Hepatitis caused by herpes viruses: A review

Viral etiologies of acute liver failure

Acute liver failure (ALF) is a rare cause of liver-related mortality worldwide, with an estimated annual global incidence of more than one million cases. While drug-induced liver injury, including acetaminophen toxicity, is the leading cause of ALF in the Western world, viral infections remain a significant cause of ALF and the most common cause in many developing nations. Given the high mortality rates associated with ALF, healthcare providers should be aware of the broad range of viral infections that have been implicated to enable early diagnosis, rapid treatment initiation when possible, and optimal management, which may include liver transplantation. This review aims to provide a summary of viral causes of ALF, diagnostic approaches, treatment options, and expected outcomes.

Could Herpesviridae be the cause of severe acute hepatitis of unknown origin in children?

INTRODUCTION

Severe acute hepatitis (SAH) is defined by a severe inflammation of hepatocytes in the liver parenchyma which can lead to an acute liver failure, a clinical condition with high mortality rate that can be triggered by several factors but is usually associated to hepatotropic viruses' infection. In 2022, cases of children with severe acute hepatitis of unknown origin hospitalized in Glasgow, Scotland, were reported. Possible causes of this condition include, but are not limited to, undiagnosed viral (and non-viral) infections, autoimmune hepatitis, drug and/or chemical toxicity, mitochondrial chain respiratory and metabolic disorders.

AREAS COVERED

Herpesviruses can cause severe acute hepatitis, but little is known about the role and the mechanisms of herpesviruses as a causative agent of this type of hepatitis. We review the role of herpesviruses as causative agent of SAH in children and other possible mechanisms involved in this disease.

EXPERT OPINION

Differential diagnosis for herpesvirus in SAH should be implemented in all settings. Alternative fluids, such as saliva and dried blood, could be used in the diagnosis to overwhelm the availability of biological specimens at sufficient volume. In the future, genetic studies could also be added to increase the knowledge about severe acute hepatitis in children.

A Pattern-Based Approach to Hepatic Infections

The evaluation of liver biopsies for infection can be a challenging and frustrating situation for diagnostic pathologists as well as clinicians. Patients often present with nonspecific symptoms, such as fever and elevated transaminases, leading to a broad differential diagnosis that typically includes malignancy and noninfectious inflammatory diseases in addition to infections. A pattern-based histologic approach can be extremely helpful in both making a diagnosis and guiding the next steps for the evaluation of the pathology specimen as well as the patient. This review discusses several of the more commonly encountered histologic patterns associated with hepatic infectious diseases, the most common pathogens with which they are associated, and helpful ancillary studies.

Ashwagandha-induced acute liver injury: A case report

Drug-induced liver injury became one of the most important liver disorders and diagnostic challenge for clinicians and pathologists. Here, we report a rare case of ashwagandha-induced acute liver injury. The patient developed jaundice 2 weeks after starting ashwagandha intake and recovered within 5 months after withdrawal without any specific treatment.

Acute cytomegalovirus hepatitis in an immunocompetent patient: A case report

BACKGROUND

Cytomegalovirus (CMV) infection is usually subclinical and asymptomatic in the healthy population, whereas severe complications occur in immunocompromised patients.

CASE SUMMARY

In this case report, we described a rare case of acute CMV hepatitis in a 35-year-old male immunocompetent patient who presented with a history of week-long intermittent fever with nonspecific constitutional symptoms. Acute hepatitis was suspected according to the initial serological tests. After ruling out other etiologies, including viral hepatitis A, B, C, drug, alcohol, autoimmune, and Wilson disease, acute CMV hepatitis was diagnosed based on positive CMV IgM and DNA quantitative tests. Because there was no any local acute hepatitis E reported in Taiwan, so hepatitis E was not checked. The patient recovered both clinically and serologically with symptomatic management and without antiviral therapy within 12 days from the onset of symptom.

