Hypoxic liver injury

The potential role of vascular alterations and subsequent impaired liver blood flow and hepatic hypoxia in the pathophysiology of non-alcoholic steatohepatitis

Non-alcoholic fatty liver disease (NAFLD) covers a spectrum of disease ranging from steatosis to steatohepatitis (NASH) and fibrosis, but the underlying pathophysiological mechanisms remain largely unknown. As there is currently no approved pharmacological therapy and the prevalence of NAFLD keeps increasing, understanding of its pathophysiology is crucial. We hypothesise that vascular alterations in early NAFLD play a role in the progression of the disease by inducing an increased intrahepatic vascular resistance and consequently relative hypoxia in the liver. Evidence of the detrimental effects of hypoxia in NAFLD has already been observed in liver surgery, where the outcomes of steatotic livers after ischaemia-reperfusion are worse than in healthy livers, and in obstructive sleep apnoea, which is an independent risk factor of NAFLD. Moreover, early histological damage in NAFLD is situated in the pericentral zone, which is also the first zone to be affected by a decreased oxygen tension because of the unique hepatic vacsular anatomy that causes the pericentral oxygen tension to be the lowest. Angiogenesis is also a characteristic of NAFLD, driven by hypoxia-induced mechanisms, as demonstrated in both animal models and in humans with NAFLD. Relative hypoxia is most probably induced by impaired blood flow to the liver, caused by increased intrahepatic vascular resistance. An increased intrahepatic vascular resistance early in the development of disease has been convincingly demonstrated in several animal models of NAFLD, whereas an increased portal pressure, a consequence of increased intrahepatic vascular resistance, has been proven in patients with NAFLD. Animal studies demonstrated a decreased intrahepatic effect of vasodilators and an increased reactivity to vasoconstrictors that results in an increased intrahepatic vascular resistance, thus the presence of a functional component. Pharmacological products that target vasoregulation can hence improve the intrahepatic vascular resistance and this might prevent or reverse progression of NAFLD, representing an important therapeutic option to study. Some of the drugs currently under evaluation in clinical trials for NASH have interesting properties related to the hepatic vasculature. Some other interesting drugs have been tested in animal models but further study in patients with NAFLD is warranted. In summary, in this paper we summarise the evidence that leads to the hypothesis that an increased intrahepatic vascular resistance and subsequent parenchymal hypoxia in early NAFLD is an important pathophysiological driving mechanism for the progression of the disease.

Hepatobiliary Manifestations in Systemic Disease

Liver disease in children occurs via a multitude of primary illnesses such as autoimmune hepatopathy, biliary atresia, and nonalcoholic fatty liver disease. However, jaundice, hepatitis, and alterations in liver tests can often be a manifestation of systemic diseases. The liver is involved in many critical functions such as circulation, immunity, toxin clearance, and metabolism; when the heart, lungs, gastrointestinal tract, immune system, or endocrine systems are compromised, the liver will be affected. This article reviews common causes of liver injury as well as highlights key associations that should not be missed when diagnosing and managing children with liver disease. Becoming familiar with patterns of liver injury and arranging clues in the context of a thorough history and physical examination can help providers navigate the broad differential diagnosis of secondary liver disease. [Pediatr Ann. 2018;47(11):e458-e464.].

Epidemiology, causes, evolution and outcome in a single-center cohort of 1116 critically ill patients with hypoxic hepatitis

Background

Hypoxic hepatitis (HH) is a type of acute hepatic injury that is histologically characterized by centrilobular liver cell necrosis and that is caused by insufficient oxygen delivery to the hepatocytes. Typical for HH is the sudden and significant increase of aspartate aminotransferase (AST) in response to cardiac, circulatory or respiratory failure. The aim of this study is to investigate its epidemiology, causes, evolution and outcome.

Methods

The screened population consisted of all adults admitted to the intensive care unit (ICU) at the Ghent University Hospital between January 1, 2007 and September 21, 2015. HH was defined as peak AST > 5 times the upper limit of normal (ULN) after exclusion of other causes of liver injury. Thirty-five variables were retrospectively collected and used in descriptive analysis, time series plots and Kaplan–Meier survival curves with multi-group log-rank tests.

Results

HH was observed in 4.0% of the ICU admissions at our center. The study cohort comprised 1116 patients. Causes of HH were cardiac failure (49.1%), septic shock (29.8%), hypovolemic shock (9.4%), acute respiratory failure (6.4%), acute on chronic respiratory failure (3.3%), pulmonary embolism (1.4%) and hyperthermia (0.5%). The 28-day mortality associated with HH was 45.0%. Mortality rates differed significantly (P = 0.007) among the causes, ranging from 33.3% in the hyperthermia subgroup to 52.9 and 56.2% in the septic shock and pulmonary embolism subgroups, respectively. The magnitude of AST increase was also significantly correlated (P < 0.001) with mortality: 33.2, 44.4 and 55.4% for peak AST 5–10× ULN, 10–20× ULN and > 20× ULN, respectively.

