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Anabolic androgenic steroids (AASs) are a group of molecules including endogenous testosterone and synthetic derivatives that have both androgenic and anabolic effects. These properties make them therapeutically beneficial in medical conditions such as hypogonadism. However, they are commonly bought illegally and misused for their anabolic, skeletal muscle building, and performance- enhancing effects. Supraphysiologic and long-term use of AASs affects all organs, leading to cardiovascular, neurological, endocrine, gastrointestinal, renal, and hematologic disorders. Hepatotoxicity is one of the major concerns regarding AASs treatment and abuse. Testosterone and its derivatives have been most often shown to induce a specific form of cholestasis, peliosis hepatis, and hepatic benign and malignant tumors. It is currently believed that mechanisms of pathogenesis of these disorders include disturbance of antioxidative factors, upregulation of bile acid synthesis, and induction of hepatocyte hyperplasia. Most toxicity cases are treated with supportive measures and liver function normalizes with discontinuation of AAS. However, some long-term consequences are irreversible. AAS-induced liver injury should be taken in consideration in patients with liver disorders, especially with the increasing unintentional ingestion of supplements containing AAS. In this paper, we review the most current knowledge about AAS-associated adverse effects on the liver, and their clinical presentations, prevalence, and pathophysiological mechanisms.

Since their introduction in 1987, hydroxymethyl glutaryl coenzyme A reductase (HMG-CoA) inhibitors, more commonly known as statins, have become some of the most widely prescribed medications in the world. Though generally considered to be safe and well tolerated, statins have been associated with several side effects including mild liver dysfunction manifested by increases in aminotransferases. Rarely, statins have been noted to induce more serious hepatic injury, including liver injury with autoimmune features. Current literature supports statin induced liver injury presenting in either hepatocellular or cholestatic patterns, though with the former being the prevailing pattern of injury. Fortunately, severe liver injury is uncommon with statin use and is generally reversible without any intervention other than offending statin cessation. When evaluating cases of suspected statin-induced liver injury, a complete medical history, laboratory tests including a complete metabolic panel, autoimmune markers, and viral panel, as well as hepatic imaging, are crucial for a complete causality analysis with validated tools such as Roussel Uclaf Causality Assessment Method. The aim of this review is to review the current evidence for statin-induced liver injury and cholestasis.

Aim Adiponectin is an adipokine that is involved in regulating hepatic fat and glucose metabolism, and also has anti-steatotic, anti-inflammatory and anti-fibrotic effects. How these different activities impact the development and progression of NAFLD is not well understood. The aim of this study was to evaluate both liver and serum adiponectin levels in patients with and without NAFLD and determine any clinical correlations. Methods Liver tissue and serum samples were collected from patients undergoing liver biopsy between April 2014 and July 2020, and categorized based on histopathologic diagnosis into hepatic steatosis (HS), non-alcoholic steatohepatitis (NASH), and hepatitis control (HC). Luminex® xMAP assay was performed on both liver and serum samples to measure adiponectin levels. Statistical analysis compared liver adiponectin (LA) and serum adiponectin (SA) levels between groups. Results 48 participants were included in the analysis with 4 in HS, 15 in NASH, and 29 in HC groups. The mean LA level was lowest in the HS group was 68.6% lower than that in the NASH group and 80.6% lower than that in the HC group (p=0.036). The mean SA level was 3.61 μg/ml for NAFLD group was significantly lower than that in the HC group, 7.51 μg/ml (p=0.001). Conclusion Adiponectin levels are lower in NAFLD compared to HC in both serum and in liver tissue. LA levels in HS patients were significantly lower than those both in NASH and HC groups, suggesting that adiponectin is related to inflammation in the liver, and probably reflects a role in pathogenesis of NAFLD. This article is protected by copyright. All rights reserved.

Primary sclerosing cholangitis (PSC) and primary biliary cirrhosis (PBC) are slow progressive diseases which have been increasing in prevalence. The pathogeneses of PBC and PSC are incompletely understood but the underlying mechanisms appear to be fundamentally autoimmune in origin. Although PBC and PSC appear to be separate entities, overlap has been described. Diagnosis depends on a combination of serological markers, imaging, and pathological criteria. The mainstay of treatment has been ursodeoxycholic acid and in some cases of extrahepatic biliary obstruction and overlap disorder, endoscopic retrograde cholangiopancreatography has been useful.

