Magnetic resonance imaging of brain in patients with cirrhotic and non-cirrhotic portal hypertension

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.

Acquired Parkinson's Disease in Alcoholic Cirrhosis: The Rarest Association

Hepatic encephalopathy is the most common neurologic complication of liver cirrhosis, whereas acquired hepatocerebral degeneration (AHD) is an underappreciated neurologic manifestation. Parkinsonism, ataxia, and neuropsychiatric symptoms are its defining characteristics. In individuals with chronic parenchymal liver disease with portosystemic shunting, it is an underrecognized etiology of psychomotor retardation. It has been hypothesized that the etiology of AHD is due to manganese buildup in the basal ganglia. This case report details a hepatocerebral degeneration (AHD) case in a patient with chronic parenchymal liver disease who improved after taking a dopamine agonist.

Cognitive Impairement in Non-Cirrhotic Portal Hypertension: Highlights on Physiopathology, Diagnosis and Management

Hepatic encephalopathy (HE) is one of the most frequent complications of cirrhosis. Several studies and case reports have shown that cognitive impairment may also be a tangible complication of portal hypertension secondary to chronic portal vein thrombosis and to porto-sinusoidal vascular disease (PSVD). In these conditions, representing the main causes of non-cirrhotic portal hypertension (NCPH) in the Western world, both overt and minimal/covert HE occurs in a non-neglectable proportion of patients, even lower than in cirrhosis, and it is mainly sustained by the presence of large porto-systemic shunt. In these patients, the liver function is usually preserved or only mildly altered, and the development of porto-systemic shunt is either spontaneous or iatrogenically frequent; HE is an example of type-B HE. To date, in the absence of strong evidence and large cooperative studies, for the diagnosis and the management of HE in NCPH, the same approach used for HE occurring in cirrhosis is applied. The aim of this paper is to provide an overview of type B hepatic encephalopathy, focusing on its pathophysiology, diagnostic tools and management in patients affected by porto-sinusoidal vascular disease and chronic portal vein thrombosis.

Early detection of hepatic encephalopathy after transjugular intrahepatic portsystemic shunt using multiparametric magnetic resonance with spectroscopy

Background

Hepatic encephalopathy (HE) is a complication of transjugular intrahepatic portosystemic shunt (TIPS).

Aims

Extend the knowledge about the early detection of multiple brain metabolic abnormalities following TIPS; these abnormalities can be detected and managed prior to the clinical manifestation of HE with use of Multiparametric Magnetic Resonance with Spectroscopy.

Methods

12 cirrhotic Patients underwent TIPS; each Patient underwent a 3 T MRI evaluation before and after TIPS. The spectroscopic images were processed measuring the values of the metabolites N-acetylaspartate (NAA) - Glutamine / Glutamate (Glx) - Colina (Cho) - Myinositol (mI) at the level of the nuclei of the base.

Results

Spectroscopic examination performed before the TIPS procedure showed low values of Cho and Mi, instead following the procedure: an increase in the Glx value, a mean reduction in the values of Cho and mI, a statistically significant reduction in the Cho / Creatine ratio, in the mI / Creatine ratio and an increase of the Glx / Creatine ratio.

Conclusions

Our study demonstrated the efficacy of spectroscopy in Patient subjected to TIPS. MR 3 T with spectroscopy can become a valid tool for monitor the dynamics of changes in brain metabolism after TIPS and to provide an early diagnosis of HE allowing an early treatment.

The brain following transjugular intrahepatic portosystemic shunt: the perspective from neuroimaging

Hepatic encephalopathy (HE) is a common complication after implantation of a transjugular intrahepatic portosystemic shunt (TIPS). Neuroimaging offers a variety of techniques for non-invasive evaluation of alterations in metabolism, as well as structural and functional changes of the brain in patients after TIPS implantation. In this article, we review the epidemiology and pathophysiology of post-TIPS HE. The potential of neuroimaging including positron emission tomography and multimodality magnetic resonance imaging to investigate the pathophysiology of post-TIPS HE is presented. We also give a perspective on the role of neuroimaging in this field.