CONCLUSION

In conclusion, a diagnosis of CMV infection should be considered when nonspecific prodromal symptoms occur in acute hepatitis with an uncertain etiology. Antiviral therapy should not be used in immunocompetent patient who had no decompensation of the liver, such as this patient. Widely available noninvasive tests for CMV can facilitate early diagnosis if used appropriately. Harm–benefit analysis is essential before using antiviral therapy in immunocompetent patients.

An Unusual Cause of Acute Isolated Hepatitis in a Cancer Patient Post-COVID Pneumonia: HSV-2

Herpes simplex virus is a rare cause of hepatitis in immunosuppressed and immunocompetent individuals. It can cause clinical pictures in patients ranging from an asymptomatic course to fatal acute fulminant hepatitis. Early diagnosis and treatment may be delayed if it is not suspected because of the patients' nonspecific clinic. This study presents a case of isolated HSV-2 hepatitis in a patient with a history of cancer chemotherapy and a recent diagnosis of COVID-19 who received steroid therapy.

Newer developments in viral hepatitis: Looking beyond hepatotropic viruses

Viral hepatitis in the entirety of its clinical spectrum is vast and most discussion are often restricted to hepatotropic viral infections, including hepatitis virus (A to E). With the advent of more advanced diagnostic techniques, it has now become possible to diagnose patients with non-hepatotropic viral infection in patients with hepatitis. Majority of these viruses belong to the Herpes family, with characteristic feature of latency. With the increase in the rate of liver transplantation globally, especially for the indication of acute hepatitis, it becomes even more relevant to identify non hepatotropic viral infection as the primary hepatic insult. Immunosuppression post-transplant is an established cause of reactivation of a number of viral infections that could then indirectly cause hepatic injury. Antiviral agents may be utilized for treatment of most of these infections, although data supporting their role is derived primarily from case reports. There are no current guidelines to manage patients suspected to have viral hepatitis secondary to non-hepatotropic viral infection, a gap that needs to be addressed. In this review article, the authors analyze the common non hepatotropic viral infections contributing to viral hepatitis, with emphasis on recent advances on diagnosis, management and role of liver transplantation.

Ultrastructural and Immunohistochemical Diagnosis of a Neonatal Herpes Simplex Virus Infection Presenting as Fulminant Hepatitis: A Case Report

TORCH (Toxoplasmosis, Rubella, Cytomegalovirus, Herpes Simplex Virus and Syphilis) infections are a major cause of intrauterine and perinatal infections with associated morbidity and mortality. Neonatal Herpes Simplex Virus infection caused by an enveloped, double-stranded DNA virus of the Herpesviridae family is devastating and fatal. Herpes Viruses are not hepatotropic but may rarely cause hepatitis. Most cases of HSV hepatitis rapidly progress to fulminant hepatic failure and often fatal before the diagnosis or transplantation. Nowadays, despite the availability of antiviral treatment (acyclovir), the outcome remains poor because of late identification of hepatic Herpes Simplex Virus (HSV) infection. We report a male neonate suspected with a metabolic/mitochondrial disease and multi-organ involvement but who developed a fulminant hepatic failure and disseminated coagulopathy secondary to HSV type 1 (HSV-1) infection. The postmortem diagnosis was performed demonstrating HSV-1 in liver tissue by transmission electron microscopy and by retrospective detection of HSV specific antigens by immunohistochemistry.

The role of natural killer cells in liver inflammation

The liver is an important immunological site that can promote immune tolerance or activation. Natural killer (NK) cells are a major immune subset within the liver, and therefore understanding their role in liver homeostasis and inflammation is crucial. Due to their cytotoxic function, NK cells are important in the immune response against hepatotropic viral infections but are also involved in the inflammatory processes of autoimmune liver diseases and fatty liver disease. Whether NK cells primarily promote pro-inflammatory or tolerogenic responses is not known for many liver diseases. Understanding the involvement of NK cells in liver inflammation will be crucial in effective treatment and future immunotherapeutic targeting of NK cells in these disease settings. Here, we explore the role that NK cells play in inflammation of the liver in the context of viral infection, autoimmunity and fatty liver disease.

