Hepatic encephalopathy

Hepatoprotective effect of sodium hydrosulfide on hepatic encephalopathy in rats

Hydrogen sulfide is well-known to exhibit anti-inflammatory and cytoprotective activities, and also has protective effects in the liver. This study aimed to examine the protective effect of hydrogen sulfide in rats with hepatic encephalopathy, which was induced by mild bile duct ligation. In this rat model, bile ducts were mildly ligated for 26 days. Rats were treated for the final 5 days with sodium hydrosulfide (NaHS). NaHS (25 µmol/kg), 0.5% sodium carboxymethyl cellulose, or silymarin (100 mg/kg) was administered intraperitoneally once per day for 5 consecutive days. Mild bile duct ligation caused hepatotoxicity and inflammation in rats. Intraperitoneal NaHS administration reduced levels of aspartate aminotransferase and alanine aminotransferase, which are indicators of liver disease, compared to levels in the control mild bile duct ligation group. Levels of ammonia, a major causative factor of hepatic encephalopathy, were also significantly decreased. Malondialdehyde, myeloperoxidase, catalase, and tumor necrosis factor-α levels were measured to confirm antioxidative and anti-inflammatory effects. N-Methyl-D-aspartic acid (NMDA) receptors with neurotoxic activity were assessed for subunit NMDA receptor subtype 2B. Based on these data, NaHS is suggested to exhibit hepatoprotective effects and guard against neurotoxicity through antioxidant and anti-inflammatory actions.

Techniques for Transjugular Intrahepatic Portosystemic Shunt Reduction and Occlusion

Transjugular intrahepatic portosystemic shunts (TIPS) effectively lower portal pressure and are commonly used to manage selected patients with variceal bleeding. Unfortunately, significant consequences are not infrequently encountered as a result of this diversion of portal venous flow. These consequences include disabling hepatic encephalopathy as well as hepatic decompensation. To manage these complications, therapeutic options include TIPS reduction and TIPS occlusion. TIPS reduction is the favored technique because of the potential for venous thrombosis and recurrent variceal hemorrhage after acute TIPS occlusion. Techniques and indications for TIPS reduction and TIPS occlusion are reviewed.

Reduced stents and stent-grafts for the management of hepatic encephalopathy after transjugular intrahepatic portosystemic shunt creation

Hepatic encephalopathy (HE) is a common complication encountered by patients after transjugular intrahepatic portosystemic shunt (TIPS) creation. Although most patients respond well to conservative medical therapy, up to 7% of patients do not and require more invasive therapeutic approaches. One option is emergent liver transplantation; however, most patients are not suitable candidates. During the past decade, various percutaneous techniques have been described that alter the hemodynamics through the TIPS by occluding it with coils or balloons or by reducing its diameter using constrained stents or stent-grafts. These endovascular techniques have produced symptomatic improvement in many patients with refractory HE, with either complete resolution or substantial reduction of HE symptoms that can be controlled with additional medical therapy. Unfortunately, despite all attempts, some patients remain incapacitated and ultimately die. Further research is necessary to improve our understanding of HE after TIPS creation so that less invasive and safer procedures can be developed to treat this difficult clinical problem.

Hepatic encephalopathy: from pathophysiology to therapeutic management

Hepatic encephalopathy is a complex and potentially reversible neuropsychiatric syndrome complicating acute or chronic liver disease. Clinical manifestations are multiple and varied, ranging from minimal neurological changes to coma. Ammonia is the main toxic substance involved in the pathogenesis of hepatic encephalopathy, although other mechanisms, such as modifications of the blood-brain barrier, disruptions in neurotransmission and abnormalities in GABAergic and benzodiazepine pathways may also play a role. The identification and treatment of precipitating factors is crucial in the management of patients with hepatic encephalopathy. Current treatments are based on reducing intestinal ammonia load by agents such as antibiotics or disaccharides, although their efficacy is yet to be clearly established.

Critical care management of patients before liver transplantation

The critical care management of patients before liver transplantation is aimed at optimizing hepatic and extrahepatic organ function before the transplant operation, with a goal to favorably influence perioperative and postoperative graft and patient outcomes. Critical illness in liver disease can present in the context of acute liver failure or acute on chronic liver failure. The differing pathophysiologic processes underlying these 2 types of liver failure necessitate specific approaches to their intensive care management. In their extreme presentations, both types of liver failure present as multiorgan system failure; and therefore, the critical care management of these entities requires a systematic multiorgan system approach to address hepatic and extrahepatic organ dysfunction. This review provides a multiorgan system-based description of critical care management of acute liver failure and acute on chronic liver failure before liver transplantation.

