Branched-chain amino acids in the management of hepatic encephalopathy: an analysis of variants

Parenteral nutrition: Revisited

The prevalence of malnutrition among critically ill patients, especially those with a protracted clinical course, has remained largely unchanged over the last two decades. The metabolic response to stress, injury, surgery, or inflammation cannot be accurately predicted and these metabolic alterations may change during the course of illness. Both underfeeding and overfeeding are common in intensive care units (ICU), resulting in large energy and other nutritional imbalances. Systematic research and clinical trials on various aspects of nutritional support in the ICU are limited and make it challenging to compile evidence-based practice guidelines.

Role of meal carbohydrate content for the imbalance of plasma amino acids in patients with liver cirrhosis

BACKGROUND AND AIM

Imbalance of circulating branched chain amino acids (BCAA) versus aromatic amino acids (AAA) and hyperinsulinemia are common metabolic alterations in patients with liver cirrhosis. The aim of this study was to characterize the effect of the carbohydrate component of a protein-rich mixed meal on postprandial plasma concentrations of 21 amino acids, insulin and C-peptide in patients with compensated liver cirrhosis. Furthermore, the effect of a dietary intervention on the metabolic alterations in cirrhotic patients was examined.

METHODS

Eighteen patients with cirrhosis and 12 healthy volunteers received a protein-rich meal (pork filet 200 g) with or without carbohydrates (bread 50 g, glucose 20 g). A subgroup of four cirrhotic patients received an isoenergetic (117 kJ/kg bw) carbohydrate-enriched (60%) and -restricted (20%) diet for 7 days each.

RESULTS

In the cirrhotic patients, basal plasma insulin and C-peptide concentrations were significantly elevated. The ingestion of a protein-rich meal without additional carbohydrates led to a significantly greater increase of insulin and C-peptide in the cirrhotic patients compared to controls. Postprandial increases of leucine and isoleucine were reduced, whereas those of phenylalanine were higher in cirrhotic patients. The addition of carbohydrates led to higher insulin and C-peptide plasma concentrations in cirrhotic patients. Postprandial BCAA increases were more impaired in the cirrhotic group after additional carbohydrate ingestion (46%vs 82%). After the carbohydrate-restricted diet for 7 days BCAA plasma levels increased but the BCAA/AAA ratio remained unaltered.

CONCLUSIONS

The carbohydrate content of a meal enhances reduction of BCAA plasma concentrations in clinically stable cirrhotic patients. An imbalanced BCAA/AAA ratio cannot be avoided by a carbohydrate-reduced diet alone, supporting mandatory BCAA supplementation.

Total Parenteral Nutrition: Challenges and Practice in the Cirrhotic Patient

Patients with cirrhosis develop metabolic derangements of protein, carbohydrate, and lipid metabolism. Malnutrition is commonplace and is associated with morbidity and mortality. Specific nutrient deficiencies may occur and enteral or parenteral nutritional support may improve outcome in appropriately selected patients. Parenteral nutrition itself has been associated with hepatic dysfunction, although the preponderance of evidence suggests that hepatic dysfunction is more a function of the underlying disorder and malabsorption. Intravenously infused organic nutrients may be metabolized differently than the same nutrient consumed enterally. The pathophysiology of total parenteral nutrition-associated liver disease is discussed as well as potential management options.

[Diagnosis and treatment of hepatic encephalopathy in Spain: results of a survey of hepatologists]

INTRODUCTION

Hepatic encephalopathy is a common complication of cirrhosis. Recent studies have challenged the efficacy of nonabsorbable disaccharides and have reported that protein restriction may pose risks to patients with cirrhosis and hepatic encephalopathy.

AIM

To determine the diagnostic and therapeutic practices of physicians treating patients with hepatic encephalopathy.

MATERIAL AND METHODS

We designed a 20-item questionnaire, which was mailed to the members of the Spanish Society for the Study of the Liver.

RESULTS

We received 128 questionnaires, completed by physicians with wide clinical experience. They reported that the most common precipitating factors in episodic encephalopathy were infections (22%), diuretics (21%), and gastrointestinal bleeding (21%). The usual treatment of episodic encephalopathy was administration of nonabsorbable disaccharides (90%) and protein restriction (52%). Patients with chronic encephalopathy were also usually treated with nonabsorbable disaccharides (94%) and protein restriction (40%). Fifty-nine percent of the hepatologists never carried out neurophysiologic or neuropsychologic assessment for the diagnosis of minimal hepatic encephalopathy.

