Modulation of hepatic encephalopathy in rats with thioacetamide-induced acute liver failure by serotonin antagonists

OBJECTIVE

Accumulated neurochemical data in different animal models of fulminant hepatic failure and in humans with hepatic encephalopathy suggest that serotoninergic tone is increased in the brain in hepatic encephalopathy. Since neurochemical alterations may not have behavioural or electrophysiological consequences the contribution of the serotoninergic system to the pathogenesis of hepatic encephalopathy was explored.

METHODS

The effects of drugs modulating serotoninergic neurotransmission, the nonselective serotonin receptor antagonist methysergide and the serotonin2 receptor antagonist seganserin were tested neuropharmacologically in thioacetamide-induced acute liver failure in rats.

RESULTS

Methysergide had no effect in control rats, but dose dependently increased motor activity in stage II-III hepatic encephalopathy by 232% (5 mg/kg methysergide), 531% (10 mg/kg) and 507% (20 mg/kg). In contrast, seganserin had no effect in encephalopathic rats.

CONCLUSION

It is suggested that the beneficial effects of methysergide are serotonin, receptor mediated. Overall the results suggest that serotoninergic mechanisms contribute to some of the behavioural manifestations of hepatic encephalopathy in this animal model.

Neurologic complications following intranasal administration of heroin in an adolescent

OBJECTIVE

To describe an adolescent patient who developed a stroke following intranasal administration of heroin.

CASE SUMMARY

A 17-year-old adolescent with no prior medical problems "snorted" an unknown quantity of heroin. The patient developed respiratory failure, shock, and seizures. When he regained consciousness, the patient had evidence of hypoxic-toxic encephalopathy on neuropsychologic examination. Magnetic resonance imaging revealed an infarct in the globus pallidus region of the brain.

DISCUSSION

Serious neurologic complications following intranasal administration of heroin have been reported rarely in children. Correlations between findings on neuropsychologic examination and magnetic resonance imaging following drug overdoses have likewise been rarely described. We reviewed literature pertaining to the etiology, pharmacology, and pathophysiology of neurologic complications resulting from heroin intoxication.

CONCLUSIONS

As the use of intranasal heroin is increasing in the pediatric population, healthcare professionals should be aware of the various potentially serious complications that may occur.

Severe recurrent hepatic encephalopathy that responded to oral branched chain amino acids

Hepatic encephalopathy is a neuropsychiatric syndrome occurring in patients with acute or chronic liver disease. Its pathogenesis remains unclear; however, it appears to be multifactorial. There are several conventional treatments for this condition, such as lactulose, neomycin, and protein restriction. There is significant controversy regarding the role of branched chain amino acids in the treatment of chronic hepatic encephalopathy. We describe a patient who had hepatic encephalopathy secondary to Budd-Chairi syndrome and a mesoatrial shunt that failed vigorous conventional therapy. She required multiple hospitalizations for severe recurrent encephalopathy. The patient was considered for a colonic exclusion procedure for the management of intractable encephalopathy. However, branched amino acid therapy was instituted as a last measure before the contemplated surgery, and the patient's encephalopathy responded in dramatic fashion, and she remained free from encephalopathy during a prolonged follow-up.

Evidence of increased guanylate cyclase activation by acetylcysteine in fulminant hepatic failure