Conclusion

This study surpasses by far the largest cohort of critically ill patients with HH. HH is more common than previously thought with an ICU incidence of 4.0%, and it is associated with a high all-cause mortality of 45.0% at 28 days. The main causes of HH are cardiac failure and septic shock, which include more than 3/4 of all episodes. Clinicians should search actively for any underlying hemodynamic or respiratory instability even in patients with moderately increased AST levels.

Low serum albumin predicts early mortality in patients with severe hypoxic hepatitis

AIM

To evaluate the incidence, etiology, and predictors of mortality of severe hypoxic hepatitis.

METHODS

We used computerized patient records to identify consecutive cases of severe hypoxic hepatitis admitted to a tertiary hospital in Singapore over a one-year period. We defined severe hypoxic hepatitis as elevation of serum transaminases more than 100 times upper limit of normal in the clinical setting of cardiac, circulatory or respiratory failure after exclusion of other causes of hepatitis. We used multivariable regression analysis to determine predictors for mortality.

RESULTS

We identified 75 cases of severe hypoxic hepatitis out of 71380 hospital admissions over one year, providing an incidence of 1.05 cases per 1000 admissions. Median age was 65 years (range 19-88); 57.3% males. The most common etiologies of severe hypoxic hepatitis were acute myocardial infarction and sepsis. Fifty-three patients (71%) died during the hospitalization. The sole independent predictive factor for mortality was serum albumin measured at the onset of severe hypoxic hepatitis. Patients with low serum albumin of less than 28 g/L have more than five-fold increase risk of death (OR = 5.39, 95%CI: 1.85-15.71).

CONCLUSION

Severe hypoxic hepatitis is uncommon but has a high mortality rate. Patients with low serum albumin are at highest risk of death.

Altered gene expression of hepatic cytochrome P450 in a rat model of intermittent hypoxia with emphysema

Patients with respiratory overlap syndrome (OS), defined as concomitant chronic obstructive pulmonary disease and obstructive sleep apnea syndrome, may exhibit an increased blood concentration of ingested drugs. This poor elimination of drugs is primarily attributed to downregulated gene expression of the drug‑metabolizing cytochrome P450 enzymes (CYPs) in the liver. However, the underlying mechanisms of the decreased expression of CYPs in OS are poorly understood. In order to address this, a rat model of intermittent hypoxia with emphysema was evaluated in the present study, by analyzing liver gene expression using the reverse transcription‑quantitative polymerase chain reaction. Intermittent hypoxia and cigarette smoke exposure caused upregulation of hepatic inflammatory cytokines, while CYPs were downregulated. This downregulation of CYPs was associated with an increase in nuclear factor (NF)‑κB expression and a decrease in the expression of nuclear receptors pregnane X receptor, constitutive androstane receptor and glucocorticoid receptor, which are the upstream regulatory molecules of CYPs. The results of the present study indicated that, during the development of OS, systematic inflammatory reactions may downregulate hepatic CYP gene expression via the NF‑κB signaling pathway.

Hypoxic hepatitis - its biochemical profile, causes and risk factors of mortality in critically-ill patients: A cohort study of 565 patients

PURPOSE

A retrospective analysis of critically-ill patients with hypoxic hepatitis (HH) to characterize the biochemical profile and to identify predictors of mortality using the Medical Information Mart for Intensive Care III database.

METHODS

HH was defined as a rapid increase in AST/ALT≥800IU/L after exclusion of other causes. We investigated the correlation between various clinical and laboratory parameters and mortality rates using regression models.

RESULTS

Among 38,645 ICU-patients, 565 (1.46%) were diagnosed with HH; 57.9% were males; median age was 63years. The unique biochemical profile of HH was confirmed; lactate dehydrogenase (LDH) was higher than both ALT and AST; AST>ALT for the first 2days then the ratio is reversed until recovery. All-cause hospital mortality was 44.1%. All-cause hospital mortality was 44.1%. On multivariate analysis, older age, higher SAPS-II, higher INR, higher bilirubin, higher LDH, acute kidney injury (AKI), and the need for vasopressors were independently associated with mortality.

CONCLUSION

Older age, higher SAPS-II, LDH, INR and bilirubin levels, concomitant AKI and the need for vasopressors were all factors associated with increased mortality. The diagnosis of HH was an important harbinger of mortality in this population, which appears to be driven mainly by the severity of the underlying conditions.

Enzyme pattern of biliary colic: A counterintuitive picture

AIM

To evaluate the diagnostic value of serial biochemical blood tests in the diagnosis of biliary colic.

METHODS

Files were reviewed of 1039 patients who were admitted to the Share’e Zedek Medical Center emergency department between the years 2012-2013, and received the coding of acute biliary disease. Of these, the first 100 cases were selected that met the following criteria: (1) a diagnosis of biliary colic or symptomatic cholelithiasis; (2) at least two biochemical blood tests performed; and (3) 18 years of age or older. Patients with other acute biliary diseases were excluded. The biochemical profile of the patients was analyzed as were their clinical and radiological findings.

