Chronic Portal-systemic Encephalopathy Research Articles

Portal‐systemic shunt encephalopathy presenting with diffuse cerebral white matter lesion: An autopsy case

We report herein an autopsy case of portal-systemic encephalopathy (PSE) presenting with diffuse tissue rarefaction in the cerebral deep white matter. Clinically, the patient showed recurrent episodes of unconsciousness, abnormal behavior and urinary incontinence, as well as flapping tremor. Cognitive impairment and peripheral neuropathy developed following recurrent episodes. Although conventional arterial portography revealed a small portal-systemic collateral vessel of a left gastro-renal venous shunt, abdominal CT and liver biopsy showed no evidence of liver cirrhosis and serum ammonia level showed a mild increase. T2-weighted MRI demonstrated symmetrical signal hyperintensities in the deep white matter. Neuropathological findings showed Alzheimer type II astrocytes in the deep layers of the cerebral cortices and severe tissue rarefaction with no or slight reactive astrocytosis in the subcortical and deep white matter. These white matter changes have been reported infrequently in patients with PSE. The present case suggests that chronic PSE without liver cirrhosis may develop diffuse white matter lesions.

In vitro Activity of Rifaximin, Metronidazole and Vancomycin against Clostridium difficile and the Rate of Selection of Spontaneously Resistant Mutants against Representative Anaerobic and Aerobic Bacteria, Including Ammonia-Producing Species

Background: Rifaximin is a rifamycin derivative characterized by a wide antibacterial activity. This drug is neither absorbed by the gastrointestinal tract nor inactivated by gastric juices, and exerts its action entirely within the intestinal lumen. Methods: In this study, the activity of this antibiotic was compared with that of metronidazole and vancomycin against 93 Clostridium difficile isolates. The rate of emergence of bacteria spontaneously resistant to the new compound was also evaluated in relation to representative gram-positive and gram-negative strains. In terms of MIC₅₀ values, rifaximin showed an intrinsic activity superior to that of the other agents. The emergence of spontaneously resistant strains was assessed with 46 aerobic (staphylococci, enterococci, Proteus spp., Citrobacter freundii, Providencia rettgeri, enteropathogenic, enteroinvasive, enterotoxigenic and entero- hemorrhagic Escherichia coli, and Salmonella enteritidis) and anaerobic (Clostridium spp., Bacteroides spp., Fusobacterium nucleatum and Peptococcus spp.) pathogens, most of them also ammonium producers. Two different methods, broth and agar dilution, were employed. Results: When liquid medium was employed, bacteria capable of sustained growth in 100 μg/ml of rifaximin were obtained after 2–5 transfers with gram-positive aerobic cocci, 2–3 transfers with gram-negative aerobic strains and 2–5 transfers with anaerobic species. At the highest dose used with the agar dilution method (8 × MIC), the frequency of emergence of spontaneously resistant mutants ranged from <1 × 10^–9 to 1.6 × 10^–8 with gram-positive aerobic and anaerobic cocci, while with aerobic and anaerobic gram-negative bacteria, this value ranged from <1 × 10^–9 to 1.7 × 10^–7. C. difficile showed a particularly low incidence of spontaneously resistant mutants (<1 × 10^–9). The low incidence of resistant subpopulations selected by levels of 8 × MIC of rifaximin suggests that the high levels of the drug which were reached in the gastrointestinal lumen may further prevent the selection of mutants. Conclusion: The low toxicity, broad antibacterial activity and very poor absorption from the gastrointestinal tract of rifaximin suggest a potential therapeutic use for this drug in gastrointestinal diseases, as well as in the management of patients with cirrhosis and chronic portal-systemic encephalopathy.

