Helicobacter pylori infection induces hyperammonaemia in Mongolian gerbils with liver cirrhosis

Hepatic Encephalopathy in the Hospitalized Patient: A Review for Hospitalists

Hepatic encephalopathy is a well-recognized complication of decompensated cirrhosis. It is a reversible state of neurocognitive decline, the etiology of which is multifactorial. Diagnosis is predominantly clinical and usually a diagnosis of exclusion. The identification of precipitating factors and their correction is an essential part of the management along with medical therapies such as lactulose and rifaxmin.

Association of Helicobacter pylori with the Risk of Hepatic Encephalopathy

BACKGROUND/OBJECTIVES

Hepatic encephalopathy is the common manifestation of decompensated cirrhosis. The association between Helicobacter pylori (H. pylori) infection and hepatic encephalopathy has been shown in many epidemiologic studies. This meta-analysis was conducted to summarize all available studies to estimate the association between H. pylori infection and hepatic encephalopathy.

METHODS

A comprehensive literature review was conducted using MEDLINE and EMBASE database through March 2017 to identify studies that reported the association between H. pylori infection and hepatic encephalopathy. Effect estimates from the individual study were extracted and combined using random-effect, generic inverse variance method of DerSimonian and Laird.

RESULTS

Of 15,233 studies, eleven studies (four cross-sectional, four case-control, and three cohort studies) met the eligibility criteria and were included in the meta-analysis. The pooled OR of hepatic encephalopathy in patients with H. pylori infection was 1.73 (95% CI 1.09-2.73) when compared with the patients without H. pylori infection. The association between H. pylori and hepatic encephalopathy was not statistically significant after the sensitivity analysis, excluding those using ELISA alone, with a pooled OR of 1.92 (95% CI 0.91-4.05, I ² = 62%). There was no publication bias of overall included studies assessed by the funnel plots and Egger's regression asymmetry test.

CONCLUSIONS

This study demonstrated a potential association between H. pylori infection and risk of hepatic encephalopathy. Future studies are required to assess the effect of chronicity of infection on the development of hepatic encephalopathy.

Effect of H pylori infection and its eradication on hyperammo-nemia and hepatic encephalopathy in cirrhotic patients

AIM: To investigate the relationship between H pylori infection, blood ammonia concentration and hepatic encephalopathy (HE), and the effect of H pylori eradication in cirrhotic patients.

METHODS: From July 2003 to January 2005, 457 cirrhotic patients in five regions of Zhejiang Province were enrolled. Patients were evaluated for demographics, number connection test, H pylori infection, liver impairment, blood ammonia concentration and HE. Patients with H pylori infection were given 1 wk therapy with omeprazole plus clarithromycin and tinidazole. ¹⁴C urea breath test was performed and mental symptoms and blood ammonia level were reassessed after bacterium eradication.

RESULTS: Overall H pylori infection rate was 60.6%, and HE occurred in 47.5% of cirrhotic patients. Subclinical HE (SHE) was detected in 55 of 117 cirrhotic patients. Blood ammonia concentration in H pylori negative (n = 180) and positive (n = 277) cirrhotic patients was 53.8 ± 51.4 and 78.4 ± 63.6 &mgr;mol/L, respectively (P < 0.01), which was significantly reduced to 53.5 ± 37.7 &mgr;mol/L after bacterium eradication (n = 126) (P < 0.01). Blood ammonia was 97.5 ± 81.0 &mgr;mol/L in H pylori-positive cirrhotic patients, and this did not significantly change in those with persistent infection after H pylori eradication (n = 11). HE was more frequently observed in patients with H pylori infection than in those without (58.5% vs 30.6%, P < 0.01). HE rate significantly dropped to 34.1% after H pylori eradiation (P < 0.01). H pylori prevalence significantly differed among cirrhotic patients with HE (74.4%), SHE (69.1%), and those without HE (53.2%) (P < 0.05). Blood ammonia level was significantly different among cirrhotic patients with HE (94.5 ± 75.6 &mgr;mol/L), SHE (59.9 ± 49.2 &mgr;mol/L), and without HE (47.3 ± 33.5 &mgr;mol/L) (P < 0.05). Logistic regression analysis showed that blood ammonia concentration, Child-Pugh stage, upper gastrointestinal bleeding, electrolyte disturbance, and urea nitrogen were risk factors for HE.

CONCLUSION: H pylori infection is an important factor for inducing high blood ammonia concentration and HE in cirrhotic patients. H pylori eradication may be helpful for treatment and prevention of HE.