RESULTS

Three-quarters of the patients were women, whose average age of 37 years was younger than the average of the men, at 50 years. According to their histories, 47% of the patients had previously known cholelithiasis. Pain in either the right upper quadrant or the epigastrium was the presenting symptom in 93% cases. The greatest change in serum biochemical results was seen during the first day of the patients’ admissions. Alanine aminotransferase (ALT) showed the highest initial rise above the reference range, followed by aspartate aminotransferase (AST), gamma-glutamyl transferase (GGT), bilirubin and alkaline phosphatase (ALKP) - all these increases were statistically significant (P < 0.05). AST showed the sharpest decline followed by bilirubin and ALT. GGT and ALKP did not fall. A sharp rise and fall in liver enzymes, especially during the first day, most prominently in AST and ALT, was seen in 70% percent of cases. In 65% of cases trans-abdominal sonography did not give diagnostic findings.

CONCLUSION

Serial serum liver enzyme measurements are helpful in the initial diagnosis of acute biliary colic.

Prognostic Impact of Combined Contrast-Induced Acute Kidney Injury and Hypoxic Liver Injury in Patients with ST Elevation Myocardial Infarction Undergoing Primary Percutaneous Coronary Intervention: Results from INTERSTELLAR Registry

BACKGROUND

Besides contrast-induced acute kidney injury(CI-AKI), adscititious vital organ damage such as hypoxic liver injury(HLI) may affect the survival in patients with ST-elevation myocardial infarction (STEMI). We sought to evaluate the prognostic impact of CI-AKI and HLI in STEMI patients who underwent primary percutaneous coronary intervention (PCI).

METHODS

A total of 668 consecutive patients (77.2% male, mean age 61.3±13.3 years) from the INTERSTELLAR STEMI registry who underwent primary PCI were analyzed. CI-AKI was defined as an increase of ≥0.5 mg/dL in serum creatinine level or 25% relative increase, within 48h after the index procedure. HLI was defined as ≥2-fold increase in serum aspartate transaminase above the upper normal limit on admission. Patients were divided into four groups according to their CI-AKI and HLI states. Major adverse cardiovascular and cerebrovascular events (MACCE) defined as a composite of all-cause mortality, non-fatal MI, non-fatal stroke, ischemia-driven target lesion revascularization and target vessel revascularization were recorded.

RESULTS

Over a mean follow-up period of 2.2±1.6 years, 94 MACCEs occurred with an event rate of 14.1%. The rates of MACCE and all-cause mortality were 9.7% and 5.2%, respectively, in the no organ damage group; 21.3% and 21.3% in CI-AKI group; 18.5% and 14.6% in HLI group; and 57.7% and 50.0% in combined CI-AKI and HLI group. Survival probability plots of composite MACCE and all-cause mortality revealed that the combined CI-AKI and HLI group was associated with the worst prognosis (p<0.0001 for both).

CONCLUSION

Combined CI-AKI after index procedure and HLI on admission is associated with poor clinical outcomes in patients with STEMI who underwent primary PCI. (INTERSTELLAR ClinicalTrials.gov number, NCT02800421.).

Ischaemic Markers in Acute Hepatic Injury

INTRODUCTION

Hepatic injury of varied aetiology may progress to Acute Liver Failure (ALF). Compromised microcirculation is thought to be a deciding factor of hepatic hypoxia may be involved in disease progression that needs early detection. Ischaemia markers like serum Ischaemia- modified albumin (IMA), ALT-LDH ratio and ALT-LDH index have been suggested for its detection at early stage.

AIM

To find out the association of Ischaemia markers like serum IMA, ALT-LDH ratio and ALT-LDH index in acute hepatic injury cases.

MATERIALS AND METHODS

Forty one diagnosed acute liver injury cases of varied aetiology admitted in Department of Medicine, and Gastroenterology of SCB Medical College, Cuttack were enrolled in the study along with 30 age and sex matched healthy controls. Blood collected at time of admission and at time of discharge (1(st) day and 7(th) day) were evaluated for FPG, RFT, LFT, Serum Albumin along with serum LDH, IMA, PT-INR and platelet count.

RESULT

Serum bilirubin, hepatic enzymes, IMA, PT-INR was more markedly raised in cases than controls on the 1(st) day of admission. ALT-LDH ratio and index were significantly low in complicated cases. However, on responding to treatment the ALT-LDH index on 7(th) day registered a rise in comparison to the 1(st) day, while serum IMA revealed an insignificant decline showing improvement in hepatic hypoxia. ALT-LDH ratio remains more or less same on response to treatment.

CONCLUSION

Serum IMA and ALT-LDH Index reveals association with disease process in Acute Hepatic Injury cases both clinically and biochemically and can be used as supportive parameters for the diagnosis of disease process.