Patients with fulminant hepatic failure (FHF) have a severe microcirculatory disturbance causing tissue hypoxia. Infusion of acetylcysteine improves survival and reduces the incidence of multiorgan failure by enhancing tissue oxygenation. Because the observed circulatory effects of acetylcysteine in FHF are similar to and synergistic with those produced by the microcirculatory vasodilator prostacyclin, we postulated that acetylcysteine might potentiate an endogenous vasodilator. Nitric oxide, a vasodilator that activates soluble guanylate cyclase, is a possible candidate as plasma cyclic 3',5'-guanosine monophosphate (cGMP) is raised in FHF, and in vitro acetylcysteine has been found to enhance soluble guanylate cyclase activity. To investigate this possible mechanism further, plasma cGMP was measured before and after acetylcysteine infusion in 24 patients with FHF and again in 6 patients after recovery from acute illness. cGMP levels were high in FHF during acute illness (median, 7.0 nmol/L [interquartile range, 2.6-10.0]) in comparison with levels taken after recovery (1.5 nmol/L [1.0-1.9]; P < .05). Levels rose further after acetylcysteine infusion in the FHF cases (mean increase, 204% [95% CI; 49 to +360]; P < .01) but not in the cases after recovery (38% [-7 to +84]). There were no significant changes in levels of plasma atrial natriuretic peptide (ANP) or cyclic adenosine monophosphate (cAMP) (mean increases, 8% [-6 to +22] and 17% [-9 to +43], respectively). The findings further support the hypothesis that the beneficial hemodynamic effects of acetylcysteine in FHF are mediated by enhancing the activity of the nitric oxide/soluble guanylate cyclase enzyme system.

Zinc supplementation and amino acid-nitrogen metabolism in patients with advanced cirrhosis

Zinc deficiency is common in cirrhosis and has been involved in the altered nitrogen metabolism. In this study, we measured the effects of zinc supplementation on the dynamics of amino acid-derived urea synthesis in cirrhosis with mild or latent encephalopathy. The hepatic conversion of amino acids into urea was studied in eight patients with advanced cirrhosis under controlled conditions of substrate availability (continuous alanine infusion), before and after 3-month oral zinc sulfate supplementation (600 mg/d). Eight more patients, matched for hepatocellular failure and encephalopathy, served as controls. Plasma zinc levels were reduced in all patients and returned to normal after oral zinc. The alanine-stimulated urea nitrogen synthesis rate in relation to alpha-amino-N concentration--the functional hepatic nitrogen clearance--increased by 25% after zinc supplementation, i.e., more urea was produced at any alpha-amino-N concentration. Basal and alanine-induced glucagon decreased by 50%, and the ammonia response to alanine decreased by 30%. Psychometric tests improved, as did routine and dynamic liver function tests and the Child-Pugh score. Also, the plasma concentration of lipid peroxides was reduced by zinc. No significant changes were observed in the control group. Our data indicate that long-term oral zinc speeds up the kinetics of urea formation from amino acids and ammonia. Changes in the hormonal drive and/or the antioxidant activity of zinc might be involved in the general improvement in liver function, whereas the beneficial effects on encephalopathy might stem from decreased ammonia.

[Lactilol (Importal, 10g in powder made by ZYMA) in the treatment of portal systemic encephalopathy]

In a group of 15 patients with portal systemic encephalopathy (PSE) associated with cirrhosis of the liver with portal hypertension and spontaneous systemic shunt of the portal circulation the authors administered Lactitol (Importal, powder à 10 g Zyma), in amounts up to 40 g/day for a period of 56 days. In the course of treatment every patient was repeatedly examined before the onset of treatment and three times during treatment. The grade of PSE was assessed on the basis of the score of the neuropsychiatric examination from which the PSE index was worked out. In the investigated group of patients with PSE the authors found a significant improvement of the PSE index during treatment with Importal Zyma. The mental condition of the patients improved, the NCT period was reduced, asterixis receded, on the EEG the delta and theta activity receded and normal alpha activity developed. The serum ammonia levels declined but did not reach statistical significance. During treatment the authors did not record changes of normal values of glucose, sodium and potassium in serum and did not detect any adverse side effects. Based on the assembled results the authors conclude that lactitol treatment extends possibilities of PSE treatment.

[Chronic hepatic encephalopathy treated by long-term intravenous administration of flumazenil in ambulatory care]

Treatment of chronic hepatic encephalopathy is difficult. Oral flumazenil has been proposed for long-term treatment but is not presently available on the market. We report the successful treatment of one case of chronic hepatic encephalopathy in cirrhosis without precipitating factors by low dose intravenous injections of flumazenil (Anexate, 1 mg/4 hours). Flumazenil is expensive and not always effective. We suggest reserving this treatment to highly selected patients (without precipitating factor, or after failure of first choice treatment).