Beneficial Effect of Carbohydrate Maldigestion Induced by a Disaccharidase Inhibitor (AO-128) in the Treatment of Chronic Portal-Systemic Encephalopathy: A Double-Blind, Randomized, Controlled Trial

Background: The most widely used treatment of portal-systemic encephalopathy (PSE) is the administration of oral, non-absorbable disaccharides. Theoretically, the inhibition of intestinal disaccharidases should induce malabsorption of disaccharides and increase delivery of undigested carbohydrates to the colon, thus stimulating the effects of lactulose and other non-absorbable disaccharides (that is, lactitol and lactose). AO-128 is an N-substituted derivative of valeolamine, an aminocyclitol that selectively inhibits intestinal disaccharidases. This study was performed to investigate whether AO-128 could be used as adjuvant therapy for the treatment of mild PSE in cirrhotic patients. Methods:

Potassium-evoked neuronal release of serotonin in experimental chronic portal-systemic encephalopathy

Potassium-evoked neuronal release of serotonin in experimental chronic portal-systemic encephalopathy

Potassium-Evoked Neuronal Release of Serotonin in Experimental Chronic Portal-Systemic Encephalopathy

Portal-systemic encephalopathy (PSE) is associated with an increased brain tissue turnover of serotonin (5-HT). Despite increased 5-HT metabolism, brain 5-HT release in rats with a portacaval shunt (PCS) seems to be unaltered. Although this may indicate that the overall 5-HT output is unaltered in PSE, it is also possible that the 5-HT release pattern might be altered in some way. In the present study, the potassium-evoked frontal neocortical release of 5-HT was studied in experimental chronic PSE. KCI (60 mM) produced marked increases in the 5-HT output compared with basal values both in PCS and sham rats. Simultaneously, the KCI challenge resulted in significant elevations in the 5-HT release of PCS compared with sham. In Ca2+-free medium, the difference between PCS and sham rats in the KCl-evoked release of 5-HT was abolished. In the presence of TTX (1 mM), both groups displayed increased extracellular 5-HT levels. Again, a difference with higher amplitude of the 5-HT release in PCS compared with sham was evident. It is concluded that in experimental chronic PSE an augmented neocortical 5-HT release compared with the normal in vivo situation is available. The possible mechanism(s) responsible for the difference in neocortical 5-HT output between PCS and sham-operated rats in response to the KCl-challenge is discussed.

P-Chloroamphetamine- and d-Fenfluramine-Induced Brain Serotonin Release in Experimental Portal-Systemic Encephalopathy

Portal-systemic encephalopathy (PSE) is associated with increased brain turnover of serotonin (5-HT) in vivo but the brain 5-HT output seems to be unaltered. Recent results suggest, however, that an augmented neocortical 5-HT release in experimental chronic PSE may prevail under certain conditions. In the present study, neocortical extracellular 5-HT and 5-hydroxyindoleacetic-3-acid (5-HIAA) levels were measured in portacaval shunted (PCS) rats and sham-operated controls following local administration of p-chloroamphetamine (pCA) and d-fenfluramine (dFEN), two specific 5-HT releasing agents. The basal neocortical extracellular 5-HT concentrations were unaltered and the 5-HIAA levels were elevated in experimental PSE, supporting an unchanged brain 5-HT output despite elevated brain 5-HT metabolism. Perfusion with pCA or dFEN (5 microM; one 20-min pulse) produced marked increases in brain 5-HT release both in PCS and sham-operated rats compared with corresponding basal values. While no difference in the 5-HT response to dFEN administration was seen between sham (5-HT levels increased by 330%) and PCS (500%) rats, a clear difference (p<0.05) in the brain 5-HT output was observed between the two experimental groups following pCA perfusion (sham, 1100% versus PCS, 1470%). These results support our previous contention of an enhanced neocortical 5-HT output in experimental chronic PSE under certain pharmacological conditions.

Precipitation of overt encephalopathy in the portacaval shunted rat: towards the development of an adequate model of chronic portal systemic encephalopathy.

