Noncirrhotic portal vein thrombosis exhibits neuropsychological and MR changes consistent with minimal hepatic encephalopathy

Prevalence of hepatic encephalopathy in patients with non-cirrhotic portal hypertension: A systematic review and meta-analysis

BACKGROUND

Hepatic encephalopathy, (HE) although commonly associated with cirrhosis, has also been reported in non-cirrhotic portal hypertension (NCPH). The importance of identifying and treating HE in NCPH lies in the fact that many patients may be wrongly diagnosed as having psychiatric or neurologic disorders. Hence, we aimed to systematically review the prevalence of HE in NCPH.

METHODS

A comprehensive search of three databases (Medline, Embase and Scopus) was conducted from inception to November 2022 for studies reporting on the prevalence of minimal HE (MHE) and overt HE (OHE) in patients with NCPH. Results were presented as pooled proportions with their 95% confidence intervals (CI).

RESULTS

Total 25 studies (n = 1487) were included after screening 551 records. The pooled prevalence of MHE in NPCH was 32.9% (95% CI: 26.7-39.0) without any difference between adult (32.9%, 95% CI: 23.5-42.3) and pediatric patients (32.6%, 95% CI: 26.1-39.1) (p = 0.941). There was no significant difference in the prevalence between patients with NCPH and compensated cirrhosis with odds ratio of 1.06 (95% CI: 0.77-1.44). The pooled event rate for prior history of OHE in NCPH was 1.2% (95% CI: 0.3-2.1).

CONCLUSION

Around one-third of the patients with NCPH have MHE, irrespective of age group. OHE is extremely rare in NCPH and is usually associated with a precipitating factor.

[Hepatic encephalopathy after portosystemic bypass surgery]

The most effective modern treatment for gastrointestinal bleeding following portal hypertension is portosystemic bypass surgery. Hepatic encephalopathy after these procedures is still an urgent problem in modern pediatric surgery, and radical treatment is unknown. To optimize treatment outcomes in children with hepatic encephalopathy, we should choose adequate treatment considering the risk of hepatic encephalopathy in the future. In this review, the authors discuss modern data on hepatic encephalopathy regarding symptoms, advantages and disadvantages of various treatment methods. Risk of hepatic encephalopathy with and without surgical treatment, as well as methods of diagnosis and treatment are particularly analyzed. Total portosystemic bypass surgery, especially portocaval shunt, is followed by higher risk of hepatic encephalopathy compared to selective shunts and physiological mesoportal bypass. The last two approaches are advisable to improve treatment outcomes in children with hepatic encephalopathy.

Portal vein thrombosis is associated with an increased risk of bone fractures

Background

Portal vein thrombosis (PVT) is a rare but severe disease that often leads to portal hypertension-related complications. It is well-known that patients with portal hypertension associated with liver cirrhosis are at increased risk for bone fractures, however data on the impact of PVT on fracture risk are lacking.

Aims

This study aimed to explore the impact of PVT on the incidence of bone fractures in a large German primary care cohort.

Methods

Patients with PVT were extensively matched to non-PVT individuals in a 1:5 ratio. The primary outcome of the study was the incidence of any bone fracture.

Results

This study included 596 patients with PVT and 2,980 non-PVT individuals. During five years of follow-up, the cumulative incidence of bone fractures was significantly higher in PVT patients (n = 87, 13.6%) than in those without PVT (n = 186, 6.7%) (p<0.001). In Cox-regression analyses, PVT was positively associated with bone fractures (HR: 2.16; 95% CI: 1.59–2.93). This association was stronger in women (HR: 2.55; 95% CI: 1.65–3.95) than in men (HR: 1.87; 95% CI: 1.22–2.87). The strongest association was observed in the age group 51–60 years (HR: 2.50, 95% CI: 1.40–4.47). The association between PVT and bone fractures was maintained in subgroup analyses of patients with (HR: 2.03, 95% CI: 1.13–3.63) and without liver cirrhosis (HR: 1.82, 95% CI: 1.28–2.58).

Conclusions

PVT is independently associated with a higher incidence of bone fractures. Patients with PVT should be critically evaluated for fracture risk and preventive measures should be considered.

Increased Morbidity and Mortality of Patients with Non-cirrhotic Portal Vein Thrombosis After Abdominal and Pelvic Surgeries: a Study of the National Inpatient Sample 2002 to 2015

BACKGROUND

A higher rate of postoperative morbidity and mortality in patients with portal hypertension from cirrhosis is well recognized; however, the rate of postoperative morbidity and mortality among patients with portal hypertension from non-cirrhotic portal vein thrombosis (NCPVT) is largely unknown.

METHOD

All adults undergoing abdominal and pelvic surgery were identified from the National Inpatient Sample database from 2002 to 2015. Patients were then categorized into three groups: non-cirrhotic non-portal vein thrombosis (NCNPVT), NCPVT, and cirrhotic portal vein thrombosis (CPVT). Inpatient mortality, type of disposition, transfusions, length of stay, postoperative complications, and total charges were compared. Logistic regression and ordinary least squares regression analyses were performed for factors associated with inpatient mortality, transfusions, surgery-related complications, and log length of stay.

RESULTS

Patients with NCPVT had significantly higher inpatient mortality rates, surgery-related complications, and longer length of stays compared with patients with NCNPVT (2.64% vs. 0.34%, 10.26% vs. 3.26%, 8 vs. 2 days) but less than patients with CPVT (2.64% vs. 6.31%, 10.26% vs. 17.48%, 8 vs. 11 days). In multiple logistic regression analyses, NCPVT groups remained associated with increased inpatient mortality rate, transfusions, and postoperative complications with odds ratios of 3.71 (1.88, 7.32), 3.43 (2.54, 4.62), and 3.08 (2.16, 4.39), respectively. NCPVT was also associated with 2.4 times increased length of stay.

DISCUSSION

Patients with NCPVT had significantly higher risks of postoperative morbidity and mortality than patients with NCNPVT but less than patients with CPVT. Future studies with detail regarding the characteristics of PVTs are needed to confirm the findings in this study.

Radiomics-based classification models for HBV-related cirrhotic patients with covert hepatic encephalopathy

INTRODUCTION

The significant abnormalities of precuneus (PC), which are associated with brain dysfunction, have been identified in cirrhotic patients with covert hepatic encephalopathy (CHE). The present study aimed to apply radiomics analysis to identify the significant radiomic features in PC and their subregions, combine with clinical risk factors, then build and evaluate the classification models for CHE diagnosis.

METHODS

106 HBV-related cirrhotic patients (54 had current CHE and 52 had non-CHE) underwent the three-dimensional T1-weighted imaging. For each participant, PC and their subregions were segmented and extracted a large number of radiomic features and then identified the features with significant discriminative power as the radiomics signature. The logistic regression analysis was employed to develop and evaluate the classification models, which are constructed using the radiomics signature and clinical risk factors.

RESULTS

The classification model (R-C model) achieved best diagnostic performance, which incorporated radiomics signature (4 radiomic features from right PC), venous blood ammonia, and the Child-Pugh stage. And the area under the receiver operating characteristic curve values (AUC), sensitivity, specificity, and accuracy values were 0.926, 1.000, 0.765, and 0.848, in the testing set. Application of the radiomics nomogram in the testing set still showed a good predictive accuracy.