CONCLUSION

Although their efficacy has been questioned, nonabsorbable disaccharides and protein restriction are the most commonly prescribed treatments for hepatic encephalopathy. Future studies are needed to assess the efficacy and risks of these treatments. Most hepatologists never assess minimal hepatic encephalopathy in patients with cirrhosis.

Flumazenil-Induced Improvement of the Central Dopaminergic System in Rats with Acute Hepatic Failure

Several reports have demonstrated the alleviation of hepatic encephalopathy by flumazenil, an antagonist of benzodiazepine receptors. As changes in central monoaminergic activity are involved in the mechanisms for hepatic encephalopathy, the effects of flumazenil on central monoaminergic activity were evaluated in acute hepatic failure produced by ischemia-reperfusion injury in rats. Eighteen male Wistar rats were evenly assigned to three groups: sham-operated group given saline, liver-ischemic group given saline, and liver-ischemic group given flumazenil. Flumazenil (1 mg/kg) or saline (10 mL/kg) was intraperitoneally administered three times, at 1, 6, and 24 hours after 90 minutes of liver ischemia produced by occlusion of the left portal vein. The extracellular concentrations of neurotransmitter amino acids, monoamines, and their metabolites were determined in the striatum using a microdialysis procedure. Another set of 12 rats was subjected to liver ischemia, and the effect of flumazenil on spontaneous motor activity was examined after 24 hours. The extracellular concentration of 3,4-dihydroxyphenylacetic acid, a metabolite of dopamine, decreased to 39% of that in sham-operated animals 24 hours after surgery (P < 0.05), although the dopamine level did not change. The treatment with flumazenil completely abolished the decrease in the metabolite (P < 0.05). Although the glutamate level in the injured animals decreased to 42% of that in sham-operated animals (P < 0.05), no remarkable increase in the glutamate level was observed in animals treated with flumazenil. Spontaneous motor activity decreased 24 hours after surgery in animals subjected to liver ischemia. Flumazenil led to improvement of spontaneous motor activity 5 minutes after administration, but this effect was not observed after 30 minutes. The restoration of the central dopaminergic function may be a contributing factor in the improvement of hepatic encephalopathy.

Changing perspectives in the nutritional management of disease

There have been substantial changes in the nutritional management of many diseases in the last 20 years, which have been accompanied by a growing recognition of its importance. Many of the changes in clinical nutrition have been associated with the introduction of standards, clinical audit and the implementation of evidence-based practice, which has led to a re-evaluation of some established dietary interventions using a hierarchy-of-evidence approach. Although there are few randomised controlled trials on which to base such work, the examination of other, often less-robust, evidence has led to some traditional dietary interventions being modified. Examples in gastroenterology include the use of low-fat diets in gall bladder disease and the restriction of protein in hepatic encephalopathy, where the current evidence suggests that neither should be used routinely in clinical practice. Where therapeutic dietary restrictions are required, as with low-Na diets in ascites, there is very little information on how these restrictions influence total nutrient intake and, if intake is impaired, how the detrimental effects of an inadequate intake should be balanced with the therapeutic effects of restriction. Studies are required to ensure that nutritional interventions are not only effective but also free from undesirable side effects. The mode and timing of the delivery of nutritional support has also been re-evaluated and the benefits of early enteral feeding have been recognised. The delivery of dietary advice is a new area that is being considered, with practitioners in clinical nutrition using behaviour-change skills to facilitate optimum nutrition rather than simply providing patients with advice. For such developments to continue in clinical nutrition it is essential that all practice should be systematically evaluated and, where necessary, modified in the light of sound current research findings, and that gaps in our present knowledge base are identified and addressed.

[Fulminant hepatitis B]

Fulminant hepatitis, or fulminant hepatic failure, is defined as a clinical syndrome of severe liver function impairment, which causes hepatic coma and the decrease in synthesizing capacity of liver, and develops within eight weeks of the onset of hepatitis. Several independent factors influence the survival of patients: age, the cause of liver disease, the degree and the duration of encephalopathy in relation to the onset of the disease, and the prevention of complications. Over the years many intensive treatments have been practiced. Liver transplantation is expensive, and patients who survive transplantation require life-long immunosuppression, clinical care and complications management. Without transplantation fulminant hepatitis and hepatic failure might be completely recovered spontaneously, and the patient could expect a normal life. Two cases of fulminant B hepatitis with intensive care treatment, and their survival despite unfavorable prognosis are presented in this paper. The management of patients with fulminant hepatitis required intensive monitoring and therapeutic measures, including corticosteroids. The prognosis for survival without transplantation in fulminant hepatitis is limited by the measures of medical treatment and new specific therapeutic modalities which must be developed through basic research.

