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.     

Chinese guidelines on management of hepatic encephalopathy in cirrhosis

The Chinese Society of Hepatology developed the current guidelines on the management of hepatic encephalopathy in cirrhosis based on the published evidence and the panelists' consensus. The guidelines provided recommendations for the diagnosis and management of hepatic encephalopathy(HE) including minimal hepatic encephalopathy(MHE) and overt hepatic encephalopathy, emphasizing the importance on screening MHE in patients with end-stage liver diseases. The guidelines emphasized that early identification and timely treatment are the key to improve the prognosis of HE. The principles of treatment include prompt removal of the cause, recovery of acute neuropsychiatric abnormalities to baseline status, primary prevention, and secondary prevention as soon as possible.     

Value of the critical flicker frequency in patients with minimal hepatic encephalopathy

Minimal hepatic encephalopathy (MHE) is mainly diagnosed using psychometric tests such as the psychometric hepatic encephalopathy score (PHES). Despite the clinical and social relevance of MHE, psychometric testing is not widespread in routine clinical care. We assessed the usefulness of the critical flicker frequency (CFF), for the diagnosis of MHE and for the prediction of the development of overt episodes of HE. The normal range of PHES in the Spanish population was evaluated in a control group. Subsequently, 114 patients with cirrhosis and 103 healthy controls underwent both PHES and CFF tests. A diagnosis of MHE was made when the PHES was lower than -4 points. Patients were followed-up every 6 months for a total of 1 year. CFF did not correlate with age, education, or sex in the control group. The mean CFF was significantly lower in patients with MHE versus non-MHE or controls. Mean CFF correlated with individual psychometric tests as well as PHES (r = 0.54; P < 0.001). CFF <38 Hz was predictive of further bouts of overt HE (log-rank: 14.2; P < 0.001). There was a weak correlation between mean CFF and Child-Pugh score but not with model for end-stage liver disease score. In multivariate analysis using Cox regression, CFF together with Child-Pugh score was independently associated with the development of overt HE. CONCLUSION: CFF is a simple, reliable, and accurate method for the diagnosis of MHE. It is not influenced by age or education and could predict the development of overt HE.     

Prognostic value of altered oral glutamine challenge in patients with minimal hepatic encephalopathy

Oral glutamine challenge (OGC) has been found to be safe, and an altered response predicts elevated risk of overt hepatic encephalopathy (HE) in patients with minimal hepatic encephalopathy (MHE). We assessed the survival prognosis of patients with cirrhosis, but without current overt HE, who have an altered OGC and MHE. MHE was inferred using 3 neuropsychological tests. Venous ammonia concentrations were measured pre- and post-60 minutes of a 10 g oral glutamine load. The median follow-up was 25.2 months, by which time 22 patients had had bouts of overt HE and 18 had died from liver-related causes. The results in 126 patients with cirrhosis, indicated 25 with MHE and abnormal OGC response. Survival among patients who developed overt HE was 59% at 1 year and 38% at 3 years. In patients without HE, survival was 96% and 86% at 1 and 3 years, respectively (log-rank 50.9, P <.0001). The presence of MHE was not related to survival (log-rank 2.21, P =.23). Patients with MHE and abnormal OGC test had elevated mortality risk (log-rank 13.1, P =.0003). Multivariate analyses indicated Child-Pugh score (hazard ratio [HR] 1.46; 95% CI, 1.46-2.08), and MHE plus altered OGC response (HR 5.5; 95% CI, 1.81-16.6) were predictors of mortality, whether from liver-related or non-liver-related causes. In conclusion, a pathological OGC response in patients with MHE appears to be associated with lower survival rate and may prove useful in the selection of candidates for liver transplantation.     

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

BACKGROUND/AIMS: We assessed the usefulness of oral glutamine challenge (OGC) and minimal hepatic encephalopathy in evaluating risk of overt hepatic encephalopathy in cirrhotic patients.METHODS: Minimal hepatic encephalopathy (MHE) was inferred using neuro-psychological tests. Venous ammonia concentrations were measured pre- and post-60 min (NH(3)-60m) of a 10 g oral glutamine load. Receiver-operating-characteristic curve analysis indicated a pathological glutamine tolerance cut-off value of NH(3)-60m >128 microg/dl. RESULTS: In healthy control subjects (n=10) ammonia concentrations remained unchanged but increased significantly in cirrhotic patients (from 70.41+/-45.2 to 127.43+/-78.6; P<0.001). In multiple logistic regression analysis, altered OGC was related to Child-Pugh (odds ratio, OR=7.69; 95% confidence interval, CI=1.72-33.3; P<0.01) and MHE (OR=5.45; 95% CI=1.17-25.4; P<0.05). In the follow-up 11 patients (15%) developed overt hepatic encephalopathy (HE). In multivariate analysis OGC (OR=14.5; 95% CI=1.26-126.3) and MHE (OR=1.56; 95% CI=1.02-21.9) were independently related with HE in the follow-up. Patients with MHE and altered OGC showed significantly higher risk of overt HE in the follow-up (60%) than patients without MHE and normal OGC (2.8%) (Log rank test=21.60; P<0.0001). CONCLUSIONS: A pathological OGC in patients with MHE appears to be a prognostic factor for the development of overt hepatic encephalopathy, whereas a normal OGC in patients without MHE could exclude risk of overt HE.     

