Dietary and nutritional indications in hepatic encephalopathy

The restriction of dietary protein has long been considered a main stay in the therapy of hepatic encephalopathy. More recently it has been recognized that protein energy malnutrition is frequent in advanced liver disease and may adversely affect the patients’outcome. Moreover studies on inter-organ ammonia exchange in liver cirrhosis have shown that the muscle may have a crucial role in ammonia detoxification. In light of these evidences nutritional guidelines have proposed that protein restriction should be avoided in patients with hepatic encephalopathy as protein requirement is even increased in cirrhotic patients. Survey about the current clinical practice show that protein restriction is still considered advisable in patients with hepatic encephalopathy, however a recent trial evidenced that a low protein diet in patients hospitalized for acute hepatic encephalopathy exacerbates protein breakdown without inducing any specific clinical benefit when compared to a normal protein regimen. The relevance of an adequate protein intake and possible strategies to implement protein tolerance are also discussed. From the 13 International Symposium on Hepatic Encephalopathy and Nitrogen Metabolism held in Abano Terme, Padova 28th April 1st May 2008     

Type and etiology of liver cirrhosis are not related to the presence of hepatic encephalopathy or health-related quality of life: a cross-sectional study

Background  

Hepatic encephalopathy has a negative impact on health-related quality of life (QoL) in liver cirrhosis. There are scarce and conflicting data on whether type or etiology of liver cirrhosis could be related to hepatic encephalopathy in patients with cirrhosis. We aimed to determine the impact of cirrhosis etiology on hepatic encephalopathy and whether hepatic encephalopathy affects health-related QoL among patients with cirrhosis of different etiologies.     

Hepatic encephalopathy as a complication of liver cirrhosis: An Asian perspective

Hepatic encephalopathy is one of the most important clinical manifestations in decompensated liver cirrhosis. Accepted concepts regarding the pathophysiology of hepatic encephalopathy are that the endogenous neurotoxic substances, including ammonia: (i) escape from catabolism by the liver due both to the impaired function of the cirrhotic liver and also to the presence of portal systemic shunting; (ii) circulate at elevated concentrations in the systemic blood flow; (iii) reach the brain through the blood‐brain barrier; and (iv) impair cerebral function leading to disturbances of consciousness. The majority of these toxic substances are produced in the intestine by the bacterial flora, and are absorbed into the portal venous flow. The epidemiology of liver cirrhosis depends particularly on its etiology, and shows a marked geographic difference worldwide between Western, and Asian countries. Hepatic encephalopathy developed at an annual rate of 8% in cirrhotics in Far Eastern studies. In Eastern and Far East countries, therapeutic options are similar to those in the western hemisphere, but pronounced application of dietary restriction, antimicrobial agents, disaccharides, shunt obliteration and branched chain amino acids is noted. In spite of improved therapeutic options for encephalopathy, the long‐term survival is still low. Thus, hepatic encephalopathy remains a serious complication of liver cirrhosis. Establishment of truly effective prevention modalities and broader application of liver transplantation will help rescue patients suffering from this complication of liver cirrhosis in the near future.     

Subclinical hepatic encephalopathy predicts the development of overt hepatic encephalopathy

OBJECTIVES: In patients with compensated liver cirrhosis the clinical repercussions of detecting subclinical hepatic encephalopathy (SHE) are unclear. We present a long-term follow-up study in cirrhotic patients to examine the relationship between SHE and subsequent episodes of overt hepatic encephalopathy. METHODS: A total of 63 cirrhotic patients were studied by Number Connection Test and auditory evoked potentials. We determined glutamine, ammonia, zinc, glutamate, urea, and ratio of branched chain amino acids to aromatic amino acids, and Child-Pugh classification. RESULTS: Of 63 patients, 34 (53%) exhibited SHE. Nineteen out of 63 (30%) developed overt hepatic encephalopathy during follow-up. Hepatic encephalopathy in follow-up was related to alcoholic etiology, ammonia, glutamine, zinc, ratio of branched chain amino acids to aromatic amino acids, liver function, presence of esophageal varices, and detection of SHE (84% of patients who exhibited hepatic encephalopathy in follow-up showed SHE). In Cox-regression, glutamine levels, SHE, esophageal varices, and Child-Pugh class were the independent variables related to hepatic encephalopathy in follow-up. CONCLUSIONS: SHE (defined on the basis of number connection test or auditory evoked potentials alteration) could predict a subsequent episode of overt hepatic encephalopathy. Lower glutamine levels, presence of esophageal varices, and liver dysfunction were also related to the development of overt hepatic encephalopathy.     