Donor preoperative oxygen delivery and post-extubation hypoxia impact donation after circulatory death hypoxic cholangiopathy

AIM: To evaluate donation after circulatory death (DCD) orthotopic liver transplant outcomes [hypoxic cholangiopathy (HC) and patient/graft survival] and donor risk-conditions.

METHODS: From 2003-2013, 45 DCD donor transplants were performed. Predonation physiologic data from UNOS DonorNet included preoperative systolic and diastolic blood pressure, heart rate, pH, SpO₂, PaO₂, FiO₂, and hemoglobin. Mean arterial blood pressure was computed from the systolic and diastolic blood pressures. Donor preoperative arterial O₂ content was computed as [hemoglobin (gm/dL) × 1.37 (mL O₂/gm) × SpO₂%) + (0.003 × PaO₂)]. The amount of preoperative donor red blood cell transfusions given and vasopressor use during the intensive care unit stay were documented. Donors who were transfused ≥ 1 unit of red-cells or received ≥ 2 vasopressors in the preoperative period were categorized as the red-cell/multi-pressor group. Following withdrawal of life support, donor ischemia time was computed as the number-of-minutes from onset of diastolic blood pressure < 60 mmHg until aortic cross clamping. Donor hypoxemia time was the number-of-minutes from onset of pulse oximetry < 80% until clamping. Donor hypoxia score was (ischemia time + hypoxemia time) ÷ donor preoperative hemoglobin.

RESULTS: The 1, 3, and 5 year graft and patient survival rates were 83%, 77%, 60%; and 92%, 84%, and 72%, respectively. HC occurred in 49% with 16% requiring retransplant. HC occurred in donors with increased age (33.0 ± 10.6 years vs 25.6 ± 8.4 years, P = 0.014), less preoperative multiple vasopressors or red-cell transfusion (9.5% vs 54.6%, P = 0.002), lower preoperative hemoglobin (10.7 ± 2.2 gm/dL vs 12.3 ± 2.1 gm/dL, P = 0.017), lower preoperative arterial oxygen content (14.8 ± 2.8 mL O₂/100 mL blood vs 16.8 ± 3.3 mL O₂/100 mL blood, P = 0.049), greater hypoxia score >2.0 (69.6% vs 25.0%, P = 0.006), and increased preoperative mean arterial pressure (92.7 ± 16.2 mmHg vs 83.8 ± 18.5 mmHg, P = 0.10). HC was independently associated with age, multi-pressor/red-cell transfusion status, arterial oxygen content, hypoxia score, and mean arterial pressure (r² = 0.6197). The transplantation rate was greater for the later period with more liberal donor selection [era 2 (7.1/year)], compared to our early experience [era 1 (2.5/year)]. HC occurred in 63.0% during era 2 and in 29.4% during era 1 (P = 0.03). Era 2 donors had longer times for extubation-to-asystole (14.4 ± 4.7 m vs 9.3 ± 4.5 m, P = 0.001), ischemia (13.9 ± 5.9 m vs 9.7 ± 5.6 m, P = 0.03), and hypoxemia (16.0 ± 5.1 m vs 11.1 ± 6.7 m, P = 0.013) and a higher hypoxia score > 2.0 rate (73.1% vs 28.6%, P = 0.006).

CONCLUSION: Easily measured donor indices, including a hypoxia score, provide an objective measure of DCD liver transplantation risk for recipient HC. Donor selection criteria influence HC rates.

Hepatic Failure

The progression of liver disease can cause several physiologic derangements that may precipitate hepatic failure and require admission to an intensive care unit. The underlying pathology may be acute, acute-on chronic, or chronic in nature. Liver failure may manifest with a variety of clinical signs and symptoms that need prompt attention. The compromised synthetic and metabolic activity of the failing liver affects all organ systems, from neurologic to integumentary. Supportive care and specific therapies should be instituted in order to improve outcome and minimize time of recovery.

In this chapter we will discuss the definition, clinical manifestations, workup, and management of acute and chronic liver failure and the general principles of treatment of these patients. Management of liver failure secondary to certain common etiologies will also be presented. Finally, liver transplantation and alternative therapies will also be discussed.

Hypoxic hepatitis in survivors of out-of-hospital cardiac arrest

INTRODUCTION

Hypoxic hepatitis (HH) is commonly observed in out-of-hospital cardiac arrest (OHCA) survivors. The objective of this study was to investigate the incidence, clinical courses, and outcomes of as well as predisposing factors for HH in OHCA survivors.

METHODS

The study was based on a registry of cardiac arrest cases from 2009 to 2012 at a tertiary university hospital. We assessed patients' serum aminotransferase levels on return of spontaneous circulation (ROSC) and at 6, 12, 24, 48, and 72 hours postarrest. Hypoxic hepatitis was defined as a rapid increase in serum aminotransferase that reached at least 20 times the upper limit of normal. The patients were classified into 2 groups: the HH group and the non-HH group; we then analyzed the outcomes of the HH group. Independent predisposing factors to HH in this cohort were identified.