BACKGROUND AND AIM Mitochondrial damage is commonly involved in liver injury. We have previously shown that normal mitochondria can be coated with a carrier protein to form complexes that are specifically taken up by liver cells in culture. The aim of the current study was to determine whether mitochondrial complexes could be specifically delivered to the livers of living rats by intravenous injection. METHODS Mitochondria were harvested from fresh mouse liver, mixed with an asialoglycoprotein-based carrier, asialoorosomucoid-polylysine (AsOR-PL), and purified to form complexes. To facilitate the release of internalized mitochondria from endosomes, an endosomolytic peptide, listeriolysin O (LLO), was coupled to AsOR to form AsOR-LLO. Mitochondria alone, mitochondrial complexes with AsOR-PL, and mitochondrial complexes plus AsOR-LLO conjugate all containing the same number of mitochondria were injected intravenously. Animals were killed, and organs were removed and analyzed by quantitative polymerase chain reaction of mouse mitochondrial DNA, electron microscopy (EM), and in situ polymerase chain reaction and hybridization followed by immunohistochemical analyses. RESULTS Calculations revealed that approximately 27% of the total injected mitochondria was detected in the liver, while less than 2% was found in spleen, and

In addition to liver injury, elevation of aminotransferases can be caused by strenuous exercise and use of muscle-building and weight-loss supplements. The purpose of this review is to discuss the various mechanisms of elevation of aminotransferases related to body building. A literature review was performed on clinical trials and case reports involving exercise or supplement use and their effects on aminotransferases. Normal aminotransferase levels varied according to gender, age, body mass index, and comorbidities. Strenuous exercise and weight lifting, especially in the unaccustomed, can cause elevated aminotransferases in the absence of liver damage. Supplements such as anabolic steroids, ephedra, and LipoKinetix, amongst others, have also been associated with aminotransferase elevations. The pattern of elevation of aminotransferases is not helpful in distinguishing liver from muscle injury. Other associated muscle enzymes can be useful in making that distinction. To prevent aminotransferase elevations, subjects not accustomed to moderate-high intensity workouts, are recommended to undertake gradual increase in intensity. When causes of liver injury have been ruled out, investigation into bodybuilding, extreme exercise, and supplement use is warranted.

Globally, hepatitis B virus (HBV) infection is recognized as a major risk factor for the development of hepatocellular carcinoma, and HBV-induced liver failure is one of the leading indications for liver transplantation. Until about two decades ago, liver transplantation in patients with chronic HBV infection was a relative contraindication, due to high risk of viral replication with the use of immunosuppressants which could result in graft infection. In the 1990s, hepatitis B immunoglobulin (HBIg) use significantly reduced the risk of graft infection, improving outcomes of liver transplant in patients with chronic HBV infection. However, very high costs, especially with the need for long-term use, became a major concern. With the advent of nucleos(t)ide analogs (NAs), there was less need for high-dose, long-term HBIg use to prevent HBV recurrence. Lamivudine was initially used but resistance soon became a major issue. This was followed by more potent NAs, such as entecavir and tenofovir, emerging as the more preferred agents. Additionally, the use of these antiviral agents (HBIg and/or NAs) have made it possible to use the grafts from donors with positivity for hepatitis B core antibody, allowing for expansion of the donor pool. Nevertheless, there is no consensus on management protocols, which vary significantly amongst centers. In this review, we appraise studies on management strategies used and the role of active vaccination in the prevention of HBV recurrence in post-liver transplant patients.

A large proportion of patients with chronic hepatitis C have associated thrombocytopenia (TCP). Due to bleeding risks, TCP, when severe, can limit diagnostic and therapeutic procedures, treatments, and increases risk of complications, especially excessive bleeding. It is important to understand the mechanisms that cause TCP in order to manage it. In general, TCP can be due to increased destruction or decreased production. Proposed mechanisms of increased destruction include autoantibodies to platelets and hypersplenism with sequestration. Proposed mechanisms of decreased production include virus-induced bone marrow suppression and decreased TPO production. Autoantibodies directed against platelet surface antigens have demonstrated an inverse correlation with platelet counts. Hypersplenism with sequestration involves the interaction of portal hypertension, splenomegaly, and platelet destruction. Decreased production mechanisms involve appropriate and inappropriate levels of TPO secretion. There is limited evidence to support viral-induced bone marrow suppression. In contrast, there is strong evidence to support low levels of TPO in liver failure as a major cause of TCP. TPO-agonists, specifically eltrombopag, have been shown in hepatitis C patients to increase platelet counts without reducing portal hypertension or splenomegaly. We conclude that TCP in hepatitis C virus-induced liver disease is often multifactorial, but an understanding of the mechanisms can lead to judicious use of new drugs for treatment.

