Antiviral therapy: role in the management of extrahepatic diseases

Management of chronic hepatitis B: Canadian Association for the Study of the Liver consensus guidelines

Chronic hepatitis B (CHB) is a dynamic disease that is influenced by host and virological factors. The management of CHB has become more complex with the increasing use of long-term oral nucleos⁄tide analogue antiviral therapies and the availability of novel diagnostic assays. Furthermore, there is often a lack of robust data to guide optimal management such as the selection of therapy, duration of treatment, potential antiviral side effects and the treatment of special populations. In November 2011, the Canadian Liver Foundation and the Canadian Association for the Study of the Liver convened a consensus conference to review the literature and analyze published data, including other international expert guidelines on CHB management. The proceedings of the consensus conference are summarized and provide updated clinical practice guidelines to assist Canadian health care providers in the prevention, diagnosis, assessment and treatment of CHB.

Neuromuscular disorders associated with hepatitis B virus infection

Approximately 400 million worldwide are chronically infected with the hepatitis B virus (HBV). During the course of illness, approximately 20% of patients develop disease manifestations outside the liver. Neuropathy develops in approximately 5% of patients with chronic HBV infection and rarely during acute HBV infection. The pathogenesis of the various HBV-associated neuropathy syndromes possibly involves deposition of immune complexes in nerves or blood vessel walls. Direct viral infection of nerves has not been demonstrated. Management entailed supportive care with antiviral and immunomodulatory treatment as clinically indicated. Rare cases of muscle disease, mostly inflammatory myopathy, have been associated with HBV infection. Presumably, HBV-associated antigens trigger immune mechanisms directed against components of muscle tissue. There is no evidence of replicative virus infection of muscle fibers. Management entailed immunomodulatory treatment, occasionally with anti-HBV therapy. Physicians should be aware that HBV infection has the potential to trigger presumed immune-mediated neuromuscular syndromes.

Treatment indication and response to standard of care with peginterferon and ribavirin in acute and chronic HCV infection

Great strides have been made in the treatment of hepatitis C virus (HCV) infection in the past decade. Although there is much focus on the development of new direct-acting antivirals (DAA), interferon and ribavirin remain the backbone of therapy for both acute and chronic HCV infections. While DAA therapy will likely eventually largely replace interferon, in much of the world and for genotype non-1 patients, peginterferon and ribavirin remain first-line therapy. Interferon-based therapy is highly effective in acute HCV with high response rates with short courses of therapy. Unfortunately once infection progresses to chronicity, treatment success rates drop off considerably. The indications, pre-treatment evaluation and efficacy of peginterferon and ribavirin therapy in the treatment of acute and chronic HCV infection are discussed with strategies to improve outcomes and manage adverse events.

[Natural history and clinical manifestations of chronic hepatitis B virus]

Hepatitis B virus (HBV) infection is a serious public health problem worldwide. In the last few decades, major advances have been achieved that have contributed to greater understanding of the natural history and clinical manifestations of this infection. The fluctuation between viral replication and the host's immune response has implications in the pathogenesis and progression of the hepatic lesion. In immunocompetent adults, most HBV infections resolve spontaneously in contrast with progression to chronic infection in most infants. Patients with chronic hepatitis due to HBV or chronic hepatitis B can present at four phases: 1) the immune tolerance phase, 2) HBeAg-positive chronic hepatitis B, 3) inactive HBsAg carrier state, and 4) HBeAg-negative chronic hepatitis. HBeAg-positive or -negative chronic hepatitis can progress to cirrhosis, liver failure and hepatocellular carcinoma. Progression to these complications is more frequent in HBeAg-negative forms, associated with mutations that affect the pre-core region and maintain active viral replication. Risk factors are HBV-DNA positive serum levels, an increase in serum transaminase levels and some genotypes. These factors highlight the need to evaluate and monitor all HBV carriers to identify those who could benefit from early antiviral treatment, thus avoiding progression to more advanced forms of liver disease. These measures could improve prevention and treatment of hepatitis B.