Quality of life in patients with minimal hepatic encephalopathy

Minimal hepatic encephalopathy (MHE) represents the mildest type of hepatic encephalopathy (HE). This condition alters the performance of psychometric tests by impairing attention, working memory, psychomotor speed, and visuospatial ability, as well as electrophysiological and other functional brain measures. MHE is a frequent complication of liver disease, affecting up to 80% of tested patients, depending of the diagnostic tools used for the diagnosis. MHE is related to falls, to an impairment in fitness to drive and the development of overt HE, MHE severely affects the lives of patients and caregivers by altering their quality of life (QoL) and their socioeconomic status. MHE is detected in clinically asymptomatic patients through appropriate psychometric tests and neurophysiological methods which highlight neuropsychological alterations such as video-spatial orientation deficits, attention disorders, memory, reaction times, electroencephalogram slowing, prolongation of latency evoked cognitive potentials and reduction in the critical flicker frequency. Several treatments have been proposed for MHE treatment such as non-absorbable disaccharides, poorly absorbable antibiotics such rifaximin, probiotics and branched chain amino acids. However, because of the multiple diagnosis methods, the various endpoints of treatment trials and the variety of agents used in trials, to date the treatment of MHE is not routinely recommended apart from on a case-by-case basis. Aim of this review is analyze the burden of MHE on QoL of patients and provide a brief summary of therapeutic approaches.     

Critical flicker frequency for diagnosis and assessment of recovery from minimal hepatic encephalopathy in patients with cirrhosis

BACKGROUND:Minimal hepatic encephalopathy (MHE) impairs quality of life and predicts overt hepatic encephalopathy (HE) in cirrhotic patients.Diagnosis of MHE requires cumbersome tests.Lactulose is effective in the treatment of MHE.This study aimed to evaluate the use of critical flicker frequency (CFF) for the diagnosis of MHE in cirrhotic patients after treatment.METHODS:One hundred and ten patients were evaluated by psychometry (number connection tests A,B or figure connection tests A,B),P300 auditory eve...     

轻微型肝性脑病诊断研究进展

轻微型肝性脑病常并发于肝硬化及各种门体分流术患者。由于缺乏典型的临床表现及生化异常,只能通过心理智能测试及神经电生理等检查发现,其发病率已升至30%～84%。轻微型肝性脑病可对患者的日常生活造成影响,无干预的轻微型肝性脑病易发展为显性肝性脑病。该病尚无公认的诊断“金标准”。本文介绍了国内外对轻微型肝性脑病的诊断方法。     

Sarcopenia and cognitive impairment in liver cirrhosis: A viewpoint on the clinical impact of minimal hepatic encephalopathy

Minimal hepatic encephalopathy(MHE) represents the mildest type of hepatic encephalopathy(HE). MHE is considered as a preclinical stage of HE and is part of a wide spectrum of typical neurocognitive alterations characteristic of patients with liver cirrhosis, particularly involving the areas of attention, alertness,response inhibition, and executive functions. MHE can be detected by testing the patients' psychometric performance, attention, working memory, psychomotor speed, and visuospatial ability, as well as by means of electrophysiological and other functional brain measures. MHE is very frequent, affecting from 20% up to80% of patients tested, depending of the diagnostic tools used. Although subclinical, MHE is considered to be clinically relevant. In fact, MHE has been related to the patients' falls, fitness to drive, and working ability. As a consequence, MHE affects the patients and caregivers lives by altering their quality of life and even their socioeconomic status. Recently sarcopenia, a very common condition in patients with advanced liver disease, has been shown to be strictly related to both minimal and overt HE. Aim of this review is to summarize the most recently published evidences about the emerging relationship between sarcopenia and cognitive impairment in cirrhotic patients and provide suggestions for future research.     

