Hepatic encephalopathy: An approach to its multiple pathophysiological features

Association of low serum 25-Hydroxy vitamin D [25(OH) d] with hepatic encephalopathy in patients with decompensated liver cirrhosis

BACKGROUND AND STUDY AIMS

The mechanism of hepatic encephalopathy is complex and has not been conclusively established. Recent studies support lower serum 25-Hydroxy Vitamin D [25(OH) D] levels in patients with hepatic encephalopathy. This study aimed to evaluate the association between serum 25(OH) D and hepatic encephalopathy in patients with decompensated cirrhosis of liver.

PATIENTS AND METHODS

A total of 70 cirrhosis patients (35 cases of hepatic encephalopathy and 35 patients without encephalopathy as control, mean age 53.07 ± 12.99 years, 67 % male) were recruited for this study. Assessment of the severity of cirrhosis was done by using a model for end-stage liver disease(MELD) and Child Turcotte Pugh (CTP) scores, and assessment of the severity of hepatic encephalopathy was done according to West Haven criteria. Serum 25 (OH) D level was measured by Chemiluminescent Microparticle Immuno Assay(CMIA).

RESULTS

The mean serum 25(OH) D level among hepatic encephalopathy patients was significantly lower in comparison to the control group without encephalopathy (18.76 ± 8.84 nmol/L vs 31.19 ± 13.9 nmol/L, P<0.0001). 91.4 % of hepatic encephalopathy patients had moderate to severe 25(OH)D deficiency as compared to 51.4 % in the control group. There was a significant correlation observed between the severity of the 25 (OH) D deficiency and the severity of liver disease (r =  - 0.35, P = 0.002). No statistically significant difference in serum 25(OH) D levels was found among patients with different hepatic encephalopathy grades (P = 0.416).

CONCLUSION

A significant association was found between a low serum 25(OH) D leveland hepatic encephalopathy. It requires further large-scale multicenter studies to establish it as a risk factor and predictor of hepatic encephalopathy.

Interventional Radiology Management of Hepatic Encephalopathy

Hepatic encephalopathy (HE) is a clinically severe and devastating complication of decompensated liver disease affecting mortality, quality of life for patients and families, hospital admission rates, and overall health-care costs globally. Depending on the cause of HE, several medical treatment options have been developed and become available. In some refractory HE, such as spontaneous portosystemic shunt-related HE (SPSS-HE) or posttransjugular intrahepatic portosystemic shunt HE (post-TIPS HE), advanced interventional radiology (IR) procedures have been used, and shown to be effective in these conditions. This review presents 2 effective IR procedures for managing SPSS-HE and post-TIPS HE.

A glimpse into multimodal neuromonitoring in acute liver failure: a case report

Introduction

Acute liver failure (ALF) is a rapidly progressing, life-threatening syndrome characterized by liver-related coagulopathy and hepatic encephalopathy (HE). Given that higher HE grades correlate with poorer outcomes, clinical management of ALF necessitates close neurological monitoring. The primary objective of this case report is to highlight the diagnostic value of utilizing multimodal neuromonitoring (MNM) in a patient suffering from ALF.

Case report

A 56-year-old male patient with a history of chronic alcoholism, without prior chronic liver disease, and recent acetaminophen use was admitted to the hospital due to fatigue and presenting with a mild flapping tremor. The primary hypothesis was an acute hepatic injury caused by acetaminophen intoxication. In the following hours, the patient's condition deteriorated, accompanied by neurological decline and rising ammonia levels. The patient's neurological status was closely monitored using MNM. Bilaterally altered pupillary light reflex assessed by decreasing in the Neurological Pupil Index values, using automated pupillometry, initially suggested severe brain oedema. However, ultrasound measurements of the optic nerve sheath diameter showed normal values in both eyes, P2/P1 noninvasive intracranial pressure waveform assessment was within normal ranges and the cerebral computed tomography-scan revealed no signs of cerebral swelling. Increased middle cerebral artery velocities measured by Transcranial Doppler and the initiation of electroencephalography monitoring yielded the presence of status epilepticus.