Fulminant hepatitis caused by hepatitis C virus during treatment for multiple sclerosis

A 55-year-old woman was treated at our hospital for multiple sclerosis. Therapy consisted of glucocorticosteroids and cyclosporin. In the 7th week after these drugs were discontinued the patient developed acute liver failure due to fulminant hepatitis (FH) and died. Post-mortem examination showed massive liver necrosis. Serologic examination was negative for hepatitis B virus-related markers. Antihepatitis C virus (anti-HCV) antibody and serum HCV RNA were negative on admission, but HCV RNA appeared concurrently with the onset of FH. Although HCV infection rarely causes FH, it was considered to be the cause of FH in this patient, since there were no other causes of acute liver injury. We suspect that underlying immunologic abnormalities in conjunction with HCV infection may have precipitated the FH.

Lactulose and combination therapy of hepatic encephalopathy: the role of the intestinal microflora

Lactulose is the most frequently utilized agent in the treatment of hepatic encephalopathy because of its efficacy and the fact that it has few serious side effects. How this nonabsorbable disaccharide works has been a matter of controversy, but evidence suggests that metabolism by the enteric flora is necessary for its mechanism of action. When the intestinal flora metabolized lactulose, bacterial incorporation of nitrogen increases as does the bacterial mass. The presence of a carbohydrate and the acidic environment caused by the production of organic acids also act to reduce the breakdown of other nitrogen-containing compounds to ammonia and other potential cerebral toxins. The administration of lactulose to humans causes an increase in fecal nitrogen, but very little increase in ammonia nitrogen. Most of the nitrogen is contained in the fecal bacterial and the soluble fractions of stool. The administration of lactulose causes a reduction in the urea production rate consistent with a reduced entry of ammonia into portal blood, but it does not appear to directly inhibit urea degradation. Other nonabsorbable saccharides, particularly those contained in dietary fiber, appear to have effects similar to those of lactulose. There is some evidence that neomycin can be given with lactulose to cause an additive effect in the treatment of hepatic encephalopathy. This effect is most prominent in patients who have not responded adequately to lactulose alone. At this point, the other antibiotics studied do not appear to have additive effects with lactulose.

Effect of flumazenil on the electroencephalogram of patients with portosystemic encephalopathy. Results of a double blind, randomised, placebo-controlled multicentre trial

The efficacy of the benzodiazepine antagonist flumazenil has been assessed clinically in a double blind, randomised, placebo-controlled multicentre study in patients with grade I-III portosystemic encephalopathy. In an ancillary study reported here the effect of flumazenil on the electroencephalogram (EEG) was analysed in 32 patients who had EEG grading according to protocol. Following the baseline observation period, patients were randomised to receive (at 1 min interval) 3 sequential bolus injections of flumazenil (0.4, 0.8 and 1 mg) or placebo followed by infusions of flumazenil (1 mg/h) or placebo for 3 h. Patients were monitored for 5 h after infusion. A positive response was defined as 1 point improvement in EEG grade. After independent analysis of the EEG gradings 5 out of 17 (29%) flumazenil treated patients showed an improvement in EEG grading (3 after bolus, 2 during follow-up) compared to 2 out of 15 (13%) placebo treated patients (1 after bolus, 1 during follow-up) (95% confidence interval of difference: -12% to + 50%). Of the 5 EEG responders after flumazenil, 3 also had an improvement in clinical PSE grading (none after bolus, 2 during infusion, 1 during follow-up), compared to neither of the 2 EEG responders after placebo. EEg responders did not differ from non-responders with respect to Child-Pugh score, basal EEG, PSE grade and positivity for benzodiazepines. In conclusion, treatment perspectives for flumazenil in portosystemic encephalopathy appear to be present for only a minority of patients; however, this study yields no support for a major role of benzodiazepine antagonists in the treatment of hepatic encephalopathy.