Risk factors for hepatic encephalopathy and mortality in cirrhosis: The role of cognitive impairment,muscle alterations and shunts

Introduction/AimMuscle alterations, portosystemic shunts (SPSS) and minimal hepatic encephalopathy (MHE) are related to hepatic encephalopathy (HE), however no studies have investigated the relative role of all these risk factors detected in the same patients. The aim of the study was to assess the prognostic impact of muscle alterations, MHE and SPSS on hepatic encephalopathy and transplant free survival.Patients/Methods114 cirrhotics were submitted to Psychometric Hepatic Encephalopathy Score (PHES) and Animal Naming Test (ANT) to detect MHE. CT scan was used to analyze the skeletal muscle index (SMI), muscle attenuation and SPSS. The incidence of the first episode of HE and survival were estimated.ResultsPrevious HE was present in 47 patients (41%). The variables independently associated to previous HE were: sarcopenia, MHE and SPSS. 44 patients (39%) developed overt HE during 14±11 months; MHE and SPSS were the only variables significantly asociated to overt HE. During the same follow-up, 42 patients died (37%); MELD and sarcopenia were the only variables significantly asociated to transplant free survival.ConclusionsMHE, sarcopenia and SPSS are clinically relevant and should be sought for in cirrhotics. In particular, MHE and SPSS are the only risk factors significantly associated to the development of HE while MELD and sarcopenia are independently associated to overall mortality.     

Assessment of minimal hepatic encephalopathy (with emphasis on computerized psychometric tests)

Minimal hepatic encephalopathy (MHE) is associated with a high risk of development of overt hepatic encephalopathy, impaired quality of life, and driving accidents. The detection of MHE requires specialized testing because it cannot, by definition, be diagnosed on standard clinical examination. Psychometric and neurophysiologic techniques are often used to test for MHE. Paper-pencil psychometric batteries and computerized tests have proved useful in diagnosing MHE and predicting its outcomes. Neurophysiologic tests also provide useful information. The diagnosis of MHE is an important issue for clinicians and patients alike. Testing strategies depend on the normative data available, patient comfort, and local expertise.     

Advances in the Evaluation and Management of Minimal Hepatic Encephalopathy

Minimal hepatic encephalopathy (MHE) is a neurocognitive disorder that affects up to 80% of cirrhotic patients. Similar to overt hepatic encephalopathy, ammonia and oxidative stress play key roles in the pathogenesis of MHE. However, MHE is characterized by subtle deficits and psychomotor abnormalities that can only be elicited by specialized psychometric tests. Although no gold standard exists for the diagnosis, MHE remains an important entity for clinicians to recognize because of its negative impact on a patient’s health-related quality of life and association with driving impairment and vehicle accidents. MHE has also been associated with an increased rate in the development of overt hepatic encephalopathy and increased mortality; therefore, identification and treatment should not be delayed. Treatment to date has been focused on reducing serum ammonia levels with agents such as lactulose, probiotics, and synbiotics. MHE is a real and growing problem that is epidemic in cirrhosis, and increasing awareness of this condition is necessary for adequate management of these patients.     

Is it a medical error if we do not screen cirrhotic patients for minimal hepatic encephalopathy?

Minimal hepatic encephalopathy (MHE) refers to subtle neurocognitive and neurophysiological defects in patients with liver cirrhosis without clinical signs of hepatic encephalopathy. Using appropriate diagnostic methods the prevalence of MHE is approximately 25-30%. MHE has clinical significance as it results in a diminished daily functioning, precedes overt hepatic encephalopathy and is associated with a poor prognosis. Treatment with non-absorbable disaccharides can reverse the neurocognitive and neurophysiological defects found in MHE. The failure to diagnose MHE in apparently normal cirrhotic patients could, therefore, be considered a medical error. However, whether treatment also improves patients' quality of life and prognosis remains to be determined.     

Primary prophylaxis of overt hepatic encephalopathy in patients with cirrhosis: an open labeled randomized controlled trial of lactulose versus no lactulose