To assess the feasibility of developing a model of overt portal-systemic encephalopathy (PSE) in rats with a surgically constructed portacaval anastomosis (PCA). The ability of increasing the load of nitrogenous substances in the gastrointestinal tract and/or further decreasing hepatocellular function to induce overt encephalopathy in rats with a PCA was determined. The load of nitrogenous substances in the gastrointestinal tract was increased by feeding a pure horse-meat diet or by gavaging with blood. Partial hepatectomy and the induction of cirrhosis were used to decrease hepatocellular function further. The severity of encephalopathy was assessed using a neurobehavioural scale. Overt encephalopathy was not induced in rats by a PCA alone, by a PCA plus a horse-meat diet, by a PCA plus induction of cirrhosis, or by a PCA plus a 50% hepatectomy. Predominantly mild, but overt, encephalopathy was induced in rats with a PCA alone by gavaging with blood and a higher incidence of more severe overt encephalopathy was induced in rats with a PCA combined with either cirrhosis or partial hepatectomy by gavaging with blood. Although these models of PSE were associated in some instances with plasma ammonia concentrations about 25 times higher than normal, no seizures were observed. A syndrome that resembles overt PSE in humans can be induced in the rat with a PCA by further reducing hepatocellular function and also gavaging with blood. Although the rat with a PCA has been. extensively used as a model in studies relating to the pathogenesis of PSE, a syndrome resembling overt PSE in humans cannot readily be induced in rats with a PCA.

Acute effects of L-tryptophan on brain extracellular 5-HT and 5-HIAA levels in chronic experimental portal-systemic encephalopathy.

Portal-systemic encephalopathy (PSE) is associated with increased brain turnover of serotonin (5-hydroxytryptamine; 5-HT). Despite this metabolic increase, neuronal release of 5-HT is unaltered in neocortex of portacaval shunted (PCS) rats. In the present study, frontal neocortical extracellular 5-HT and 5-hydroxyindole-3-acetic acid (5-HIAA) levels were determined in PCS rats and sham-operated controls prior to, as well as, after acute challenge with L-tryptophan (L-TRP; a bolus dose of 280 mg/kg i.p. followed by 5 consecutive hourly doses of 50 mg/kg). Neither basal 5-HT nor 5-HIAA extracellular levels were significantly altered in PCS rats compared to controls. L-TRP administration resulted in unaltered extracellular 5-HT but elevated 5-HIAA levels in PCS and sham rats. These findings do not suggest that changes in brain neuronal 5-HT release play any major functional role in the pathogenesis of chronic PSE. The present data also emphasize the importance of distinguishing between brain 5-HT metabolism and brain 5-HT release.

Neuropsychiatric implications of brain tryptophan perturbations appearing in hepatic encephalopathy.

The metabolic encephalopathies exhibit CNS-symptoms that rapidly may alter in location of brain region of engagement, indicating a continuous fluctuation of the level of which brain functions are disturbed. This is particularly obvious in chronic conditions, such as chronic or latent hepatic encephalopathy (HE), where the fluctuating level of consciousness may be a dangerous sudden developing symptom in a person otherwise appearing to have normal brain functions. If these individuals are occupied with e.g. driving vehicle in traffic or working in heavy industrial practice, such chronic portal-systemic encephalopathy (PSE) (Sherlock et al., 1954) may be a particular hazard to both themselves and others. Unfortunately, the pathogenesis of PSE is still unknown. Hence, the delineation of the pathogenesis for HE/PSE, and therapeutic modalities developing therefrom, is highly warrented. Numerous pathogenetic mechanisms and etiological factors for PSE have been suggested (Conn and Liebertahl, 1979).