[Acute liver failure as the initial manifestation of Wilson disease]

BACKGROUND

Establishing an early diagnosis is crucial to successfully treat mostly young patients with sudden onset acute hepatic failure as the initial symptom of Wilson's disease. Recognition of the entity of Wilsonian fulminant hepatitis is important, because liver transplantation improves survival if performed in a timely fashion.

METHODS

Retrospective case analysis regarding characteristic profile of standard laboratory parameters and clinical course of acute Wilsonian hepatic failure.

RESULTS

In two female patients (age 17 and 27 years) with non-autoimmune hemolysis serum AST and ALT levels were only moderately elevated with a conspicuously diminished ALT activity and relatively low serum alkaline phosphatase (AP) levels. Despite immediate application of D-Penicillamin one patient died from complications of multiorgan failure.

CONCLUSION

In fulminant Wilsonian hepatic failure the AP/bilirubin ratio is usually below 2. Additionally calculation of free copper concentration in serum and renal excretion of ionic copper in combination with non-autoimmune hemolysis provide clues to establish an early diagnosis of Wilsonian hepatic failure.

[Effects of lactitol on fecal bacterial flora in patients with liver cirrhosis and hepatic encephalopathy]

Lactitol, a non-absorbable synthetic disaccharide, was administered at a dose of 36g/day for 3-4 weeks to 8 patients with liver cirrhosis and hepatic encephalopathy in order to investigate its effects on fecal bacterial flora and clinical symptoms of hepatic encephalopathy. Lactitol significantly increased occupation ratio (ratio to total bacterial number) of anaerobic Bifidobacterium (before administration 7.1% --> after 4 weeks 46.0% (p < 0.05) as well as bacterial count of Lactobacillus. On the other hand, bacterial counts of Bacteroides and Clostridium, which are considered to be NH3-producing bacteria, and that of total aerobic bacteria were not markedly changed, but their occupation ratio were decreased after the administration. Further, tendencies toward decreased fecal pH, increased frequency of defecation and soft stools were observed. As for clinical efficacy, a decrease in blood ammonia concentration, improvement in mental state and flapping tremor were also observed.

Effects of lactitol [correction of lactilol] on hepatic encephalopathy and plasma amino-acid imbalance

Hepatic encephalopathy in liver cirrhosis is due to several factors, including amino acid imbalance and hyperammonemia. Lactitol [correction of lactilol], a non adsorbable disaccharide, improves hepatic encephalopathy increasing bowel movements, modifying colonic bacteria and pH, and reducing blood ammonium. Ten patients with liver cirrhosis and longstanding stable hepatic encephalopathy were treated, after a period of drugs wash-out, with lactitol. A significant improvement of hepatic encephalopathy was observed, with a significant decrease of blood ammonium, related with the increase of stool frequency/day. Atrial natriuretic peptide decreased as well. Moreover, an increase of the ratio of plasma aliphatic amino acids (valine, leucine and isoleucine)/aromatic amino acid (tyrosine and phenylalanine) was observed. Lactitol is an effective drug in the treatment of chronic hepatic encephalopathy; its mechanism of action involves not only a decrease of blood ammonium but also modifications of the degree of plasma amino acid imbalance, and fluid and circulatory adjustments.

Flumazenil therapy for hepatic encephalopathy. A double-blind cross over study

OBJECTIVES AND METHODS

Thirty-one patients with acute or chronic liver disease were included in the study to investigate the effect of flumazenil on hepatic encephalopathy. After screening for recent benzodiazepine use or non-hepatic causes of encephalopathy, 18 patients entered a double-blind cross-over study. The 13 remaining patients, most of them with renal failure or recent use of benzodiazepines, were given flumazenil in an open study. In the controlled study, flumazenil (1.0 mg) or placebo was given in a single injection on two separate days to study the immediate effect; half the patients received a continuous infusion of flumazenil (0.25 mg/h) or placebo for two 3-day periods to study a potential steady state effect. In the open study, a single bolus of flumazenil (1.0 mg) was given.