Diagnosis and treatment of hepatic encephalopathy

Hepatic encephalopathy arises from the combination of hepatocellular dysfunction and portal-systemic shunting. Encephalopathy is more prominent in advanced stages of liver cirrhosis and signals the presence of fulminant hepatic failure in patients with acute liver injury. As important as the extent of shunting is the presence of large spontaneous collaterals. Ammonia continues to be a leading toxin influencing brain function. Endogenous benzodiazepines and cytokines may contribute to one of ammonia's key effects in the brain: astrocyte swelling. The diagnosis of hepatic encephalopathy is a diagnosis of exclusion; the search for a precipitating factor should be started immediately in all cases of encephalopathy. The treatment of hepatic encephalopathy has three aims: decrease the nitrogenous load from the gut, improve the extra-intestinal elimination of ammonia and counteract central abnormalities of neurotransmission. The mainstay of treatment is directed at the colon. Newer approaches targeting the brain, such as flumazenil, have become available.     

Management of hepatic encephalopathy in patients with cirrhosis

The term hepatic encephalopathy encompasses a spectrum of neuropsychiatric abnormalities seen in patients with liver dysfunction. Distinct syndromes are identified in acute liver failure and cirrhosis. Rapid deterioration in consciousness level and increased intracranial pressure that may result in brain herniation and death are a feature of acute liver failure whereas manifestations of hepatic encephalopathy in cirrhosis include psychomotor dysfunction, impaired memory, increased reaction time, sensory abnormalities, poor concentration and in severe forms, coma. In patients with acute-on-chronic liver failure the pathophysiology remains undefined. Ammonia has been considered central to its pathogenesis. In the brain, the astrocyte is the main site for ammonia detoxification, during the conversion of glutamate to glutamine. An increased ammonia level raises the amount of glutamine within astrocytes, causing an osmotic imbalance resulting in cell swelling and ultimately brain oedema. Recent studies suggest that inflammation and it modulators may play a synergistic role with ammonia in the pathogenesis of hepatic encephalopathy. Therapy of hepatic encephalopathy is directed primarily at reducing ammonia generation and increasing its detoxification. The currently accepted regimens to treat hepatic encephalopathy such as lactulose and protein restricted diets need further clinical trials and therefore placebo controlled clinical trials in hepatic encephalopathy are justified. In liver failure, ammonia metabolism involves multiple organs and therefore ammonia reduction will require simultaneous targeting of these organs. The present review describes the pathophysiological basis of hepatic encephalopathy and evaluates the available therapies.     

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.     

Minimal hepatic encephalopathy: time to recognise and treat

Minimal hepatic encephalopathy represents a part of the spectrum of hepatic encephalopathy and is the mildest form. While patients with hepatic encephalopathy have impaired intellectual functioning, personality changes, altered levels of consciousness, and neuromuscular dysfunction, patients with minimal hepatic encephalopathy have no recognisable clinical symptoms of hepatic encephalopathy but have mild cognitive and psychomotor deficits. The prevalence of minimal hepatic encephalopathy has been reported to vary between 30% and 84% in patients with liver cirrhosis and is higher in patients with poor liver function. The diagnosis is usually made by neuropsychological and/or neurophysiological testing in cirrhotic patients who are otherwise normal on neurological examination. Minimal hepatic encephalopathy is a clinically significant disorder that impairs the health-related quality of life, predicts the development of overt encephalopathy and is probably associated with a poor prognosis. Thus screening all patients with cirrhosis for minimal hepatic encephalopathy using psychometric testing is recommended. Pharmacologic therapy is recommended for patients diagnosed with minimal hepatic encephalopathy. The pathogenesis of minimal hepatic encephalopathy is considered similar to that of overt hepatic encephalopathy and ammonia plays a key role. Thus ammonia lowering agents such as lactulose, L-ornithine and L-aspartate that have good safety profiles are recommended. Future studies will better define the role of probiotics, levocarnitine and sodium benzoate.     