Background and Aim: Development of overt hepatic encephalopathy (HE) is associated with poor prognosis in patients with cirrhosis. Lactulose is used for the treatment of HE. There is no study on the prevention of overt HE using lactulose in patients who never had HE earlier. Methods: Consecutive cirrhotic patients who never had an episode of overt HE were randomized to receive lactulose (Gp‐L) or no lactulose (Gp‐NL). All patients were assessed by psychometry (number connection test [NCT‐A and B], figure connection test if illiterate [FCT‐A and B], digit symbol test [DST], serial dot test [SDT], line tracing test [LTT]) and critical flicker frequency test (CFF) at inclusion and after 3 months. These patients were followed every month for 12 months for development of overt HE. Results: Of 250 patients screened, 120 (48%) meeting the inclusion criteria were randomized to Gp‐L (n = 60) and Gp‐NL (n = 60). Twenty (19%) of 105 patients followed for 12 months developed an episode of overt HE. Six (11%) of 55 in the lactulose (Gp‐L) group and 14 (28%) of 50 in the Gp‐NL (P = 0.02) developed overt HE. Ten (20%) of 50 patients in Gp‐NL and five (9%) of 55 patients in the Gp‐L group died, P = 0.16. Number of patients with minimal hepatic encephalopathy (MHE) were comparable in two groups at baseline (Gp‐L vs Gp‐NL, 32:36, P = 0.29). Lactulose improved MHE in 66% of patients in Gp‐L. Taking a cutoff < 38 Hz sensitivity and specificity of CFF in predicting HE were 52% and 77% at baseline and 52% and 82% at 3 months of treatment. On multivariate analysis, Child's score and presence of MHE at baseline were significantly associated with development of overt HE. Conclusions: Lactulose is effective for primary prevention of overt hepatic encephalopathy in patients with cirrhosis.     

Management options for minimal hepatic encephalopathy

Minimal hepatic encephalopathy (MHE) is a neurocognitive dysfunction that is present in the majority of patients with cirrhosis. MHE has a characteristic cognitive profile that cannot be diagnosed clinically. This cognitive dysfunction is independent of sleep dysfunction or problems with overall intelligence. MHE has a significant impact on quality of life, the ability to function in daily life and progression to overt hepatic encephalopathy. Driving ability can be impaired in MHE and this may be a significant factor behind motor vehicle accidents. A crucial aspect of the clinical care of MHE patients is their driving history, which is often ignored during routine care and can add a vital dimension to the overall disease assessment. Driving history should be an integral part of the care of patients with MHE. The preserved communication skills and lack of specific signs and insight make MHE difficult to diagnose. The predominant strategies for MHE diagnosis are psychometric or neurophysiological testing. These are usually limited by financial, normative or time constraints. Studies into inhibitory control, cognitive drug research and critical flicker frequency tests are encouraging. These tests do not require a psychologist for administration and interpretation. Lactulose and probiotics have been studied for their potential use as therapies for MHE, but these are not standard-of-care practices at this time. Therapy can improve the quality of life in MHE patients but the natural history, specific diagnostic strategies and treatment options are still being investigated.     

Neuropsychological assessment of hepatic encephalopathy: ISHEN practice guidelines

Low‐grade or minimal hepatic encephalopathy (MHE) is characterised by relatively mild neurocognitive impairments, and occurs in a substantial percentage of patients with liver disease. The presence of MHE is associated with a significant compromise of quality of life, is predictive of the onset of overt hepatic encephalopathy and is associated with a poorer prognosis for outcome. Early identification and treatment of MHE can improve quality of life and may prevent the onset of overt encephalopathy, but to date, there has been little agreement regarding the optimum method for detecting MHE. The International Society on Hepatic Encephalopathy and Nitrogen Metabolism convened a group of experts for the purpose of reviewing available data and making recommendations for a standardised approach for neuropsychological assessment of patients with liver disease who are at risk of MHE. Specific recommendations are presented, along with a proposed methodology for further refining these assessment procedures through prospective research.     

Minimal hepatic encephalopathy matters in daily life

Minimal hepatic encephalopathy is a neuro-cognitive dysfunction which occurs in an epidemic proportion of cirrhotic patients, estimated as high as 80% of the population tested. It is characterized by a specific, complex cognitive dysfunction which is independent of sleep dysfunction or problems with overall intelligence. Although named ＂minimal＂, minimal hepatic encephalopathy （MHE） can have a far-reaching impact on quality of life, ability to function in daily life and progression to overt hepatic encephalopathy. Importantly, MHE has a profound negative impact on the ability to drive a car and may be a significant factor behind motor vehicle accidents. A crucial aspect of the clinical care of MHE patients is their driving history, which is often ignored in routine care and can add a vital dimension to the overall disease assessment. Driving history should be an integral part of care in patients with MHE. The lack of specific signs and symptoms, the preserved communication skills and lack of insight make MHE a difficult condition to diagnose. Diagnostic strategies for MHE abound, but are usually limited by financial, normative or time constraints. Recent studies into the inhibitory control and critical flicker frequency tests are encouraging since these tests can increase the rates of MHE diagnosis without requiring a psychologist. Although testing for MHE and subsequent therapy is not standard of care at this time, it is important to consider this in cirrhotics in order to improve their ability to live their life to the fullest.     

