What is Hepatitis B?
Hepatitis B is a virus that infects the liver potentially resulting in acute and occasionally chronic liver disease. The virus is transmitted through sexual contact or the blood and may be spread from mother to child. Individuals with acute infection may have fever, abdominal discomfort, malaise, nausea, vomiting, and jaundice. Patients with chronic infection often develop cirrhosis and have features of chronic liver disease such as ascites, esophageal varices, upper gastrointestinal bleeding, and confusion (hepatic encephalopathy).
Chronic infection associated with cirrhosis has a poor prognosis. Patients are at increased risk for developing liver cancer (hepatocellular carcinoma) and have a high rate of mortality.
What Causes Hepatitis B?
Hepatitis B is a virus that infects the liver resulting in acute and potentially chronic injury and inflammation. This can lead to scarring of the liver (cirrhosis) and progressive liver failure. Rarely, patients develop liver failure during the acute infection. It is transmitted through the blood or sexual contact. Pregnant women may pass the infection to their child during pregnancy. Unprotected sex and injection drug use are common routes of infection.
How Common is Hepatitis B?
About 2 billion people in the world have had or currently have hepatitis B infection. Worldwide, approximately 250 million people carry the virus. The virus is responsible for about 600,000 deaths each year related to liver disease. Rates of infection related complications such as cancer and death have also doubled in the past 10 years. Healthy individuals have a less than 5% chance of progressing to chronic hepatitis B. These people also have a less than 1% chance of developing liver failure.
Signs and Symptoms
Symptoms and signs depend on the presence of acute or chronic infection. Acute hepatitis B is often asymptomatic but may produce the following features:
- Abdominal discomfort
- Nausea & vomiting
A small subset of patients may also progress to fulminant liver failure.
Chronic hepatitis B infection can be asymptomatic or result in symptoms and signs of liver cirrhosis. This can include:
- Esophageal varices – upper gastrointestinal bleeding
- Ascites – accumulation of fluid within the abdomen
- SBP – spontaneous bacterial peritonitis
- Confusion – hepatic encephalopathy
- Lower extremity edema
Patients frequently develop liver cancer (hepatocellular carcinoma) or die as a complication of chronic liver disease.
The diagnosis based on symptoms, history, and physical examination, but typically confirmed with laboratory studies. Your doctor will usually first check a CMP (comprehensive metabolic panel) to evaluate your liver function. Specific liver tests typically include AST, ALT, alkaline phosphatase, bilirubin, and coagulation studies (PT/INR, PTT).
If these laboratory values are abnormal and you have evidence of liver disease, your doctor will typically confirm the diagnosis of acute infection with serologies such as hepatitis B surface antigen (HBsAg) and IgM antibody to hepatitis B core antigen. The diagnosis of chronic HBV infection is based upon the persistence of HBsAg for more than six months. If you test positive, your doctor will also usually check a hepatitis B virus DNA level. Occasionally they will obtain an antigen (HBeAg), which is a marker of viral infectivity. Viral DNA levels and HBeAg are typically evaluated in individuals that are being considered for antiviral therapy. Individuals that are immune to hepatitis B after vaccination should only have a positive anti-HBs antibody.
If you have liver function abnormalities, your doctor will also normally obtain imaging of the liver with abdominal ultrasound or CT scan. Occasionally, your doctor will order an MRI of the abdomen. In atypical cases, your doctor may recommend a liver biopsy. Patients with advanced liver disease often receive routine upper endoscopies to screen for esophageal varices (dilated esophageal veins).
Hepatitis B Medication and Treatment
The prevention of the infection begins with immunization. High-risk groups are typically immunized such as:
- Healthcare workers
- Persons with underlying liver disease
- Immunocompromised patients (e.g., HIV/AIDS)
- Patients receiving immunosuppressive therapy
- Neonates of HBsAg positive mothers
- Persons born in endemic areas
- Persons with multiple sexual partners
- Persons with history of sexually transmitted infection
- Inmates of correctional facilities
- Persons with a history of injection drug use
- Dialysis patients
- Family members & sexual contacts of HBV-infected persons
The treatment depends on patient factors such as the severity of liver function abnormalities, the presence of liver cirrhosis, and viral DNA levels. The goals are to reduce viral DNA levels, decrease in viral infectivity (measured with HBeAg testing), and eliminate HBsAg.
Patients with acute hepatitis B and severe liver function abnormalities typically receive treatment with a nucleoside/nucleotide analogue such as:
- Vemlidy (tenofovir alafenamide)
- Baraclude (entecavir)
Antiviral agents for chronic hepatitis B include Pegasys (pegylated interferon) or nucleoside/nucleotide analogs such as Vemlidy (tenofovir alafenamide) or Baraclude (entecavir). Special treatment considerations are typically made for patients with liver cirrhosis, abnormal kidney function, or those who are pregnant.
- Lok AS, McMahon BJ. Chronic hepatitis B: update 2009. Hepatology 2009; 50:661. - https://www.ncbi.nlm.nih.gov/pubmed/19714720
- LeFevre ML, U.S. Preventive Services Task Force. Screening for hepatitis B virus infection in nonpregnant adolescents and adults: U.S. Preventive Services Task Force recommendation statement. Ann Intern Med 2014; 161:58. - https://www.ncbi.nlm.nih.gov/pubmed/24863637
- Terrault NA, Bzowej NH, Chang KM, et al. AASLD guidelines for treatment of chronic hepatitis B. Hepatology 2016; 63:261. - https://www.aasld.org/sites/default/files/2019-06/Terrault_et_al-2016-Hepatology.pdf
The above information is an educational aid only. It is not intended as medical advice for individual conditions or treatments. Talk to your doctor, nurse or pharmacist before following any medical regimen to see if it is safe and effective for you.