Discussion

The utilization of MNM facilitated a more comprehensive understanding of the mechanisms underlying the patient's clinical deterioration in the setting of HE. Nonetheless, future studies are needed to show feasibility and to yield valuable insights that can enhance the outcomes for patients with HE using such an approach. Given the absence of specific guidelines in this particular context, it is advisable for physicians to give further consideration to the incorporation of MNM in the management of unconscious patients with ALF.

Impaired Enzymatic Antioxidant Defense in Erythrocytes of Rats with Ammonia-Induced Encephalopathy: Role of NMDA Receptors

Hepatic encephalopathy (HE), a neuropsychiatric disorder developing in patients with severe hepatic dysfunction, has been known for more than a century. However, pathogenetic mechanisms of cerebral dysfunction associated with liver disease are still poorly understood. There is a consensus that the primary cause of HE is accumulation of ammonia in the brain as a result of impaired liver detoxification capacity or the portosystemic shunt. Current evidence suggests that ammonia toxicity is mediated by hyperactivation of glutamate receptors, mainly N-methyl-D-aspartate receptors (NMDARs), and affects brain aerobic metabolism, which provides energy for multiple specific functions and neuronal viability. Recent reports on the presence of functional NMDARs in erythrocytes and the data on the deviations of blood parameters from their normal ranges indicate impaired hemodynamics and reduced oxygen-carrying capacity of erythrocytes in most patients with HE, thus suggesting a relationship between erythrocyte damage and cerebral dysfunction. In order to understand how hyperammonemia (HA)-induced disturbances in the energy metabolism in the brain (which needs a constant supply of large amounts of oxygen in the blood) lead to encephalopathy, it is necessary to reveal ammonia-induced impairments in the energy metabolism and antioxidant defense system of erythrocytes and to explore a potential role of ammonia in reduced brain oxygenation. To identify the said missing link, the activities of antioxidant enzymes and concentrations of reduced glutathione (GSH), oxidized glutathione (GSSG), and H2O2 were measured in the erythrocytes of rats with HA that were injected with the noncompetitive NMDAR antagonist MK-801. We found that in rats with HA, ammonia was accumulated in erythrocytes (cells lacking ammonia removal enzymes), which made them more susceptible to the prooxidant environment created during oxidative stress. This effect was completely or partially inhibited by MK-801. The data obtained might help to identify the risk factors in cognitive disorders and facilitate prediction of unfavorable outcomes of hypoperfusion in patients with a blood elevated ammonia concentration.

Is NMDA-Receptor-Mediated Oxidative Stress in Mitochondria of Peripheral Tissues the Essential Factor in the Pathogenesis of Hepatic Encephalopathy?

Background: Hepatic encephalopathy (HE) is a neuropsychiatric syndrome of increased ammonia-mediated brain dysfunction caused by impaired hepatic detoxification or when the blood bypasses the liver. Ammonia-activated signal transduction pathways of hyperactivated NMDA receptors (NMDAR) are shown to trigger a cascade of pathological reactions in the brain, leading to oxidative stress. NMDARs outside the brain are widely distributed in peripheral tissues, including the liver, heart, pancreas, and erythrocytes. To determine the contribution of these receptors to ammonia-induced oxidative stress in peripheral tissues, it is relevant to investigate if there are any ammonia-related changes in antioxidant enzymes and free radical formation and whether blockade of NMDARs prevents these changes. Methods: Hyperammonemia was induced in rats by ammonium acetate injection. Oxidative stress was measured as changes in antioxidant enzyme activities and O2•− and H2O2 production by mitochondria isolated from the tissues and cells mentioned above. The effects of the NMDAR antagonist MK-801 on oxidative stress markers and on tissue ammonia levels were evaluated. Results: Increased ammonia levels in erythrocytes and mitochondria isolated from the liver, pancreas, and heart of hyperammonemic rats are shown to cause tissue-specific oxidative stress, which is prevented completely (or partially in erythrocyte) by MK-801. Conclusions: These results support the view that the pathogenesis of HE is multifactorial and that ammonia-induced multiorgan oxidative stress-mediated by activation of NMDAR is an integral part of the disease and, therefore, the toxic effects of ammonia in НЕ may be more global than initially expected.

