Hepatitis B

Introduction

• HBV is a leading cause of chronic hepatitis, cirrhosis, and hepatocellular carcinoma.
• Transmission of HBV occurs sexually, parenterally, and perinatally. In the United States, transmission occurs predominantly through sexual contact or injection-drug use. International travel is also an important risk factor.
• Approximately 20% of patients with chronic HBV infection develop complications of decompensated cirrhosis, including hepatic insufficiency and portal hypertension as their compensated cirrhosis progresses to decompensated cirrhosis within a 5-year period. HBV is a risk factor for development of hepatocellular carcinoma.
• There are three phases of HBV infection. The incubation period for HBV is 4 to 10 weeks during which patients are highly infective. This is followed by a symptomatic phase with intermittent flares of hepatitis and marked increases in aminotransferase serum levels. The final phase is seroconversion to anti–hepatitis B core antigen (anti-HbcAg). Patients who continue to have detectable hepatitis B surface antigen (HbsAg) and HBcAg and a high serum titer of HBV DNA for longer than 6 months have chronic HBV.

Clinical Presentation of Acute Hepatitis B

Signs and symptoms

• Easy fatigability, anxiety, anorexia, and malaise
• Ascites, jaundice, variceal bleeding, and hepatic encephalopathy can manifest with liver decompensation
• Hepatic encephalopathy is associated with hyperexcitability, impaired mentation, confusion, obtundation, and eventually coma
• Vomiting and seizures

Physical examination

• Icteric sclera, skin, and secretions
• Decreased bowel sounds, increased abdominal girth, and detectable fluid wave
• Asterixis
• Spider angiomata

Laboratory tests

• Presence of hepatitis B surface antigen for >6 months
• Intermittent elevations of hepatic transaminase (alanine transaminase [ALT] and aspartate transaminase [AST]) and hepatitis B virus DNA >20,000 IU/mL (105 copies/mL or 108 copies/L)
• Liver biopsies for pathologic classification aschronic persistent hepatitis, chronic active hepatitis, or cirrhosis.

PREVENTION

• Prophylaxis of HBV can be achieved by vaccination or by passive immunity in post exposure cases with HBV Ig.
• Two products are available for prevention of HBV infection: HBV vaccine, which provides active immunity, and HBV Ig, which provides temporary passive immunity.
• The goal of immunization against viral hepatitis is prevention of the short-term viremia that can lead to transmission of infection, clinical disease, and chronic HBV infection.
• Side effects of the vaccines include soreness at the injection site, headache, fatigue, irritability, and fever.

TREATMENT

• Goals of therapy: The goals are to increase the likelihood of seroclearance of the virus, prevent disease progression to cirrhosis or hepatocellular carcinoma, and minimize further liver injury. Successful therapy is associated with loss of HBcAg status and seroconversion to anti-HBcAg.
• Some patients with chronic HBV infection should be treated. Recommendations for treatment consider the patient’s age, serum HBV DNA and ALT levels, and histologic evidence and clinical progression of the disease. A suggested treatment algorithm for chronic HBV is shown for patients without and with cirrhosis
• All patients with chronic HBV infection should be counseled on preventing disease transmission, avoiding alcohol, and on being immunized against HBV.
• The immune-mediating agents approved as first-line therapy are interferon (IFN)-alfa and pegylated (peg) IFN-alfa. The antiviral agent’s lamivudine, telbivudine, adefovir, entecavir, and tenofovir are all approved as first-line therapy options for chronic HBV.
• For HBeAg-positive patients, treatment is recommended until HBeAg seroconversion and an undetectable HBV viral load are achieved and for 6 months of additional treatment. In HBeAg-negative patients, treatment should be continued until HBsAg clearance.

Recommendations for HBV Vaccination

Infants, Adolescents, including all previously unvaccinated children 1 partner/6 months), Men who have sex with men, Injection-drug users, Household contacts and sex partners of persons with chronic HBV infection and healthcare and public safety workers with exposure to blood in the workplace, Clients and staff of institutions for the developmentally disabled, International travelers to regions with high or intermediate levels (HBsAg prevalence ≥2%) of endemic, HBV infection Recipients of clotting factor concentrates, Sexually transmitted disease clinic patients, HIV patient/HIV-testing patients, Drug abuse treatment and prevention clinic patients, Correctional facilities inmates, Chronic dialysis/ESRD patients, Persons with chronic liver disease.