CONCLUSIONS

This study presented the radiomic features of the right PC, as a potential image marker of CHE. The radiomics nomogram that incorporates the radiomics signature and clinical risk factors may facilitate the individualized prediction of CHE.

Causes and Management of Non-cirrhotic Portal Hypertension​

PURPOSE OF THE REVIEW

Non-cirrhotic portal hypertension (NCPH) includes a heterogeneous group of conditions. The aim of this paper is to make an overview on the denominations, diagnostical features and management of porto-sinusoidal vascular disease (PSVD) and chronic portal vein thrombosis (PVT) being the main causes of NCPH in the Western world.

RECENT FINDINGS

The management of NCPH consists in the treatment of associated diseases and of portal hypertension (PH). PH due to PSVD or PVT is managed similarly to PH due to cirrhosis. TIPS placement and liver transplantation are considerable options in patients with refractory variceal bleeding/ascites and with progressive liver failure. Anticoagulation is a cornerstone both in the treatment of thrombosis in PSVD and in the prevention of thrombosis recurrence in patients with portal cavernoma. Physicians should be aware of the existence of PSVD and chronic PVT and actively search them in particular settings. To now, the management of portal hypertension-related complications in NCPH is the same of those of cirrhosis. Large cooperative studies on the natural history of NCPH are necessary to better define its management.

Escalating interventional recanalization therapy in non-cirrhotic, non-malignant acute portal vein thrombosis

OBJECTIVE

To evaluate the effectiveness of interventional therapy in acute, non-malignant, non-cirrhotic portal vein thrombosis.

METHODS

We present a retrospective study of eight consecutive patients who presented with an acute non-malignant, non-cirrhotic portal vein thrombosis and were treated by mechanical recanalization using an escalating scheme including local aspiration, thrombolysis, rheolysis and the implantation of transjugular intrahepatic portosystemic shunt or other visceral stents.

RESULTS

Recanalization rates applying the escalating scheme were good, with a success rate of 75%. However, major complications occurred in 50% of patients, mostly due to bleeding at the percutaneous access site, and minor complications in 12.5% of patients.

CONCLUSION

Interventional therapy is effective in acute portal vein thrombosis, but should only be performed at specialized centers and based on an individual treatment decision.

Current knowledge in pathophysiology and management of Budd-Chiari syndrome and non-cirrhotic non-tumoral splanchnic vein thrombosis

Budd-Chiari syndrome and non-cirrhotic non-tumoral portal vein thrombosis are 2 rare disorders, with several similarities that are categorized under the term splanchnic vein thrombosis. Both disorders are frequently associated with an underlying prothrombotic disorder. They can cause severe portal hypertension and usually affect young patients, negatively influencing life expectancy when the diagnosis and treatment are not performed at an early stage. Yet, they have specific features that require individual consideration. The current review will focus on the available knowledge on pathophysiology, diagnosis and management of both entities.

Radiological Intervention for Shunt Related Encephalopathy

Hepatic Encephalopathy (HE) is a neuropsychiatric syndrome that occurs in up to 30% of patients with cirrhosis. HE may be a consequence of pure liver failure, as in patients with fulminant hepatitis, or of the combination of liver failure and portal-systemic shunting, as in patients with liver cirrhosis. Several clinical and pathophysiologic observations suggest the importance of portal-systemic shunts in the development of HE. Episodes of HE are usually related to precipitating events, such as infections or gastrointestinal bleeding; a minority of cirrhotic patients experienced a chronic HE, refractory to standard medical treatment. This latter type of HE should be related to spontaneous or radiological (such as Transjugular Intrahepatic Portosystemic Shunt (TIPS)) portal systemic shunts, that could be restricted or occluded in patients with chronic HE. Both TIPS reduction and shunt occlusion are radiological procedures, safe and effective to ameliorate neurological symptoms in patients with refractory HE.

Stroop Test Validation to Screen for Minimal Hepatic Encephalopathy in Pediatric Extrahepatic Portal Venous Obstruction

OBJECTIVES

Minimal hepatic encephalopathy (MHE) has been reported in children with extrahepatic portal vein obstruction (EHPVO). MHE assessment is restricted to research situations as neuropsychiatric tests are time-intensive. Computerized Stroop Test (CST) has been used in cirrhotic adults for MHE screening. The study aims to assess MHE frequency in young Indian children with EHPVO and validate CST for MHE screening in pediatric EHPVO.

METHODS

Thirty-seven children with EHPVO between 7 and 12 years of age and 37 age- and sex-matched controls were enrolled. Fasting plasma ammonia was measured. MHE was diagnosed by Revised Amsterdamse Kinder Intelligentie Test. The performance of a Tamil language version of CST in MHE screening was assessed.

RESULTS

MHE was diagnosed in 18.9% (7/37) of EHPVO (EHPVO-MHE). Plasma ammonia levels were higher in EHPVO-MHE compared to EHPVO without MHE (EHPVO-No-MHE) but abnormal plasma ammonia levels are unsuitable for MHE screening. CST was administered in 35 EHPVO and 37 controls. EHPVO-MHE, compared to EHPVO-No-MHE, had longer "on time," "off time," "(on+off) time," and "(on-off) time." For MHE diagnosis, specificity and sensitivity of "(on+off) time" were 100% and 89.6% for a cutoff of >180.4 seconds (area under receiver operating characteristic = 0.97).

CONCLUSIONS

In the absence of other risk factors for neurological insult or patent surgical shunts, MHE frequency in young Indian children with EHPVO, determined by Revised Amsterdamse Kinder Intelligentie Test, was lesser than in earlier studies. CST is suitable for MHE screening in clinical practice to select patients for neuropsychiatric evaluation.

Minimal hepatic encephalopathy in children with chronic liver disease: Prevalence, pathogenesis and magnetic resonance-based diagnosis

BACKGROUND & AIMS

Data on minimal hepatic encephalopathy (MHE) in children is scarce. We aimed to study MHE in children with chronic liver disease (CLD) and to validate non-invasive objective tests which can assist in its diagnosis.

METHODS

We evaluated 67 children with CLD (38 boys; age 13 [7-18] years) and 37 healthy children to determine the prevalence of MHE. We also assessed the correlation of MHE with changes in brain metabolites by magnetic resonance spectroscopy (¹HMRS), diffusion tensor imaging (DTI) derived metrics, blood ammonia and inflammatory cytokines (interleukin-6 [IL6], tumor necrosis factor alpha [TNF-α]). In addition, the accuracy of MR-based investigations for diagnosis of MHE in comparison to neuropsychological tests was analysed.