Immune checkpoint inhibitors (ICIs) suppress the function of immune checkpoints, which are involved in downregulating immune responses. These lead to an increased activation of the function of T cells, increased release of cytokines, and decreased activity of regulatory T cells. This allows for a more significant and less regulated immune response and subsequent enhanced cytotoxic activity against cancer cells. A number of cancers are now being treated with these agents and this increased use has resulted in more reports of toxicity. While almost every organ can be affected, the skin, gastrointestinal tract, liver, and endocrine glands are most commonly involved. It is necessary that gastroenterologists and hepatologists familiarize themselves with diagnostic steps and management plan in patients with these undesirable outcomes. When assessing for possible ICIs induced hepatotoxicity, it is of utmost importance to use a formal scoring system such as the Roussel Uclaf causality assessment method (RUCAM) to assess for risk factors, alternative causes, and response to cessation and re-exposure of a given drug. While this review is based on studies with and without RUCAM, the conclusions were carefully established mainly from studies that used RUCAM. The aim of this review is to provide information on the epidemiology, risk factors, clinical presentation, diagnostic tools, and management plan based on the most recent studies of immunotherapy-induced hepatotoxicity.

Interleukin (IL) 1 superfamily members are a cornerstone of a variety of inflammatory processes occurring in various organs including the liver. Progression of acute and chronic liver diseases regardless of etiology depends on the stage of hepatocyte damage, the release of inflammatory cytokines and disturbances in gut microbiota. IL1 cytokines and receptors can have pro- or anti- inflammatory roles, even dual functionalities conditioned by the microenvironment. Developing novel therapeutic strategies to block the IL1/IL1R signaling pathways seems like a reasonable option. This mode of action is now exploited by anakinra and canakinumab, which are used to treat different inflammatory illnesses, and studies in liver diseases are on the way. In this mini review, we have focused on the IL1 superfamily members, given their crucial role in liver inflammation diseases, specifically discussing their potential role in developing new treatment strategies.

Primary sclerosing cholangitis is a disease affecting around 0.006-0.016% of the population. Of these, around 75% have concomitant inflammatory bowel disease (IBD) according to the most recent epidemiological studies. Several theories have been proposed regarding the pathogenesis of primary sclerosing cholangitis (PSC). These include changes in the function of cholangiocytes, effects of the gut microbiome, association with specific human leukocyte antigen haplotypes and dysregulation of the immune system. However, these do not explain the observed association with IBD. Moreover, there are considerable differences in the frequency and outcomes between patients with PSC and ulcerative colitis compared with PSC and Crohn's disease. The aim of this review is to appraise the most recent studies that have contributed to the epidemiology, advances in the pathophysiology, and characterization of important clinical aspects of the association of PSC and IBD.

Hepatitis C (HCV) is a viral infection that affects an estimated 71 million people worldwide, with over 1 million new infections yearly. While medical treatments exist, HCV continues to be a significant public health concern. Primary prevention and transmission risk factor identification remain key in helping decrease disease prevalence. While intravenous drug use, healthcare exposure (i.e. blood transfusions and surgical care), and body modification (i.e. tattooing and piercings) are well accepted risk factors for HCV transmission, others remain controversial. Because dental practice is often associated with procedures and bleeding, the possibility of HCV transmission seemed reasonable to investigate. Here, we review the evidence for dental care as a potential risk factor for HCV transmission. We identified a total of 1,180 manuscripts related to HCV and dental care, of which 26 manuscripts were included in the study after exclusionary criteria were applied. As per our review of the available literature, in the developing world, the improper use of sterile technique and lack of provider education likely increases the risk of HCV transmission during dental care. In developed nations, on the other hand, general dental care does not appear to be a significant risk factor for HCV transmission in non-intravenous drug user patients; although, the improper use and reuse of anesthetics during procedures poses a rare potential risk for viral transmission.