Resolution of Severe Neurologic Signs Following Intravenous Lipid Emulsion Therapy in a Young Dog With a Portosystemic Shunt: Case Report

A 5-month-old male intact Great Pyrenees was presented for an acute onset of severe neurologic signs (stupor, absent menace, intermittent head turn to the left). The patient's history included possible naproxen ingestion with a maximum ingested dose of 59 mg/kg, exceeding the reported dose of >50 mg/kg known to cause neurologic signs. Blood sampling for baseline bloodwork was performed, and intravenous lipid emulsion (ILE) was subsequently administered, for treatment of the suspected toxicosis. Due to severe and life-threatening neurologic signs, other methods of decontamination were contraindicated and unlikely to be effective; extracorporeal therapy was also unavailable. Complete resolution of neurologic signs occurred 30 min after completion of ILE therapy. At this time, the owners found the missing naproxen tablets after returning home and the bloodwork results returned revealing findings consistent with hepatic encephalopathy. The fasted blood ammonia concentration immediately prior to ILE administration was 702.1 μg/dL (reference interval, RI: 24–36 μg/dL) and decreased to 194.1 μg/dL 24 h later. In the first 24 h, the patient also received three doses of lactulose, N-acetylcysteine, and intravenous fluids. The patient was subsequently diagnosed with a single, large intrahepatic portosystemic shunt via computed tomography and underwent an endovascular coil embolization procedure. Given the rapid and dramatic improvement in severe neurologic signs after ILE therapy alone, it is strongly suspected that this treatment resulted in improvement of hepatic encephalopathy.

Do Triphasic Waves and Nonconvulsive Status Epilepticus Arise From Similar Mechanisms? A Computational Model

PURPOSE

Triphasic waves arising in patients with toxic metabolic encephalopathy (TME) are often considered different from generalized periodic discharges (GPDs) in patients with generalized nonconvulsive status epilepticus (GNCSE). The primary objective of this study was to investigate whether a common mechanism can explain key aspects of both triphasic waves in TME and GPDs in GNCSE.

METHOD

A neural mass model was used for the simulation of EEG patterns in patients with acute hepatic encephalopathy, a common etiology of TME. Increased neuronal excitability and impaired synaptic transmission because of elevated ammonia levels in acute hepatic encephalopathy patients were used to explain how triphasic waves and GNCSE arise. The effect of gamma-aminobutyric acid-ergic drugs on epileptiform activity, simulated with a prolonged duration of the inhibitory postsynaptic potential, was also studied.

RESULTS

The simulations show that a model that includes increased neuronal excitability and impaired synaptic transmission can account for both the emergence of GPDs and GNCSE and their suppression by gamma-aminobutyric acid-ergic drugs.

CONCLUSIONS

The results of this study add to evidence from other studies calling into question the dichotomy between triphasic waves in TME and GPDs in GNCSE and support the hypothesis that all GPDs, including those arising in TME patients, occur via a common mechanism.

Outcome of non-surgical dietary treatment with or without lactulose in dogs with congenital portosystemic shunts

Background

Congenital portosystemic shunts (CPSS) are vascular anomalies, allowing portal blood to bypass the hepatic parenchyma, thereby accumulating toxic substances such as ammonia in the systemic circulation resulting in hepatic encephalopathy.

Aim

To evaluate the outcome of non-surgically treated dogs with a CPSS.

Methods

Case records of 78 dogs with a single congenital CPSS confirmed by ultrasound and/or computed tomography between September 2003 and February 2015 were reviewed. Median age at diagnosis of CPSS in dogs was 10.8 months (range 2–133 months). Non-surgical treatment was started as an adjusted diet (a diet restricted in protein) with or without lactulose. Owners were contacted by telephone to determine survival time and presumed cause of death, if applicable. In addition, a questionnaire was used to retrospectively assess quality of life (QoL) and CPSS scores in 37 dogs before and during non-surgical treatment. Differences between Kaplan–Meier curves were tested by a Log rank test.

Results

Overall estimated median survival time (EMST) was 38.5 months (range 1 day − 91 months; 78 dogs). No significant differences between EMSTs were found between dogs with extra- (n = 48) or intrahepatic (n = 29) shunts, nor between treatment with only an adjusted diet, or an adjusted diet combined with lactulose. During non-surgical treatment, significant improvement in perceived QoL and CPSS scores were found (P < 0.01).

