Childhood hepatitis E infection complicated by acute immune thrombocytopenia

Viral Biology and Immune Privilege in the Development of Extrahepatic Manifestations During Hepatitis E Virus Infection

Hepatitis E virus (HEV) exhibits tropism toward hepatocytes and thus affects the liver; however, HEV may also affect other tissues, including the heart, kidneys, intestines, testicles, and central nervous system. To date, the pathophysiological links between HEV infection and extrahepatic manifestations have not yet been established. Considering that HEV infects multiple types of cells, the direct effects of virus replication in peripheral tissues represent a plausible explanation for extrahepatic manifestations. In addition, since the immune response is crucial in the development of the disease, the immune characteristics of affected tissues should be revisited to identify commonalities explaining the effects of the virus. This review summarizes the most recent advances in understanding the virus biology and immune-privileged status of specific tissues as major elements for HEV replication in diverse organs. These discoveries may open avenues to explain the multiple extrahepatic manifestations associated with HEV infection and ultimately to design effective strategies for infection control.

Clinical Manifestations of Hepatitis E

The clinical manifestations of hepatitis E are similar to those of other types of viral hepatitis. While acute hepatitis E is usually self-limited, pregnant women and chronic liver disease patients suffering from acute hepatitis E usually present with severe clinical manifestations that may develop into fulminant hepatic failure. Chronic HEV infection is typically seen in organ transplant patients; most HEV cases are asymptomatic and rarely display jaundice, fatigue, abdominal pain, fever, fatigue, or ascites. The clinical manifestations of HEV infection in neonates are diverse and have varied clinical signs, biochemistry, and virus-biomarkers. Lastly, the extrahepatic manifestations and complications of hepatitis E are in need of further study.

Extrahepatic manifestations related to hepatitis E virus infection and their triggering mechanisms

Hepatitis E virus (HEV) infection has many extrahepatic manifestations as well as liver symptoms. Multiple studies have shown that HEV infection has symptoms related to the nervous system, kidneys, cryoglobulinemia, hematological system, reproductive system, autoimmunity and pancreas. Hence, HEV infection should be considered as a systemic disease, rather than solely a liver disease. The extrahepatic manifestations induced by different genotypes of HEV vary. The severity of these diseases does not necessarily correlate with the severity of HEV infection, and even asymptomatic HEV infection may trigger and cause systemic diseases. Patients with systemic manifestations of HEV infection should have priority for antiviral therapy, which could alleviate or improve the extrahepatic manifestations related to HEV infection. However, the extrahepatic manifestations caused by different genotypes of HEV and their corresponding mechanisms have not been clearly identified. This review discusses the extrahepatic manifestations related to HEV infection and their triggering mechanisms.

Hepatitis E: an underestimated emerging threat

Hepatitis E virus (HEV) is the most common cause of viral hepatitis in the world. It is estimated that millions of people are infected every year, resulting in tens of thousands of deaths. However, these estimates do not include industrialized regions and are based on studies which employ assays now known to have inferior sensitivity. As such, this is likely to represent a massive underestimate of the true global burden of disease. In the developing world, HEV causes large outbreaks and presents a significant public-health problem. Until recently HEV was thought to be uncommon in industrialized countries, and of little relevance to clinicians in these settings. We now know that this is incorrect, and that HEV is actually very common in developed regions. HEV has proved difficult to study in vitro, with reliable models only recently becoming available. Our understanding of the lifecycle of HEV is therefore incomplete. Routes of transmission vary by genotype and location: endemic regions experience large waterborne epidemics, while sporadic cases in industrialized regions are zoonotic infections likely spread via the food chain. Both acute and chronic infection has been observed, and a wide range of extrahepatic manifestations have been reported. This includes neurological, haematological and renal conditions. As the complete clinical phenotype of HEV infection is yet to be characterized, a large proportion of cases go unrecognized or misdiagnosed. In many cases HEV infection does not feature in the differential diagnosis due to a lack of knowledge and awareness of the disease amongst clinicians. In combination, these factors have contributed to an underestimation of the threat posed by HEV. Improvements are required in terms of recognition and diagnosis of HEV infection if we are to understand the natural history of the disease, improve management and reduce the burden of disease around the world.

EASL Clinical Practice Guidelines on hepatitis E virus infection

Infection with hepatitis E virus (HEV) is a significant cause of morbidity and mortality, representing an important global health problem. Our understanding of HEV has changed completely over the past decade. Previously, HEV was thought to be limited to certain developing countries. We now know that HEV is endemic in most high-income countries and is largely a zoonotic infection. Given the paradigm shift in our understanding of zoonotic HEV and that locally acquired HEV is now the commonest cause of acute viral hepatitis in many European countries, the focus of these Clinical Practice Guidelines will be on HEV genotype 3 (and 4).