Molecular basis and current treatment for alcoholic liver disease

Alcohol use disorders and alcohol dependency affect millions of individuals worldwide. The impact of these facts lies in the elevated social and economic costs. Alcoholic liver disease is caused by acute and chronic exposure to ethanol which promotes oxidative stress and inflammatory response. Chronic consumption of ethanol implies liver steatosis, which is the first morphological change in the liver, followed by liver fibrosis and cirrhosis. This review comprises a broad approach of alcohol use disorders, and a more specific assessment of the pathophysiologic molecular basis, and genetics, as well as clinical presentation and current modalities of treatment for alcoholic liver disease.

A double-blind, randomized, placebo-controlled trial of intravenous L-ornithine-L-aspartate on postural control in patients with cirrhosis

INTRODUCTION

Hepatic encephalopathy (HE) is a complication of liver disease. Several treatments have been introduced but only L-ornithine-L-aspartate (LOLA) shows proven efficacy. This double-blind, randomized, placebo-controlled trial evaluated the effect of LOLA on postural control in cirrhotics.

METHODS

Forty patients were randomized to either LOLA or a placebo. HE was evaluated by psychometric testing (PSE Syndrome Test) and critical flicker frequency (CFF). Posturography [equilibrium score (ES)] provided information regarding postural control. Peripheral blood was analysed for ammonia concentration (NH(3)) and the partial pressure of ammonia (pNH(3)).

RESULTS

Both groups were comparable regarding baseline variables. Posturography and PSE Syndrome Test improved in both groups; improvement was greater in the LOLA group (ES: 5.3%; PSE: 1.9) compared with the placebo (ES: 3.9%; PSE: 1.3) but did not reach significance (ES: P=0.3; PSE: P=0.5). CFF remained unchanged during treatment and between groups (P=NS). NH(3) decreased in the LOLA group (Delta: -15 micromol/L) and slightly increased in the placebo group (Delta: 11.1 micromol/L), but the differences did not reach statistical significance (P=0.07). pNH(3) remained largely unchanged (LOLA Delta: -1.2 x 10(-5) mmHg vs. placebo Delta: -0.3 x 10(-5) mmHg; P=0.21).

CONCLUSION

In the LOLA group, an improvement of posturographic control and PSE Syndrome Test was observed, but a similar improvement was also achieved by the placebo. In LOLA, ammonia levels tended to decrease while they tended to increase in the placebo group. LOLA might augment the improvement achieved by intravenous fluids alone but a larger cohort will be needed to show this effect with statistical significance.

Pathogenesis of hepatic encephalopathy and its prevention after transjugular intrahepatic portosystemic shunt

With the increasing use of transjugular intrahepatic portosystemic shunt (TIPS), we have obtained a breakout progress in the therapy of acute esophageal and gastric-fundus variceal bleeding and refractory ascites. whereas the patency of stent and hepatic encephalopathy (or namely portal-systemic encephalopathy, PSE) after TIPS become two great problems for TIPS. The patency of stent has been improved greatly after the use of covered stent such as Viator stents or covered vascular stents. But the problem of hepatic encephalopathy has not been well solved. In this review, we try to explore the pathogenesis of hepatic encephalopathy and its prevention after TIPS.

Associative learning deficit in two experimental models of hepatic encephalopathy

People with hepatic insufficiency can develop hepatic encephalopathy (HE), a complex neuropsychological syndrome covering a wide range of neurological and cognitive and motor alterations. The cognitive deficits include disturbances in intellectual functions such as memory and learning. In spite of its high prevalence in western societies, the causes of HE have not yet been clearly established. For this reason, experimental models of HE are used to study this condition. In this work, two experimental models were used, one Type B HE (portacaval shunt) and the other Type C HE (cirrhosis by intoxication with thioacetamide), to evaluate its effect on two tasks of associative learning: two-way active avoidance and step-through passive avoidance. The results show an impediment both in acquisition and retention of active avoidance in both models of HE. However, in passive avoidance, only the rats with portacaval shunt presented a memory deficit for the aversive event. In our opinion, these results can be explained by alterations in the neurotransmission system presented by animals with hepatic insufficiency, which are mainly caused by a rise in cerebral histamine and a dysfunction of the glutamatergic system.