Neuropsychological impairment in severe acute viral hepatitis is due to minimal hepatic encephalopathy

Background and Aims: Minimal hepatic encephalopathy (MHE) in patients with liver cirrhosis may have prognostic significance with regard to the development of clinical hepatic encephalopathy (HE) and deterioration in patient quality of life. Its prevalence in acute viral hepatitis (AVH) is not known. Patients and Methods: Consecutive 20 AVH patients (age, 29.9±7.9 years; M:F 18:2, hepatitis A:B:E: 2:16:2) without overt encephalopathy were evaluated for MHE and followed up. All patients underwent number connection tests – A and B, figure connection tests – A and B, digit symbol test and object assembly test and critical flicker frequency (CFF) at baseline and after the resolution of icterus. MHE was diagnosed if two or more psychometric tests were abnormal. Results: Prevalence of MHE (n=5) was 25%, which resolved on follow‐up during the anicteric resolution phase. Five (25%) patients had greater than two abnormal psychometry tests and four (20%) had CFF <38 Hz. CFF alone had sensitivity and specificity of 80 and 100%, respectively, in the diagnosis of MHE. There was significant difference in the performance of CFF during the icteric and resolution phase of AVH (40.6±3.4 vs 41.8±2.1 Hz, P=0.04). Arterial ammonia level were higher in patients with MHE compared with patients without MHE (88.2±23.5 vs 53.8±10.9 μmol/L, P=0.001). On univariate analysis fasting ammonia level at baseline was significantly associated with all the psychometric tests (P=0.001). None of the patients developed HE either in MHE group or in those who did not had MHE at baseline. Conclusions: MHE occurs in 25% of patients with AVH and resolves on follow up with recovery of AVH. Raised arterial ammonia during the icteric phase is associated with development of MHE.     

Demonstration of interstitial cerebral edema with diffusion tensor MR imaging in type C hepatic encephalopathy

Brain water may increase in hepatic encephalopathy (HE). Diffusion tensor imaging was performed in patients with cirrhosis with or without HE to quantify the changes in brain water diffusivity and to correlate it with neuropsychological (NP) tests. Thirty-nine patients with cirrhosis, with minimal (MHE) or overt HE, were studied and compared to 18 controls. Mean diffusivity (MD) and fractional anisotropy (FA) were calculated in corpus callosum, internal capsule, deep gray matter nuclei, periventricular frontal, and occipital white matter regions in both cerebral hemispheres. The MD and FA values from different regions in different groups were compared using analysis of variance and Spearman's rank correlation test. In 10 patients with MHE, repeat studies were performed after 3 weeks of lactulose therapy to look for any change in MD, FA, and NP scores. Significantly increased MD was found with insignificant changes in FA in various regions of brain in patients with MHE or HE compared with controls, indicating an increase in interstitial water in the brain parenchyma without any microstructural changes. A significant correlation was found between MD values from corpus callosum, internal capsule, and NP test scores. After therapy, MD values decreased significantly and there was a corresponding improvement in NP test scores. Further analysis showed that MD values were different for different grades of minimal or overt HE. In conclusion, the increase in MD with no concomitant changes in FA in cirrhosis with minimal or early HE indicates the presence of reversible interstitial brain edema.     

Intracortical inhibitory and excitatory circuits in subjects with minimal hepatic encephalopathy: a TMS study

Minimal hepatic encephalopathy (MHE) is the earliest form of hepatic encephalopathy (HE) and affects up to 80 % of patients with liver cirrhosis. By definition, MHE is characterized by psychomotor slowing and subtle cognitive deficits,  but obvious clinical manifestations are lacking. Given its covert nature, MHE is often underdiagnosed. This study was aimed at detecting neurophysiological changes, as assessed by means of transcranial magnetic stimulation (TMS), involved in the early pathogenesis of the HE. We investigated motor cortex excitability in 15 patients with MHE and in 15 age-matched age-matched cirrhotic patients without MHE; the resting motor threshold, the short-interval intracortical inhibition (SICI) and the intracortical facilitation (ICF) were examined. Paired-pulse TMS revealed significant increased SICI and reduced ICF in the patients with MHE. These findings may reflect abnormalities in intrinsic brain activity and altered organization of functional connectivity networks. In particular, the results suggest a shift in the balance between intracortical inhibitory and excitatory mechanisms towards a net increase of inhibitory neurotransmission. Together with other neurophysiological (in particular EEG) and neuroimaging techniques, TMS may thus provide early markers of cerebral dysfunction in cirrhotic patients with MHE.