Branched-chain amino acids for hepatic encephalopathy

BACKGROUND

Hepatic encephalopathy may be caused by a decreased plasma ratio of branched-chain amino acids (BCAA) to aromatic amino acids. Treatment with BCAA may therefore have a beneficial effect on patients with hepatic encephalopathy.

OBJECTIVES

To evaluate the beneficial and harmful effects of BCAA for patients with hepatic encephalopathy.

SEARCH STRATEGY

We identified trials through The Cochrane Hepato-Biliary Group Controlled Trials Register (September 2002), (Issue 3, 2002), MEDLINE (1966-2002/09) and EMBASE (1980-2002/05), manual searches of bibliographies and journals, authors of trials, and pharmaceutical companies.

SELECTION CRITERIA

Randomised trials comparing BCAA with any kind of control therapy for hepatic encephalopathy were included, regardless of blinding, language, or publication status.

DATA COLLECTION AND ANALYSIS

Trial inclusion and data extraction were made independently by two reviewers. Our primary outcome was improvement of hepatic encephalopathy. Statistical heterogeneity was tested using random effects and fixed effect models. Binary outcomes are reported as risk ratios (RR) based on a random effects model.

MAIN RESULTS

Eleven randomised trials (556 patients) assessing BCAA versus carbohydrates, neomycin/lactulose, or isonitrogenous control were included. The median number of patients in each trial was 55 (range 22 to 75). Follow-up after treatment was reported in four trials (median 17 days (range 6 to 30 days)). Compared to the control regimens, BCAA significantly increased the number of patients improving from hepatic encephalopathy at the end of treatment (risk ratio (RR) 1.31, 95% confidence interval (CI) 1.04 to 1.66, nine trials). We found no evidence of an effect of BCAA on survival (RR 1.06, 95% CI 0.98 to 1.14, eight trials) or adverse events (RR 0.97, 95% CI 0.41 to 2.31, three trials). Sensitivity analyses indicated that methodological quality had significant impact on the results. We found no evidence of an effect of BCAA on improvement of hepatic encephalopathy in trials with adequate generation of the allocation sequence (RR 1.01, 95% CI 0.84 to 1.23, three trials), adequate allocation concealment (RR 1.09, 95% CI 0.89 to 1.33, five trials), or adequate double-blinding (RR 1.20, 95% CI 0.83 to 1.73, three trials).

REVIEWER'S CONCLUSIONS

We did not find convincing evidence that BCAA had a significant beneficial effect on patients with hepatic encephalopathy. The trials performed in this field were small with short follow-up and most had low methodological quality.

Management of hepatic encephalopathy

Hepatic encephalopathy (HE) is seen as a clinical manifestation of low grade chronic cerebral edema, which is accompanied by alterations in glioneural communication. Different factors such as ammonia, inflammatory cytokines, benzodiazepines and electrolyte imbalances may precipitate or aggravate glia edema, thereby explaining precipitation of HE episodes by a variety of unrelated factors. Recognition and rigorous treatment of these precipitating factors is the most important measure in HE therapy which may be augmented by dietary and medical approaches. Among these approaches, evidence for proven therapeutical efficacy in HE on the basis of placebo-controlled trials is existing only for transplantation, protein restriction, administration of vegetable proteins, ornithine-aspartate, oral branched-chain amino acid treatment as well as lactulose enemas. The efficacy of oral lactulose has not been demonstrated on the basis of placebo-controlled trials.

Hepatic Encephalopathy

A characteristic feature of the neuropsychiatric changes in hepatic encephalopathy (HE) is the potential for a complete recovery in the majority of patients. In this review, we limit our discussion to HE in individuals with chronic liver disease. The optimal approach to the management of HE includes the following elements. Provide standard supportive therapy for patients with an altered mental status. This is the mainstay of therapy in the majority of clinical situations and includes administration of parenteral fluids and nutrition, care of vascular and bladder catheters, control of self-injurious activities, and instituting aspiration precautions. Rule out or control concomitant causes of encephalopathy. The diagnosis of HE has positive and negative criteria, and ruling out other causes of change in mental status is an essential component of the diagnosis. Identify and correct the precipitating factors of HE. In the majority of patients with HE, a clearly defined precipitating factor usually is identified, and the reversal or control of these factors is a key step in management. Institute gut-cleansing and ammonia-lowering measures. These measures are based on clinical and pathogenic characteristics of HE and are aimed at neutralizing the putative encephalogenic toxins (namely ammonia).