Conclusion

Our study demonstrated that an overall median EMST of 3.2 years was reached and that owners retrospectively perceived that non-surgical treatment resulted in an improved QoL and clinical performance, irrespective of intrahepatic or extrahepatic CPSS location.

Retrograde Transvenous Obliteration (RTO): A New Treatment Option for Hepatic Encephalopathy

Hepatic Encephalopathy (HE) is a complication of liver disease, consisting of brain dysfunction often due to portosystemic shunting of blood flow in the liver. HE can range from minimal HE, presenting with normal neurological function, to overt HE, with neurological and neuropsychiatric abnormalities. Various clinical grading systems are used to differentiate HE to provide the appropriate treatments. Traditional treatment of HE aims to identify and resolve precipitating factors through targeting hyperammonemia and administering antibiotics or probiotics. While retrograde transvenous obliteration (RTO), including balloon-occluded retrograde transvenous obliteration, coil-assisted retrograde transvenous obliteration or plug-assisted retrograde tranvenous obliteration, is an established procedure to manage gastric varices, little is known about its potential to treat HE. RTO is a procedure to occlude a spontaneous portosystemic shunt, minimizing shunting of portal blood to systemic circulation. Though there is not a large study with HE patients who have undergone RTO; the results appear promising in reducing HE. Side effects, however, should be considered in the treatment of HE such as the transient worsening of portal hypertension and the formation of additional shunts. While additional studies are needed to assess the long-term success, RTO appears to be an effective alternative method to alleviate clinical symptoms of HE when pharmacological therapies and other conservative medical managements have failed.

Efficacy of orally administered sodium benzoate and sodium phenylbutyrate in dogs with congenital portosystemic shunts

BACKGROUND

Hyperammonemia can result in hepatic encephalopathy, which in severe cases eventually can lead to coma and death. In dogs, congenital portosystemic shunts (CPSS) are the most common cause for hyperammonemia. Conservative treatment consists of a protein modified diet, nonabsorbable disaccharides, antibiotics, or some combinations of these. Sodium benzoate (SB) and sodium phenylbutyrate (SPB) both are used in the acute and long-term treatment of humans with hyperammonemia caused by urea cycle enzyme deficiencies. Both treatments are believed to lower blood ammonia concentrations by promoting excretion of excess nitrogen via alternative pathways.

OBJECTIVES

To evaluate the efficacy and safety of PO treatment with SB and SPB on hyperammonemia and clinical signs in CPSS dogs.

METHODS

Randomized, double-blind, placebo-controlled crossover trial. Concentrations of blood ammonia and bile acids were measured in CPSS dogs before and after a 5-day treatment with SB, SPB, and placebo. A wash-out period of 3 days was used between treatments. A standard questionnaire was developed and distributed to owners to evaluate clinical signs before and after each treatment.

RESULTS

Blood ammonia concentrations were not influenced by any of the treatments and were comparable to those observed during placebo treatment. In addition, SB and SPB treatment did not result in improvement of clinical signs. Adverse effects during treatment included anorexia, vomiting, and lethargy.

CONCLUSIONS AND CLINICAL IMPORTANCE

Based on our results, we conclude that SB or SPB are not useful in the conservative treatment of hyperammonemia in dogs with CPSS.

Acetyl-L-carnitine for patients with hepatic encephalopathy

BACKGROUND

Hepatic encephalopathy is a common and devastating neuropsychiatric complication of acute liver failure or chronic liver disease. Ammonia content in the blood seems to play a role in the development of hepatic encephalopathy. Treatment for hepatic encephalopathy is complex. Acetyl-L-carnitine is a substance that may reduce ammonia toxicity. This review assessed the benefits and harms of acetyl-L-carnitine for patients with hepatic encephalopathy.

OBJECTIVES

To assess the benefits and harms of acetyl-L-carnitine for patients with hepatic encephalopathy.

SEARCH METHODS

We searched the Cochrane Hepato-Biliary Group Controlled Trials Register, CENTRAL, MEDLINE Ovid, Embase Ovid, LILACS, and Science Citation Index Expanded for randomised clinical trials. We sought additional randomised clinical trials from the World Health Organization Clinical Trials Search Portal and ClinicalTrials.gov. We performed all electronic searches until 10 September 2018. We looked through the reference lists of retrieved publications and review articles, and we searched the FDA and EMA websites.

