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PubMed2002

Central nervous system alterations in liver cirrhosis: the role of portal-systemic shunt and portal hypoperfusion.

The role of portal-systemic shunting and portal liver hypoperfusion in the pathophysiology of central nervous system dysfunction of cirrhosis is not yet well defined. It is well known that one of the most important collateral vessels (CV) is a patent paraumbilical vein (PUV) but there is controversy regarding its clinical significance. We have evaluated the relationships between neuropsychological and EEG alterations, ammonia plasma level (NH4), hepatic function, and portal hemodynamics (Doppler Ultrasound) in 95 cirrhotic patients. Patency, diameter, or flow of PUV or the presence of other CV were not related to an increased prevalence of neuropsychological or EEG abnormalities. Patients with effective portal flow (EPF = portal flow - PUV flow) lower than 692 mL/min (median) had a significantly higher risk of failing the neuropsychological test, or of having an altered EEG. Low EPF and prothrombin time (<50%), and high NH4 (> or = 51 micromol/L) were independent predictors of an abnormal EEG. Considering both low EPF and the numerosity of CV, only low EPF was found to explain EEG alterations. In conclusion, portal liver hypoperfusion and decreased liver function were associated with an increased risk of central nervous system dysfunction in cirrhotic patients, whereas PUV patency per se was not.

Brain↗
PubMed2002

[A case of portal-systemic shunt encephalopathy due to congenital portal vein hypoplasia presenting with abnormal cerebral white matter lesions on the MRI].

A 49-year-old woman, without any past history of liver diseases and blood transfusion, was admitted to our service because of somnolence, and flapping tremor. Neurologically, she was drowsy and disoriented. She had bilateral pyramidal tract signs and flapping tremor. Although the laboratory examination showed marked hyperammonemia (217 micrograms/dl), neither abdominal CT nor liver biopsy showed any evidence of liver cirrhosis. An abdominal angiography showed portal vein hypoplasia associated with the portal-systemic shunt. A T2-weighted MRI showed the high intensity areas in the bilateral deep cerebral white matter, and the posterior limbs of the bilateral internal capsules. This is a rare case of portal-systemic shunt encephalopathy due to congenital portal vein hypoplasia presenting with abnormal cerebral white matter lesions on the MRI.

Female↗
PubMed1996

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.

Animals↗
PubMedDate not supplied

Relationship between endotoxin antibody levels and portal systemic shunt evaluated by per-rectal portal scintigraphy.

The reasons for the high frequency of endotoxaemia in cirrhosis, whether poor liver function or abnormal portal circulation, are not known. Accurate measurement of endotoxin itself is difficult. Instead, in this study an enzyme-linked immunosorbent assay was used to measure levels of IgA, IgG and IgM antibodies to endotoxin in patients with chronic liver disease and underlying hepatic viral infection. The relationships between the results and clinical symptoms or the presence of a portal systemic shunt were investigated. The median level of IgA antibodies was not different in patients with chronic hepatitis and those with cirrhosis, and the same was found for IgM, but the median level of IgG antibodies was significantly higher in the patients with cirrhosis. When patients with cirrhosis were grouped by the presence or absence of ascites or hepatocellular carcinoma, no significant difference was observed in any of these antibody levels. However, in cirrhotic patients with varices, the level of IgG antibodies to endotoxin was significantly higher than in patients without varices. For evaluation of the portal systemic shunt, the per-rectal portal shunt index was calculated. There was a significant correlation (R = 0.431, P < 0.001) between the per-rectal portal shunt index and the level of IgG antibodies to endotoxin. That is, the degree of abnormality in the portal haemodynamics was correlated with the level of IgG antibodies to endotoxin in patients with liver disease.

Antibodies, Bacterial↗
PubMed1995

Evaluation of intestinal absorption into the portal system in enterohepatic circulation by measuring the difference in portal-venous blood concentrations of diclofenac.

PURPOSE: We evaluated the first-pass effects in vivo by the intestine and liver during enterophepatic circulation (EHC) by simultaneously measuring the portal and venous plasma concentrations of the rat. METHODS: The venous and upper portal blood vessels were cannulated through the jugular and the pyloric veins, respectively, to obtain simultaneously blood samples from both sites. After diclofenac was injected as a bolus through the jugular vein, the concentrations of diclofenac in the portal and jugular veins were measured at time intervals. The absorption rate from the intestinal tract into the portal system was determined using the portal-venous difference in plasma concentrations of diclofenac, considering 40% partitioning of diclofenac into erythrocytes. RESULTS: After one hour, the plasma concentration in the portal vein was always higher than that in the jugular vein in awakening rats with intact EHC (portal-venous blood concentration difference). No portal-venous difference was observed in awakening rats with bile-duct cannulation. Therefore, it was concluded that this portal-venous concentration difference was not due to the hepatic clearance but to diclofenac reabsorption from the intestinal tract. CONCLUSIONS: Approximately 40% of the dose of diclofenac was reabsorbed over 8 hours from the intestinal tract into the portal system. By comparing the reabsorbed amounts in the portal system and in the systemic circulation, the hepatic extraction ratio in vivo (FH) of diclofenac was estimated to be 63%.