Effects of a branched-chain amino acid-enriched diet on chronic hepatic encephalopathy in dogs

A decreased ratio of branched-chain amino acids (BCAA) to aromatic amino acids (AAA) is considered an important pathogenetic factor in hepatic encephalopathy (HE). A relationship between the deranged BCAA/AAA ratio and dopaminergic dysfunction through the formation of "false" neurotransmitters has been postulated. The intermediate lobe of the pituitary is more pronounced in dogs than in humans and because it is primarily under dopaminergic inhibitory influence, it may serve as an indicator of alterations in dopaminergic neurotransmission. We investigated the effects of a diet with a high BCAA/AAA ratio (HR) and an isonitrogenous diet with a low BCAA/AAA ratio (LR) on several physical and biochemical parameters including pituitary function in dogs with portocaval shunts and 40% hepatectomy and in sham-operated pair-fed controls, in a double-blind, randomized cross-over study. Portocaval-shunted dogs had hyperammonemia (33+/-3 microM (mean +/- SEM) before and 214+/-21 after surgery)) and signs of HE. Their BCAA/AAA ratio in plasma and CSF decreased from 4.3+/-0.3 and 2.3+/-0.3 before surgery to 1.3+/-0.1 and 0.5+/-0.1 after surgery, respectively. These parameters remained unaltered in the control dogs. The consumption of the LR diet was significantly higher than consumption of the HR diet. In the portocaval-shunted dogs, plasma ammonia concentration was higher on the HR diet than on the LR diet (344+/-52 v 246+/-45) and the HE grade was worse. The BCAA/AAA ratio remained abnormal in HE dogs during the feeding of both diets. The basal and haloperidol-stimulated release of alpha-melanotropin and cortisol in plasma were not significantly different between or within groups during any period. In contrast, urinary cortisol excretion was increased in the HE dogs after surgery (urinary cortisol:creatinine ratio (x10(-6)) 8.5+/-1.4 before and 30.4+/-8.9 after surgery). The basal plasma concentration of adrenocorticotropin in HE dogs was decreased after surgery (68.3+/-10.2 ng/L before and 40.8+/-4.4 after surgery). This indicates a non-pituitary-dependent hyperresponsiveness of the adrenals. We conclude from these results that chronic HE in dogs is not associated with an abnormal dopaminergic neurotransmission at least at the level of the pituitary, and that it is not the content of the dietary neutral amino acids but rather the total protein intake that may have a beneficial effect on HE.

Abnormalities in branched-chain amino acid metabolism in cirrhosis: influence of hormonal and nutritional factors and directions for future research

Plasma branched-chain amino acid (BCAA) levels are decreased in patients with liver cirrhosis, owing to an increase in BCAA tissue uptake and/or catabolism and a decrease in BCAA production from proteins. Non-specific factors such as malnutrition worsen this picture. Studies of BCAA fluxes and protein turnover in cirrhotic patients have given conflicting results due to patient heterogeneity, differences in method and bias in the expression of results. In well compensated cirrhosis, muscle wasting is moderate and probably due more to decreased protein synthesis than to increased protein catabolism. Hyperinsulinemia has been suggested as the main cause of decreased BCAA levels, by increasing BCAA uptake in muscle and additionally in adipose tissue. However, as depletion of fat stores is frequent in cirrhosis, this effect is certainly quantitatively weak. Also, there is no correlation between state of hyperinsulinemia and decrease in BCAA levels. An effect of cytokines (IL1 and TNF) on muscle BCAA catabolism is a possibility. Until recently, the contribution of the liver to abnormal BCAA metabolism has been underestimated. In cirrhotic liver an increase in liver transamination of branched-chain keto acids (BCKAs) has been suggested and may result from inhibition of liver BCKA dehydrogenase. A modification of protein turnover in cirrhotic liver must be also considered. Lastly, the contribution of non-hepatocyte liver cells, which are activated in cirrhosis, remains to be assessed.