Helicobacter pylori infection does not correlate with plasma ammonia concentration and hepatic encephalopathy in patients with cirrhosis

BACKGROUND/AIMS: In patients with cirrhosis, infection of the stomach with Helicobacter pylori may increase ammonia production and, consequently, the incidence of hepatic encephalopathy. To test this hypothesis a retrospective analysis was performed in patients with a transjugular intrahepatic portosystemic shunt. These patients are regarded to be ideal candidates for such a study since they have a high bioavailability of gut-derived ammonia and many of them develop spontaneous hepatic encephalopathy. METHODOLOGY: In 132 patients (Child-Pugh class A: 24%, B: 49%, C: 27%) with stable transjugular intrahepatic portosystemic shunt function for more than 3 months (mean follow-up: 15.5 +/- 10.8 months) the diagnosis of H. pylori infection was established by a specific and sensitive immunoblot assay for IgG- and IgA-antibodies. During follow-up, hepatic encephalopathy was assessed by clinical examination and a structured questionnaire. Venous plasma ammonia concentration was measured at the time of antibody determination (end of study period). RESULTS: Eighty-four patients (64%) had negative and 48 patients (36%) had positive immunoblots for H. pylori. The groups were comparable with respect to age, gender, etiology of cirrhosis, Child-Pugh class, follow-up after transjugular intrahepatic portosystemic shunt, and shunt function. The ammonia concentrations of the patients without (group 1) and with antibodies against H. pylori (group 2) were 73 +/- 27 and 69 +/- 28 mumol/L (mean +/- SD), respectively. Hepatic encephalopathy occurred in 23 of 84 patients (27%) of group 1 and in 11 of 48 patients (23%) of group 2. CONCLUSIONS: A positive immunoblot for H. pylori antibodies neither correlates with plasma ammonia concentration nor with the incidence of hepatic encephalopathy in patients with cirrhosis of the liver and portosystemic shunt.     

Rifaximin in the treatment of hepatic encephalopathy

Hepatic encephalopathy is a frequent and serious complication of liver cirrhosis. Usually it is treated by non-absorbable disaccharides or antibiotics and its treatment is often difficult and associated with undesirable effects. The objective of our investigation was to evaluate the safety and effectiveness of a new antibiotic used in this indication--rifaximine. With rifaximine, 400 mg three times per day, a total of 25 patients were treated for a 10-day period. Significant improvement of the manifestations of encephalopathy occurred (evaluated by the grade of encephalopathy, test of combining numerals, the degree of flapping tremor and the arterial ammonia level). None of the patients developed undesirable effects. Rifaximine seems an effective, safe drug for hepatic encephalopathy.     

Malnutrition and hypermetabolism are not risk factors for the presence of hepatic encephalopathy: a cross-sectional study

Background and Aim: Hepatic encephalopathy is a frequent complication of cirrhosis. The present retrospective investigation was conducted to characterize metabolic alterations in cirrhotic patients with and without hepatic encephalopathy. We tested the hypothesis that reduced nutritional status or the degree of tissue catabolism are associated with the presence of hepatic encephalopathy. Methods: We investigated 223 patients with histologically confirmed nonalcoholic cirrhosis without hepatic encephalopathy and with hepatic encephalopathy (grades 1–3). To assess liver function, nutritional status, and energy metabolism, a variety of biochemical and clinical tests were performed including anthropometric measurements, bioelectrical impedance analysis, and indirect calorimetry. Results: Nutritional status and tissue catabolism were not significantly different between patients with and without hepatic encephalopathy. Conclusions: Our data do not support the hypothesis that malnutrition or tissue catabolism are independent risk factors for the presence of hepatic encephalopathy in patients with nonalcoholic cirrhosis.     