Clinical Manifestations of Hepatitis E

The clinical manifestations of hepatitis E are similar to those of other types of viral hepatitis. While acute hepatitis E is usually self-limited, pregnant women and chronic liver disease patients suffering from acute hepatitis E usually present with severe clinical manifestations that may develop into fulminant hepatic failure. Chronic HEV infection is typically only seen in organ transplant patients; most HEV cases are asymptomatic and rarely display jaundice, fatigue, abdominal pain, fever, fatigue, or ascites. The clinical manifestations of HEV infection in neonates are diverse and have varied clinical signs, biochemistry, and virus biomarkers. Lastly, the extrahepatic manifestations and complications of hepatitis E are in need of further study.

Hepatitis E virus: Infection beyond the liver?

Hepatitis E virus (HEV) infections are not limited to the liver but may also affect other organs. Several diseases, including Guillain-Barré syndrome, neuralgic amyotrophy, glomerulonephritis, cryoglobulinemia, pancreatitis, lymphoma, thrombopenia, meningitis, thyroiditis and myocarditis have been observed in the context of hepatitis E. To date, the definite pathophysiological links between HEV and extrahepatic manifestations are not yet established. However, it is suggested that HEV infection might be causative based on serological studies, case series, in vitro data and animal models. In particular, neuronal and renal diseases as well as pancreatitis seem to be caused by HEV, while a causative relationship between HEV and other diseases is more doubtful. Either direct cytopathic tissue damage by extrahepatic replication, or immunological processes induced by an overwhelming host immune response, are possible origins of HEV-associated extrahepatic manifestations. Hepatologists should be aware of the possibility that acute or chronically HEV-infected patients could develop extrahepatic manifestations. Neurologists, nephrologists, rheumatologists and other groups of physicians should consider HEV infection as a potential differential diagnosis when observing one of the diseases described in this review. Ribavirin and steroids have been used in small groups of patients with extrahepatic manifestations of HEV, but the efficacy of these drugs still needs to be verified by large, multicenter studies. This article comprehensively reviews the published literature regarding HEV and extrahepatic manifestations. We discuss the probability of specific extrahepatic diseases being caused by previous or ongoing HEV infection, and summarize the published knowledge about antiviral treatment in extrahepatic disorders.

Hepatitis E virus: A potential threat for patients with liver disease and liver transplantation

Immunocompromised patients are at risk of acquiring acute hepatitis E virus infection (HEV), leading to chronicity. Chronic HEV infection is associated with persistent viraemia, raised transaminase activity, histological features associated with chronic hepatitis and evidence of rapid development of cirrhosis. Extrahepatic manifestations have been associated with HEV. Most frequently reported are neurological disorders with predominantly involvement of the peripheral nervous system. In patients using immunosuppressive drugs antibody production is often delayed and HEV RNA detection is superior to serology to detect infection. Therapeutic options for chronic HEV includes tapering immunosuppressive and secondly ribavirin, pegylated interferon alpha (PEG-IFN). Present recommendation is to treat chronic HEV patients for 3 months, asses serum HEV RNA and stool HEV RNA and stop therapy if both are undetectable. Studies are required to determine which other antiviral agents than ribavirin and (PEG-)IFN are of clinical utility in treating HEV in the minority of patients who do not respond to ribavirin.

Extrahepatic manifestations of hepatitis E virus

Hepatitis E virus can cause acute, fulminant and chronic hepatitis and has been associated with a range of extrahepatic manifestations. Guillain-Barré syndrome, neuralgic amyotrophy and encephalitis are the main neurological manifestations associated with acute and chronic hepatitis E virus infection. Renal injuries have been also reported, including membranoproliferative glomerulonephritis with or without cryoglobulinemia and membranous glomerulonephritis. Acute pancreatitis, haematological disorders and other autoimmune extrahepatic manifestations of hepatitis E virus, such as myocarditis and thyroiditis, have been also reported. In this comprehensive article, we review all published reports describing hepatitis E virus-associated extrahepatic manifestations.

Extra-hepatic manifestations associated with hepatitis E virus infection: a comprehensive review of the literature

Background and aims: Hepatitis E virus (HEV) infection is a significant public health problem that afflicts almost 20 million individuals annually and causes acute liver injury in 3.5 million, with approximately 56 000 deaths. As with other viral hepatitides, extra-hepatic manifestations could represent an important aspect of this infection. The spectrum of these manifestations is still emerging. Acute pancreatitis and neurological, musculoskeletal, hematological, renal, and other immune-mediated manifestations have been described. The aim of this article is to comprehensively review the published literature of extra-hepatic manifestations associated with HEV infection.

Data sources: We searched the PubMed database using the MeSH term “hepatitis E” and each of the extra-hepatic manifestations associated with HEV infection. No language or date restrictions were set in these searches. Searches retrieving articles with non-A, non-B hepatitis were excluded. Additional articles were identified through the reference lists of included articles.