A novel endovascular adjustable polytetrafluoroethylene-covered stent for the management of hepatic encephalopathy after transjugular intrahepatic portosystemic shunt

Transjugular intrahepatic portosystemic shunt (TIPS) is frequently complicated by hepatic encephalopathy. When medical therapy fails, TIPS narrowing and resultant increase in the portosystemic pressure gradient and blood flow to the liver is performed in order to reverse the encephalopathy. We present a method for reducing the TIPS using a polytetrafluoroethylene-covered balloon expandable stent placed over a self-expanding stent. This results in a narrowed TIPS that not only rapidly increases the portosystemic gradient but also can be adjusted by dilating the balloon expandable stent. This method was successful in narrowing the patient's TIPS, acutely increasing the portosystemic gradient and reversing the hepatic encephalopathy.

Review article: bacterial flora and pathogenesis in hepatic encephalopathy

The aetiology of hepatic encephalopathy has not been conclusively established, but it is widely agreed that ammonia derived primarily from enteric bacterial flora plays a central role. Recent research on the pathogenesis of hepatic encephalopathy reinforces previous findings, supporting an integral role of bacteria-derived ammonia and reveals other potential mechanisms by which bacterial flora and pathogens may be pathophysiologically important. This review discusses this research and considers its implications for the therapeutic management of hepatic encephalopathy. Besides producing ammonia, the enteric flora generates other neurotoxic products, such as phenols and mercaptans, that may potentiate the effects of ammonia. Bacteria may also constitute a primary source of the benzodiazepine-like compounds implicated in neuropsychiatric symptoms in patients with liver disease. New evidence suggests that acute bacterial infections, long recognized as important precipitants of hepatic encephalopathy, may mediate clinical worsening through effects on systemic inflammatory responses. Considered together, these data suggest wide-ranging pathophysiological contributions of bacteria to hepatic encephalopathy and underline the potential for an integral role of antibiotics and other bactericidal agents in its management.

Limitation of the model for end-stage liver disease for outcome prediction in patients with cirrhosis-related complications

The model for end-stage liver disease (MELD) has been used to prioritize cirrhotic patients awaiting liver transplantation. Bleeding esophageal varices, spontaneous bacterial peritonitis and hepatic encephalopathy are major complications of cirrhosis and traditional indications for liver transplantation evaluation. However, these complications are not included in the MELD and it is not clear if these complications correlate with MELD score in terms of outcome prediction. This study aimed to investigate the feasibility of cirrhosis-related complication as a prognostic predictor in 290 cirrhotic patients. The MELD score and outcome were compared between patients with and without cirrhosis-related complications. There was no significant difference of the MELD score between patients with (n = 67) and without (n = 223) complications (11.6 +/- 2.9 vs. 12.2 +/- 3.2, p = 0.184). The area under the receiver operating characteristic curve was 0.687 for MELD vs. 0.604 for complications (p = 0.174) at six months, and the area was 0.641 for MELD vs. 0.611 for complications (p = 0.522) at 12 months. A high MELD score and presence of complications had a similar profile of predictive accuracy and both were significant predictors of mortality at six and 12 months in multivariate logistic regression analysis. Patients with cirrhosis-related complications at presentation had a decreased survival compared with those without complications (p < 0.0001). In conclusion, the occurrence of cirrhosis-related complications is a predictor of poor prognosis. While early transplantation referral is recommended, these patients do not necessarily have a higher MELD score and could be down-staged in the MELD era.

Nitric oxide production in striatum and pallidum of cirrhotic rats

Ammonium and manganese are neurotoxic agents related to brain metabolic disturbances observed after prolonged liver damage. The aim of this study was to assess the production of nitric oxide (NO) in the brain of cirrhotic rats exposed to manganese. We induced cirrhosis by bile duct ligation for 4 weeks in rats. From brain, striatum and globus pallidus were dissected out, and NO synthase activity and the content of nitrites plus nitrates (NOx) were determined. In pallidum we found a diminished constitutive NO synthase activity from cirrhotic rats, independently of manganese exposure. This result was confirmed by low levels of NOx in the same brain area (P<0.05, two-way ANOVA). This finding was not related to protein expression of NO synthase since no differences were observed in immunoblot signals between cirrhotic and sham-operated animals. Results from present study suggest that the production of NO is reduced in basal ganglia during cirrhosis.

An overview of psychiatric issues in liver disease for the consultation-liaison psychiatrist

Liver disease is a common cause of morbidity and mortality in the United States and elsewhere. Arising from infectious, hereditary, or toxin-induced sources, the detection of liver disease often requires a high index of suspicion. Clinical presentations are highly variable and are often accompanied by neuropsychiatric symptoms. This fact, along with an increased incidence of liver disease among patients with primary psychiatric disorders and the presence of varied drug use, complicates the tasks of providing care to patients with liver disease. To assist the consultation-liaison psychiatrist, the authors present the first of a two-part series focused on psychiatric issues in liver disease.