International audience; In patients with chronic hepatitis B (CHB), loss of hepatitis B surface antigen (HBsAg) is considered a functional cure. However, HBsAg loss is uncommon with existing therapies, and predictive factors associated with HBsAg seroreversion are unknown. Using pooled data from three phase 3 clinical trials of patients with CHB treated with nucleos(t)ide analogue (NUC) monotherapy or peginterferon (Peg-IFN) ± NUC combination therapy, we conducted a retrospective analysis to characterize patients who achieved sustained HBsAg loss, the predictors of HBsAg seroreversion, and the impact of hepatitis B surface antibody (anti-HBs) seroconversion on durability of HBsAg loss. In these three international trials, 1,381 adults with CHB received either NUC monotherapy for up to 10 years or Peg-IFN-containing regimens for up to 1 year. A total of 55 patients had confirmed HBsAg loss, defined as two or more consecutive negative-qualitative HBsAg results, with a minimum of one repeat result after the end of treatment. Throughout a median of 96 (quartile [Q]1, Q3, 46, 135) weeks follow-up after HBsAg loss, HBsAg loss was durable in 82% (n = 45) of patients, with 10 patients experiencing HBsAg seroreversion. Anti-HBs seroconversion was observed during follow-up in 78% of patients who lost HBsAg and in 60% of those who subsequently seroreverted. In analyzing predictors of HBsAg seroreversion, study treatment was significant, yet anti-HBs seroconversion and treatment duration after initial HBsAg loss were not. Risk of HBsAg seroreversion was observed to be lower if HBsAg loss was sustained through the off-treatment week 24 visit (8/10 seroreversions occurred by posttreatment week 24). Conclusion: HBsAg loss after NUC or Peg-IFN-containing regimens was durable in 82% of patients with CHB. Anti-HBs seroconversion and treatment duration after initial HBsAg loss were not significantly associated with durability of HBsAg loss.

Hepatitis C virus (HCV) has been shown to affect many tissues other than liver. However, of the many extrahepatic manifestations (EMs) that have been associated with HCV, including cryoglobulinemia, lymphoma, insulin resistance, type 2 diabetes and neurological disorders, only a few have been shown to be directly related to HCV infection of extrahepatic tissues. HCV-triggered immune- mediated mechanisms account for most of the EMs. It is estimated that up to 74% of patients with chronic hepatitis C can develop at least one EM. All HCV patients with EMs should be considered for antiviral therapy, although not all will resolve with sustained virological response.

Background and Aims: As the major energy source for mammalian cells, mitochondria have been the subject of numerous studies. However, the isolation and purification of healthy mitochondria, especially from fresh tissue, remains challenging. The most popular methods and kits involve various centrifugation steps which require substantial time and equipment but do not consistently provide pure preparations of functional mitochondria. The aim of this study was to determine whether methods could be devised to improve the purity and yield of functional mitochondria from fresh tissue. Methods: Fresh mouse liver was homogenized, and cells lysed. Particle size analysis, quantitation of mitochondrial DNA, mitochondrial oxygen consumption, and purity of mitochondria (by electron microscopy) were measured in samples after various purification steps and significant differences determined. Results: A two-step procedure consisting of centrifugation followed by filtration through 1.2μ and 0.8μ filters resulted in uniform mitochondrial preparations with diameters between 520–540 nm, and approximately 5-times more pure samples. The mitochondria thus obtained had oxygen consumption and sensitivities to mitochondrial inhibitors that were indistinguishable from those purified by centrifugation alone. Electron microscopy confirmed the presence of more uniform and 4–5 times greater concentrations of mitochondria compared to centrifugation alone. Conclusions: A two-step procedure consisting of sequential centrifugation followed by filtration is a rapid method for the production of highly purified, uniform and functional mitochondria.

Hepatocellular carcinoma (HCC), one of the most common malignant tumors worldwide, is known for its grim prognosis, with untreated life expectancy being only a matter of months after the diagnosis. The difficulty in making a diagnosis early is one of the main contributing factors to the poor prognosis. Alpha-fetoprotein (AFP) had long been used as a surveillance tool, but suboptimal specificity and sensitivity has prompted liver societies to abandon the recommendation for its universal use, even in combination with ultrasonography. Most studies have shown no obvious correlation between serum AFP level and HCC tumor size, stage, or survival post-diagnosis. However, some studies concluded that a gradual rise or persistent elevation in AFP were positive predictors for tumor development. Other studies reported a fall in AFP followed by a rise in patients with HCC as well as persistently rising AFP levels without development of HCC on follow up. Our calculation of the sensitivity and specificity of persistently rising AFP for HCC were both low, at 60% and 35.8%, respectively, indicating that the presence of persistently rising AFP per se did not offer diagnostic benefit. In addition, our calculated mean slopes of persistently rising AFP levels in HCC and non-HCC patients were numerically very different, but the difference was not statistically significant. We conclude that the published data do not support a role for rising AFP levels per se in the diagnosis of HCC.