SELECTION CRITERIA

We searched for randomised clinical trials in any setting, recruiting people with hepatic encephalopathy. Trials were eligible for inclusion if they compared acetyl-L-carnitine plus standard care (e.g. antibiotics, lactulose) versus placebo or no acetyl-L-carnitine plus standard care. We are well aware that by selecting randomised clinical trials, we placed greater focus on potential benefits than on potential harms.

DATA COLLECTION AND ANALYSIS

We selected randomised clinical trials, assessed risk of bias in eight domains, and extracted data in a duplicate and independent fashion. We estimated risk ratios (RRs) for dichotomous outcomes and mean differences (MDs) for continuous outcomes. We measured statistical heterogeneity using I² and D² statistics. We subjected our analyses to fixed-effect and random-effects model meta-analyses. We assessed bias risk domains to control systematic errors. We assessed overall quality of the data for each individual outcome by using the GRADE approach.

MAIN RESULTS

We identified five randomised clinical trials involving 398 participants. All trials included only participants with cirrhosis as the underlying cause of hepatic encephalopathy. Trials included participants with covert or overt hepatic encephalopathy. All trials were conducted in Italy by a single team and assessed acetyl-L-carnitine compared with placebo. Oral intervention was the most frequent route of administration. All trials were at high risk of bias and were underpowered. None of the trials were sponsored by the pharmaceutical industry.None of the identified trials reported information on all-cause mortality, serious adverse events, or days of hospitalisation. Only one trial assessed quality of life using the Short Form (SF)-36 scale (67 participants; very low-quality evidence). The effects of acetyl-L-carnitine compared with placebo on general health at 90 days are uncertain (MD -6.20 points, 95% confidence interval (CI) -9.51 to -2.89). Results for additional domains of the SF-36 are also uncertain. One trial assessed fatigue using the Wessely and Powell test (121 participants; very low-quality evidence). The effects are uncertain in people with moderate-grade hepatic encephalopathy (mental fatigue: MD 0.40 points, 95% CI -0.21 to 1.01; physical fatigue: MD -0.20 points, 95% CI -0.92 to 0.52) and mild-grade hepatic encephalopathy (mental fatigue: -0.80 points, 95% CI -1.48 to -0.12; physical fatigue: 0.20 points, 95% CI -0.72 to 1.12). Meta-analysis showed a reduction in blood ammonium levels favouring acetyl-L-carnitine versus placebo (MD -13.06 mg/dL, 95% CI -17.24 to -8.99; 387 participants; 5 trials; very low-quality evidence). It is unclear whether acetyl-L-carnitine versus placebo increases the risk of non-serious adverse events (8/126 (6.34%) vs 3/120 (2.50%); RR 2.51, 95% CI 0.68 to 9.22; 2 trials; very low-quality evidence). Overall, adverse events data were poorly reported and harms may have been underestimated.

AUTHORS' CONCLUSIONS

This Cochrane systematic review analysed a heterogeneous group of five trials at high risk of bias and with high risk of random errors conducted by only one research team. We assessed acetyl-L-carnitine versus placebo in participants with cirrhosis with covert or overt hepatic encephalopathy. Hence, we have no data on the drug for hepatic encephalopathy in acute liver failure. We found no information about all-cause mortality, serious adverse events, or days of hospitalisation. We found no clear differences in effect between acetyl-L-carnitine and placebo regarding quality of life, fatigue, and non-serious adverse events. Acetyl-L-carnitine reduces blood ammonium levels compared with placebo. We rated all evidence as of very low quality due to pitfalls in design and execution, inconsistency, small sample sizes, and very few events. The harms profile for acetyl-L-carnitine is presently unclear. Accordingly, we need further randomised clinical trials to assess acetyl-L-carnitine versus placebo conducted according to the SPIRIT statements and reported according to the CONSORT statements.

[Multiple organ manifestations of liver failure in acute small bowel obstruction]

Modern surgical and intensive care achievements did not result decrease of mortality in patients with acute small bowel obstruction (ASBO). Direct cause of mortality in ASBO patients is peritonitis followed by multiple organ failure syndrome including acute failure of liver, kidneys, lungs and other organs. Publications devoted to the problem of acute liver failure and its complicationsare reviewed in the article. Mechanisms of pathogenesis and clinical manifestations of multiple organ failure syndrome in patients with acute small bowel obstruction are analyzed.

