Hepatitis B is an infectious disease of the liver. It is transmitted by exposure to infectious blood or bloody fluids. Risk factors include intravenous drug use, blood transfusion and sexual exposure. Although most patients with acute hepatitis B will make a complete recovery from the infection, the disease can be chronic and progress to cirrhosis of the liver or liver cancer.
Symptoms of hepatitis B infection may occur weeks many weeks after exposure to the virus. This is known as the incubation period. Typically symptoms include fatigue, nausea, vomiting, yellowing of the skin, dark urine and light colored stools. Chronic infection of hepatitis B may be asymptomatic. Patients who develop end stage liver disease or cirrhosis may suffer from complications including confusion, abdominal swelling, gastrointestinal bleeding and liver cancer.
Diagnosis of hepatitis B is suspect when patients present associated symptoms. Laboratory tests demonstrate abnormal liver enzymes in the blood. Sophisticated blood tests can be performed to detect and measure the virus in the bloodstream. A biopsy of the liver may be required to determine the degree of inflammation and scarring present. Imaging studies such as ultrasound, CAT scan and MRI may be required to look for evidence of cirrhosis and to screen for the development of hepatocellular cancer.
Hepatitis B can be prevented through appropriate vaccination. Patients with acute hepatitis B typically require supportive care. Patients with chronic hepatitis B may be candidates for medical therapies to try and eliminate the virus from the body or suppress it to prevent progression to chronic liver disease or liver cancer. Patients with liver failure due to cirrhosis may ultimately require liver transplantation.