RESULTS

Of a total of 535 OHCA cases, 148 patients were enrolled in this study. Hypoxic hepatitis was identified in 13.5% (n = 20) of them. Serum aminotransferase rapidly increased in the first day after return of spontaneous circulation. Of the patients who developed HH, 5 (25%) survived to hospital discharge, and none of these individuals had good neurologic outcomes (Glasgow-Pittsburgh cerebral performance categories 1 and 2). Using multivariate logistic regression, we found that the no flow time was independent predictors of HH (odds ratio, 1.085 [95% confidence interval, 1.027-1.146]; P = .003).

CONCLUSIONS

Hypoxic hepatitis occurred frequently in survivors of OHCA. The no flow time was an independent risk factor for HH, which was significantly related to death and poor neurologic outcomes.

Phosphorylation dynamics of radixin in hypoxia-induced hepatocyte injury

The most prominent ezrin-radixin-moesin protein in hepatocytes is radixin, which is localized primarily at the canalicular microvilli and appears to be important in regulation of cell polarity and in localizing the multidrug resistance-associated protein 2 (Mrp-2) function. Our aim was to investigate how hypoxia affects radixin distribution and Mrp-2 function. We created wild-type and mutant constructs (in adenoviral vectors), which were expressed in WIF-B cells. The cellular distribution of Mrp-2 and radixin was visualized by fluorescence microscopy, and a 5-chloromethylfluorescein diacetate (CMFDA) assay was used to measure Mrp-2 function. Under usual conditions, cells infected with wild-type radixin, nonphosphorylatable radixin-T564A, and radixin-T564D (active phospho-mimicking mutant) were found to be heavily expressed in canalicular membrane compartment vacuoles, typically colocalizing with Mrp-2. In contrast, after hypoxia for 24 h, both endogenous and overexpressed wild-type radixin and the radixin-T564A mutant were found to be translocated to the cytoplasmic space. However, distribution of the radixin-T564D mutant, which mimics constant phosphorylation, was remarkably different, being associated with canalicular membranes even in hypoxic conditions. This dominant-active construct also prevented dissociation of radixin from the plasma membrane. Hypoxia also led to Mrp-2 mislocalization and caused Mrp-2 to be dissociated from radixin; the radixin phospho-mimicking mutant (T564D) abrogated this effect of hypoxia. Finally, hypoxia diminished the secretory response (measured using the CMFDA assay) in WIF-B cells, and the dominant-active construct (radixin-T567D) rescued this phenotype. Taken collectively, these findings suggest that radixin regulates Mrp-2 localization and function in hepatocytes and is important in hypoxic liver injury.

The challenges of multiple organ dysfunction syndrome and extra-corporeal circuits for drug delivery in critically ill patients

The multiple organ dysfunction syndrome (MODS) is characterized by more than one organ system failing, especially during critical illness. MODS is the leading cause of morbidity and mortality in current ICU practice; moreover, multiple organ dysfunction, especially liver and kidneys, may significantly affect the pharmacokinetics (PKs) of different drugs that are currently administered in critically ill patients. These PK alterations may either result in insufficient drug concentrations to achieve the desired effects or in blood and tissue accumulation, with the development of serious adverse events. The use of extra-corporeal circuits, such as extracorporeal membrane oxygenation (ECMO) and continuous renal replacement therapy (CRRT), may further contribute to PKs changes in this patients' population. In this review, we have described the main PK changes occurring in all these conditions and how drug concentrations may potentially be affected. The lack of prospective studies on large cohorts of patients makes impossible any specific recommendation on drug regimen adjustment in ICU patients. Nevertheless, the clinicians should be aware of these abnormalities in order to better understand some unexpected therapeutic issues occurring in such patients.

Serum transaminase determined in the emergency room predicts outcomes in patients with acute ST-segment elevation myocardial infarction who undergo primary percutaneous coronary intervention

BACKGROUND

Elevated serum aspartate and alanine aminotransferase (AST and ALT) are often observed in patients with acute ST-segment elevation myocardial infarction (STEMI) and the condition is ascribed to liver hypoperfusion. We evaluated the prevalence and prognostic implication of hypoxic liver injury (HLI) in STEMI.

METHODS

Patients with STEMI and no preexisting liver disease who underwent primary percutaneous coronary intervention (PCI) were enrolled. A blood test was performed at the time of presentation and transthoracic echocardiography was performed after the index PCI. We reviewed medical records and contacted families of the patients by telephone to assess outcomes.

