Acute hepatitis B

Disease Description (Causes and Symptoms)

• Definition: Acute hepatitis caused by the hepatitis B virus (HBV), in which immune-mediated hepatocellular injury resulting from viral infection is the primary pathophysiology.
• Causes and transmission: The main routes are direct contact through blood and bodily fluids (semen, vaginal secretions, saliva, etc.), contaminated injection needles and instruments, blood transfusion (rare today), sexual contact, and vertical transmission from mother to newborn (transmission immediately after birth).
• Summary of pathophysiology: HBV penetrates hepatocytes → viral antigens are expressed, and the host immune response (especially cellular immunity) is activated, causing hepatocellular injury and elevated liver enzymes.
• Main symptoms: Fatigue, malaise, muscle aches, low-grade fever, loss of appetite, nausea and vomiting, abdominal pain, diarrhea → as the disease progresses, jaundice (yellowing of the skin and eyes), dark urine, itching, and generalized weakness.
• Typical test findings (for clinical reference): Elevated ALT/AST (GOT/GPT) (normally approximately ≤40 IU/L; in acute cases, they may rise to several hundred or several thousand), and elevated bilirubin. Symptoms may begin within 2 weeks to 2 months after the appearance of HBsAg. In acute infection, IgM anti-HBc is observed as positive. HBV DNA and HBeAg reflect active viral replication.

Treatment Methods and Precautions

• General principles
  • Most adults recover with supportive treatment for symptoms (rest, hydration and nutritional supplementation, and symptomatic treatment) (most recover within 12 weeks, and many recover within 6 months at the latest).
  • Hospitalization and active treatment are necessary when severe liver injury or acute liver failure (such as coma, coagulopathy with elevated INR, or a rapid rise in bilirubin) is suspected.
• Antiviral medications
  • In general, the standard treatment for mild acute hepatitis B is supportive management rather than antiviral medication.
  • Antiviral medications (e.g., the nucleos[t]ide analogues tenofovir and entecavir) may be considered for severe or progressive hepatitis, the pre-acute-liver-failure stage, persistent HBV replication in an immunosuppressed state, or certain high-risk groups.
• In severe disease or liver failure
  • In cases of severe progression or acute liver failure (such as coma or elevated INR), consultation with a hepatologist is needed for emergency treatment and evaluation for liver transplantation.
• Lifestyle management and precautions
  • Avoid alcohol and hepatotoxic medications (e.g., excessive acetaminophen use).
  • Get sufficient rest and consume a balanced diet.
  • To prevent transmission through contact with blood and bodily fluids, do not share personal items (such as razors and toothbrushes), and properly manage open wounds.
  • Condom use is recommended during sexual contact (until HBsAg negativity is confirmed).
  • During pregnancy, consult medical staff immediately (measures such as preventing maternal-fetal transmission and providing neonatal vaccination and immunoglobulin may be necessary).
• Risk of complications
  • Acute liver failure (in some cases), progression to chronic hepatitis B (approximately 5% in adults), and the subsequent risk of cirrhosis and hepatocellular carcinoma (if the infection becomes chronic).
• Contact management and prevention
  • Exposed newborns: Administration of HBIG (immunoglobulin) and the first dose of the HBV vaccine immediately after birth is recommended (to prevent vertical transmission).
  • Vaccination is recommended for unvaccinated adults and children. Post-exposure vaccination and, when necessary, immunoglobulin use should be considered.

Checklist Before an Outpatient Visit (Examples of Items, Records, and Questions to Prepare)

• Items and information to bring
  • A list of medications currently being taken (prescription medicines, OTC medications, herbal medicines, etc.).
  • Past medical history (especially liver disease, medication and alcohol use, and whether immunosuppressive treatment has been received).
  • Recent test results (liver function tests (ALT/AST), bilirubin, prothrombin time/INR, HBsAg, anti-HBc, HBV DNA, etc.) (a printed copy or electronic file, if available).
  • A record of when symptoms began and how they progressed (the date symptoms were first noticed, the date jaundice appeared, changes in urine color, etc.).
  • Recent history of blood exposure (transfusion, injections/procedures, tattooing/piercing), changes in sexual partners, and the possibility of pregnancy (for women).
  • Information about the vaccination and HBV status of contacts (family members and sexual partners), if known.
• Symptoms to check before an outpatient visit (matters to report immediately)
  • Changes in consciousness (confusion, drowsiness), bleeding or bruising (suspected coagulopathy), inability to eat or drink due to persistent high fever or vomiting, or worsening abdominal pain → immediate evaluation at an emergency medical institution is required.

Examples of General Questions to Ask the Doctor

• "What do my current test results (ALT/AST, bilirubin, HBsAg, IgM anti-HBc, and HBV DNA) mean?"
• "What are the side effects and precautions for this medication (the prescribed antiviral medication or symptomatic treatment)?"
• "How likely am I to transmit the infection to other people? What preventive measures should be taken for my family and sexual partner(s)?"
• "What is the prognosis, and how often should I undergo follow-up testing?"
• "What should I avoid in terms of lifestyle (alcohol consumption, medications, going to work, etc.)?"

Examples of Disease-Specific Questions

• "My test shows that IgM anti-HBc is positive and HBsAg is still positive (or negative). What is the risk of progression to chronic infection, and which tests should be followed up?"
• "I am pregnant (or my spouse is pregnant). What preventive measures should be taken for the newborn, and by when after birth should the newborn receive HBIG and the vaccine?"