RESULTS

Thirty-four (50.7%) children with CLD had MHE on neuropsychological tests. MHE patients had higher BA (30.5 [6-74] vs. 14 [6-66]μmol/L; p=0.02), IL-6 (8.3 [4.7-28.7] vs. 7.6 [4.7-20.7]pg/ml; p=0.4) and TNF-α (17.8 [7.8-65.5] vs. 12.8 [7.5-35]pg/ml; p=0.06) than No-MHE. ¹HMRS showed higher glutamine (2.6 [2.1-3.3] vs. 2.4 [2.0-3.1]; p=0.02), and lower choline (0.20 [0.14-0.25] vs. 0.22 [0.17-0.28]; p=0.1) and myo-inositol (0.25 [0.14-0.41] vs. 0.29 [0.21-0.66]; p=0.2) in MHE patients than those without MHE. Mean diffusivity (MD) on DTI was significantly higher in 6/11 brain areas in patients with MHE vs. no MHE. Brain glutamine had a significant positive correlation with blood ammonia, IL-6, TNF-α and MD of various brain regions. Neuropsychological tests showed a negative correlation with blood ammonia, IL6, TNF-α, glutamine and MD. Frontal white matter MD had a sensitivity and specificity of 73.5% and 100% for diagnosing MHE.

CONCLUSIONS

In children with CLD, 50% have MHE. There is a significant positive correlation between markers of hyperammonemia, inflammation and brain edema and these correlate negatively with neuropsychological tests. MD on DTI is a reliable tool for diagnosing MHE.

LAY SUMMARY

Fifty percent of children with chronic liver disease develop minimal hepatic encephalopathy (MHE) and perform poorly on neuropsychological testing. These children have raised blood ammonia, inflammatory cytokines and mild cerebral edema on diffusion tensor imaging as compared to children without MHE. The higher the ammonia, inflammatory cytokines and cerebral edema levels the poorer the performance on neuropsychological assessment. The estimation of mean diffusivity on diffusion tensor imaging is an objective and reliable method for diagnosing MHE.

A pilot study using lactulose in management of minimal hepatic encephalopathy in children with extrahepatic portal vein obstruction

BACKGROUND

Minimal hepatic encephalopathy (MHE) is not associated with overt neuropsychiatric symptoms but rather with subtle changes in psychometric and/or neurophysiologic tests. We aimed to diagnose MHE in children with extrahepatic portal vein obstruction (EHPVO) and to evaluate the effect of lactulose on MHE.

METHODS

A prospective study was carried out on 30 patients with EHPVO (21 males; mean age 10±2.5 years). The study was carried out in the Pediatric Hepatology Unit, Cairo University Pediatric Hospital, Cairo, Egypt, between 2011 and 2013. All patients were subjected to clinical and laboratory assessment, neuropsychmetric testing using the arabic version of Wechsler intelligence tests, neurophysiological testing by visual electroencephalogram and P300 event related potentials (ERP).

RESULTS

The prevalence of MHE among children with EHPVO was 20% (6/30). After randomization to treatment and no-treatment groups using lactulose, all tests were repeated after three months. Among four patients with MHE who received lactulose, three (75%) improved. On the other hand, one of the patients in the no-treatment group developed MHE. Only one patient in the treatment arm had to discontinue lactulose because of severe diarrhea.

CONCLUSIONS

This pilot study revealed that the prevalence of MHE was 20%. Improvement on psychometic tests was seen in 75% of our patients (3/4) after treatment with lactulose. Lactulose treatment was well tolerated.

Magnetic Resonance Spectroscopy for Evaluating Portal-Systemic Encephalopathy in Patients with Chronic Hepatic Schistosomiasis Japonicum

Portal-systemic encephalopathy (PSE) is classified as type B hepatic encephalopathy. Portal-systemic shunting rather than liver dysfunction is the main cause of PSE in chronic hepatic schistosomiasis japonicum (HSJ) patients. Owing to lack of detectable evidence of intrinsic liver disease, chronic HSJ patients with PSE are frequently clinically undetected or misdiagnosed, especially chronic HSJ patients with covert PSE (subclinical encephalopathy). In this study, we investigated whether magnetic resonance spectroscopy (MRS) could be a useful tool for diagnosing PSE in chronic HSJ patients. Magnetic resonance (MR) T1-weighted imaging, diffusion-weighted imaging, and MRS were performed in 41 chronic HSJ patients with suspected PSE and in 21 age-matched controls. The T1 signal intensity index (T1SI) and apparent diffusion coefficient (ADC) value were obtained in the Globus pallidus. Liver function was also investigated via serum ammonia and liver function tests. Higher T1SI and ADC values, increased lactate and glutamine levels, and decreased myo-inositol were found in the bilateral Globus pallidus in chronic HSJ patients with PSE. No significantly abnormal serum ammonia or liver function tests were observed in chronic HSJ patients with PSE. On the basis of these findings, we propose a diagnostic procedure for PSE in chronic HSJ patients. This study reveals that MRS can be useful for diagnosing PSE in chronic HSJ patients.

Portal-systemic encephalopathy (PSE) is classified as type B hepatic encephalopathy. Portal-systemic shunting rather than liver dysfunction is the main cause of PSE in chronic hepatic schistosomiasis japonicum (HSJ) patients. Chronic HSJ patients with PSE are frequently misdiagnosed as suffering from dementia, depression, and other psychiatric disorders. However, there are few studies of this type of encephalopathy. In this study, magnetic resonance spectroscopy (MRS) was used as a noninvasive tool to detect abnormalities in brain metabolism in chronic HSJ patient with PSE. The results demonstrate that MRS would be useful for the diagnosis of PSE in chronic HSJ patients. Based on the results, a diagnostic procedure for PSE has also been proposed.

Evaluation of cognitivity, proinflammatory cytokines, and brain magnetic resonance imaging in minimal hepatic encephalopathy induced by cirrhosis and extrahepatic portal vein obstruction

BACKGROUND AND AIMS

Minimal hepatic encephalopathy (MHE) is the mildest form of hepatic encephalopathy (HE) and is characterized by deficits in neurocognitive performance without any clinical symptoms of HE. In the current study, we aim to evaluate and compare the neurocognitive, biochemical, and brain magnetic resonance (MR) imaging changes between patients with cirrhotic MHE and extrahepatic portal vein obstruction (EHPVO) MHE.

METHODS

Thirty-three cirrhotic and 14 EHPVO patients were diagnosed with MHE and were included in the analysis along with 24 normal healthy volunteers. All subjects underwent MR imaging including diffusion tensor imaging and proton MR spectroscopy (¹ H-MRS) followed by cognitive assessments, critical flicker frequency (CFF) measurements, quantification of blood ammonia, and serum proinflammatory cytokine levels.

RESULTS

We observed abnormal neurocognitive functions and CFF measurements in both cirrhotic MHE and EHPVO MHE patients as compared with controls. Significantly increased blood ammonia, serum proinflammatory cytokines (IL-6, TNF-α) level, mean diffusivity in multiple brain sites, ¹ H-MRS derived glutamate/glutamine (Glx)/creatine (Cr), and significantly decreased ¹ H-MRS derived myo-inositol/Cr were observed in both cirrhotic MHE and EHPVO MHE compared with those of controls. Choline/Cr level was significantly decreased in cirrhotic MHE as compared with controls and EHPVO MHE.