Chronic rejection following primary adult liver transplantation under tacrolimus: [formula omitted]. Pittsburgh Transplantation Institute, University of Pittsburgh, Pittsburgh, PA

A portal hemodynamic study was made in 7 consecutive patients with chronic portal-systemic encephalopathy by percutaneous transhepatic catheterization of the portal vein and injecting contrast medium into the superior mesenteric vein or by superior mesenteric arterial portography in comparison with patients without encephalopathy studied by percutaneous catheterization of these veins. All 7 patients had a large gastro-renal or spleno-renal shunt, and a large proportion of superior mesenteric venous blood was being shunted as estimated from the diameter of the portal and the collateral vein, whereas in nonencephalopathic patients in whom part of the superior mesenteric venous blood was shunting this diversion was much less (P < 0.001). Only one of the chronic portal-systemic encephalopathic patients had esophageal varices, insignificant in size, and the incidence of esophageal varices was significantly less compared to the 12 nonencephalopathic control patients with portal hypertension who had either a gastro-renal or spleno-renal shunt (P < 0.05). It is suggested that chronic portal-systemic encephalopathy is a result of a large collateral route shunting a large proportion of the superior mesenteric venous blood into systemic circulation, and that development of such collaterals precludes formation of large esophageal varices.

Hepatic hemodynamic features in patients with esophageal or gastric varices

One hundred and fifty cirrhotic patients with or without esophageal varices and/or gastric varices were investigated by endoscopy and hepatic venous catheterization to evaluate differences in the degree of portal hypertension, main portal venous diameter and frequency of portal systemic encephalopathy. Hemodynamic values were correlated with varices size as assessed by endoscopy. Patients with large gastric varices had wedged hepatic venous pressures and hepatic venous pressure gradients which were lower than patients with esophageal varices only, but similar to patients without varices. In addition, in patients with large gastric varices, a decrease in the diameter of the main portal vein and an increase in the incidence of chronic portal systemic encephalopathy were noted. Our results implied that patients with large gastric varices presented different hemodynamic features including the degree of portal hypertension and the incidence of portal systemic encephalopathy from patients with esophageal varices only.

Review: 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.

Traditional Management of Liver Disorders

Dietary measures have achieved mixed results in the management of liver disorders. Although a high energy diet may shorten the course of viral hepatitis by a relatively small amount, dietary restriction is usually of no benefit in compensated cirrhosis. Restriction of sodium intake to 22 to 60 mol/day leads to resolution of cirrhotic ascites in approximately 20% of patients, and reduces the requirement for diuretics in the remainder. In advanced liver disease, diet plays an important role in the avoidance of portal-systemic encephalopathy (PSE), with the tolerance of most nutrients, most importantly protein, being sharply reduced. Despite the frequent presence of carbohydrate intolerance in liver disease, carbohydrate supplementation may be required to ensure adequate utilisation of the reduced dietary protein intake. Zinc supplementation may also be required in liver cirrhosis to compensate for a deficiency. Bed rest is an important component of the management of acute and chronic liver disorders, together with the avoidance of fatigue. Abstinence from alcohol is required in alcoholic liver disease patients, who should receive parenteral thiamine 100 mg and other vitamin and mineral supplementation as required. Agents acting on the ascending loop of Henle [such as furosemide (frusemide)] or the distal tubule (such as spironolactone) are the diuretics most frequently employed to mobilise ascites in cirrhosis, the latter drug being the more effective in nonazotaemic patients. In the absence of oedema, the diuresis should be restricted to a maximum of 750 ml/day; however, patients with oedema may safely undergo a diuresis of less than or equal to 1.5 L/day. Diuretic therapy is often associated with renal complications, such as azotaemia (usually reversible) and severe hyponatraemia in cirrhotic patients with ascites; spironolactone may produce antiandrogenic adverse effects. Lactulose, used in the treatment of acute and chronic PSE, acts by inhibiting gastrointestinal absorption of ammonia and other toxic nitrogenous substances, and by reducing urea degradation. Other pharmacological treatments, such as branched-chain amino acids and benzodiazepine antagonists have a limited role in the management of PSE. Chronic cholestasis has been treated with cholestyramine and fat-soluble vitamins, whereas ursodeoxycholic acid appears to be a promising agent in the treatment of primary biliary cirrhosis. In chronic hepatitis, the prevention of development of cirrhosis is a primary treatment goal which has been attempted with variable success using antifibrotic drugs such as penicillamine and colchicine.(ABSTRACT TRUNCATED AT 400 WORDS)

Brain 5-HT1 and 5-HT2 binding sites following portacaval shunt in the rat.