New aspects on etiology, biochemistry, and therapy of portal systemic encephalopathy: a critical survey

There is scientific agreement that portal systemic encephalopathy (PSE) is caused morphologically by portal systemic shunts and biochemically by constituents of the portal venous blood. Ammonium has a key role in the pathogenesis of PSE. Direct correlations with the degree of PSE have been established exclusively with glutamine, i.e. the terminal product of the peripheral detoxification of ammonium. In PSE, ammonium is probably responsible for damage to astrocytic and neuronal cells. Ammonium's toxic effect is due to the intracerebral glutamine synthesis. After several metabolic steps, which will be discussed in detail, brain cell damage is caused directly or indirectly (exitotoxically) by energy deficiency. Hyperammonemia and PSE are each well defined though different forms of disturbance. Therefore, ammonium is not the sole decisive factor in the pathogenesis of PSE. We performed a detailed and critical analysis of all studies on amino acid therapy of PSE, especially those that were randomized and controlled. This analysis revealed a close and direct correlation between qualitative and quantitative dosages of amino acids on one hand, and parallel improvements of amino acid imbalance (essentially associated with PSE) and degree of PSE on the other. A close and direct dose/efficacy correlation must be assumed. Disturbed plasmatic amino acid homeostasis and cerebral monoaminergic neurotransmission are probably important pathogenic factors of PSE. A fundamental cofactor in the efficacy of each adequate amino acid therapy might be a substantial decrease of endogenous ammonium production. Physiologic benzodiazepines may also have an important function in the pathogenesis of PSE: not so, however, the glutamate-ergic and GABA-ergic neurotransmission, which are disturbed principally in PSE. In close correlation to pathogenesis, established and proposed therapies of PSE are critically discussed.

Clinical economics review: nutritional support

Nutritional support currently accounts for about 1% of the total health care costs in the USA. Interestingly, most of the prospective randomized controlled trials to date have not been able to demonstrate that this therapeutic intervention alters morbidity or mortality. In fact, parenteral nutritional support may predispose the recipients to developing systemic infections. There have been a few areas in which nutritional support may be of benefit. Enteral supplements given to underweight women who suffer hip fractures reduce the hospital stay and, presumably, overall cost. Preoperative parenteral nutritional support may produce a small absolute reduction in post-operative morbidity, but its cost becomes prohibitive. Preoperative enteral nutritional support, especially if carried out in the home, may be of benefit (using the most optimistic interpretation of a small number of trials); if so, it is an economically defensible intervention. Particular nutrients or diets may have specific effects on certain disease processes. Indirect comparisons have suggested that elemental diets can be used to treat flares of Crohn's disease (perhaps because putative food antigens are removed). However, corticosteroid therapy is more efficacious. Furthermore, it is less expensive to employ 6-mercaptopurine as the next modality in steroid failures. Branched-chain amino acid infusions may have some effect on hepatic encephalopathy, but again, lactulose is less expensive. Nutritional support is one area of medicine in which there has been far more enthusiasm than the data justify. Disease-associated malnutrition probably is a secondary phenomenon, not an important cause of morbidity. The widespread use of this modality cannot be justified in a cost-constrained health care system.

Portal systemic encephalopathy

The goal of this article is to update the status of Portal systemic encephalopathy (PSE) in the light of new data. First, PSE is the context of other types of hepatic encephalopathy. Subsequently, current views of the pathogenesis of the disorder are discussed, followed by an analysis of therapeutic options. Diagnosis will not be considered, as no major new developments have recently been documented in this area.

A clinical hepatologist's predictions about non-absorbed carbohydrates for the early twenty-first century

To put these predictions into perspective, the primary indication for lactulose therapy in the treatment of HE and SHE is presented and discussed. Six secondary indications for lactulose therapy are also listed and briefly commented upon. A dozen predictions about the status of lactulose are presented and briefly discussed. A. Lactulose will be the treatment of choice for HE.B. TIPS will be the most common cause of HE.C. Lactulose will not be approved in Mexico. D. Lactulose plus anti-diarrheal drugs will be agents for treatment of HE. E. Lactulose will not be the treatment of choice for constipation. F. Lactulose will not be used for Salmonella or Shigella carrier states. G. Lactulose will be routinely administered prophylactically after TIPS. H. Lactulose will be administered prophylactically to cirrhotic patients with portal hypertension. I. Lactulose plus anti-diarrheal drugs will be used for a variety of diverse purposes: (i) Suppression of bacterial growth; (ii) prevention of bacteriuria; (iii) diminution of cholesterol saturation of bile; (iv) adjunct treatment of gallstones with ursodeoxycholic acid; (v) Prevention of colon carcinoma.