CONCLUSIONS

Cirrhotic MHE showed more severe changes on mean diffusivity in multiple brain sites and inflammation as compared with EHPVO MHE. This study confirms that there are significant difference in neurocognitive, biochemical, and MR profile between cirrhotic MHE and EHPVO MHE, which may help to understand the pathophysiologies of these two types of MHE and may contribute to improve their clinical managements.

Hepatic encephalopathy in patients with non-cirrhotic portal hypertension: Description, prevalence and risk factors

BACKGROUND

Hepatic encephalopathy (HE) is a common complication of cirrhosis but it is less studied in patients with non-cirrhotic portal hypertension (NCPH).

AIMS

To describe the prevalence of cognitive impairment (overt and covert HE) in NCPH patients and to identify the risk factors for its development.

METHODS

51 patients with NCPH, 35 with chronic portal vein thrombosis (PVT) and 16 with idiopathic non-cirrhotic portal hypertension (INCPH), were evaluated for the presence of previous or present overt HE (OHE). The psychometric hepatic encephalopathy score and the SCAN battery were used to detect the presence of covert HE (CHE). 34 compensated cirrhotic patients were used as control. In NCPH patients, abdominal scans were performed to detect the presence of shunts.

RESULTS

None of the patients experienced OHE at evaluation while 5.7% of PVT and 12.5% of INCPH patients referred at least one documented episode of previous OHE, similarly to patients with cirrhosis (14.7%). Even if lower than in patients with cirrhosis (64.7%), a considerable proportion of patients with chronic PVT (34.3%) and INCPH (25%) had CHE (p=0.008). The presence of a large portal-systemic shunt was the only factor significantly correlated to cognitive impairment in NCPH patients.

CONCLUSION

HE is a tangible complication of NCPH and is mainly related to the presence of portal-systemic shunts.

Minimal hepatic encephalopathy: A review

Minimal hepatic encephalopathy (MHE) is the earliest form of hepatic encephalopathy and can affect up to 80% of patients with liver cirrhosis. By definition, MHE is characterized by cognitive function impairment in the domains of attention, vigilance and integrative function, but obvious clinical manifestation are lacking. MHE has been shown to affect daily functioning, quality of life, driving and overall mortality. The diagnosis can be achieved through neuropsychological testing, recently developed computerized psychometric tests, such as the critical flicker frequency and the inhibitory control tests, as well as neurophysiological procedures. Event related potentials can reveal subtle changes in patients with normal neuropsychological performances. Spectral analysis of electroencephalography (EEG) and quantitative analysis of sleep EEG provide early markers of cerebral dysfunction in cirrhotic patients with MHE. Neuroimaging, in particular MRI, also increasingly reveals diffuse abnormalities in intrinsic brain activity and altered organization of functional connectivity networks. Medical treatment for MHE to date has been focused on reducing serum ammonia levels and includes non-absorbable disaccharides, probiotics or rifaximin. Liver transplantation may not reverse the cognitive deficits associated with MHE. We performed here an updated review on epidemiology, burden and quality of life, neuropsychological testing, neuroimaging, neurophysiology and therapy in subjects with MHE.

Current diagnosis and management of post-transjugular intrahepatic portosystemic shunt refractory hepatic encephalopathy

Transjugular intrahepatic portosystemic shunt has evolved into an important option for management of complications of portal hypertension. The use of polytetrafluoroethylene covered stents enhances shunt patency. Hepatic encephalopathy (HE) remains a significant problem after TIPS placement. The approach to management of patients with refractory hepatic encephalopathy typically requires collaboration between different specialties. Patient selection for TIPS requires careful evaluation of risk factors for HE. TIPS procedure-related technical factors like stent size, attention to portosystemic pressure gradient reduction and use of adjunctive variceal embolization maybe important. Conservative medical therapy in combination with endovascular therapies often results in resolution or substantial reduction of symptoms. Liver transplantation is, however, the ultimate treatment.

[Treatment of non-cirrhotic, non-tumoural portal vein thrombosis]

Thrombosis of the splenoportal axis not associated with liver cirrhosis or neoplasms is a rare disease whose prevalence ranges from 0.7 to 3.7 per 100,000 inhabitants. However, this entity is the second most common cause of portal hypertension. Prothrombotic factors are present as an underlying cause in up to 70% of patients and local factors in 10-50%. The coexistence of several etiological factors is frequent. Clinical presentation may be acute or chronic (portal cavernomatosis). The acute phase can present as abdominal pain, nausea, vomiting, fever, rectorrhagia, intestinal congestion, and ischemia. In this phase, early initiation of anticoagulation is essential to achieve portal vein recanalization and thus improve patient prognosis. In the chronic phase, symptoms are due to portal hypertension syndrome. In this phase, the aim of treatment is to treat or prevent the complications of portal hypertension. Anticoagulation is reserved to patients with a proven underlying thrombophilic factor.

Portal vein thrombosis

Portal vein thrombosis is an important cause of portal hypertension. PVT occurs in association with cirrhosis or as a result of malignant invasion by hepatocellular carcinoma or even in the absence of associated liver disease. With the current research into its genesis, majority now have an underlying prothrombotic state detectable. Endothelial activation and stagnant portal blood flow also contribute to formation of the thrombus. Acute non-cirrhotic PVT, chronic PVT (EHPVO), and portal vein thrombosis in cirrhosis are the three main variants of portal vein thrombosis with varying etiological factors and variability in presentation and management. Procoagulant state should be actively investigated. Anticoagulation is the mainstay of therapy for acute non-cirrhotic PVT, with supporting evidence for its use in cirrhotic population as well. Chronic PVT (EHPVO) on the other hand requires the management of portal hypertension as such and with role for anticoagulation in the setting of underlying prothrombotic state, however data is awaited in those with no underlying prothrombotic states. TIPS and liver transplant may be feasible even in the setting of PVT however proper selection of candidates and type of surgery is warranted. Thrombolysis and thrombectomy have some role. TARE is a new modality for management of HCC with portal vein invasion.

Review article: portal vein obstruction--epidemiology, pathogenesis, natural history, prognosis and treatment

BACKGROUND

Portal vein obstruction may be due to portal vein thrombosis (PVT) or its sequale, the portal cavernoma. PVT is a common complication in liver cirrhosis, however, it may also occur as a primary vascular disorder, in absence of any liver disease.

AIM

To review the current knowledge on nomenclature, etiology, pathophysiology, clinical presentation, diagnostic workup and management of adult patients with obstruction in the portal vein, either as a primary vascular disease in adults, or as a complication of liver cirrhosis.

METHODS

A structured search in PubMed was performed using defined keywords (portal vein obstruction, extra-hepatic portal vein obstruction, PVT and portal cavernoma), including full text articles and abstracts in English language.

RESULTS

Several causes, operating both at local and systemic level, might play an important role in the pathogenesis of PVT. Frequently, more than one risk factor could be identified; however, occasionally no single factor is discernible. Diagnosis of portal vein obstruction depends on clinical presentation, imaging and laboratory investigations. Prompt treatment greatly affects the patient's outcome.