Jaundice as a Rare Manifestation of Epstein-Barr Virus Primary Infection

Epstein-Barr virus (EBV) primary infection usually presents with classic symptoms of infectious mononucleosis (IM) like fever, lymphadenopathies and tonsillopharyngitis. Liver damage is frequently mild and self-limited and there are only a few cases of severe EBV-induced cholestatic hepatitis and jaundice reported in the literature. The authors present the case of a 22-year-old woman who was admitted with acute fever and jaundice. Physical examination revealed posterior cervical lymphadenopathies and painful hepatosplenomegaly. Laboratorial findings suggested an obstructive cause for jaundice but ultrasound and magnetic resonance cholangiopancreatography excluded biliary duct pathology. Heterophile antibodies were negative but EBV-specific antibodies revealed isolated positive viral capsid antigen (VCA) immunoglobin (Ig) M suggesting the diagnosis of early phase of EBV primary infection. The diagnosis of EBV-induced cholestatic hepatitis was confirmed after identification of EBV deoxyribonucleic acid (DNA) in blood and by liver biopsy. Supportive management was provided and, despite an initial clinical deterioration, the patient had a favorable outcome. EBV is a virus with a high prevalence worldwide, mainly subclinical, and jaundice is a rare manifestation of the infection. Although the majority of the patients recover without sequelae, progression to liver failure has been described and a careful assessment for complications is mandatory. Therefore, EBV infection should be included in the comprehensive differential diagnosis of jaundice in all age groups.

Atypical case of syphilitic hepatitis

A 31-year-old immunocompetent, heterosexual man with no relevant medical history presented with 1 week of jaundice, abdominal pain, cough and headache. Examination revealed scleral icterus, right upper quadrant tenderness and hepatomegaly. Initial investigations revealed hyperbilirubinaemia and elevated transaminases. Serum studies were positive for antinuclear antibodies, antimitochondrial antibodies, and herpes simplex virus IgM. Despite being started on intravenous acyclovir, his bilirubin and transaminase levels continued to rise. He was subsequently tested for syphilis given his maculopapular rash on the soles of his feet and it returned positive. He improved clinically with the initiation of penicillin. In this case, we will discuss the presentation, diagnosis and treatment of syphilitic hepatitis.

Human hepatitis viruses-associated cutaneous and systemic vasculitis

Human hepatitis viruses (HHVs) include hepatitis A virus, hepatitis B virus (HBV), hepatitis C virus (HCV), hepatitis delta virus, and hepatitis E virus and can cause liver inflammation in their common human host. Usually, HHV is rapidly cleared by the immune system, following acute HHV invasion. The morbidities associated with hepatitis A virus and hepatitis E virus infection occur shortly after their intrusion, in the acute stage. Nevertheless, the viral infectious process can persist for a long period of time, especially in HBV and HCV infection, leading to chronic hepatitis and further progressing to hepatic cirrhosis and liver cancer. HHV infection brings about complications in other organs, and both acute and chronic hepatitis have been associated with clinical presentations outside the liver. Vascular involvement with cutaneous and systemic vasculitis is a well-known extrahepatic presentation; moreover, there is growing evidence for a possible causal relationship between viral pathogens and vasculitis. Except for hepatitis delta virus, other HHVs have participated in the etiopathogenesis of cutaneous and systemic vasculitis via different mechanisms, including direct viral invasion of vascular endothelial cells, immune complex-mediated vessel wall damage, and autoimmune responses with stimulation of autoreactive B-cells and impaired regulatory T-cells. Cryoglobulinemic vasculitis and polyarteritis nodosa are recognized for their association with chronic HHV infection. Although therapeutic guidelines for HHV-associated vasculitis have not yet been established, antiviral therapy should be initiated in HBV and HCV-related systemic vasculitis in addition to the use of corticosteroids. Plasma exchange and/or combined cyclophosphamide and corticosteroid therapy can be considered in patients with severe life-threatening vasculitis manifestations.