Large spleno-caval shunt not accompanied by cirrhosis or encephalopathy

A 40-year-old man with a large spleno-caval shunt through the azygos vein is described. This was considered a rare case, because the patient had no accompanying advanced liver disease, or episodes of hepatic encephalopathy. During checks after abnormal liver function test results, a shunt vessel was detected incidentally by ultrasonography. Computed tomography, magnetic resonance imaging, and angiography demonstrated that it was a large shunt between the splenic vein and superior vena cava through the coronary and azygos veins. The patient was a hepatitis B virus carrier and was positive for anti-HBe, and had a history of heavy drinking. However, on laparoscopic examination, the liver was not cirrhotic and the biopsy revealed only mild chronic hepatitis without bridging fibrosis. There were no esophageal varices or hepatosplenomegaly. On hemodynamic evaluation, the wedge hepatic vein pressure was slightly elevated and hepatic blood flow was reduced to half the normal value. Despite the large portal-systemic shunt, the patient had no history or signs of hepatic encephalopathy. The clinical features of this rare case are discussed.

Overview of randomized clinical trials of oral branched-chain amino acid treatment in chronic hepatic encephalopathy

BACKGROUND

The role of oral branched-chain amino acid supplements in the prevention and treatment of chronic hepatic encephalopathy is not yet established, and conflicting opinions are expressed in authoritative textbooks. We aimed to review and pool the published controlled studies by means of meta-analytical techniques.

METHODS

A computerized search of published papers identified nine studies, controlled against placebo, energy, alimentary proteins, or casein. Their quality score was calculated according to the protocol of Chalmers. The value of the portal-systemic encephalopathy index was chosen as main outcome, because of lack of more significant clinical outcomes. To cope with differences in trial design and data presentation, individual data were requested to authors.

RESULTS

After 18 months, we received the individual data of only two studies, thus precluding any meta-analysis. Two studies, accounting for over 60% of total enrolled patients, were in favor of branched-chain amino acids. Their quality score was much better than that of the remaining seven negative small studies, carrying a significant risk of type II error.

CONCLUSIONS

Based on the results of the two largest, long-term studies, the use of oral branched-chain amino acids in the prevention and treatment of chronic encephalopathy may only be proposed for patients with advanced cirrhosis, intolerant to alimentary proteins. Large, multicenter, long-term studies, considering more important clinical outcomes, are needed to provide definite answers to an aged question.

Nutritional management of liver disease

The provision of adequate nutrition to the patient with liver disease is a challenge. The practitioner must avoid overwhelming the remaining metabolic capabilities of the damaged organ. The ability of the liver to regenerate and the patient to recover depends on the availability of sufficient nutrients. There is no default diet for the patient with liver disease. Each patient must be evaluated individually, with consideration given to the type and origin of the liver disease, the current extent of hepatic dysfunction, and the patient's previous dietary history. Efforts should be directed at the provision of an energy intake adequate to maintain body weight and a protein intake as close to normal as can be tolerated without precipitating signs of hepatic encephalopathy.

Effects of an infusion of branched-chain amino acids on neurophysiological and psychometric testings in cirrhotic patients with mild hepatic encephalopathy

Psychotropic action of a branched-chain-enriched amino acid solution (Aminoleban) was quantitatively and visually examined in six cirrhotic patients with mild hepatic encephalopathy (grades I and II) using electrophysiological and psychometric methods. Neurophysiological effects of the amino acid solution were observed by comparing topographic spectrum analyses of electroencephalography (EEG) before and immediately after an intravenous 3 h infusion of the solution. The delta wave in the frontal region diminished from 61 +/- 13 to 12 +/- 4% (P < 0.01) and the alpha wave in the occipital region increased from 11 +/- 3 to 51 +/- 11% (P < 0.01). Latencies of the P3 wave in visual evoked potentials, which were topographically recorded in the occipital region, shortened from 220 +/- 32 to 148 +/- 19 ms (P < 0.01). Latencies of the P300 wave in event-related potentials, which were topographically recorded in the centro-temporal region, shortened from 493 +/- 81 to 360 +/- 93 ms (P < 0.05). Topographic reaction pattern of P300 was irregular toward the occipital or parietal region in cirrhotic patients. The EEG frequency power spectrum, illustrated by the colour density spectral array of computer-aided polysomnography analysis, clearly showed a gradual increase of the alpha wave spectrum and a gradual decrease of the delta wave spectrum after initiation of the infusion. These immediate neurophysiological changes were confirmed by improvement of quantitative psychometric tests including number connection test, reaction time to sound, and digit symbol and block design tests of Wechsler Adult Intelligence Scale.(ABSTRACT TRUNCATED AT 250 WORDS)

Rationale and efficacy of specialized enteral nutrition

Enteral nutrition, whenever feasible, is the preferred route of nutrition support. There has been a tremendous increase in the number of enteral products available on the market. Many of these are designed for use in specific disease states. This review will summarize the scientific rationale and supporting research for specialized enteral nutrition.