Results: Several extra-hepatic manifestations associated with HEV infection have been published. The temporal association between some extra-hepatic manifestations and HEV infection and the exclusion of other possible etiologies suggests that HEV infection could have caused some of them. According to the available data, HEV infection appears to be strongly associated with acute pancreatitis, neurological disorders (with primarily dominant peripheral nerve involvement, most commonly manifested as Guillain-Barré syndrome, followed by neuralgic amyotrophy), hematological diseases (hemolytic anemia due to glucose phosphate dehydrogenase deficiency, and severe thrombocytopenia), glomerulonephritis, and mixed cryoglobulinemia. More data are needed to clarify whether an association exists with musculoskeletal or other immune-mediated manifestations.

Conclusions: HEV infection should be considered in patients with acute pancreatitis, Guillain-Barré syndrome, neuralgic amyotrophy, hemolytic anemia due to glucose phosphate dehydrogenase deficiency, severe thrombocytopenia, glomerulonephritis, and mixed cryoglobulinemia. Alternatively, signs and symptoms of these conditions should be sought in patients with acute or chronic HEV infection. More data are needed to confirm the role of HEV in other extra-hepatic disorders.

Hepatitis E in three immunocompromized children in southeastern France

Hepatitis E virus (HEV) causes an emerging autochthonous disease in developed countries where links with a viral porcine reservoir have been evidenced. Moreover, chronic HEV infection and associated-cirrhosis have been described in severely immunocompromized patients. Nonetheless, only few studies have focused on pediatric HEV infections worldwide and only four autochthonous cases have been reported in children in developed countries. We describe here acute hepatitis E in three immunocompromized children. Case no. 1 was a 9-year-old liver transplant recipient girl in whom H1N1 2009 flu infection was diagnosed concurrently with hepatitis E. Case no. 2 was a 12-year-old boy presenting early medullar relapse of lymphoblastic leukemia of type B and in whom HEV RNA was detected over a 29-week period. Case no. 3 was a 9-year-old boy with a rare primary immunodeficiency due to XIAP deficiency. HEV infections were all autochthonously acquired and involved different viruses classified as subtype f, c, and e of genotype 3, which are those described in autochthonous cases in Europe. These three observations prompt to consider HEV as a causative agent of hepatitis in children in developed countries, and to perform particularly HEV testing in those severely immunocompromized who may develop chronic hepatitis E.

Clinical presentation of hepatitis E

Hepatitis E is a form of acute hepatitis, which is caused by infection with hepatitis E virus. The infection is transmitted primarily through fecal-oral route and the disease is highly endemic in several developing countries with opportunities for contamination of drinking water. In these areas with high endemicity, it occurs as outbreaks and as sporadic cases of acute hepatitis. The illness often resembles that associated with other hepatotropic viruses and is usually self-limiting; in some cases, the disease progresses to acute liver failure. The infection is particularly severe in pregnant women. Patients with chronic liver disease and superimposed HEV infection can present with severe liver injury, the so-called acute-on-chronic liver failure. In recent years, occasional sporadic cases with locally acquired hepatitis E have been reported from several developed countries in Europe, United States, and Asia. In these areas, in addition to acute hepatitis similar to that seen in highly endemic areas, chronic hepatitis E has been reported among immunosuppressed persons, in particular solid organ transplant recipients. HEV-infected mothers can transmit the infection to foetus, leading to premature birth, increased fetal loss and hypoglycaemia, hypothermia, and anicteric or icteric acute hepatitis in the newborns. Occasional cases with atypical non-hepatic manifestations, such as acute pancreatitis, hematological abnormalities, autoimmune phenomena, and neurological syndromes have been reported from both hyperendemic and non-endemic regions. The pathogenesis of these manifestations remains unclear.

Exacerbation of chronic idiopathic thrombocytopenic purpura following reactivation of an occult hepatitis B

Immune thrombocytopenia is a disease mediated by platelet autoantibodies that accelerate platelet destruction and inhibit their production. Most cases are considered idiopathic, whereas others are secondary to coexisting conditions such as infectious diseases. All hepatotropic viruses seem able to cause thrombocytopenia. The advent of molecular techniques has revealed the possible persistence of hepatitis B virus genome in HBsAg-negative individuals with or without serologic markers of previous infection. This form of infection is named occult. We report a case of autoimmune thrombocytopenia associated with acute reverse seroconversion of hepatitis B in a patient who was initially hepatitis B virus surface antigen negative and hepatitis B virus surface antibody positive. The search for occult HBV infection before immunosuppressive therapy and monitoring for reactivation is today diagnostic standard and several reports have been presented in literature about HBV reactivation following immunosuppressive therapy. In our patient, reactivation of dormant HBV happened prior to any immunosuppressive therapy. The case we report offers the occasion to emphasize the importance of medium-term and long-term hemovigilance also in other kind of patients than in subjects on immunosuppressive therapy. A deeper follow-up is advisable even in patients showing an unexplainable worsening of their hematological conditions.