What are Hepatitis A, B, and C?

Hepatitis A, B, and C: Overview and Management

Hepatitis A, B, and C are viral infections that affect the liver, with distinct transmission routes, clinical courses, and prevention strategies, with hepatitis B and C having significantly higher risk for progression to chronic liver disease, cirrhosis, and hepatocellular carcinoma compared to hepatitis A, which is always acute and self-limiting.

Hepatitis A

Characteristics

• RNA virus in the Picornaviridae family 1
• Acute infection only; never becomes chronic
• Transmitted via fecal-oral route through:
  • Contaminated food or water
  • Close personal contact with infected individuals
  • Sexual contact (particularly among men who have sex with men)

Clinical Manifestations

• Incubation period: 15-50 days (average 28 days) 1
• Clinical presentation varies by age:
  • Children <6 years: >90% asymptomatic
  • Older children and adults: >66% develop jaundice 1
• Typical symptoms:
  • Prodromal phase: Anorexia, malaise, fever, nausea, vomiting
  • Dark urine (bilirubinuria)
  • Clay-colored stool
  • Jaundice (sclera, skin, mucous membranes)
  • Hepatomegaly

Complications

• Relapsing disease: 10-15% of patients (lasting up to 6 months) 1
• Cholestatic hepatitis
• Fulminant hepatitis (rare but more common in patients >50 years or with underlying chronic liver disease) 1
• Mortality rate: 0.01-2% 1

Prevention

• Hepatitis A vaccine:
  • Inactivated, whole-cell virus vaccines
  • Two single-antigen vaccines available: Vaqta and Havrix 1
  • Recommended for all susceptible persons with HCV infection 1, 2

Hepatitis B

Characteristics

• DNA virus
• Can cause both acute and chronic infection
• Transmission routes:
  • Perinatal exposure
  • Percutaneous exposure (needles, blood products)
  • Sexual contact
  • Close person-to-person contact 1

Risk of Chronic Infection

• 90% in newborns of HBeAg-positive mothers
• 25-30% in infants and children under 5 years
• <10% in adults 1
• Higher risk in immunosuppressed persons

Clinical Manifestations

• Acute infection: Similar to hepatitis A but more likely to progress to chronic infection
• Chronic infection:
  • May be asymptomatic for decades
  • Progressive liver damage leading to cirrhosis
  • Increased risk of hepatocellular carcinoma

Diagnosis

• HBsAg positive for >6 months indicates chronic infection
• HBeAg status and HBV DNA levels help determine disease activity
• Liver function tests and assessment of fibrosis are important 1

Prevention

• Hepatitis B vaccine
• Screening high-risk individuals
• Post-exposure prophylaxis

Treatment

• Entecavir and other antivirals for chronic infection 3
• Warning: Severe acute exacerbations can occur upon discontinuation of therapy 3

Hepatitis C

Characteristics

• RNA virus
• Primary mode of transmission: Exposure to infected blood 1
• Sexual transmission less common but occurs, particularly in men with HIV who have sex with men 1

Clinical Manifestations

• Often asymptomatic in acute phase
• 75-85% develop chronic infection
• Progressive liver fibrosis leading to cirrhosis in 10-20% of chronically infected individuals
• Extrahepatic manifestations including cryoglobulinemic vasculitis, lymphoma, and cardiovascular, neurologic, metabolic, or renal diseases 1

Diagnosis

• Initial screening with anti-HCV antibody test 2
• Confirmation of active infection with HCV RNA testing 2
• Assessment of liver disease severity with noninvasive tests or liver biopsy 1

Prevention

• No vaccine available
• Screening high-risk individuals
• Universal screening recommended for all adults aged 18-79 years at least once 2
• Education about preventing transmission

Treatment

• Direct-acting antiviral (DAA) therapy is standard of care 2
• Treatment recommended for all adults with acute or chronic HCV infection 1
• Treatment duration typically 8-12 weeks 2
• Goal: Sustained virological response (undetectable HCV RNA 12 weeks after completion) 2

Co-infection Considerations

HBV-HCV Co-infection

• Faster progression to advanced liver disease 4
• Significantly higher risk of hepatocellular carcinoma (46 times higher than controls) 4

Hepatitis A in Patients with HBV or HCV

• More severe disease course
• Higher risk of acute hepatic failure
• Higher fatality rates 5, 6

Management Recommendations

Vaccination

1. All susceptible persons with HCV infection should be vaccinated against hepatitis A and B 1, 2
2. Vaccination should be administered early upon HCV diagnosis as response decreases with liver disease progression 6
3. Pneumococcal vaccination recommended for all persons with cirrhosis 1

Lifestyle Modifications

1. Abstinence from alcohol for all persons with viral hepatitis 1, 2
2. Weight management through physical exercise and dietary control 2

Surveillance

1. Regular assessment of liver disease severity
2. Ultrasound surveillance every 6 months for patients with cirrhosis 2
3. Continued surveillance for hepatocellular carcinoma even after achieving SVR in HCV patients with cirrhosis 2

Patient Education

All persons with viral hepatitis should receive education about:

• Preventing transmission to others 1
• Avoiding hepatotoxic medications
• Importance of treatment adherence
• Signs and symptoms requiring medical attention

Common Pitfalls to Avoid

• Failing to screen for all viral hepatitis in patients with one form of viral hepatitis
• Discontinuing HBV treatment without close monitoring (risk of severe flares) 3
• Assuming hepatitis A is always mild (can be severe in patients with underlying liver disease)
• Missing extrahepatic manifestations of HCV
• Neglecting vaccination against HAV and HBV in patients with chronic liver disease