Saline is as effective as nitrogen scavengers for treatment of hyperammonemia

Urea cycle enzyme deficiency (UCED) patients with hyperammonemia are treated with sodium benzoate (SB) and sodium phenylacetate (SPA) to induce alternative pathways of nitrogen excretion. The suggested guidelines supporting their use in the management of hyperammonemia are primarily based on non-analytic studies such as case reports and case series. Canine congenital portosystemic shunting (CPSS) is a naturally occurring model for hyperammonemia. Here, we performed cross-over, randomized, placebo-controlled studies in healthy dogs to assess safety and pharmacokinetics of SB and SPA (phase I). As follow-up safety and efficacy of SB was evaluated in CPSS-dogs with hyperammonemia (phase II). Pharmacokinetics of SB and SPA were comparable to those reported in humans. Treatment with SB and SPA was safe and both nitrogen scavengers were converted into their respective metabolites hippuric acid and phenylacetylglutamine or phenylacetylglycine, with a preference for phenylacetylglycine. In CPSS-dogs, treatment with SB resulted in the same effect on plasma ammonia as the control treatment (i.e. saline infusion) suggesting that the decrease is a result of volume expansion and/or forced diuresis rather than increased production of nitrogenous waste. Consequentially, treatment of hyperammonemia justifies additional/placebo-controlled trials in human medicine.

Cerebral hemodynamic and metabolic changes in fulminant hepatic failure

ABSTRACT Intracranial hypertension and brain swelling are a major cause of morbidity and mortality of patients suffering from fulminant hepatic failure (FHF). The pathogenesis of these complications has been investigated in man, in experimental models and in isolated cell systems. Currently, the mechanism underlying cerebral edema and intracranial hypertension in the presence of FHF is multi-factorial in etiology and only partially understood. The aim of this paper is to review the pathophysiology of cerebral hemodynamic and metabolism changes in FHF in order to improve understanding of intracranial dynamics complication in FHF.

Improvement of sleep architecture parameters in cirrhotic patients with recurrent hepatic encephalopathy with the use of rifaximin

BACKGROUND AND AIM

Sleep disorders are frequently reported in patients with cirrhosis and hepatic encephalopathy (HE). This study assessed the effect of rifaximin on sleep architecture parameters in patients with recurrent HE.

PATIENTS AND METHODS

This sequential, prospective, and exploratory study involved all patients with cirrhosis and recurrent HE admitted between June 2014 and September 2015. HE was assessed according to the West-Haven Classification. Patients underwent 24-h polysomnography (PSG) and 7-day actigraphy. Rapid eye movement (REM) sleep was considered to be an indicator of good sleep quality. Patients completed questionnaires assessing the quality of sleep and sleepiness. After a 28-day course of rifaximin, the same assessment was repeated.

RESULTS

Fifteen patients were included (nine men, mean age: 57±11 years). Child-Pugh scores ranged from B7 to C15. Before rifaximin, the mean HE score was 2.7±0.7. Data from PSG analysis indicated long total sleep time (TST): 571±288 min, and limited REM sleep: 2.5% TST (0-19). Seven-day actigraphy showed an impaired number of steps: 1690/24 h (176-6945). Questionnaires indicated that patients experienced impaired sleep quality and excessive daytime sleepiness. After rifaximin, HE scores decreased to 1.7±0.6 (P<0.001). REM sleep increased to 8.5% TST (0-25) (P=0.003). No changes were observed for TST, number of steps, and on questionnaires.

CONCLUSION

Patients with recurrent HE suffer from poor sleep quality and excessive daytime sleepiness. On 24-h PSG, rifaximin improves objective sleep architecture parameters with no changes in the subjective quality of sleep and sleepiness.

Delineation of microhemorrhage in acute hepatic encephalopathy using susceptibility-weighted imaging

INTRODUCTION

Microhemorrhages (MH's) in patients with acute hepatic encephalopathy (AHE) have scarcely been described. This study set out to assess if MH's occur in characteristic locations and frequency in patients with AHE superimposed on chronic liver failure, and to determine if such findings correlate with the clinical and MRI severity.