CONCLUSIONS

Portal vein obstruction occurring either due to thrombosis in the portal vein or due to the portal cavernoma, can contribute to significant morbidity and mortality in patients with or without cirrhosis. In recent years our understanding of etio-pathogenesis of portal vein obstruction has evolved tremendously, which has led to significant improvement in treatment outcomes. There are still areas where more studies are needed to better clarify the management issues of portal vein obstruction.

How I treat splanchnic vein thrombosis

Antithrombotic treatment of splanchnic vein thrombosis (SVT) is a clinical challenge. Depending on the site of thrombosis, patients are at risk of developing liver insufficiency, portal hypertension, or bowel infarction and may experience recurrence in both the splanchnic veins and other vein segments. To prevent recurrence, anticoagulant therapy should be started as soon as possible after diagnosis and is often continued for an indefinite period of time. However, active bleeding is not infrequent at the time of SVT diagnosis, and major risk factors for bleeding, such as esophageal varices or a low platelet count, are frequently present in these patients. In real-world clinical practice, a proportion of SVT patients are left untreated because the risks associated with anticoagulant therapy are felt to exceed its benefits. However, the majority of patients receive anticoagulant drugs, with heterogeneous timing of initiation, drug choice, and dosages. Evidence to drive treatment decisions is limited because no randomized controlled trials have been carried out in these patients. This review provides practical guidance for the use of anticoagulant drugs in patients presenting with SVT, including symptomatic as well as incidentally detected events.

Brain magnetic resonance in hepatic encephalopathy

The term hepatic encephalopathy (HE) covers a wide spectrum of neuropsychiatric abnormalities caused by portal-systemic shunting. The diagnosis requires demonstration of liver dysfunction or portal-systemic shunts and exclusion of other neurologic disorders. Most patients with this condition have liver dysfunction caused by cirrhosis, but it also occurs in patients with acute liver failure and less commonly, in patients with portal-systemic shunts that are not associated with hepatocellular disease. Various magnetic resonance (MR) techniques have improved our knowledge about the pathophysiology of HE. Proton MR spectroscopy and T1-weighted imaging can detect and quantify accumulations of brain products that are normally metabolized or eliminated such as glutamine and manganese. Other MR techniques such as T2-weighted and diffusion-weighted imaging can identify white matter abnormalities resulting from disturbances in cell volume homeostasis secondary to brain hyperammonemia. Partial or complete recovery of these abnormalities has been observed with normalization of liver function or after successful liver transplantation. MR studies have undoubtedly improved our understanding of the mechanisms involved in the pathogenesis of HE, and some findings can be considered biomarkers for monitoring the effects of therapeutic measures focused on correcting this condition.

Minimal hepatic encephalopathy in children with liver cirrhosis: diffusion-weighted MR imaging and proton MR spectroscopy of the brain

INTRODUCTION

The aim of this work was to detect minimal hepatic encephalopathy (minHE) in children with diffusion-weighted MR imaging (DWI) and proton magnetic resonance spectroscopy (1H-MRS) of the brain.

METHODS

Prospective study conducted upon 30 consecutive children (age range 6-16 years, 21 boys and 9 girls) with liver cirrhosis and 15 age- and sex-matched healthy control children. Patients with minHE (n = 17) and with no minHE (n = 13) groups and control group underwent DWI, 1H-MRS, and neuropsychological tests (NPTs). The glutamate or glutamine (Glx), myoinositol (mI), choline (Cho), and creatine (Cr) at the right ganglionic region were determined at 1H-MRS. The apparent diffusion coefficient (ADC) value and metabolic ratios of Glx/Cr, mI/Cr, and Cho/Cr were calculated.

RESULTS

There was elevated ADC value and Glx/Cr and decreased mI/CI and Ch/Cr in patients with minHE compared to no minHE and control group. There was significant difference between minHE, no minHE, and control group in the ADC value (P = 0.001 for all groups), GLx/Cr (P = 0.001 for all groups), mI/Cr (P = 0.004, 0.001, and 0.001, respectively), Ch/Cr (P = 0.001 for all groups), and full-scale IQ of NPT (P = 0.001, 0.001, and 0.143, respectively). The NPT of minHE had negative correlation with ADC value (r = -0.872, P = 0.001) and GLx/Cr (r = -0.812, P = 0.001) and positive correlation with mI/Cr (r = 0.732, P = 0.001).

CONCLUSION

DWI and 1H-MRS are imaging modalities that can detect minHE in children with liver cirrhosis and correlate well with parameters of NPT.

Arterial ammonia levels in cirrhosis are determined by systemic and hepatic hemodynamics, and by organ function: a quantitative modelling study

BACKGROUND & AIMS

Hyperammonaemia is a common complication of chronic liver failure. Two main factors are thought to underlie this complication: a loss of hepatic detoxification function and the development of portosystemic shunting. However, few studies have tried to quantify the importance of portosystemic shunting. Here, we used a theoretical approach to test the hypothesis that the development of portosystemic shunting is sufficient to cause hyperammonaemia in cirrhosis.

METHODS

Two mathematical models are developed. The first one describes the main vascular resistances of the circulation and is used to provide scenarios for the distributions of organ blood flow in cirrhosis, which are necessary to run the second model. The second model predicts arterial ammonia levels resulting from ammonia metabolism in gut, liver, kidney, muscle and brain, and the distribution of organ blood flow.

RESULTS

The fraction of gastrointestinal blood flow shunted through collaterals was estimated to be 41% in mild cirrhosis, 69% in moderate and 85% in severe cases. In the second model, the redistribution of organ blood flow associated with severe cirrhosis was sufficient to cause hyperammonaemia, even when the hepatic detoxification function and the ammonia production were set to normal.

CONCLUSIONS

The model indicates that the development of portosystemic shunting in cirrhosis is sufficient to cause hyperammonaemia. Interventions that reduce the fraction of shunting may be future targets of therapy to control severity of hyperammonaemia.

Minimal hepatic encephalopathy

Minimal hepatic encephalopathy (MHE) is the earliest form of hepatic encephalopathy and can affect up to 80% of cirrhotic patients. By definition, it has no obvious clinical manifestation and is characterized by neurocognitive impairment in attention, vigilance and integrative function. Although often not considered to be clinically relevant and, therefore, not diagnosed or treated, MHE has been shown to affect daily functioning, quality of life, driving and overall mortality. The diagnosis of MHE has traditionally been achieved through neuropsychological examination, psychometric tests or the newer critical flicker frequency test. A new smartphone application (EncephalApp Stroop Test) may serve to function as a screening tool for patients requiring further testing. In addition to physician reporting and driving restrictions, medical treatment for MHE includes non-absorbable disaccharides (eg, lactulose), probiotics or rifaximin. Liver transplantation may not result in reversal of the cognitive deficits associated with MHE.

Impaired brain activity in cirrhotic patients with minimal hepatic encephalopathy: Evaluation by near-infrared spectroscopy

AIM

Near-infrared spectroscopy (NIRS) is a tool that could non-invasively measure the regional cerebral oxygenated hemoglobin (oxy-Hb) concentration with high time resolution. The aim of the present study is to reveal the time-dependent regional cerebral oxy-Hb concentration change coupled with brain activity during task performance in patients with minimal hepatic encephalopathy (MHE).