RESULTS

In the controlled study, fifteen minutes after bolus injection, the clinical grade of hepatic encephalopathy decreased in 6 patients after injection of flumazenil, whereas a decrease was found in 2 after the placebo (P = 0.06). However, the EEG grade did not change in any of the patients, and the changes in the mean dominant frequency as measured by spectral analysis did not differ between flumazenil and the placebo. Furthermore, patients on flumazenil did not differ significantly from those on placebo during the infusion period. Subgroup analysis of underlying liver disease and the causes of encephalopathy revealed a trend for clinical improvement only in the patients with chronic liver disease, but without significant changes in the mean dominant frequency. In the open study, the clinical grade of encephalopathy decreased in 3 patients and, in contrast to the controlled study, the EEG also improved in 2 patients and the mean dominant frequency increased significantly. Responders had previously used benzodiazepines.

CONCLUSION

Our study does not support a major therapeutic effect of flumazenil on hepatic encephalopathy.

[The effect of lactitol (NS-4) on the concentrations of ammonia and amino acids in blood and cerebrospinal fluid in Eck fistula (portacaval-shunted) dogs]

Lactitol and lactulose were compared in their effect on the concentrations of ammonia and amino acids in blood and cerebrospinal fluid (CSF) in Eck fistula dogs. Drugs were administered intragastrically for four weeks from three weeks after the portacaval-shunt operation. The concentration of ammonia in the blood and CSF had increased three- to five-fold three weeks after the operation and increased gradually thereafter. Eck fistula dogs showed a characteristic profile of plasma amino acids, with increased concentrations of tryptophan (Trp) and aromatic amino acids (AAA) and reduced concentrations of branched-chain amino acids. The profile of CSF amino acids revealed substantial increases in the concentrations of AAA as well as glutamine (Gln), Trp and glutamic acid. Lactitol at doses of 1 and 3 g/kg/day significantly decreased the ammonia concentration in both the blood and CSF after administration for two and four weeks. Lactitol at a dose of 3 g/kg/day significantly decreased the concentration of Trp in the plasma and the concentrations of valine, leucine, AAA and Gln in CSF. Lactulose showed effects similar to those of lactitol. These findings suggest that lactitol may be a promising agent for the clinical treatment of hyperammonemia and hepatic encephalopathy, since it decreased the concentration of ammonia in the blood and CSF and the elevated concentrations of AAA in CSF associated with the development of hepatic encephalopathy.

[Ameliorating effect of lactitol on experimental hepatic encephalopathy in Eck fistula dogs]

Eck fistula (portacaval shunted) dogs were prepared for use as an experimental model of chronic hepatic encephalopathy. The effect of lactitol on hepatic encephalopathy was investigated by observing the behavior, electroencephalograms (EEGs) and visually evoked potentials (VEPs) of the experimental dogs. Lactitol was administered intragastrically once a day for 12 weeks from the third week after the portacaval-shunt operation and the behavior, EEGs and VEPs of the dogs were observed every two weeks. Dogs not given lactitol became sluggish, then apparently blind, and eventually fell into a coma, over a period of several weeks after the operation. Some dogs died. The EEGs revealed low-voltage slow waves and, at a later stage, displayed flattening in some dogs. The VEPs displayed prolonged latency of both the positive and the negative component as well as an increased amplitude. Lactitol at 1 or 3 g/kg/day suppressed the behavioral symptoms and the changes in the EEGs and the VEPs. These results suggest that lactitol may be useful for the treatment of various nervous symptoms in patients with hepatic encephalopathy accompanied by hyperammonemia.

Effect of a transjugular intrahepatic portosystemic shunt on liver biochemical profiles

PURPOSE

Transjugular intrahepatic portosystemic shunts (TIPS) have markedly simplified the care of patients with refractory variceal bleeding. Follow-up of liver biochemical profiles, however, has not been done in a prospective fashion.

PATIENTS AND METHODS

Twenty-nine patients undergoing TIPS placement for refractory variceal bleeding underwent serial laboratory tests and assessment of encephalopathy to determine the effect of TIPS. Prothrombin time and aspartate aminotransferase, alanine aminotransferase, total bilirubin, alkaline phosphatase, serum albumin, serum creatinine, and venous ammonia levels were checked prior to the procedure, at the time of discharge, and at 3 weeks, 3 months, and 6 months following the procedure.