Reversal of Low-Grade Cerebral Edema After Lactulose/Rifaximin Therapy in Patients with Cirrhosis and Minimal Hepatic Encephalopathy

OBJECTIVES:

Decreased magnetization transfer ratio (MTR) in the brain characterizes cerebral edema (CE) in patients with liver cirrhosis, but the role of treatment on its reversibility has not been studied in patients who have minimal hepatic encephalopathy (MHE). This study was carried to evaluate the reversibility of CE with lactulose and rifaximin treatment in patients with MHE and role of ammonia, pro-inflammatory interleukins (IL-1, IL-6) and tumor necrosis factor (TNF)-α in its pathogenesis.

METHODS:

Twenty-three patients with cirrhosis (14 with MHE, 9 without MHE (NMHE)) and 6 healthy controls underwent ammonia, IL-1, IL-6, TNF-α estimation, and MTR in frontal white matter (FWM), parietal white matter (PWM), internal capsule (IC), and basal ganglia (BG).

RESULTS:

Ammonia was significantly higher in the cirrhosis group compared with controls and in MHE compared with the NMHE group. Ammonia correlated positively with IL-1 and IL-6. MTRs in FWM, PWM, IC, and BG were significantly lower in the MHE group compared with controls and in PWM, IC, and BG compared with the NMHE group. MHE patients showed significant MTR increase in FWM, PWM, and IC with treatment. IL-6 and ammonia had significant negative and significant positive psychometric hepatic encephalopathy score (PHES) correlation with MTR in various regions.

CONCLUSIONS:

This study, for the first time, demonstrated the reversibility of low-grade CE with treatment in patients with MHE. Negative correlation between ammonia, IL-6 levels, and MTR and positive correlation between PHES and MTR in MHE patients suggests the role of inflammation and ammonia in the genesis of low-grade CE.

Minimal hepatic encephalopathy impairs quality of life

Minimal hepatic encephalopathy (MHE) is the mildest form of the spectrum of neurocognitive impairment in cirrhosis. It is a frequent occurrence in patients of cirrhosis and is detectable only by specialized neurocognitive testing. MHE is a clinically significant disorder which impairs daily functioning, driving performance, work capability and learning ability. It also predisposes to the development of overt hepatic encephalopathy, increased falls and increased mortality. This results in impaired quality of life for the patient as well as significant social and economic burden for health providers and care givers. Early detection and treatment of MHE with ammonia lowering therapy can reverse MHE and improve quality of life.

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.

Dopamine from cirrhotic liver contributes to the impaired learning and memory ability of hippocampus in minimal hepatic encephalopathy

Background Defective learning/memory ability is a feature of MHE. However, the exact pathophysiological mechanisms leading to the impairment of learning/memory ability in MHE remain not clearly understood. Methods MHE rat modeling by intraperitoneal injection of TAA was successfully established using a Morris water maze, BAEP, and EEG tests. COMT inhibitor, a protein involved in the accumulation of dopamine (DA), was found to be up-regulated in cirrhotic livers in MHE by 2-DE/MS. Results The levels of DA in cirrhotic livers, serums and hippocampuses in the MHE group were more significantly increased than in the control group. In the hippocampuses of MHE rats, NMDA-induced formation of cGMP was reduced by 40 % as determined by in vivo brain microdialysis. Activation of sGC by NO was reduced by 38 %. The expression of NMDAR1, CaM, nNOS and sGC in the hippocampus in the MHE group were more significantly decreased than in controls. Chronic exposure of cultured hippocampus neurons to DA (50 μM) reduced by 53 % the NMDA-induced formation of cGMP. Activation of sGC by NO in these neurons was reduced by 44 %. Down-regulated NMDAR1, CaM, nNOS and sGC were also detected in neurons treated with dopamine, in contrast with the controls. Conclusions This study suggests that when the glutamate-NO-cGMP pathway in the hippocampus is inhibited by the elevation of DA from cirrhotic livers, this in turn may lead to the impairment of learning and memory ability of MHE.