Sphincter of Oddi dysfunction (SOD) encompasses a spectrum of clinical syndromes that are not fully understood, and various diagnostic and therapeutic methods have had varying results depending on the type of dysfunction. This review explored various mechanisms that might play a role in SOD and methods of diagnosis and management. It is important to rule out other causes of abdominal pain with laboratory testing, imaging studies, and endoscopic procedures. Medications that affect sphincter motility should be identified as well. Manometry is the gold standard for diagnosis but it is not always required. For example, patients with type I SOD may have symptomatic improvement with sphincterotomy without need for a diagnostic manometry. Hepatobiliary scintigraphy and fatty meal sonography may also have diagnostic utility. Sphincterotomy is not always effective for symptomatic improvement in type II and III SOD. Alternate therapies with calcium channel blockers and botulinum toxin have been studied and might be considered as options after discussing the risks and benefits with the patients.

Defects in mitochondria are responsible for various genetic and acquired diseases. Mitochondrial transplantation, a method that involves introduction of healthy donor mitochondria into cells with dysfunctional mitochondria, could offer a novel approach to treat such diseases. Some studies have demonstrated the therapeutic benefit of mitochondrial transplantation and targeted delivery in vivo and in vitro within hepatocytes and the liver. This review discusses the issues regarding isolation and delivery of mitochondria to hepatocytes and the liver, and examines the existing literature in order to elucidate the utility and practicality of mitochondrial transplantation in the treatment of liver disease. Studies reviewed demonstrate that mitochondrial uptake could specifically target hepatocytes, address the challenge of non-specific localization of donor mitochondria, and provide evidence of changes in liver function following injection of mitochondria into mouse and rat disease models. While potential benefits and advantages of mitochondrial transplantation are evident, more research is needed to determine the practicality of mitochondrial transplantation for the treatment of genetic and acquired liver diseases.

This chapter covers the following conditions: gut malabsorption, enzyme deficiencies, lactase deficiency, lactase, vitamin B12, vitamin B12 deficiency, pernicious anemia, and small intestinal bacterial overgrowth. This chapter includes drug class, brand/trade names, manufacturer, dosage, indications, contraindications/cautions, adverse effects, drug interactions, pregnancy advice, lactation safety, relative cost of rifaxamin, amoxicillin-clavulanate, neomycin, tetracycline, doxycycline, trimethoprim-sulfamethoxazole, ciprofloxacin, norfloxacin, metronidazole, probiotics, prebiotics, synbiotics, short bowel syndrome, proton pump inhibitors, octreotide, histamine-2 receptor antagonists, clonidine, tincture of opium, teduglutide, cholestyramine, somatropin, and exenatide. This chapter includes convenient algorithms for the treatment of small bowel bacterial overgrowth and short bowel syndrome.

This chapter covers the following conditions: acute pancreatitis and chronic pancreatitis. This chapter includes drug class, brand/trade names, manufacturer, dosage, indications, contraindications/cautions, adverse effects, drug Interactions, pregnancy advice, lactation safety, relative cost of tramadol, hydromorphone, gabapentin, amitriptyline, duloxetine, octreotide, celiac/splanchnic nerve block.

Background In a recent Phase 3 study (Study 4018) in HBV patients suppressed on TDF treatment, switching to TAF demonstrated non-inferior efficacy to continued TDF with superior bone and renal safety at Week 48. This study is to assess the safety and efficacy of switching to TAF from TDF in patients of Asian descent with risk factors for TDF toxicity as per current EASL and AASLD guidelines. Methods Virally suppressed patients (HBV DNA Results Among the 400 Asian patients enrolled, 288 (72%) had at least 1 TDF RF. At Week 48, similar proportions with ≥1 RF had HBV-DNA Conclusions Virally suppressed Asian patients with CHB and risk factors for TDF who switched to TAF showed improved bone and renal safety while efficacy was well-maintained.