RESULTS

Of 456 patients (age 60 ± 13 years, 370 males), 31 patients (7%) died during follow-up (duration: 754 ± 540 days). Those patients were older (72 ± 10 vs. 59 ± 13 years), had higher AST (179 ± 224 vs. 64 ± 103 U/L), ALT (56 ± 79 vs. 35 ± 33 U/L), blood urea nitrogen (25 ± 15 vs. 17 ± 7 mg/dL), uric acid (6.9 ± 2.9 vs. 5.8 ± 1.6 mg/dL), creatine kinase-myocardial band isoenzyme (76 ± 104 vs. 41 ± 79 ng/mL), troponin I (19.9 ± 23.0 vs. 10.8 ± 19.1 ng/mL), and lower albumin (4.0 ± 0.5 vs. 4.2 ± 0.4 g/dL) at the time of presentation (p<0.05 for all). Particularly, AST independently predicted all-cause mortality (per 10 U/L increase, hazard ratio: 1.06, 95% confidence interval: 1.02-1.10, p=0.007), whereas cardiac markers did not. HLI (>2-fold elevation of AST or ALT upper normal limits) showed close correlation with reduced left ventricular ejection fraction (β=-0.12, p=0.03) and patients with the condition (n=100 [20%]) had poorer survival than the others (Log-Rank, p=0.005).

CONCLUSION

The presence of HLI predicts mortality in patients with STEMI who undergo successful primary PCIs.

Ischaemic hepatitis precipitated by recurrent episodes of atrial fibrillation

We report a case of ischaemic hepatitis associated with recurrent fast atrial fibrillation (AF) episodes in a 59-year-old male who presented with shortness of breath, nausea and vomiting. The patient had a history of ischaemic cardiomyopathy. An emergency electrocardiogram showed fast AF with a ventricular rate of 190 min(-1). The aspartate aminotransferase (AST) level was 2222Ul(-1), alanine aminotransferase (ALT) was 1255Ul(-1), lactate dehydrogenase (LDH) was 1842Ul(-1) and serum creatinine was 150 μmoll(-1). An ultrasound of the abdomen showed an enlarged liver with hypoechoic lesions. The patient received digoxin. In the next few days, while liver enzymes and serum creatinine started to return to normal levels, the patient had two attacks of fast AF, each associated with elevated liver enzymes and a concomitant rise in serum creatinine. The patient was transferred to the intensive care unit to improve control of his AF, after which his liver enzymes and renal function gradually returned to normal.

Ischemic hepatitis after percutaneous nephrolitotomy: A case report

INTRODUCTION

Ischemic hepatitis (IH) is the necrosis of the centrilobular hepatocytes of liver and is secondary to liver hypoperfusion in most of the cases. The diagnosis is usually based on biochemical findings due to the absence of symptoms and signs. Although the disease course is often mild, and sometimes is even not diagnosed, the outcome is poor if the etiology of hypotension and liver anoxia is not promptly corrected.

PRESENTATION OF CASE

A 64-year-old patient who underwent percutaneous nephrolithotomy (PNL) for right renal pelvic stone developed acute IH at first postoperative day as a result of hemorrhage related severe hypotension. After restoring hemodynamic parameters, she completely recovered 2 weeks after the operation.

DISCUSSION

IH is a frequent cause of marked serum aminotransferase elevation and most commonly occurs as a result of arterial hypoxemia and insufficient hepatic perfusion. Although no specific treatment of IH exists, stabilizing the hemodynamic parameters of the patient resolves the problem in most of the cases.

CONCLUSION

This case is presented to demonstrate that ischemic hepatitis should be kept in mind if severe hemorrhage occurs during PNL.

Perioperative liver protection

PURPOSE OF REVIEW

This review presents important pathophysiological alterations associated with impaired liver function and discusses protective perioperative strategies and the various anaesthetic agents recommended.

RECENT FINDINGS

Perioperative liver impairment is a serious complication of anaesthesia and surgery. Unfortunately, clinicians are provided with only crude macrohaemodynamic monitoring devices to optimize their therapy. Technical improvements have revealed some complex mysteries of perioperative microcirculatory alterations and have disclosed a large heterogeneity between different vascular beds. The present review will critically discuss current clinical concepts of optimizing global haemodynamic variables and the often contrasting effects of vasoactive agents on the microcirculatory nutritional blood flow. Finally, promising protective experimental interventions of pharmacological or ischaemic preconditioning are presented and their often disillusioning transition into recent clinical trials is highlighted.

SUMMARY

Targeted perioperative liver protection still lacks adequate monitoring tools and is currently based on optimization of global haemodynamic variables. While there is currently no evidence suggesting a positive effect of ischaemic preconditioning, promising experimental results of pharmacological preconditioning and therapeutic hypothermia require further evaluation in larger randomized clinical trials.

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 occurring in cirrhosis after variceal bleeding: still a lethal disease

BACKGROUND

Hypoxic hepatitis (HH) occurring after gastrointestinal bleeding in cirrhotic patients has been scarcely studied and is reported as a rare occurrence carrying a severe prognosis. The management of bleeding from esophageal varices (BEV) and similarly the prognosis has improved in the last decades.

GOALS

To evaluate retrospectively the incidence, clinical features, risk factors, and outcome of HH occurring in cirrhotic patients with BEV treated with the current standard therapy. Cirrhotics with BEV consecutively admitted from 2004 to 2008 were considered. Standard therapy consisted of intensive care support, somatostatin, antibiotics, and band ligation. HH was diagnosed if an elevation of alanine aminotransferase >10-fold from basal occurred.

