was observed in centrilobular hepatocytes, the sites of the toxicity. Subsequent studies with the MPT inhibitor cyclosporine A showed that cyclosporine A (CYC; 10mg/kg) reduced HIF-1α induction in APAP treated mice at 1 and 4h and did not inhibit the metabolism of APAP (depletion of hepatic non-protein sulfhydryls and hepatic protein adduct levels). The data suggest that HIF-1α induction in the early stages of APAP toxicity is secondary to oxidative stress via a mechanism involving MPT. In addition, APAP toxicity is not mediated by a hypoxia mechanism.