HBV

Acute Hepatitis B

• Clinical manifestations range from asymptomatic to icteric hepatitis; may rarely lead to fulminant hepatitis.
• Acute illness typically resolves within 2-3 weeks; full clinical recovery by 16 weeks.
• Perinatal or childhood infections have high chronicity (90%); adult infections exhibit low chronicity rates (1-5%).
• Immunocompromised patients are at higher risk for chronic HBV infection.

Chronic Hepatitis B

• Chronic HBV infection is diagnosed when HBsAg and high HBV DNA persist for over 6 months.
• Symptoms include fatigue; physical exams reveal signs of chronic liver disease.
• 10-30% of patients with chronic hepatitis B may exhibit symptoms.
• Serious complications include cirrhosis and hepatocellular carcinoma (HCC).
• Acute disease flares can mimic acute hepatitis.

Diagnosis and Serological Markers

• Elevated serum aminotransferase levels characterize acute hepatitis B; marked cholestasis is not present.
• Key serological markers include:
  • HBsAg: First indicator of acute infection; becomes undetectable in recovering patients.
  • Anti-HBs: Signifies recovery and non-infectivity; may show a "window period" before detection.
  • Anti-HBc IgM: Indicates active acute hepatitis B; appears shortly after HBsAg.
  • Anti-HBc IgG: Indicates recovery; appears with anti-HBs.
  • HBeAg: Indicates HBV replication; appears shortly after HBsAg.
  • Anti-HBe: Signals diminished viral replication; appears after HBeAg.

Prognosis and Statistics

• Acute hepatitis B resolves in 90-95% of adults within 3-6 months.
• Acute liver failure occurs in <1% of cases with high mortality (up to 60%).
• Risk of cirrhosis in chronic HBV is 40%; higher in co-infected patients (HCV/HIV).
• Annual HCC risk in cirrhosis patients is 3-5%.

Prevention Strategies

• Regular screening for high-risk groups and all pregnant women for HBsAg is essential.
• Blood donation screening significantly reduces transfusion-related hepatitis risk.
• Universal vaccination programs have shown promising results in endemic areas.

Immunoprophylaxis

• HBV Vaccine: Recommended for infants, children, and high-risk adults. Safe in pregnancy, with various formulations available.
• Hepatitis B Immune Globulin (HBIG): Provides post-exposure prophylaxis if given within 7 days after exposure. Critical for newborns from HBsAg-positive mothers.

Treatment of Hepatitis B

• Acute Hepatitis B: Primarily supportive; may require antiviral treatment in severe cases.
• Chronic Hepatitis B:
  • No complete cure; aim for "functional cure" (loss of HBsAg and HBV DNA).
  • Two primary antiviral therapy types: Nucleoside and Nucleotide analogs (NUCs) and Pegylated Interferon Alpha (PEG-IFNα).

Antiviral Therapy

• Nucleoside and Nucleotide Analogs (NUCs):
  • Include lamivudine, entecavir, adefovir, TDF, and TAF.
  • High barrier to resistance; long-term therapy required.
  • Entecavir and TDF are first-line treatments; TAF has less renal toxicity.
• Pegylated Interferon Alpha (PEG-IFNα):
  • Alternative to NUCs with both antiviral and immunomodulatory effects.
  • Limited course; potential for sustained response post-treatment.
  • Common side effects include flu-like symptoms and myelosuppression.

Monitoring and Follow-Up

• Monitoring for HBsAg loss and virial suppression is crucial after antiviral therapy.
• Close follow-up is necessary for patients at high risk of reactivation following NUC discontinuation.

This quiz delves into the clinical manifestations of acute hepatitis B, covering asymptomatic, icteric, and fulminant cases. It examines the recovery timeline and contrasts perinatal versus adult-acquired infections. Test your understanding of this important viral infection's characteristics and outcomes.