RESULTS

Among 349 patients admitted for BEV, 24 (6.8%) had HH. Most patients were over 60 years old and had advanced liver disease; 41.7% had hepatocellular carcinoma, and 29.2% had portal vein thrombosis (PVT). Hypovolemic shock occurred in 16 (66.7%) patients, and failure to control initial bleeding in 12 (50%) patients. The 6-week mortality rate was 83.3% in HH compared with 24.6% in non-HH patients. Causes of death were massive bleeding in 4, hepatic encephalopathy in 7, and renal failure in 9. Binary logistic regression analysis showed that failure to control initial bleeding, diabetes, and PVT were factors independently associated with the development of HH.

CONCLUSIONS

HH occurring in cirrhosis with gastrointestinal bleeding still carries an ominous prognosis. The severity of hemorrhage as expressed by failure to control bleeding contributes heavily to HH; in addition, the presence of PVT and diabetes further compromising the hepatic circulatory reserve may favor hypoxic damage.

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.

Silencing of enzymes involved in ceramide biosynthesis causes distinct global alterations of lipid homeostasis and gene expression

Dysregulation of ceramide synthesis has been associated with metabolic disorders such as atherosclerosis and diabetes. We examined the changes in lipid homeostasis and gene expression in Huh7 hepatocytes when the synthesis of ceramide is perturbed by knocking down serine pal mitoyltransferase subunits 1, 2, and 3 (SPTLC123) or dihydroceramide desaturase 1 (DEGS1). Although knocking down all SPTLC subunits is necessary to reduce total ceramides significantly, depleting DEGS1 is sufficient to produce a similar outcome. Lipidomic analysis of distribution and speciation of multiple lipid classes indicates an increase in phospholipids in SPTLC123-silenced cells, whereas DEGS1 depletion leads to the accumulation of sphingolipid intermediates, free fatty acids, and diacylglycerol. When cer amide synthesis is disrupted, the transcriptional profiles indicate inhibition in biosynthetic processes, downregulation of genes involved in general endomembrane trafficking, and upregulation of endocytosis and endosomal recycling. SPTLC123 silencing strongly affects the expression of genes involved with lipid metabolism. Changes in amino acid, sugar, and nucleotide metabolism, as well as vesicle trafficking between organelles, are more prominent in DEGS1-silenced cells. These studies are the first to provide a direct and comprehensive understanding at the lipidomic and transcriptomic levels of how Huh7 hepatocytes respond to changes in the inhibition of ceramide synthesis.

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.

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.

Acute liver failure and liver assist devices

Survival of patients presenting with acute liver failure (ALF) has improved over the past decades due to earlier disease recognition, advances in supportive measures, intensive care, and liver transplantation. Liver assist devices may have a role in future care of patients with ALF, bridging them to recovery or to transplantation. A multidisciplinary team approach to the care of patients with ALF is critical for achieving good patient outcomes.

Hepatobiliary manifestations of critically ill and postoperative patients

Liver dysfunction is common in both the critically ill and postoperative patient. Metabolic derangements secondary to sepsis, poor hepatic perfusion, total parenteral nutrition, in addition to hemodynamic and anesthetic-induced changes that occur during surgery, can cause liver damage ranging from small self-limited abnormalities in liver chemistries to acute liver failure. Early recognition, supportive care, and effective treatment of the underlying disease process are crucial steps in managing liver disease in a critically ill patient.

Pulmonary diseases and the liver

Chronic liver disease is associated with many pulmonary complications. Several, including hepatopulmonary syndrome, portopulmonary hypertension, and hepatic hydrothorax have been extensively reviewed. However, hepatobiliary manifestations of primary pulmonary diseases have received less attention. This review focuses on hepatobiliary complications of respiratory failure, cystic fibrosis, α-1 antitrypsin deficiency, sarcoidosis, and tuberculosis.

Acute liver failure following hemodialysis arteriovenous graft placement: a case report

Introduction

Severe high-output cardiac failure is a serious complication of high-flow vascular access requiring immediate intervention. Ischemic hepatitis is defined as a massive increase in serum transaminase levels due to an imbalance between hepatic oxygen supply and demand in the absence of other acute causes of liver damage. It is typically preceded by hypotension, hypoxemia, or both, and occurs mostly in elderly patients with right-sided congestive heart failure.

Case presentation

We report a fatal case of acute liver failure in an 84-year-old Caucasian man with high-output cardiac failure due to arteriovenous hemodialysis access. The chronological sequence of acute liver failure in the context of vascular access created two days before suggests that ischemic hepatitis was the result of high-output cardiac failure due to vascular access.

Conclusions

A thorough cardiac assessment should be performed in patients with severe cardiac disease prior to placing an arteriovenous access, and arteriovenous fistula should be the preferred vascular access.