Background TAF demonstrated noninferior efficacy to TDF with a superior bone and renal safety profile, in viremic chronic HBV (CHB) patients through week 96, and in virally suppressed patients switched from TDF to TAF at 48 weeks. The duration of prior TDF therapy may influence the degree and rate of recovery of bone and renal function following switch to TAF. Here, we evaluate the impact of prior TDF treatment duration on the safety profile of TAF in virally suppressed patients. Methods In a double-blind, randomized, multicenter, active-controlled, Phase 3 study, 488 CHB patients who were virologically suppressed on TDF for 1 year, and on TDF monotherapy for 6 months were randomized 1:1 to switch to TAF or continue TDF for 48 weeks. In patients originally randomized to receive TAF, renal, bone, and lipid parameters were categorically evaluated by the duration of prior TDF treatment: Results Of the 243 patients switched to TAF from TDF, 105 (43%) and 138 (57%) had received TDF for 50 years, 74% male, 80% Asian, median eGFRCG91 mL/min, 4% and 12% had osteoporosis at hip and spine, respectively. Similar changes in renal, bone, and lipid parameters following 48 weeks of TAF treatment were observed by TDF treatment duration. A comparable increase in median eGFRCG, decreases in tubular biomarkers (beta-2 microglobulin/creatinine ratio, retinol binding protein/creatinine ratio), increases in mean percent change in hip and spine BMD, and decreases in bone turnover markers (C-type collagen sequence, procollagen type 1 N-terminal propeptide) were observed among patients previously treated with Conclusions In virally suppressed patients on TDF a median of 4 years who switched to TAF treatment, improvements in bone and renal parameters and changes in fasting lipids were not impacted by prior duration of TDF use.

Metabolic dysfunction-associated fatty liver disease (commonly known as MAFLD) impacts global health in epidemic proportions, and the resulting morbidity, mortality and economic burden is enormous. While much attention has been given to metabolic syndrome and obesity as offending factors, a growing incidence of polypharmacy, especially in the elderly, has greatly increased the risk of drug-induced liver injury (DILI) in general, and drug-induced fatty liver disease (DIFLD) in particular. This review focuses on the contribution of DIFLD to DILI in terms of epidemiology, pathophysiology, the most common drugs associated with DIFLD, and treatment strategies.

Aminotransferases are commonly found to be elevated in patients with celiac disease in association with two different types of liver dysfunction: cryptogenic liver disorders and autoimmune disorders. The purpose of this review is to discuss the mechanisms by which aminotransferases become elevated in celiac disease, clinical manifestations, and response to gluten-free diet. Many studies have shown that celiac patients with cryptogenic liver disease have normalization in aminotransferases, intestinal histologic improvement and serologic resolution after 6-12 months of strict gluten-free diet. In patients with an underlying autoimmune liver disease, simultaneous treatment for both conditions resulted in normalized elevated aminotransferases. The literature suggests that intestinal permeability may be at least one of the mechanisms by which liver damage occurs. Patients with celiac disease should have liver enzymes routinely checked and treated with a strict gluten-free diet if found to be abnormal. Lack of improvement in patients who have strictly adhered to gluten-free diet should prompt further workup for other causes of liver disease.

Human cytomegalovirus (HCMV) infection is common and affects between 40-100% of the worldwide population. However, the majority of cases are asymptomatic and when severe disease occurs, it is usually restricted to immunocompromised patients. Liver involvement by HCMV differs significantly, accordingly to the immune status of the host. In immunocompromised patients, particularly liver transplant patients, it often causes clinically significant hepatitis. On the other hand, in immunocompetent patients, HCMV hepatitis requiring hospitalization is extremely rare. This review aims to appraise studies regarding the pathophysiology of HCMV hepatitis, including mechanisms of latency and reactivation and its contribution to disease development, clinical presentation, diagnostic modalities and treatment, with a focus on comparing different aspects between immunocompromised and immunocompetent hosts.

Hepatitis E virus (HEV) is a global health problem, affecting about 20 million people worldwide. There is significant overlap of hepatitis B virus (HBV) and HEV endemicity in many Asian countries where dual infections with HEV and HBV can occur. Though the clinical course of HEV is largely self-limited, HEV superinfection in patients with chronic hepatitis B (CHB) can result in acute exacerbation of underlying CHB. HEV superinfection in patients with CHB-related cirrhosis has been identified as a risk factor for decompensated cirrhosis and an independent predictor of mortality. Whereas acute HEV infection in pregnancy can cause fulminant liver failure, the few studies on pregnant patients with dual HBV and HEV infection have shown a subclinical course. Immunosuppression is a risk factor for the development of chronic HEV infection, which can be managed by decreasing the dose of immune-suppressants and administering ribavirin. Vaccination for HEV has been developed and is in use in China but its efficacy in patients with CHB has yet to be established in the USA. In this review, we appraise studies on dual infection with HEV and HBV, including the effect of HEV superinfection and coinfection in CHB, management strategies used and the role of active vaccination in the prevention of HEV.