METHODS

Cerebral oxy-Hb concentration was measured by using NIRS in 29 cirrhotic patients without overt hepatic encephalopathy (HE). Of those, 16 patients who had abnormal electroencephalography findings were defined as having MHE. Responsive increase in oxy-Hb during a word-fluency task was compared between MHE and non-MHE patients.

RESULTS

There was no difference in the maximum value of oxy-Hb increase between patients with and without MHE (0.26 ± 0.12 vs 0.32 ± 0.22 mM·mm, P = 0.37). However, the pattern of the time course changes of oxy-Hb was different between the two groups. The MHE group was characterized by a gradual increase of oxy-Hb throughout the task compared to steep and repetitive increase in the non-MHE group. Increase in oxy-Hb concentration at 5 s after starting the task was significantly small in the MHE group compared to the non-MHE (0.03 ± 0.05 vs 0.11 ± 0.09 mM·mm, P = 0.006).

CONCLUSION

The cerebral oxygen concentration is poorly reactive in response to tasks among cirrhotic patients without overt HE but having abnormal electroencephalography findings. These impaired responses in regional cerebral oxy-Hb concentration may be related to the latent impairment of brain activity seen in MHE.

The C57BL/6J mouse exhibits sporadic congenital portosystemic shunts

C57BL/6 mice are the most widely used strain of laboratory mice. Using in vivo proton Magnetic Resonance Spectroscopy (¹H MRS), we have repeatedly observed an abnormal neurochemical profile in the brains of both wild-type and genetically modified mice derived from the C57BL/6J strain, consisting of a several fold increase in cerebral glutamine and two fold decrease in myo-inositol. This strikingly abnormal neurochemical “phenotype” resembles that observed in chronic liver disease or portosystemic shunting and appeared to be independent of transgene, origin or chow and was not associated with liver failure. As many as 25% of animals displayed the abnormal neurochemical profile, questioning the reliability of this model for neurobiology. We conducted an independent study to determine if this neurochemical profile was associated with portosystemic shunting. Our results showed that 100% of the mice with high brain glutamine displayed portosystemic shunting by concomitant portal angiography while all mice with normal brain glutamine did not. Since portosystemic shunting is known to cause alterations in gene expression in many organs including the brain, we conclude that portosystemic shunting may be the most significant problem associated with C57BL/6J inbreeding both for its effect on the central nervous system and for its systemic repercussions.

Portal vein thrombosis: should anticoagulation be used?

Portal vein thrombosis (PVT) can contribute to significant morbidity and mortality; in patients with cirrhosis, this can make transplant more technically challenging. Additionally, the clot may extend further into the mesenteric and splenic veins, and disturbance of the hepatic blood flow may lead to faster progression of the cirrhosis. Development of PVT is associated with local risk factors, and many patients have associated systemic prothrombotic factors. Anticoagulation in noncirrhotic patients should be initiated at diagnosis, using low-molecular-weight heparin overlapping with vitamin K antagonists. Cirrhotic patients with PVT should be screened for varices and then anticoagulated with low-molecular-weight heparin for at least a 6-month period. All patients should be assessed for triggering factors and tumors, as well as systemic prothrombotic factors. Newer evidence suggests that prophylactic anticoagulation in patients with cirrhosis may have a role in clinical management with decreased incidence of PVT and improved survival; further study is needed.

Brain magnetic resonance imaging findings in young patients with hepatosplenic schistosomiasis mansoni without overt symptoms

The purpose of this study was to describe the brain magnetic resonance imaging (MRI) findings in young patients with hepatosplenic schistosomiasis mansoni without overt neurologic manifestations. This study included 34 young persons (age range = 9-25 years) with hepatosplenic schistosomiasis mansoni who had been previously treated. Patients were scanned on a 1.5-T system that included multiplanar pre-contrast and post-contrast sequences, and reports were completed by two radiologists after a consensus review. Twenty (58.8%) patients had MRI signal changes that were believed to be related to schistosomiasis mansoni. Twelve of the 20 patients had small focal hyperintensities on T2WI in the cerebral white matter, and eight patients had symmetric hyperintense basal ganglia on T1WI. There was a high frequency of brain MRI signal abnormalities in this series. Although not specific, these findings may be related to schistosomiasis.

Congenital portosystemic vascular malformations

Congenital portosystemic shunts are developmental abnormalities of the portal venous system resulting in the diversion of portal blood away from the liver to the systemic venous system. Such malformations are believed to come from an insult occurring between the fourth and eighth week of gestation during the development of hepatic and systemic venous systems, and could explain their frequent association with cardiac and other vascular anomalies. They are currently categorized into end-to-side shunts (type I) or side-to-side shunts (type II). This article aims to review the common symptoms and complications encountered in congenital portosystemic shunts, the surgical and endovascular treatment, and the role of liver transplantation in this disease. We will also focus on the current controversies and the areas where there is potential for future studies.

Hepatic encephalopathy after transjugular intrahepatic portosystemic shunt

Transjugular intrahepatic portosystemic shunt (TIPS) has been used for more than 20 years to treat some of the complications of portal hypertension. When TIPS was initially proposed, it was claimed that the optimal calibration of the shunt could allow an adequate reduction of portal hypertension, avoiding, at the same time, the occurrence of hepatic encephalopathy (HE), a neurologic syndrome. However, several clinical observations have shown that HE occurred rather frequently after TIPS, and HE has become an important issue to be taken into consideration in TIPS candidates and a problem to be faced after the procedure.

Lactulose for minimal hepatic encephalopathy in patients with extrahepatic portal vein obstruction

BACKGROUND/AIMS

Minimal hepatic encephalopathy (MHE) is common in patients with extrahepatic portal vein obstruction (EHPVO). There is no study on the treatment of MHE using lactulose in patients with EHPVO.

PATIENTS AND METHODS

Consecutive EHPVO patients were assessed by psychometric (number connection test (NCT-A and B), digit symbol test (DST), serial dot test (SDT), line tracing test (LTT)), and critical flicker frequency (CFF) at inclusion. Patients diagnosed as MHE were treated with lactulose and psychometric tests, CFF, and were reassessed after 3 months.

RESULTS

Of the 70 patients screened, the prevalence of abnormal psychometric test was as follows: NCT-A (41%), NCT-B (53%), DST (38%), SDT (40%), and LTT (44%). Thirty patients (43%) had two or more than two abnormal (>2 SD) psychometry tests. Lactulose improved MHE in 16/30 (53%) of patients after 3 months of treatment. Arterial ammonia decreased after lactulose treatment compared to baseline (83.7±19.1 vs. 65.1±19.3 μmol/l, P=0.001). A total of 9 (75%) of 12 patients with large spontaneous shunt and 7 (39%) of 18 patients without spontaneous shunt improved with lactulose (P=0.07). CFF in patients with MHE (n=30) was significantly lower than those without MHE (n=40) (38.1±2.4 vs. 41.5±3.1 Hz, P=0.01). CFF was less than 38 Hz in 21 (70%) of 30 patients before treatment and in 10 (33%) patients after lactulose therapy in MHE patients. All patients could tolerate lactulose without any significant side effects. Four patients (13%) developed transient diarrhea in whom dose needed reduction, 3 (10%) did not like its taste but have continued, and 2 (6%) developed abdominal bloating sensation.