Occurrence of cirrhosis-related complications is a time-dependent prognostic predictor independent of baseline model for end-stage liver disease score

BACKGROUND

The model for end-stage liver disease (MELD) is used to prioritize cirrhotic patients awaiting liver transplantation. Many cirrhosis-related complications are indications for transplantation but are not included in MELD. This study investigated the impact of these complications on survival and association with MELD.

METHODS

The mortality risk of cirrhosis-related complications, including bleeding esophageal varices, spontaneous bacterial peritonitis, hepatic encephalopathy, hepatorenal syndrome and hepatic decompensation, was analyzed using a time-dependent Cox regression model in 227 cirrhotic patients.

RESULTS

A total of 281 episodes of complications occurred in 142 (63%) patients. Patients who died had a significantly higher baseline MELD score compared with those who survived (14.5 +/- 4.5 vs 12.8 +/- 3.9, P = 0.004). There was no significant difference in the MELD score between patients with and without the occurrence of complications (13.6 +/- 4.3 vs 12.9 +/- 4.0, P = 0.093). Patients with a higher baseline MELD score tended to develop early complications (rho = -0.598, P< 0.001). Using the Cox regression model, the risk ratio of mortality was 4.9 (95% confidence interval: 3.9-6.3, P< 0.0001) for each additional episode of complication.

CONCLUSIONS

The mortality risk increases as the number of complication episodes increases. While patients with repeated complications have a poor outcome, they do not necessarily have a higher baseline MELD score and could be down-staged in the MELD era.

Differences in long-term survival after transjugular intrahepatic portosystemic shunt for refractory ascites and variceal bleed

OBJECTIVE

To compare the survival after transjugular intrahepatic portosystemic shunt (TIPS) for refractory ascites and variceal bleed, and to identify the factors predictive of survival.

METHODS

Single tertiary center, retrospective-prospective study. Chart review was performed on all patients who underwent TIPS between 1993 and 2000 and prospective follow-up to determine survival. Pre- and post-TIPS clinical parameters were compared and Kaplan-Meier analysis was applied to compare the survival of both groups. Cox regression was used to identify predictors of survival after TIPS.

RESULTS

A total of 163 patients were included, 62 with refractory ascites and 101 with variceal bleed. Both groups had similar age (48.2 vs 48.9 year; P = 0.65) and consisted of predominantly Caucasians (51%) and Mexican-Americans (39%). More than 75% had chronic hepatitis C, alcoholic liver disease or both. Overall, the median survival was significantly better for variceal bleed (2 years) compared with refractory ascites (6 months) (P < 0.001). This survival advantage persisted in patients with Mayo risk score greater than 1.17. Transjugular intrahepatic portosystemic shunt improved severe ascites in 45% of patients (P = 0.03). Mayo risk score was highly predictive of survival after TIPS with a hazard ratio of 2.3, followed by Child-Pugh score, creatinine, albumin and ethnicity, with better survival among Mexican-Americans. Shunt dysfunction (31%) and hepatic encephalopathy (27%) were the most common complications of TIPS.

CONCLUSIONS

Patients who received TIPS for variceal bleed had significantly longer survival compared with those for refractory ascites. Mexican-Americans had an improved long-term survival compared with Caucasians. The reason for this ethnic difference in survival is unclear and warrants further prospective evaluation.

TIPS-related hepatic encephalopathy: management options with novel endovascular techniques

Hepatic encephalopathy is a common complication that develops after creation of a transjugular intrahepatic portosystemic shunt (TIPS). Although most patients respond well to conservative medical therapy (ie, protein-restricted diet, nonabsorbable disaccharides, nonabsorbable antibiotics), a small percentage of patients (3%-7%) do not benefit from these methods and require more invasive therapeutic approaches. One option is emergent liver transplantation, but the majority of patients are not suitable candidates. Recently, various percutaneous techniques have been described that alter the hemodynamics through the shunt by occluding it with coils or balloons or by reducing its diameter by inserting constrained stents or stent-grafts. Other techniques have been used for patients with TIPS-related hepatic encephalopathy in whom spontaneous splenorenal shunts are present. In many patients with refractory hepatic encephalopathy, these percutaneous techniques have produced symptomatic improvement, with either a complete resolution or a substantial reduction in hepatic encephalopathy symptoms that can be controlled with medical therapy. Unfortunately, despite all attempts, some patients remain incapacitated and ultimately die. Further research is necessary to improve our understanding of TIPS-related hepatic encephalopathy so that newer, less invasive and safer procedures can be developed to treat this difficult clinical problem.