Hepatic encephalopathy

The approach to the management of patients with HE is summarized in Table 3. Other diagnoses need to be excluded and, after a diagnosis of HE is made on clinical and possibly electroencephalographic grounds, a search made for precipitants. Sedatives and opiates should be avoided, and steps taken to avoid hypoglycaemia, fluid overload or electrolyte imbalance. Protein restriction should be instituted, and disaccharide such as lactitol or lactulose started. Neomycin may be added for more difficult cases for short duration. Branched chain amino acids should not be used routinely, but a trial of flumazenil may be justified for recalcitrant cases.

Long-term treatment of latent portosystemic encephalopathy with branched-chain amino acids. A double-blind placebo-controlled crossover study

This trial was undertaken to assess the safety and efficacy of long-term oral supplementation with branched-chain amino acids as an adjunct to conventional therapy in patients with stable cirrhosis and latent encephalopathy. Latent encephalopathy was diagnosed by psychometric testing, used to assess automobile driving capacity. Seventeen patients with impaired driving capacity received either branched-chain amino acids or placebo for 8 weeks before being crossed over to the other regimen for an equal period. Branched-chain amino acids but not placebo significantly improved psychomotor disturbances (p < 0.01) and driving capacity (p < 0.002). No adverse reactions were observed. We conclude that long-term branched-chain amino acid supplementation is well tolerated and effective in the treatment of impaired automobile driving capacity associated with latent portosystemic encephalopathy.

Controlled trial on nutrition supplementation in outpatients with symptomatic alcoholic cirrhosis

A controlled trial on nutrition supplementation in ambulatory patients with decompensated alcoholic liver disease was carried out during 1 year. Fifty-one patients were studied; 26 were assigned to an experimental group receiving a daily supplement of 1000 kcal and 34 g of proteins given as a casein-based enteral nutrition product and 25 to a control group receiving one placebo capsule. Patients were examined in a special clinic once a month or more if required. Sixty-eight percent of patients admitted to alcohol ingestion or had alcohol in urine samples on at least one occasion. Dietary recalls showed a significantly higher protein and caloric intake in case patients subjects (p < .0001). Nine patients died during the study, three case patients and six control patients (p = NS). The frequency of hospitalizations was significantly less in the experimental group. This difference was attributed to a reduction in severe infections. Mid-arm circumference, serum albumin concentration, and hand grip strength improved earlier in case patients, although both groups had a significant improvement in these parameters. Bilirubin and aspartate aminotransferase decreased and prothrombin time increased significantly in both groups during the study period, without differences between groups. It is concluded that nutrition support decreases nutrition-associated complications in patients with alcoholic liver disease.

Recent developments in the pathophysiology and treatment of hepatic encephalopathy

The pathophysiology of HE has not yet been clarified. At present the main mechanisms under discussion are the combined effects of different toxins, such as ammonia, mercaptans, phenols and short- and medium-chain fatty acids, as well as a change particularly in GABAergic and glutamatergic neurotransmission. In this chapter the current views on the importance of these individual factors in the pathophysiology of HE are discussed; possible connections between changes in neurotransmission and the effect of different neurotoxins are presented. In addition, possible therapies resulting from recent knowledge of the pathophysiology of this disease are discussed, such as the use of Bz receptor antagonists.

Accelerated improvement of alcoholic liver disease with enteral nutrition

This prospective study compared the effects of tube-fed nutrition with those of a regular diet in alcoholic liver disease. The high prevalence of malnutrition in patients with alcoholic liver disease requires clarification of the benefits of aggressive nutritional support. Patients were randomly assigned a regular diet without or with tube-fed supplementation, delivering 1.5 g/kg protein and 167 kJ/kg daily. Comparisons of encephalopathy, antipyrine clearance, metabolic rate, and biochemical parameters were performed weekly for 4 weeks. Sixteen patients receiving enteral supplementation had antipyrine half-life (50% vs. 3% reduction), serum bilirubin (25% vs. 0% reduction), and median encephalopathy scores that improved more rapidly than those of controls. Initially, 15 controls did not consume adequate calories to meet measured resting energy expenditure. Aggressive nutritional intervention accelerated improvement in alcoholic liver disease. Adverse effects did not offset the demonstrated benefits of a 2-cal/mL, casein-based tube-fed supplement. These findings support the use of standard, casein-based solutions in the treatment of alcoholic liver disease and as the control condition for future studies.