CONCLUSIONS

Lactulose is effective in the treatment of MHE in patients with EHPVO.

Noncirrhotic hyperammonaemic encephalopathy

Adult hyperammonaemia is associated with severe liver disease in 90% of cases. In the remainder, noncirrhotic causes should be considered. Measurements of serum ammonia level must be part of the basic work-up in all patients presenting with encephalopathy of unknown origin, even when liver function is normal. Clinician awareness of noncirrhotic hyperammonaemic encephalopathy can contribute to early diagnosis and the initiation of sometimes life-saving treatment. This review focuses on the physiology, aetiology and underlying mechanisms of noncirrhotic hyperammonaemic encephalopathy and discusses the available treatment modalities.

Gut-brain chemokine changes in portal hypertensive rats

BACKGROUND

Hepatic encephalopathy is a syndrome whose physiopathology is poorly understood; therefore, current diagnostic tests are imperfect and modern therapy is nonspecific. Particularly, it has been suggested that inflammation plays an important role in the pathogenesis of portal hypertensive encephalopathy in the rat.

AIM

We have studied an experimental model of portal hypertension based on a triple partial portal vein ligation in the rat to verify this hypothesis.

METHODS

One month after portal hypertension we assayed in the splanchnic area (liver, small bowel and mesenteric lymph nodes) and in the central nervous system (hippocampus and cerebellum) fractalkine (CX3CL1) and stromal cell-derived factor alpha (SDF1-α) as well as their respective receptors (CX3CR1 and CXCR4) because of their key role in inflammatory processes.

RESULTS

The significant increase of fractalkine in mesenteric lymph nodes (P<0.05) and its receptor (CX3CR1) in the small bowel (P<0.05) and hippocampus (P<0.01), associated with the increased expression of SDF1-α in the hippocampus (P<0.01) and the cerebellum (P<0.01) suggest that prehepatic portal hypertension in the rat induces important alterations in the expression of chemokines in the gut-brain axis.

CONCLUSION

The present study revealed that portal hypertension is associated with splanchnic-brain inflammatory alterations mediated by chemokines.

Biexponential analysis of diffusion-tensor imaging of the brain in patients with cirrhosis before and after liver transplantation

BACKGROUND AND PURPOSE

DTI has shown increased MD of water molecules in the brain of patients with cirrhosis, consistent with low-grade edema. This study further characterizes this edema by using biexponential analysis of DTI data, a technique that may differentiate cytotoxic and vasogenic edema.

MATERIALS AND METHODS

A total of 41 patients with cirrhosis awaiting liver transplantation and 16 healthy controls were studied by DTI by using a single-shot echo-planar technique with 11 b-values (range, 0-7500 s/mm(2)) and 6 noncollinear directions. Measurements were fitted to biexponential function to determine MD and FA for the fast and slow diffusion components. Regions of interest were selected in the parietal white matter and corticospinal tract. The assessment was repeated 1 year after liver transplantation in 24 of these patients.

RESULTS

In parietal white matter, patients with cirrhosis showed an increase in fast MD and a decrease in fast FA that normalized after liver transplantation. In the corticospinal tract, there was an increase in fast and slow MD that normalized after transplantation, and a decrease in FA that persisted posttransplantation. There was no association of DTI parameters with minimal HE (n =12).

CONCLUSIONS

Biexponential analysis of DTI supports the presence of edema in the brain of patients with cirrhosis that reverts after transplantation. In parietal white matter, the increase in brain water was mainly located in the interstitial compartment, while the corticospinal tract showed a mixed pattern (intra- and extracellular). In addition, the findings on posttransplantation were consistent with microstructural damage along the corticospinal tract.

Pro-inflammatory cytokines are raised in extrahepatic portal venous obstruction, with minimal hepatic encephalopathy

BACKGROUND AND AIMS

Minimal hepatic encephalopathy (MHE) and hyperammonemia are seen in patients with extrahepatic portal venous obstruction (EHPVO). Inflammation has been shown to play an important role in the pathogenesis of hepatic encephalopathy in cirrhotics. This study assessed serum pro-inflammatory cytokines and their correlation with hyperammonemia, (1)H-magnetic resonance (MR) spectroscopy-derived brain glutamine, and diffusion tensor imaging (DTI)-derived metrics in patients with EPHVO, with and without MHE.

METHODS

Neuropsychological tests, DTI, (1)H-MR spectroscopy, and estimation of blood ammonia and pro-inflammatory cytokines (tumor necrosis factor-α[TNF-α] and interleukin-6 [IL-6]) were done in 20 patients with EHPVO and eight healthy controls.

RESULTS

Pro-inflammatory cytokines (TNF-α and IL-6), blood ammonia, brain glutamine, and mean diffusivity were increased in both patient groups, as compared to controls. Patients with MHE (n-12) had significantly higher TNF-α, IL-6, blood ammonia, brain glutamine, and mean diffusivity, signifying brain edema, than controls. A significant, positive correlation was seen between TNF-α and IL-6 and between blood ammonia and TNF-α, IL-6, and brain glutamine. Significant, positive correlations of TNF-α, IL-6, and blood ammonia with mean diffusivity values were seen in various brain regions, including spectroscopy voxel-derived mean diffusivity.

CONCLUSION

Patients with extrahepatic portal vein obstruction have inflammation and hyperammonemia made evident by higher blood TNF-α, IL-6, ammonia, and brain glutamine levels. A significant correlation between hyperammonemia, pro-inflammatory cytokines, and cerebral edema on DTI in various brain regions suggests that both these factors play a role in the pathogenesis of MHE in these patients.

New assessment of hepatic encephalopathy

Hepatic encephalopathy (HE) is a common complication of cirrhosis that requires careful appraisal of the clinical manifestations, evaluation of the underlying neurological disorders, and assessment of liver function and the portal-systemic circulation. This article reviews recent developments in the assessment of HE and discusses the controversy regarding the use of a categorical or a continuous approach in measuring the severity of this condition. New scales facilitate effective monitoring and assessment of episodic HE. Neuropsychological test batteries and neurophysiological tests are of value for evaluating cognitive function in outpatients and can establish the diagnosis of minimal HE, and the severity of low-grade HE. These tools allow better evaluation of the origin of cognitive complaints and help in estimating the risk of accidents. It is now possible to complete the evaluation with measurement of the effects of cognitive impairment on daily living. In difficult cases, imaging of the brain and portal-systemic circulation with magnetic resonance imaging is especially helpful. Based on these studies, neurological signs and symptoms can be attributed to HE in patients with mild liver disease and in those with complex neurological manifestations. The new methods presented are also valuable for investigating the neurological manifestations occurring after liver transplantation.

Effect of surgical portosystemic shunt on prevalence of minimal hepatic encephalopathy in children with extrahepatic portal venous obstruction: assessment by magnetic resonance imaging and psychometry

OBJECTIVE

The aim of this study was to evaluate the effect of surgical portosystemic shunt (PSS) on the prevalence of minimal hepatic encephalopathy (MHE) in patients with extrahepatic portal venous obstruction.