Hypoxic hepatitis - epidemiology, pathophysiology and clinical management

Hypoxic hepatitis (HH), also known as ischemic hepatitis or shock liver, is characterized by centrilobular liver cell necrosis and sharply increasing serum aminotransferase levels in a clinical setting of cardiac, circulatory or respiratory failure. Nowadays it is recognized as the most frequent cause of acute liver injury with a reported prevalence of up to 10% in the intensive care unit. Patients with HH and vasopressor therapy have a significantly increased mortality risk in the medical intensive care unit population. The main underlying conditions contributing to HH are low cardiac output and septic shock, although a multifactorial etiology is found in the majority of patients. HH causes several complications such as spontaneous hypoglycemia, respiratory insufficiency due to the hepatopulmonary syndrome, and hyperammonemia. HH reverses after successful treatment of the basic HH-causing disease. No specific therapies improving the hepatic function in patients with HH are currently established. Early recognition of HH and its underlying diseases and subsequent initiation of therapy is of central prognostic importance. The purpose of this review is to provide an update on the epidemiology, pathophysiology, and diagnostic and therapeutic options of HH.

Incidence and outcome of ischemic hepatitis complicating septic shock

AIM

The specific incidence of ischemic hepatitis in septic shock patients remains unknown. The aim of this study was to evaluate the incidence of ischemic hepatitis in septic shock and its relationship with mortality.

METHODS

We retrospectively studied 181 patients with septic shock admitted to the intensive care unit (ICU). We defined ischemic hepatitis as having a value of serum aminotransferases equal to or higher than 1000 IU/L. We recorded the age, sex, comorbidity, site of infection, the Sequential Organ Failure Assessment (SOFA) score on admission to the ICU, maximum SOFA score and inadequate antibiotic therapy.

RESULTS

Twenty-five (13.8%) patients developed ischemic hepatitis. In-hospital mortality was 57% (103 patients). In the ischemic hepatitis group, mortality increased up to 84.0% (21 patients) compared with 52.6% (82 patients) in patients without ischemic hepatitis (control group) (odds ratio [OR]: 4.7; 95% confidence interval [CI]: 1.6-14.4; P = 0.003). The development of ischemic hepatitis, age, maximum SOFA score and inadequate antibiotic therapy were independently associated with an increased risk of death. The odds of death increased by 247% in ischemic hepatitis (OR: 3.47; 95% CI: 1.02-11.8; P = 0.047).

CONCLUSION

Ischemic hepatitis is a common complication in septic shock patients, associated with a high mortality.

ICU management of acute liver failure

Survival of patients presenting with acute liver failure (ALF) has improved because of earlier disease recognition, better understanding of pathophysiology of various insults leading to ALF, and advances in supportive measures including a team approach, better ICU care, and liver transplantation. This article focuses on patient management and evaluation that takes place in the ICU for patients who have acute liver injury. An organized team approach to decision making about critical care delivered during this period of time is important for achieving a good patient outcome.

Catecholamines induce an inflammatory response in human hepatocytes

OBJECTIVE

The liver is an early target organ in sepsis, severe sepsis, and septic shock, contributing to multiple organ failure, and both lipopolysaccharide and gut-derived catecholamines are implicated in the occurrence of hepatocellular dysfunction. Treatment of septic shock involves administration of vasoactive agents such as exogenous catecholamines or vasopressin in order to reestablish blood pressure. As a prelude to clinical application, we tested the hypothesis that catecholamines could modulate the lipopolysaccharide-induced inflammatory response and function in human liver.

DESIGN

An in vitro human cell culture study.

SETTING

Research laboratory of an academic institution.

SUBJECTS

Primary human hepatocytes and human hepatoma HepaRG cells.

INTERVENTIONS

Primary human hepatocytes and human hepatoma HepaRG cells were exposed to lipopolysaccharide to evaluate effects of epinephrine and several other compounds (norepinephrine, dobutamine, dopamine, dopexamine, phenylephrine, clonidine, salbutamol, and vasopressin). Markers of inflammation (interleukin-6, C-reactive protein) and drug metabolism (cytochrome P450 [CYP] 3A4, CYP2B6, CYP1A2, CYP2E1, constitutive androstane receptor, pregnane X receptor) were analyzed.

MEASUREMENTS AND MAIN RESULTS

Transcripts of C-reactive protein and CYP3A4 were strongly increased and depressed respectively after a 24-hr treatment with 10 ng/mL lipopolysaccharide. Co-treatment with either of the catecholamines failed to reverse lipopolysaccharide effects, whereas when added alone, epinephrine, and to a lesser extent norepinephrine, salbutamol, and dobutamine, mimicked lipopolysaccharide effects. Suppression of CYP3A4 implicated beta-adrenergic receptors and was mediated through overproduction of interleukin-6. By contrast, vasopressin did not elicit an inflammatory response or modify CYP3A4 expression.

CONCLUSIONS

Some catecholamines can induce an inflammatory response and exacerbate the hepatic dysfunction observed during sepsis, favoring the idea that catecholamines could alter the biotransformation of drugs metabolized by CYP3A4 and that alternative vasoactive agents, such as vasopressin, merit further investigation in septic shock patients.