Brain serotonin 5-HT1 and 5-HT2 binding properties were investigated in experimental chronic portal-systemic encephalopathy (PSE). End-to-side portacaval shunted (PCS) rats were subjected to open field behavioral testing (spontaneous activity and exploration) 3 weeks after the shunt procedure. Each individual animal was then assayed for 5-HT1 and 5-HT2 binding properties (Bmax and KD) in the cortex + hippocampus by the use of radioligand binding and rapid filtration technique. (3H)serotonin was used to label 5-HT1 binding sites and (3H)ketanserin to label 5-HT2 binding sites. Results revealed that the PCS rats exhibited significant behavioral changes with decreased spontaneous activity and exploratory behavior as compared with sham-operated controls (sham). The affinity for, and the number of, 5-HT1 and 5-HT2 binding sites, respectively, were not different between PCS and sham rats. The brain 5-HT1 and 5-HT2 binding properties were within the range of Bmax and KD previously reported for normal rats when similar techniques are used. This first report in PCS rats on the subject of brain 5-HT1 and 5-HT2 binding properties demonstrates that no major alterations are likely to occur. This contrasts the knowledge of a markedly increased brain serotonin synthesis rate in the PCS rat, suggesting minor functional relevance of the perturbed brain serotonin metabolism associated with chronic PSE.

Portal hemodynamics in patients with gastric varices: A study in 230 patients with esophageal and/or gastric varices using portal vein catheterization

The hemodynamic features of gastric varices are not well documented. The purpose of this study was to investigate the nature of hepatofugal collateral veins, their origins, the direction of blood flow in the major veins and collateral veins, and portal venous pressure. To this end, 230 patients, mostly cirrhotic, who had esophageal or gastric varices, or both, demonstrated by endoscopy were investigated by portal vein catheterization. The findings were correlated with endoscopically assessed degrees of varices. Gastric varices were seen in 57% of the patients with varices due to portal hypertension. In most of the patients with advanced gastric varices, esophageal varices were minimal or absent. When patients with gastric varices were compared with those having predominantly esophageal varices, it was found that advanced gastric varices were more frequently supplied by the short and posterior gastric veins, they were almost always associated with large gastrorenai shunts, and portal venous pressure in patients with large gastric varices was lower. Chronic portal systemic encephalopathy was more common in patients with large gastric varices due to hepatofugal flow of superior mesenteric venous blood in the splenic vein than in patients with predominantly esophageal varices. Thus, the hemodynamics in patients with large gastric varices are distinctly different from those in patients with mainly esophageal varices, and such differences seem to account for the differing incidence of chronic encephalopathy and variceal bleeding.

Lactitol versus lactulose in the treatment of acute portal systemic encephalopathy (PSE): A controlled trial

Preliminary data suggest that lactitol (beta-galactoside-sorbitol), a new synthetic non-absorbable disaccharide, has beneficial effects on chronic portal systemic encephalopathy. To compare the efficacy of lactitol vs. lactulose in the treatment of acute portal systemic encephalopathy (PSE), 40 cirrhotic patients with an acute episode of PSE were randomly allocated to one of two groups: group A (20 patients) received lactulose (30 ml/6 h) and group B (20 patients) lactitol (12 g/6 h). These doses were adjusted daily to obtain two bowel movements per day. The duration of treatment was 5 days. Age, sex, hepatic and renal function, precipitating factors and level of PSE measured by clinical examination, EEG and number connection test were similar in the two groups. A complete clinical resolution of PSE occurred in 11 patients in each group. In 5 patients of the lactulose group and in 6 of the lactitol group there was a moderate improvement of PSE during the study. Finally, 4 patients in the lactulose group and 3 in the lactitol group did not respond to treatment. No side effects attributable to therapy were observed in either group. These results indicate that lactitol is as effective as lactulose in the management of patients with cirrhosis and acute PSE.