Epigallocatechin-3-Gallate Toxicity in Children: A Potential and Current Toxicological Event in the Differential Diagnosis With Virus-Triggered Fulminant Hepatic Failure

The use of nutraceuticals is considerably increasing worldwide with a demand for organic and clean foods in the last two decades, which is probably incomparable with other periods of our civilization. The consistent application of nutraceuticals and so-called "superfood" may have remarkable effects on the prevention of several chronic diseases, including cancer. Moreover, the increased rate of overweight and obesity in Western countries does not spare childhood and youth, and the number of parents using natural remedies for preventing pediatric illness is vastly increasing worldwide. However, the overwhelming effects on diseases often overshadow the side effects of such nutrition, particularly in societies without millennial experience with botanicals and natural elements. Thus, the final result may be disastrous for some individuals. The liver is the most important and conspicuous target organ of numerous molecular compounds, and the cell damage is particularly striking on the infantile and pediatric liver due to the immaturity of the hepatocytes. Here, we target some generic data on fulminant hepatic failure, the benefits, and toxicity of epigallocatechin-3-gallate, which is one of the major components of green tea, and the histopathology of the "green-tea"-associated liver disease.

Characterization of polyclonal antibodies to Herpes Simplex Virus types 1 and 2

Infections with herpes simplex virus (HSV) types 1 and 2 have been linked to oral, facial, genital lesions, as well as some visceral organ changes in patients under immunosuppressed conditions. Immunohistochemistry (IHC) with HSV antibodies is used for identification of the viruses in tissue samples. In this study, two polyclonal antibodies, prepared separately with HSV-1 and HSV-2 immunogens, were characterized in comparison to a monoclonal antibody to HSV-1 (10A3). The polyclonal anti-HSV-1 and monoclonal antibody 10A3 were shown to be reactive to viral proteins of both HSV-1 and HSV-2 on Western blots, while the polyclonal anti-HSV-2 was reactive to HSV-2 proteins, but not to those of HSV-1. Cross-reactivity was not observed to proteins of six other frequently encountered herpes viruses. IHC characterization was performed on 29 cases of HSV-infected tissue samples, 61 samples infected with other herpes viruses and 35 samples without known infection. By IHC, the polyclonal anti-HSV-1 and a monoclonal antibody 10A3 exhibited a signal, mainly in a nuclear pattern, in all of the HSV-infected samples and not in other tissue types. A positive signal, mainly in the cytoplasm, was identified with the polyclonal anti-HSV-2 in 21 of the 29 HSV-infected samples. Genotyping analysis was successful in 14 of the HSV-infected samples, with IHC HSV-2 positivity correlative to the HSV-2 genotype. The results demonstrate that these antibodies are useful tools for identification of HSV-1 and HSV-2, and their combinatorial application may help to distinguish between these two types of infection.

Acute hepatitis and acute liver failure: Pathologic diagnosis and differential diagnosis

Acute hepatitis and acute liver failure are severe medical conditions that require early clinical intervention. Histopathologic findings on a liver biopsy or a liver explant may help identify the underlying etiology or provide an important direction for further clinical, laboratory and radiographical investigation. This review is divided into two main portions. The first portion concentrates on various etiologies and discusses unique histologic features that can be associated with specific etiologies. The second portion describes the general morphologic features based on which the diagnosis of acute hepatitis and acute liver failure are made. Histopathologic distinction between collapse and cirrhosis and limitations of histopathologic assessment for underlying etiologies are addressed in this portion. Another focus of this review is non-necrotic acute liver failure, which typically features diffuse microvesicular steatosis secondary to various etiologies causing mitochondrial dysfunction. Molecular testing serves an increasingly important role in the diagnosis and management of this group of disorders.