Animals↗
PubMed1983

Abdominal colectomy for chronic encephalopathy due to portal-systemic shunt.

Chronic portal-systemic encephalopathy (CPSE) following portal-systemic shunts may be incapacitating and non-responsive to intensive medical management. Between 1960 and 1980, 12 patients with cirrhosis who were institutionalized with CPSE underwent colonic exclusion. Cirrhosis was due to alcohol in ten patients and to cryptogenic liver disease in two. Nine patients had previously undergone end-to-side portacaval shunts and two patients had had mesocaval shunts. One patient had a spontaneous shunt between splenic and renal veins. Ten patients underwent colectomy and ileosigmoidostomy; one had colectomy, ileostomy, and mucous fistula; and one had colonic bypass and ileosigmoidostomy. Four patients died postoperatively. Survivors were clinically improved and able to leave a closed institutional environment. Colectomy may be considered in disabling cases of CPSE unresponsive to medical therapy; it is a final effort at functional rehabilitation. Although mortality is high, improvement in functional status can be expected among survivors of the operation.

Adult↗
PubMed1999

Portal systemic shunting of insulin does not lead to insulin resistance in patients with extrahepatic portal vein obstruction.

There is no clear relation between portal systemic shunting, reduced hepatic insulin extraction leading to an increased systemic delivery of insulin, and, resultant peripheral hyperinsulinemia and insulin resistance. Extrahepatic portal vein obstruction is a natural human model of portal systemic shunting with essentially normal liver function. To investigate the role of portal systemic shunting of insulin in creating systemic hyperinsulinemia and insulin resistance, we studied nine subjects with portal systemic shunting and nine controls matched for age (+/- 2 years), body weight (+/- 2 kg) and height (+/- 5 cm). We carried out an oral glucose tolerance test and hyperinsulinemic euglycemic clamp study at insulin infusion rate of 40 mU/m2/ min. Comparable (p = 0.61) basal insulin concentrations in the two groups (Mean (SE): 21.0 (3.98) vs. 24.1 (4.28) mU/L) demonstrated a lack of hyperinsulinemia in the presence of portal systemic shunting. The lower (p = 0.03) insulin area under curve on oral glucose tolerance test in presence of portal systemic shunting (7.40 (0.95) vs. 10.83 (1.15) U/L-min) indicated that lower extraction of insulin by the liver leads to a lower requirements in the periphery. The coefficient of variation for plasma glucose between 60 and 120 min of the clamps was 4.44 (0.55)%. Comparable (p = 0.82) M-values (6.21 (0.67) vs. 6.38 (0.45) mg/kg/min) in the two groups proved a lack of significant insulin resistance in the presence of portal systemic shunting. We conclude that isolated portal systemic shunting leads to neither hyperinsulinemia nor insulin resistance.

Adult↗
PubMed1994

Time-of-flight MR angiography of portal system and collaterals in portal hypertension using a 2-DFT fast spoiled gradient recalled steady-state precession technique.

MR angiographic examinations were performed in 26 patients. Approximately 30 contiguous fast spoiled GRASS images (8.1/3.1/30 degrees, TR/TE/flip angle) were acquired during single breath-holding for about 35 s, and then new images were reconstructed with maximum intensity projection technique. Spoiled GRASS images (40/12/40) of 2 to 3 slices were taken during breath-holding for about 13 s, and these processes were repeated to obtain about 30 individual images for conventional MR angiography. The new MR angiograms were compared quantitatively and qualitatively with conventional MR angiograms with arterial portography as the gold standard. The new MR angiograms could visualize blood vessels with smooth margins, and provided almost the same anatomic information about the portal vein and collateral vessels as the conventional MR angiograms. Contrast-to-noise ratios between the portal or hepatic vein and liver parenchyma were significantly higher with fast spoiled GRASS images. The new MR angiograms using fast spoiled GRASS images provided useful diagnostic mapping of the collateral venous pathways within a shorter examination time.

Adult↗
PubMed2002

Portal-systemic encephalopathy in two patients without liver cirrhosis and portal hypertension.

The portal-systemic venous shunt is uncommon in patients without portal hypertension. We present two cases of portal-systemic encephalopathy due to extrahepatic shunt without liver cirrhosis and portal hypertension. Two women in their seventies were admitted to our hospital because of recurrent episodes of altered sensorium, drowsiness, slurred speech, disorientation, asterexis and high blood ammonia levels. There was no history of abdominal surgery or abdominal trauma. Clinical examination revealed no signs of portal hypertension or stigmata of chronic liver diseases. Brain CT and MRI scanning were unremarkable except for a high intensity signal in the basal ganglia on T1 weighted MRI images. Laboratory tests were almost normal except for the hyperammonemia occurring on several occasions. There was no evidence of liver cirrhosis by imaging. However, color Doppler showed an extra-hepatic shunt in both patients and pulsed Doppler showed decreased velocity and volume of the portal venous flow. These sonographic findings were confirmed during percutaneous transhepatic portography (PTP). Portal pressures measured during PTP were 9 and 11 mmHg. Needle biopsy ruled out idiopathic portal hypertension and liver cirrhosis. The diagnosis was portal systemic encephalopathy due to extra-hepatic portosystemic venous shunting. Both patients were treated by embolization of the shunting vessel with metallic coils.