MATERIALS AND METHODS

Over a 4.5-year period, AHE patients with SWI MRI were included. The maximum plasma ammonia level (PAL), number and location of "frank" hemorrhages (>5mm size) or MH's (<5mm) on SWI, and severity of DWI and FLAIR were recorded. Susceptibility foci in the basal ganglia were disregarded, as those changes might represent common mineralization. The presence of MH's was correlated with the MRI and clinical severity.

RESULTS

Punctate MH foci were found in 18/38 (47.4%) patients. The most common locations were periventricular white matter (6/38 patients, 15.8%) and cerebral cortex (5/38, 13.2%). Of 47 MH's, only a tiny minority (8.5%) occurred in regions of abnormality on FLAIR or DWI. Both the MRI severity on FLAIR (r=0.420, p=0.013) and DWI (r=0.320, p=0.045) mildly correlated with clinical outcome, but the correlation was not significant after Bonferroni correction. No significant correlation was found between the number of MH's and the clinical score, clinical outcome, FLAIR severity, or DWI severity (range r=-0.083-0.152, p=0.363-0.618). The number of MH's was not significantly different among various vasculopathies. Foci on SWI improved in two patients following liver transplantation.

CONCLUSION

SWI-positive foci outside of the basal ganglia (presumed MH's) are present in nearly half of AHE patients, but do not portend outcome. Regions with the most observed MH's were the periventricular white matter, cortical gray matter, and subcortical white matter.

Keto analogue and amino acid supplementation and its effects on ammonemia and performance under thermoneutral conditions

Keto analogue and amino acid supplementation decreases ammonemia during exercise without affecting performance.

Factors associated with consciousness recovery time after liver transplantation in recipients with hepatic encephalopathy

BACKGROUND

Hepatic encephalopathy (HE) occurs as a result of liver failure and is often considered to be a clinical indication for liver transplantation (LT). An assessment of post-transplantation consciousness level in recipients with HE is crucial, because recovery of consciousness implies reestablishment of transplant liver function and lack of perioperative brain damage. The purpose of this study is to evaluate factors associated with consciousness recovery time after LT in recipients with HE.

METHODS

Out of 633 adult recipients who underwent LT, recipients who exhibited HE at the time of LT were analyzed retrospectively. The time between graft reperfusion and postoperative consciousness recovery was determined, and recipients were divided into 2 groups: group E with recovery of consciousness early (≤48 hours), and group L with recovery of consciousness late (>48 hours). Analyzed variables included recipient sex, age, graft type, Model for End-Stage Liver Disease score, HE history/duration/type/grade, and preoperative laboratory values, including blood ammonia concentration.

RESULTS

HE was present at the time of LT in 69 (10.9%) of 633 recipients. Among the 69 recipients, 11 recipients who died or underwent reoperation before consciousness recovery were excluded, and 58 recipients (group E: n = 32; group L: n = 26) were enrolled into analysis. Multivariate analysis showed that HE duration >5 days (odds ratio [OR], 15.58; 95% confidence interval [CI], 1.35-179.56; P = .028) and HE type C (OR, 30.90; 95% CI, 1.67-573.48; P = .021) were the independent factors associated with late recovery from HE after LT.

CONCLUSIONS

We suggest that recipients with long-duration or type C HE should be carefully managed during the post-transplantation period to prevent deterioration of HE.

Hepatic encephalopathy in patients with acute decompensation of cirrhosis and acute-on-chronic liver failure

Hepatic encephalopathy in a hospitalized cirrhotic patient is associated with a high mortality rate and its presence adds further to the mortality of patients with acute-on-chronic liver failure (ACLF). The exact pathophysiological mechanisms of HE in this group of patients are unclear but hyperammonemia, systemic inflammation (including sepsis, bacterial translocation, and insulin resistance) and oxidative stress, modulated by glutaminase gene alteration, remain as key factors. Moreover, alcohol misuse, hyponatremia, renal insufficiency, and microbiota are actively explored. HE diagnosis requires exclusion of other causes of neurological, metabolic and psychiatric dysfunction. Hospitalization in the ICU should be considered in every patient with overt HE, but particularly if this is associated with ACLF. Precipitating factors should be identified and treated as required. Evidence-based specific management options are limited to bowel cleansing and non-absorbable antibiotics. Ammonia lowering drugs, such as glycerol phenylbutyrate and ornithine phenylacetate show promise but are still in clinical trials. Albumin dialysis may be useful in refractory cases. Antibiotics, prebiotics, and treatment of diabetes reduce systemic inflammation. Where possible and not contraindicated, large portal-systemic shunts may be embolized but liver transplantation is the most definitive step in the management of HE in this setting. HE in patients with ACLF appears to be clinically and pathophysiologically distinct from that of acute decompensation and requires further studies and characterization.

