MICI: Viral Hepatitis

Overview of Viral Hepatitis

• Hepatitis is liver inflammation caused by factors like autoimmune diseases, alcohol, drugs, genetic disorders, or viral infections.
• Viral hepatitis types include A, B, C, D, and E.
• Hepatitis A and E are transmitted fecal-orally through contaminated food or water.
• Hepatitis B, C, and D are transmitted through blood or bodily fluids.
• Symptoms can include jaundice, abdominal pain, fatigue, vomiting, weight loss, and clay-colored feces.
• Symptoms may appear years after infection due to liver damage from immune responses.

Hepatitis A (HAV)

• HAV is a single-stranded RNA, non-enveloped virus transmitted through the fecal-oral route.
• Common in areas with poor sanitation, uncommon in areas with good sanitation.
• Symptoms include jaundice, fever, and fatigue.
• Diagnosis involves detecting IgM antibodies.
• Vaccination is recommended for travelers and high-risk individuals.

Hepatitis B (HBV)

• HBV is a DNA virus with an envelope that uses reverse transcriptase for replication.
• Transmitted through bodily fluids, contaminated equipment, or during childbirth.
• Highly infectious with a 30% risk of infection from needle sticks.
• Infection can be asymptomatic, with chronic infections leading to liver cancer.
• Serological markers are used to diagnose infection:
  • Acute: HBsAg present, anti-HBc IgM positive.
  • Chronic: Persistent HBsAg over 6 months, with or without HBeAg.
• Vaccination is crucial, especially for healthcare workers.
• HBV vaccination indirectly protects against Hepatitis D.

Hepatitis C (HCV)

• HCV is a single-stranded RNA virus primarily transmitted through blood contact.
• 40-60% of infections lead to chronic liver disease, increasing the risk of cirrhosis and liver cancer.
• Symptoms are often mild or asymptomatic with a long incubation period (2-20 weeks).
• Diagnosis involves detection of anti-HCV antibodies and PCR for viral RNA.
• High cure rate with antiviral therapy.
• No vaccine is available.

Hepatitis D (HDV)

• HDV is an incomplete RNA virus that requires HBV for replication.
• Transmitted through co-infection or superinfection with HBV.
• Co-infection with HBV increases disease severity.
• Prevention focuses on HBV vaccination to block HDV replication.

Hepatitis E (HEV)

• HEV is an RNA virus transmitted through the fecal-oral route, mainly through contaminated water.
• Symptoms are similar to HAV, but can be severe in pregnant women.
• Typically does not cause chronic infection.
• Prevention focuses on safe drinking water and proper sanitation.

Immunization and Prevention

• Vaccines are available for Hepatitis A and B.
• No vaccines are currently available for Hepatitis C and E.
• Control measures include blood screening, hand hygiene, avoidance of contaminated food/water, and reduction of risky behavior like needle-sharing.

Diagnosis and Key Serological Markers

• Hepatitis A: Confirmed by IgM antibodies against HAV.
• Hepatitis B:
  • Acute infection: Positive HBsAg and IgM anti-HBc.
  • Chronic infection: Persistent HBsAg over 6 months; anti-HBs absent.
  • Immunity: Presence of anti-HBs (after vaccination or recovery).
• Hepatitis C: Detected through anti-HCV antibodies or PCR for viral RNA.
• Hepatitis D: Detected through anti-HDV antibodies in conjunction with HBV markers.
• Hepatitis E: Detected through IgM anti-HEV in symptomatic patients.

Key Review Points for Test Preparation

• Transmission Routes:
  • A & E: Fecal-oral
  • B & C: Blood-to-blood
  • D: Requires HBV
• Symptoms and Progression:
  • Distinguish between acute and chronic infection; higher chronicity in B and C.
• Preventive Measures:
  • Focus on vaccines (A, B) and behavioral modifications.
• High-Risk Populations:
  • Healthcare workers (HBV needle-stick risks) and travelers to endemic areas (HAV).
• Serology Tables and Diagnostic Criteria:
  • Familiarize with serological markers to understand acute, chronic, and immune states in HBV.

Hepatitis A Transmission

• Fecal-oral route is the primary mode of transmission for Hepatitis A.

Hepatitis and Liver Cancer

• Hepatitis B is most closely associated with the risk of developing liver cancer.

Hepatitis Transmission

• Hepatitis A is transmitted via the fecal-oral route.

Hepatitis B Genetic Material

• Hepatitis B virus possesses DNA as its genetic material.

Hepatitis D Dependence

• Hepatitis D virus requires the presence of Hepatitis B virus for its replication.

Chronic Hepatitis B Diagnosis

• Hepatitis B surface antigen (HBsAg) is indicative of a chronic Hepatitis B infection.

Chronic Hepatitis C Risk

• Approximately 80% of individuals infected with Hepatitis C develop chronic liver disease.

Hepatitis B Vaccination

• Hepatitis B vaccine is recommended for preventing Hepatitis B infection.

Viral Hepatitis Symptoms

• Diarrhea is typically NOT associated with viral hepatitis.

Reverse Transcriptase Role

• Reverse transcriptase, an enzyme in Hepatitis B virus, transcribes DNA from RNA.

Hepatitis Severity Risk

• Immunosuppression is a significant risk factor, increasing the severity of hepatitis infections.

Hepatitis E Transmission

• Hepatitis E is primarily transmitted via the fecal-oral route.

Hepatitis E Prevention

• Vaccination is NOT effective against hepatitis E.

Acute Hepatitis B Serological Marker

• Hepatitis B surface antigen (HBsAg) indicates an acute infection of hepatitis B.

Hepatitis Prevention Vaccines

• Hepatitis A and B vaccines are available for hepatitis prevention.

Chronic Hepatitis E State

• Chronic liver disease is typically NOT associated with hepatitis E infection.

Hepatitis D Infection

• Hepatitis D infection is likely to occur in individuals co-infected with hepatitis B.

Hepatitis B Risk Groups

• Healthcare workers are at a higher risk for hepatitis B due to specific exposure.

Hepatitis B Immunity Marker

• Anti-HBs (hepatitis B surface antibody) indicates immunity to hepatitis B after recovery or vaccination.

Hepatitis E Diagnosis

• Anti-HEV IgM is primarily used for diagnosing hepatitis E in symptomatic patients.

Hepatitis B Resolution Marker

• Anti-HBc IgM is most typically associated with resolving an acute Hepatitis B infection.

Chronic Hepatitis B Marker

• HBsAg in the presence of anti-HBc signifies a chronic infection status in HBV.

Hepatitis B Vaccination Marker

• Anti-HBs alone, without other markers, strongly suggests a patient has been vaccinated against Hepatitis B.

Recent Hepatitis B Infection Marker

• HBsAg and anti-HBc IgM are present in a recent infection, in contrast to a long-standing infection.

Active Hepatitis B Markers

• HBsAg, anti-HBc, and anti-HBe are usually present in an individual with an active Hepatitis B infection.