Enteral alimentation: administration and complications

Tube feeding is commonly used for providing essential calories and nutrients to the patient otherwise unable to eat. In the last two decades there has been significant expansion in the number and quality of enteral formulas. In this review, we evaluate the indications for each major class of formula, and survey complications associated with formulas and devices that deliver formula. Recommendations for future research are listed.

Nutrition and alcoholic liver disease

While the rate of malnutrition is relatively modest in alcoholic patients without alcoholic liver disease, the rate of malnutrition is virtually 100% in patients with alcoholic hepatitis and/or alcoholic cirrhosis. The reasons for malnutrition in the alcoholic hepatitis patient include various factors such as anorexia, poor diet, malabsorption, and altered metabolic state. When the patient is hospitalized, the malnutrition frequently worsens because of fasting for tests, continued anorexia, and complications such as gastrointestinal bleeding. Patients with severe acute hepatitis appear to be both hypermetabolic and hypercatabolic, whereas data are much more conflicting concerning patients with more stable liver disease. Most studies suggest that patients with alcoholic liver disease require at least 60 g of protein per day to maintain positive nitrogen balance. Consistent alterations in plasma amino acid profiles occur in alcoholic liver disease, and specialized nutritional formulations have been devised to correct this amino acid profile with the intent of improving overall nutritional status, hepatic encephalopathy, and mortality. The effects of nutritional support (including use of specialized products) on outcome, on acute hepatic encephalopathy, and on chronic or latent portal systemic encephalopathy are reviewed.

Pathophysiology and clinical basis of prevention and treatment of complications of chronic liver disease

Chronic liver failure is characterized by the appearance of jaundice, ascites, encephalopathy and/or gastrointestinal bleeding. Acute episodes of hepatic decompensation are frequently precipitated by additional events, e.g. septicaemia, diuretic therapy or excessive protein intake. Identification, correction and treatment of these precipitating factors are first steps in the management of chronic liver failure. Nutritional support is important in the treatment of cirrhotic patients, because malnutrition is one of the major determinants of patient outcome. Management of encephalopathy reduces the appearance of gut-derived nitrogenous toxins and corrects imbalances in amino acid metabolism. Treatment of ascites is salt restriction supported by gentle and incremental administration of diuretics. Ursodesoxycholic acid has become a new and promising modality in the management of cholestatic liver diseases. If conservative therapy fails to recompensate liver function, liver transplantation may be indicated.

Branched chain amino acids in the management of chronic liver disease. Facts and fantasies

The liver plays a central role in protein and amino acid metabolism. It processes dietary amino acids and reprocesses amino acids released from muscle protein degradation. It utilises amino acids for protein synthesis and gluconeogenesis, regulates the supply of amino acids to peripheral tissues and converts excess amino acids to urea. In patients with liver disease the liver's ability to control both plasma and tissue amino acid fluxes may be seriously disturbed. The resultant changes in amino acid metabolism may be implicated in the genesis of the neuropsychiatric abnormalities and the deterioration in nutritional status commonly observed in patients with hepatic failure. Thus, on theoretical grounds, amelioration of these amino acid abnormalities might benefit patients with liver disease who have hepatic encephalopathy or are malnourished. However, there is, at present, no consensus as to the efficacy, practicality or cost-effectiveness of 'amino acid therapy' in patients with liver disease.

Branched-chain-enriched amino acid solutions in patients with liver failure: an early example of nutritional pharmacology

The use of BCAA in the treatment of hepatic failure has been controversial. Even in retrospect, it is difficult to know why this controversy existed and why it has been so emotional, except for the fact that such a treatment modality has flown in the face of conventional therapy of hepatic encephalopathy, and also, probably more importantly, directly attacked some of the cherished notions of the nature of hepatic encephalopathy. Time and distance have allowed some of the controversy to die down, and as time has elapsed it has become clear that at least in the area of nutritional support of patients with hepatic failure, BCAA are the preferred alternative to treat patients who are otherwise protein intolerant. A recent unbiased review using the techniques of meta-analysis has concluded that the BCAA are efficacious for the treatment of patients with hepatic encephalopathy. Since this manuscript was completed another study has been reported. In this study, it was notable that those patients treated with oral BCAA became neurologically normal, a finding which the authors found very striking.