Blood manganese levels in patients with hepatic encephalopathy

PROJECT

Hepatic encephalopathy is an increasingly common disease. Identification of prognosis risk factors in patients with liver damage may lead to preventive actions, towards decreasing its mortality. Manganese (Mn) levels are increased in basal ganglia of patients with hepatic encephalopathy as well as in cases of cirrhotic and liver failure patients. The present is a clinical, prospective, prolective and observational study developed at the Internal Medicine Service from "Dr. Darío Fernández Fierro" General Hospital, ISSSTE, Mexico City. The objective of this work was to report whole blood Mn levels and mortality in encephalopathic patients.

PROCEDURE

Consecutive patients over 18 years of age, diagnosed with hepatic encephalopathy were recruited at the emergency room service. An informed consent, signed by their families was collected. Patients' clinical characteristics, biochemical tests of renal function, hemoglobin, glucose, bilirubins and albumin levels were obtained along with a blood sample to analyze Mn. Patients evolution was followed up for 6 months.

RESULTS

Blood Mn in patients [median, (range)] [20.5, (10.5-39.5) μg/L] were higher than blood levels from a group of healthy volunteers [7.5, (6.1-12.8) μg/L] (P<0.001). Among 9 patients studied four died, 2 women and 2 men, those patients showed higher (P=0.032) Mn levels [28, (17-39.5) μg/L] than those alive [13.5, (10.5-32) μg/L] after the follow up period.

CONCLUSIONS

In this pilot study, Mn blood levels were higher in hepatic encephalopathy that died as consequence of the disease that those that survived in a 6 month follow up period. Blood Mn could be a potential prognosis factor for death in patients with hepatic encephalopathy.

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.

The role of magnetic resonance imaging and spectroscopy in hepatic encephalopathy

Hepatic encephalopathy (HE) is a diverse manifestation of acute and chronic liver failure, ranging from cognitive impairment, only detectable on psychometric evaluation through to confusion, coma and death from cerebral oedema. While there is widespread acceptance of its importance, there is little consensus on how best to diagnose and monitor HE. Clinical descriptions, psychometric testing, electroencephalography and magnetic resonance (MR) imaging (and lately, MR spectroscopy) have all been proposed. MR techniques, in contrast to other modalities, have the benefit of objectivity and of being able to interrogate the brain directly with respect to changes in brain size, function and the metabolic disturbances thought to underlie HE, particularly in the context of astrocyte swelling. Modern clinical MRI scanners with multinuclear MR spectroscopy capabilities and brain mapping software can demonstrate structural and functional cellular changes using volumetric MRI, magnetization transfer MRI, diffusion-weighting MRI, functional MRI with oxygenation measurements and in vivo and in vitro (1)H and (31)P MR spectroscopy. This review describes the relative merits of these techniques and provides guidance on the directions for future research and translation into clinical practice.

Minimal hepatic encephalopathy

Minimal hepatic encephalopathy (MHE) is the mildest form of spectrum of hepatic encephalopathy (HE). Patients with MHE have no recognizable clinical symptoms of HE but have mild cognitive and psychomotor deficits. The prevalence of MHE is high in patients with cirrhosis of liver and varies between 30% and 84%; it is higher in patients with poor liver function. The diagnostic criteria for MHE have not been standardized but rest on careful patient history and physical examination, normal mental status examination, demonstration of abnormalities in cognition and/or neurophysiological function, and exclusion of concomitant neurological disorders. MHE is associated with impaired health-related quality of life, predicts the development of overt HE and is associated with poor survival. Hence, screening all patients with cirrhosis for MHE using psychometric tests, and treatment of those patients diagnosed to have MHE has been recommended. Ammonia plays a key role in the pathogenesis of MHE, which is thought to be similar to that of overt HE. Thus, ammonia-lowering agents such as lactulose and probiotics have been tried. These agents have been shown to improve cognitive and psychometric deficits, and have good safety profile. Future studies will better define the role of other drugs, such as rifaximin, acetyl L-carnitine and L-ornithine L-aspartate.