Lactitol vs. lactulose in the treatment of chronic recurrent portal systemic encephalopathy (PSE)

Lactitol vs. lactulose in the treatment of chronic recurrent portal systemic encephalopathy (PSE)

Beneficial Effect of Vegetable Protein Diet Supplemented With Psyllium Plantago in Patients With Hepatic Encephalopathy and Diabetes Mellitus

A controlled crossover study was performed in 8 diabetic patients with chronic portal-systemic encephalopathy. After a basal period the patients were treated during periods A and B. During period A, a meat protein diet (0.8 g/kg body wt, approximately 1800 kcal/day) was consumed and neomycin plus laxatives were given. During period B patients received vegetable protein (0.8 g/kg body wt, 1800 kcal/day). This diet was supplemented with psyllium fiber to reach 35 g of fiber per day. Four patients were randomly assigned to receive the treatments in the order A-B and the other 4 patients in the order B-A. At the end of the first experimental period, fasting glucose levels were 204 +/- 86 mg% in the meat protein diet group and 127 +/- 8 mg% in the vegetable protein diet group (p less than 0.014). The patients were receiving 2.5 +/- 0.2 g/day and 2.1 +/- 0.5 g/day of tolbutamide at the end of the meat protein diet and vegetable protein diet, respectively. In all cases, fasting glucose levels decreased at the end of the vegetable diet period regardless of the previous treatment. An improvement of greater than or equal to 25 mg% of fasting glucose levels was observed in 7 of the 8 patients after the vegetable protein diet and in no case after the meat protein diet (p less than 0.0078). The parameters of encephalopathy were comparable at the end of both the meat protein diet and the vegetable protein diet. A significant increase in the number of bowel movements was noticed after the vegetable diet plus fiber (p less than 0.01). We propose the use of vegetable diet plus fiber to facilitate the treatment of patients with both diabetes and hepatic encephalopathy.

Portal hemodynamics in chronic portal-systemic encephalopathy: Angiographic study in seven cases

A portal hemodynamic study was made in 7 consecutive patients with chronic portal-systemic encephalopathy by percutaneous transhepatic catheterization of the portal vein and injecting contrast medium into the superior mesenteric vein or by superior mesenteric arterial portography in comparison with patients without encephalopathy studied by percutaneous catheterization of these veins. All 7 patients had a large gastro-renal or spleno-renal shunt, and a large proportion of superior mesenteric venous blood was being shunted as estimated from the diameter of the portal and the collateral vein, whereas in nonencephalopathic patients in whom part of the superior mesenteric venous blood was shunting this diversion was much less (P less than 0.001). Only one of the chronic portal-systemic encephalopathic patients had esophageal varices, insignificant in size, and the incidence of esophageal varices was significantly less compared to the 12 nonencephalopathic control patients with portal hypertension who had either a gastro-renal or spleno-renal shunt (P less than 0.05). It is suggested that chronic portal-systemic encephalopathy is a result of a large collateral route shunting a large proportion of the superior mesenteric venous blood into systemic circulation, and that development of such collaterals precludes formation of large esophageal varices.

Abdominal Colectomy for Chronic Encephalopathy-Reply

In Reply. —Dr Braslow raises the question of postcolectomy colonization of the distal part of the small bowel with colonic bacteria that might limit the effectiveness of colectomy in ameliorating the severity of chronic portal-systemic encephalopathy. Such colonization does occur, but the benefits of colectomy persisted during the follow-up period in our patients. The encephalopathy that recurred was more amenable to standard medical therapy, including oral antibiotics. The reasons are theoretic but include the following: elimination of the reservoir function of the colon, more rapid transit time through the ileum and distal colon, quantitative decrease in total mass of urea-splitting organisms in the small bowel as compared with the colon, and more effective reduction of bacteria with oral antibiotics. The role and efficacy of antireflux ileal valves in the long-term prevention of reflux or bacterial colonization of the small bowel remain to be proved.