Helicobacter pylori, gastric juice, and arterial ammonia levels in patients with cirrhosis

Helicobacter pylori urease activity is a potential source of ammonia in the stomach of patients with cirrhosis. However, the possible role of H. pylori in the pathogenesis of hepatic encephalopathy deserves further investigations. The current study evaluates the relationship among H. pylori infection, gastric juice ammonia concentrations, and arterial ammonia levels in patients with cirrhosis. Overall, 14 patients with cirrhosis with overt hepatic encephalopathy, 19 with subclinical hepatic encephalopathy, and 13 without encephalopathy were enrolled. All patients underwent upper endoscopy, and gastric biopsy specimens were taken for H. pylori assessment (rapid urease test, histology, and culture). A gastric juice sample and an arterial blood sample were obtained for ammonia level assessment. Patients with overt encephalopathy had both higher arterial ammonia levels and a more severe hepatic impairment than the remaining patients, whereas gastric juice ammonia concentrations did not differ among the three groups. H. pylori prevalence was similar among groups. Patients with H. pylori infection had significantly higher gastric juice ammonia concentrations than those without infection (2.3 +/- 1.3 vs. 0.9 +/- 0.6 mmol/L, respectively; p = 0.003); however, no difference in arterial ammonia levels emerged between the two groups (37.7 +/- 18.6 vs. 37.6 +/- 18.8 micromol/L, respectively). No significant correlation was found between gastric juice ammonia concentrations and arterial ammonia levels. The data suggest that liver impairment remains crucial in ammonia disposal in patients with cirrhosis, whereas H. pylori infection does not seem to play a major role in the pathogenesis of hyperammonemia in these patients.     

肝硬化患者轻微肝性脑病临床相关危险因素分析

目的评估肝硬化人群中轻微型肝性脑病（MHE）发生的相关因素.方法在121例肝硬化患者,分别进行心理肝性脑病得分（PHES）和临界闪烁频率（CFF）测定,并评估肝功能分级状态.结果在121例肝硬化患者中,检出MHE者70例（57.9%）.性别、受教育程度、肝病病因、肝功能Child-Pugh分级、血浆氨浓度等因素对肝硬化患者发生MHE无统计学意义（P〉0.05）;经Logistic多因素回归分析,仅发现年龄为MHE发生的危险因素（P=0.041, OR=1.035）,而MHE发生与性别、教育程度、肝病病因、肝功能Child-Pugh分级和血浆氨浓度无关（P〉0.05）.结论在肝硬化患者中MHE发生率较高,年龄增长是肝硬化患者发生MHE的危险因素.     

Serum natremia affects health-related quality of life in patients with liver cirrhosis: a prospective,single centre study

Introduction. Hyponatremia is associated with high mortality and predicts hepatic encephalopathy but its effect on health-related quality of life remains to be established.Material and methods. In this study we prospectively analyzed the relationship between hyponatremia, clinical features and quality of life in a cohort of 116 patients with cirrhosis. Chronic Liver Disease Questionnaire and Medical Outcomes Study 36-Item Short Form Health Survey were performed to assess quality of life. Evaluation of hepatic encephalopathy included West-Haven criteria, Psychometric Hepatic Encephalopathy Score and Critical Flicker Frequency analysis. Severity of liver disease was assessed with Child-Pugh score and MELD. Univariate and multivariate analysis were implemented to evaluate the influence of analyzed factors on quality of life.Results. Multivariate analysis has identified serum natremia, Psychometric Hepatic Encephalopathy Score, Critical Flicker Frequency and severity of liver disease measured with MELD and Child-Pugh score as independent factors affecting quality of life in patients with cirrhosis. West Heaven criteria failed to show the relationship with quality of life in analyzed subjects. Serum kalemia showed correlation with neither quality of life, hepatic encephalopathy nor severity of the disease.Conclusion. In patients with cirrhosis serum natremia along with severity of liver disease and hepatic encephalopathy exerts a significant effect on patients’ quality of life.     

