Viral Hepatitis B
Hepatitis B is a virus which can damage the liver.
Transmission occurs via contaminated blood (hence known as a blood-borne virus) and body fluids through activities such as childbirth or unprotected sexual intercourse.
The virus has 3 viral antigen components (Ag) - core antigen, e-antigen and surface antigen. These can trigger the immune system to produce the corresponding antibodies (Ab) - core antibodies, e-antibodies and surface antibodies.
The diagnosis of acute or chronic hepatitis B infection is made from the blood results of the antigen and antibody markers.
The natural history depends on the age of the patient when the infection occurs as illustrated above. If the infection occurs at a young age (when the immune system is immature), the majority develop chronic hepatitis B and remain as long term carriers.
The patient’s immune system is the most important ‘weapon’ to control (or eliminate) the virus. When the immune system engages in a fight with the virus, a hepatitis ‘flare’ may occur as evident by abnormal LFTs. In chronic hepatitis B, liver damage occurs when there is high viral activity and persistent severe or multiple flares. This may take many years to develop. Patients with chronic hepatitis B often do not manifest any symptom until there is advanced liver damage/ liver failure.
Liver blood tests (LFTs) give an indication about the inflammatory activity in the liver. The virus activity can be measured directly as hepatitis B DNA titre. The liver ultrasound appearance provides a clue about underlying damage but detailed assessment of scarring (fibrosis or cirrhosis) requires a liver biopsy or a liver fibroscan.
The current anti-viral treatment, whether oral medications or pegylated interferon (injection), are good at suppressing the virus replication. They are less effective at curing or eliminating the virus. Anti-viral treatment may not be helpful or needed in every patient.
The anti-viral medications should only be started when indicated (see below). In general, once a oral medication is started, it is continued for many years or long term. Good compliance is essential to minimise the risk of emerging viral resistance to the medications.
Indications for Anti-viral Medications
- Patients with positive e-antigen whereby the immune system engages but not winning the fight over the virus
- Patients with increasing viral activity, abnormal LFTs, risk factors or objective evidence of progressive liver scarring
- There is baseline advanced liver scarring or vulnerability to further damage and complications like liver cancer
- Prophylaxis for impaired immune system (e.g. patients undergoing chemotherapy)
- Prophylaxis in antenatal women (third trimester to 3 months post partum)
- Healthcare workers as per Department of Health guidance
Specialist Endoscopies and more . . .