Elevated cerebral lactate: Implications in the pathogenesis of hepatic encephalopathy

Hepatic encephalopathy (HE), a complex neuropsychiatric syndrome, is a frequent complication of liver failure/disease. Increased concentrations of lactate are commonly observed in HE patients, in the systemic circulation, but also in the brain. Traditionally, increased cerebral lactate is considered a marker of energy failure/impairment however alterations in lactate homeostasis may also lead to a rise in brain lactate and result in neuronal dysfunction. The latter may involve the development of brain edema. This review will target the significance of increased cerebral lactate in the pathogenesis of HE.

Induction of systemic oxidative stress leads to brain oedema in portacaval shunted rats

BACKGROUND & AIMS

The pathogenesis of hepatic encephalopathy (HE) is multifactorial and often associated with the development of brain oedema. In addition to ammonia playing a central role, systemic oxidative stress is believed to aggravate the neuropsychological effects of ammonia in patients with chronic liver disease (CLD). The aim of this study was to (i) induce systemic oxidative stress in hyperammonaemic portacaval anastomosed (PCA) rats by inhibiting the antioxidant glutathione using Dimethyl maleate (DEM) and (ii) investigate whether a synergistic relationship between ammonia and oxidative stress contributes to the pathogenesis of brain oedema in CLD.

METHODS

Four-week PCA and sham-operated rats received DEM (0.4-4 mg/kg/day) for the last 10 days before sacrifice when oxidative stress markers [reactive oxygen species (ROS) and malondialdehyde (MDA)] were assessed in blood and frontal cortex. Brain water content was measured using a specific gravimetric technique.

RESULTS

Dimethyl maleate induced an increase in ROS and MDA in the blood, but not in the brain, of the PCA rats, compared with non-treated PCA rats. This was accompanied with an increase in brain water content (PCA+DEM: 78.45 ± 0.13% vs. PCA: 77.38 ± 0.11%, P < 0.001). Higher doses of DEM induced systemic oxidative stress in sham-operated controls, but brain oedema did not develop.

CONCLUSIONS

Dimethyl maleate provoked systemic, not central, oxidative stress in PCA rats, resulting in the development of brain oedema. Independently, hyperammonaemia and systemic oxidative stress do not precipitate brain oedema; therefore, our findings sustain that a synergistic effect between hyperammonaemia and systemic oxidative stress is responsible for the development of brain oedema in HE.

Ornithine Transcarbamylase Deficiency: Diagnostic and Management Challenges in the ICU

A young male patient presented with altered sensorium and rapid clinical deterioration following a short period of nonspecific illness and was subsequently diagnosed with ornithine transcarbamylase deficiency (OTCD). We discuss the pathophysiology of OTCD, the difficulties surrounding diagnosis and treatment, and highlight some of the controversies and general management issues of the disease.

Current pathogenetic aspects of hepatic encephalopathy and noncirrhotic hyperammonemic encephalopathy

Hepatic encephalopathy is a medical phenomenon that is described as a neuropsychiatric manifestation of chronic or acute liver disease that is characterized by psychomotor, intellectual and cognitive abnormalities with emotional/affective and behavioral disturbances. This article focuses on the underlying mechanisms of the condition and the differences between hepatic encephalopathy and noncirrhotic hyperammonemic encephalopathy. Hepatic encephalopathy is a serious condition that can cause neurological death with brain edema and intracranial hypertension. It is assumed that approximately 60%-80% of patients with liver cirrhosis develop hepatic encephalopathy. This review explores the complex mechanisms that lead to hepatic encephalopathy. However, noncirrhotic hyperammonemic encephalopathy is not associated with hepatic diseases and has a completely different etiology. Noncirrhotic hyperammonemic encephalopathy is a severe occurrence that is connected with multiple pathogeneses.