Hepatic encephalopathy: Ever closer to its big bang

Hepatic encephalopathy(HE) is a neuropsychiatric disorder that commonly complicates the course of patients with liver disease. Despite the fact that the syndrome was probably first recognized hundreds of years ago, the exact pathogenesis still remains unclear. Minimal hepatic encephalopathy(MHE) is the earliest form of HE and is estimated to affect more that 75% of patients with liver cirrhosis. It is characterized by cognitive impairment predominantly attention, reactiveness and integrative function with very subtle clinical manifestations. The development of MHE is associated with worsen in driving skills, daily activities and the increase of overall mortality. Skeletal muscle has the ability to shift from ammonia producer to ammonia detoxifying organ. Due to its large size, becomes the main ammonia detoxifying organ in case of chronic liver failure and muscular glutaminesynthase becomes important due to the failing liver and brain metabolic activity. Gut is the major glutamine consumer and ammonia producer organ in the body. Hepatocellular dysfunction due to liver disease, results in an impaired clearance of ammonium and in its interorgan trafficking. Intestinal bacteria, can also represent an extra source of ammonia production and in cirrhosis, small intestinal bacterial overgrowth and symbiosis can be observed. In the study of HE, to get close to MHE is to get closer to its big bang; and from here, to travel less transited roads such as skeletal muscle and intestine, is to go even closer. The aim of this editorial is to expose this road for further and deeper work.     

Role of Helicobacter pylori infection in hyperammonemia and subclinical hepatic encephalopathy in cirrhosis of liver.

INTRODUCTION: Gastric Helicobacter pylori infection is believed to be associated with a higher risk of hepatic encephalopathy among patients with cirrhosis of liver. However, the role of this infection in causation of subclinical hepatic encephalopathy has not been studied in detail. METHODS: Patients with cirrhosis of liver but no hepatic encephalopathy underwent venous blood ammonia measurement, psychometric tests (number connection tests [NCT] and figure connection tests [FCT]), and gastric biopsies for presence of H. pylori infection. The results of blood ammonia and psychometric tests in the H. pylori-positive and -negative study subjects were compared. RESULTS: Of 58 patients with liver cirrhosis studied, 31 had evidence of gastric H. pylori infection. Venous blood ammonia levels were comparable in patients with (median 29 mmol/L; range 18-47) and without (34 [15-48] mmol/L; p=ns) H. pylori infection. The time taken to complete NCT trail A (median 37 s [range 25-69] versus 36.5 [26-62]), NCT trail B (64 s [48-91] versus 63.5 [42-88]), FCT trail A (59 s [31-115] versus 58 [38-590]) and FCT trail B (76 s [55-187] versus 82 [36-125]) were similar in those with and those without H. pylori infection. For each of the four tests, the proportion of subjects with abnormal test results was similar among H. pylori-positive and -negative subjects. CONCLUSION: Presence of H. pylori infection among patients with cirrhosis of liver but no overt hepatic encephalopathy is not associated with increase in blood ammonia concentration or deterioration in psychomotor function.     

MR and 1H MR spectroscopy of the brain in patients with liver cirrhosis and early stages of hepatic encephalopathy

BACKGROUND/AIMS: Hepatic encephalopathy is a serious problem in patients with liver cirrhosis and precise pathophysiological mechanisms responsible for encephalopathy are not fully understood. Magnetic resonance imaging and magnetic resonance spectroscopy can be used to detect specific morphological and metabolic abnormalities in the brain even in patients with early stages of hepatic encephalopathy. METHODOLOGY: Twenty patients with liver cirrhosis and 14 patients with grade I-II hepatic encephalopathy were studied with magnetic resonance and proton magnetic resonance spectroscopy. Localized magnetic resonance spectra were acquired in the parietal gray/white matter regions and basal ganglia. Control group consisted of 20 healthy volunteers. RESULTS: Frequency and degree of brain atrophy and bilateral signal hyperintensities in globus pallidus were similar in groups with liver cirrhosis and with encephalopathy. Decreased myoinositol, choline and increased glutamine levels were noted in both groups whereas N-acetylaspartate levels were unchanged. The statistically significant differences between cirrhotic and encephalopathic groups were observed only in myoinositol/creatine ratio in basal ganglia. There were no significant differences in metabolic concentrations between parietal and basal ganglia regions. CONCLUSIONS: Metabolic brain alterations occur earlier than clinical evidence of hepatic encephalopathy but there is no correlation between presence of symptoms encephalopathy and magnetic resonance and magnetic resonance spectroscopy findings.     