Journal Article↗
PubMed1984

Increased blood flow through the portal system in cirrhotic rats.

Portal venous pressure is the result of the interplay between portal venous blood flow and the vascular resistance offered to that flow. Whether portal hypertension is maintained only by an increased portal venous resistance or also by an increased blood flow within the portal venous system is still open to speculation. To resolve these differences, splanchnic and systemic hemodynamics were evaluated in cirrhotic rats, induced by CCl4. Blood flow and portal-systemic shunting were measured by radioactive microsphere techniques. All cirrhotic rats had portal hypertension (portal venous pressure 13.5 +/- 1.1 vs. 9.0 +/- 0.5 mmHg, in normal control rats; p less than 0.01), but portal-systemic shunting in cirrhosis (31% +/- 13% vs. 0.2% +/- 0.02%; p less than 0.05) was variable, ranging from 1% to 97%. Portal venous inflow, the total blood flow within the portal system, was increased in cirrhotic rats (5.75 +/- 0.04 vs. 4.52 +/- 0.36 ml/min per 100 g; p less than 0.05). Total splanchnic arterial resistance was reduced in cirrhotic rats (3.3 +/- 0.2 vs. 5.8 +/- 0.5 dyn X s X cm-5 X 10(5); p less than 0.01). Portal venous resistance, however, was not abnormally elevated in cirrhotic rats (4.6 +/- 0.5 vs. 4.7 +/- 0.5 dyn X s X cm-5 X 10(4), p = NS). Splanchnic hemodynamics in cirrhotic rats demonstrate that portal hypertension is maintained, at least in part, by a hyperdynamic portal venous inflow. The hemodynamic data in cirrhotic rats provided evidence that supports the role of an increased portal blood flow in portal hypertension and gives a quantitative definition of splanchnic hemodynamics in intrahepatic portal hypertension.

Animals↗
PubMed1996

Portal-systemic shunting in a patient with normal portal vain pressures and histological evidence of idiopathic portal hypertension.

Although idiopathic portal hypertension (IPH) is clinically characterized by portal hypertension and marked splenomegaly, we have experienced a case of spontaneous portal-systemic shunt without splenomegaly in whom the liver histology resembled IPH but with normal portal pressure. We admitted a 64 year old man who had suffered from hepatic encephalopathy for 2 years. Laparoscopy revealed a dark grey liver with a sharp edge and a concave surface. Examination of a liver biopsy specimen revealed peri-portal fibrosis consistent with IPH. A single, large, portal-systemic shunt was identified by percutaneous transhepatic portography. The shunt arose from the left gastric vein and flowed through the left renal vein into the inferior vena cava. No varices were identified. There were no morphological changes in the hepatic or portal veins. Portal vain pressure was normal. There was a slight difference between the portal pressure and the wedged hepatic vein pressure, suggesting a presinusoidal block. This case raises important questions concerning the aetiology of IPH and the relationship between portal hypertension and the development of collateral venous circulation.

Collateral Circulation↗
PubMed1997

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.

Animals↗
PubMed1997

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.

Animals↗
PubMedDate not supplied

Portal-systemic encephalopathy: neuropsychiatric manifestations.

Portal-systemic encephalopathy, which occurs as a consequence of cirrhosis of the liver, is associated with a variety of neuropsychiatric symptoms. Problems related to the differential diagnosis and medical management of portal-systemic encephalopathy, as compared to other more usual psychiatric disorders, are discussed. Also addressed are issues of particular concern to psychiatry, such as the use of pharmacotherapeutics and the rehabilitation of alcoholism, which are commonly seen in individuals with portal-systemic encephalopathy and liver disease, as well as in the general psychiatric patient population.

Diagnosis, Differential↗
PubMed1992

The use of quantitative scintigraphy in the measurement of portal-systemic shunting in rats.

Portal-systemic shunting was studied in 54 portal hypertensive rats both in vivo and in vitro using radioactive microspheres. The animals underwent partial portal vein ligation around needles of varying diameter to produce a wide range of shunting. Two to four weeks later, quantitative lung-liver scintigraphic and whole body images were obtained in vivo following ileocolic vein injection with 99mTc-MAA. After sacrifice, the lung and liver activities were determined by the gamma camera, a dose calibrator, and a well counter. Portal-systemic shunting ranged from 0.1-97.6%. When shunting was compared in vivo and in vitro, an excellent correlation was found (r = 0.99, p < 0.001). A subgroup of 24 animals had consecutive injections of 99mTc-MAA and 51Cr-labeled 15 microns microspheres, which, although different in size, yielded similar results (r = 0.89, p < 0.001). We conclude that in small laboratory animals a wide range of shunting can be measured accurately in vivo by quantitative scintigraphy.

Animals↗