PATIENTS AND METHODS

Forty-two children with extrahepatic portal venous obstruction (17 with surgical PSS, 25 without surgical shunt) and 20 healthy children were evaluated with blood ammonia (BA), psychometry, H magnetic resonance spectroscopy, critical flicker frequency (CFF), and diffusion tensor imaging. Serum tumor necrosis factor-α and interleukin-6 were measured in 10 patients and 8 controls.

RESULTS

Patients with surgical PSS had significantly higher BA and glutamine/creatine on H-MR spectroscopy than those without surgical shunt. Both groups of patients had significantly higher BA and glutamate/creatine than controls. Myoinositol was reduced in patients with surgical PSS. MHE was present in 41% cases with and 32% cases without surgical PSS (p-ns). Raised mean diffusivity on diffusion tensor imaging signifying low-grade cerebral edema was seen only in MHE cases. Patients had significantly higher serum tumor necrosis factor-α and interleukin-6 levels than controls. CFF was abnormal in 5 of 15 patients with MHE.

CONCLUSIONS

Patients with surgical PSS have significantly higher BA and Glx/creatine than those without surgical PSS. MHE prevalence was higher in surgically shunted than in the nonshunted patients, but the difference was not significant. Cerebral edema is present in patients with MHE. CFF has limited diagnostic utility for MHE in children.

Cerebral oedema in minimal hepatic encephalopathy due to extrahepatic portal venous obstruction

BACKGROUND

Minimal hepatic encephalopathy (MHE) has recently been reported in patients with extrahepatic portal venous obstruction (EHPVO).

AIMS

To evaluate brain changes by magnetic resonance studies in EHPVO patients.

METHODS

Blood ammonia level, critical flicker frequency (CFF), brain metabolites on 1H-magnetic resonance (MR) spectroscopy and brain water content on diffusion tensor imaging and magnetization transfer ratio (MTR) were studied in 31 EHPVO patients with and without MHE, as determined by neuropsychological tests. CFF and magnetic resonance imaging studies were also performed in 23 controls.

RESULTS

Fourteen patients (14/31, 45%) had MHE. Blood ammonia level was elevated in all, being significantly higher in the MHE than no MHE group. CFF was abnormal in 13% (4/31) with EHPVO and in 21% (3/14) with MHE. On 1H-MR spectroscopy, increased Glx/Cr, decreased mIns/Cr, and no change in Cho/Cr were noted in patients with MHE compared with controls. Significantly increased mean diffusivity (MD) and decreased (MTR) were observed in the MHE group, suggesting presence of interstitial cerebral oedema (ICE). MD correlated positively with blood ammonia level (r=0.65, P=0.003) and Glx (r=0.60, P=0.003).

DISCUSSION

MHE was detected in 45% of patients with EHPVO while CFF was abnormal in only 13%. ICE was present in 7/10 brain regions examined, particularly in those with MHE. Hyperammonaemia elevated cerebral Glx levels correlated well with ICE.

CONCLUSIONS

MHE was common in EHPVO; CFF could identify it only in a minority. ICE was present in EHPVO, particularly in those with MHE. It correlated with blood ammonia and Glx/Cr levels. Hyperammonaemia seems to contribute to ICE in EHPVO.

Pathogenesis and diagnosis of hepatic encephalopathy

Hepatic encephalopathy (HE) is a common and potentially devastating neuropsychiatric complication of acute liver failure and cirrhosis. Even in its mildest form, minimal HE (MHE), the syndrome significantly impacts daily living and heralds progression to overt HE. There is maturity in the scientific understanding of the cellular processes that lead to functional and structural abnormalities in astrocytes. Hyperammonemia and subsequent cell swelling is a key pathophysiological abnormality, but this aspect alone is insufficient to fully explain the complex neurotransmitter abnormalities that may be observable using sophisticated imaging techniques. Inflammatory cytokines, reactive oxygen species activation and the role of neurosteroids on neurotransmitter binding sites are emerging pathological lines of inquiry that have yielded important new information on the processes underlying HE and offer promise of future therapeutic targets. Overt HE remains a clinical diagnosis and the neurophysiological and imaging modalities used in research studies have not transferred successfully to the clinical situation. MHE is best characterized by psychometric evaluation, but these tests can be lengthy to perform and require specific expertise to interpret. Simpler computer-based tests are now available and perhaps offer an opportunity to screen, diagnose and monitor MHE in a clinical scenario, although large-scale studies comparing the different techniques have not been undertaken. There is a discrepancy between the depth of understanding of the pathophysiology of HE and the translation of this understanding to a simple, easily understood diagnostic and longitudinal marker of disease. This is a present area of focus for the management of HE.

Minimal hepatic encephalopathy: consensus statement of a working party of the Indian National Association for Study of the Liver

Hepatic encephalopathy (HE) is a major complication that develops in some form and at some stage in a majority of patients with liver cirrhosis. Overt HE occurs in approximately 30-45% of cirrhotic patients. Minimal HE (MHE), the mildest form of HE, is characterized by subtle motor and cognitive deficits and impairs health-related quality of life. The Indian National Association for Study of the Liver (INASL) set up a Working Party on MHE in 2008 with a mandate to develop consensus guidelines on various aspects of MHE relevant to clinical practice. Questions related to the definition of MHE, its prevalence, diagnosis, clinical characteristics, pathogenesis, natural history and treatment were addressed by the members of the Working Party.

Brain MR imaging and 1H-MR spectroscopy changes in patients with extrahepatic portal vein obstruction from early childhood to adulthood

BACKGROUND AND PURPOSE

MR imaging and (1)H-MR spectroscopy changes are well reported in cirrhotic patients, whereas they are inadequately reported in EHPVO. The aim of this study was to investigate age-related changes in brain MR imaging and metabolite profile in EHPVO with and without MHE and to explore any correlation of imaging and (1)H-MR spectroscopy parameters with blood ammonia.

MATERIALS AND METHODS

Sixty-three patients with EHPVO (children, 7-12 years [n = 22], adolescents, 13-18 years [n = 15] and adults, 19-41 years [n = 26]) and 47 healthy age/sex-matched volunteers were studied. Neuropsychological tests, MR imaging, (1)H-MR spectroscopy, and blood ammonia estimation were performed in all subjects.

RESULTS

Of 63 EHPVO patients, 25 (40%) who had MHE showed significantly increased MD, Glx, and blood ammonia in all 3 age groups; however, myo-inositol was significantly lower only in adults when compared with controls. MD positively correlated with blood ammonia and Glx in all age groups. Brain choline levels were normal in all patients with different age groups.

CONCLUSIONS

Increases in brain MD, Glx, and blood ammonia were associated with MHE in all age groups. Normal brain choline in EHPVO signifies healthy liver and may serve as a diagnostic marker for its differentiation from cirrhosis-induced encephalopathy. Significant decrease of myo-inositol in adults is probably due to cellular osmoregulation secondary to long-standing hyperammonemia.