Saccadic latency in hepatic encephalopathy: a pilot study

Hepatic encephalopathy is a common complication of cirrhosis. The degree of neuro-psychiatric impairment is highly variable and its clinical staging subjective. We investigated whether eye movement response times—saccadic latencies—could serve as an indicator of encephalopathy. We studied the association between saccadic latency, liver function and paper- and pencil tests in 70 patients with cirrhosis and 31 patients after liver transplantation. The tests included the porto-systemic encephalopathy (PSE-) test, critical flicker frequency, MELD score and ammonia concentration. A normal range for saccades was established in 31 control subjects. Clinical and biochemical parameters of liver, blood, and kidney function were also determined. Median saccadic latencies were significantly longer in patients with liver cirrhosis when compared to patients after liver transplantation (244 ms vs. 278 ms p < 0.001). Both patient groups had prolonged saccadic latency when compared to an age matched control group (175 ms). The reciprocal of median saccadic latency (μ) correlated with PSE tests, MELD score and critical flicker frequency. A significant correlation between the saccadic latency parameter early slope (σ_E) that represents the prevalence of early saccades and partial pressure of ammonia was also noted. Psychometric test performance, but not saccadic latency, correlated with blood urea and sodium concentrations. Saccadic latency represents an objective and quantitative parameter of hepatic encephalopathy. Unlike psychometric test performance, these ocular responses were unaffected by renal function and can be obtained clinically within a matter of minutes by non-trained personnel.     

氨甲酰磷酸合成酶-Ⅰ和鸟氨酸氨基甲酰转移酶与肝性脑病的关系

目的 探讨血清氨甲酰磷酸合成酶Ⅰ(CPS-Ⅰ)和鸟氨酸氨基甲酰转移酶(OCT)在肝性脑病(HE)发生中的作用.方法 2008年1月-2009年12月在我院住院的120例肝硬化患者,其中HE患者25例,非肝性脑病(非HE)患者95例.对照组为我院健康体检正常者60例.收集研究对象的血清和血浆,采用酶联免疫吸附试验方法测定血清CPS-Ⅰ、OCT,VITROS-250干化学分析仪测定血氨.分析HE组、非HE组、对照组CPS-Ⅰ和OCT水平;分析肝硬化患者CPS-Ⅰ、OCT与肝功能及血氨的相关性;分析CPS-Ⅰ、OCT水平与肝硬化患者Child-Pugh分级之间的相关性.应用SPSS15.0软件进行数据分析,采用x2和t检验,计量资料两组间比较采用成组t检验,多组间的比较采用方差分析、q检验,两变量相关分析采用Pearson相关分析法.结果 HE组血清CPS-Ⅰ、OCT水平分别为(143.3±48.5)U/L和(297.0±102.6)×10 U/L,非HE组分别为(180.3±51.5)U/L和(351.8±109.0)×10 U/L,t值分别为2.53和2.78,P值均＜0.01;HE组、非HE组血清CPS-Ⅰ、OCT水平均低于正常对照组,t值分别为3.21、4.16和2.12、3.15,P值均＜0.05.CPS-Ⅰ与OCT相关性好,r=0.946,P＜0.05;CPS-Ⅰ、OCT与ALT、AST呈负相关,r值分别为-0.284、-0.239、-0.303、-0.322,P值均＜0.05.肝硬化患者CPS-Ⅰ、OCT水平和Child分级密切相关,F值分别为10.13,20.28,P值均＜0.01.结论 肝硬化患者CPS-Ⅰ和OCT活性影响血氨水平,CPS-Ⅰ和OCT与肝性脑病的发生密切相关.