Helicobacter pylori and hepatocellular carcinoma: correlated or uncorrelated?

Helicobacter pylori can be detected in liver tissue resected from patients with hepatocellular carcinoma. Conflicting reports regarding the relationship between H. pylori and hepatocellular carcinoma mean it is uncertain whether H. pylori acts as a troublemaker, co-risk factor or innocent bystander to the development of hepatocellular carcinoma. Clinical studies in patients without known causes of hepatocellular carcinoma are important to discover whether H. pylori is involved in the carcinogenesis of hepatocellular carcinoma. High quality prospective studies in patients with hepatocellular carcinoma, hepatitis C virus infection and no cirrhosis are needed to determine whether H. pylori is a co-risk factor for hepatocellular carcinoma.

Hepatic encephalopathy and Helicobacter pylori: a critical reappraisal

Hepatic encephalopathy (HE) is a frequent complication of liver cirrhosis, and plasma ammonia plays a pivotal role in its pathogenesis. Ammonia disposal in cirrhotics depend on intricately balanced enzyme and transport systems, involving liver, large and small bowel, muscle, and kidney. Recently, it has been suggested that Helicobacter pylori could contribute to hyperammonemia in cirrhotics, but conflicting data are available in the literature. This is a systematic review of experimental (animals and humans), epidemiological, case-control, and prospective studies, to evaluate the arguments in favor and against the role of H. pylori in HE pathogenesis. Although H. pylori produces ammonia in the stomach, several studies have shown that both basal ammonia levels and HE prevalence did not significantly differ between cirrhotics with and without infection. Moreover, some prospective studies have documented that both blood ammonia levels and mental status in HE cirrhotics are not significantly affected by H. pylori eradication. Even if a small sub-group of cirrhotics with both a high bacterial density and more severe hepatic impairment seems to benefit by bacterial eradication, data indicate that ammonia production in the stomach by H. pylori urease appears to be inadequate to clinically affect ammonia disposal in the majority of cirrhotic patients. Further studies are warranted in this field.

Helicobacter pylori infection in patients with liver cirrhosis: facts and fictions

Helicobacter pylori infection could play a role in different clinical alterations observed in cirrhosis, from gastroduodenal lesions to hepatic encephalopathy. Although its prevalence in cirrhotics is similar to that in controls, H. pylori infection is responsible for the increased prevalence of peptic ulcer observed in these patients. The ammonia production by H. pylori urease does not seem to increase blood ammonia levels during cirrhosis, indicating that its role in hepatic encephalopathy could be marginalized in clinical practice. Dual and triple therapies have been shown to be equally effective for H. pylori eradication in these patients.

Altered response to oral glutamine challenge as prognostic factor for overt episodes in patients with minimal hepatic encephalopathy

BACKGROUND/AIMS

We assessed the usefulness of oral glutamine challenge (OGC) and minimal hepatic encephalopathy in evaluating risk of overt hepatic encephalopathy in cirrhotic patients.

METHODS

Minimal hepatic encephalopathy (MHE) was inferred using neuro-psychological tests. Venous ammonia concentrations were measured pre- and post-60 min (NH(3)-60m) of a 10 g oral glutamine load. Receiver-operating-characteristic curve analysis indicated a pathological glutamine tolerance cut-off value of NH(3)-60m >128 microg/dl.

RESULTS

In healthy control subjects (n=10) ammonia concentrations remained unchanged but increased significantly in cirrhotic patients (from 70.41+/-45.2 to 127.43+/-78.6; P<0.001). In multiple logistic regression analysis, altered OGC was related to Child-Pugh (odds ratio, OR=7.69; 95% confidence interval, CI=1.72-33.3; P<0.01) and MHE (OR=5.45; 95% CI=1.17-25.4; P<0.05). In the follow-up 11 patients (15%) developed overt hepatic encephalopathy (HE). In multivariate analysis OGC (OR=14.5; 95% CI=1.26-126.3) and MHE (OR=1.56; 95% CI=1.02-21.9) were independently related with HE in the follow-up. Patients with MHE and altered OGC showed significantly higher risk of overt HE in the follow-up (60%) than patients without MHE and normal OGC (2.8%) (Log rank test=21.60; P<0.0001).

CONCLUSIONS

A pathological OGC in patients with MHE appears to be a prognostic factor for the development of overt hepatic encephalopathy, whereas a normal OGC in patients without MHE could exclude risk of overt HE.