RESULTS

There was no statistically significant change in any of the obtained laboratory values at up to 6 months of follow-up. The change in aspartate aminotransferase level approached but did not reach statistical significance at the time of discharge and was thought to be secondary to hepatocellular trauma associated with the procedure. New onset of encephalopathy occurred in 18.2% of patients and was easily controlled with medical therapy.

CONCLUSIONS

TIPS does not appear to have a significant effect on the liver biochemical profile with short-term follow-up. Hepatic encephalopathy does occur, however, in a significant number of patients but is easily controlled with medical therapy.

Flumazenil therapy for hepatic encephalopathy in cirrhotic patients: a double-blind pragmatic randomized, placebo study

OBJECTIVE

To evaluate the effects of flumazenil on hepatic encephalopathy in patients with cirrhosis.

DESIGN

Double-blind randomized study.

SETTING

Liver intensive care unit over a 2-year period.

PATIENTS

Fourteen patients with cirrhosis (median age 54 years, range 41-73 years), comprising 10 men and four women enrolled during 18 episodes of hepatic encephalopathy.

METHODS

Placebo or flumazenil (1 mg at 0.1 mg/min infusion rate) was infused in coded vials. The patients' hepatic encephalopathy was graded clinically and by electroencephalography (EEG).

RESULTS

In eight episodes of hepatic encephalopathy the placebo was infused first and no improvement occurred (0%). During 12 episodes of hepatic encephalopathy, flumazenil was administered and the EEG recording improved within 7 min (range 4-47 min; 12 out of 18 cases; 66 versus 0% for flumazenil versus placebo, respectively; P < 0.01); a modest clinical improvement in hepatic encephalopathy was observed within 83 min (range 30-340 min). The amount of flumazenil infused averaged 0.7 mg (range 0.4-1 mg).

CONCLUSIONS

The infusion of 0.4-1 mg flumazenil results in a modest but rapid improvement in the EEG grading of hepatic encephalopathy and to a moderate but delayed improvement in the clinical grade of hepatic encephalopathy.

Brain and plasma levels of opioid peptides are altered in rats with thioacetamide-induced fulminant hepatic failure: implications for the treatment of hepatic encephalopathy with opioid antagonists

Although plasma levels of Met-enkephalin and beta-endorphin are elevated in patients suffering from liver failure, it is not known whether central nervous system (CNS) opioidergic neurotransmission is altered in these patients. Such changes may contribute to the motor dysfunction, psychiatric abnormalities and CNS depression observed in hepatic encephalopathy (HE). Therefore, Met- and Leu-enkephalin, dynorphin A and beta-endorphin levels were measured in discrete brain regions and plasma from thioacetamide-treated rats in Stages II to IV of HE. Pituitary and plasma beta-endorphin, Met- and Leu-enkephalin concentrations increased with the severity of HE by 50 to 290%. Pituitary and brainstem dynorphin A levels increased whereas plasma levels decreased in rats with thioacetamide-induced fulminant hepatic failure. Both striatal Met- and Leu-enkephalin levels increased and hypothalamic concentrations decreased in HE. Concurrent with the increase in striatal Met-enkephalin levels was a 26 to 48% decrease in the density of striatal and hypothalamic delta receptors. No change in either the density or affinity of radioligand binding to mu or delta receptors was observed in the CNS. Finally, administering (+/-)-naloxone (5 and 10 mg/kg) or (+/-)-naltrexone (5-15 mg/kg), but not (+)-naloxone (10 mg/kg), significantly increased the motor activity of rats with Stage III HE. Whereas elevated plasma levels of opioid peptides may play a role in the peripheral manifestations of hepatic failure (ascites and hypotension), increased CNS levels of these peptides may be involved in the neuropsychiatric abnormalities characteristic of HE. Thus, opioid antagonists may be effective in ameliorating some of the neurological manifestations of HE.