Hepatitis A Virus

Snapshot

• A 28-year-old man presents to his primary care physician for fatigue, malaise, and abdominal pain. He reports his symptoms began a few days ago and have progressively worsened. His symptoms are associated with nausea, 2 episodes of emesis, and generalized pruritus. Social history is significant for recent travel to India. He is currently sexually active with multiple men and does not use condoms. Physical examination is notable for scleral icterus, generalized jaundice, and hepatomegaly. Serologic testing is remarkable for anti-HAV IgM antibodies.

Introduction

• Classification
  • a Hepatovirus in the Picornaviridae family
    • single-stranded positive-sense RNA virus with an icosahedral capsid
• Epidemiology
  • risk factors
    • sexual contact
    • working in a daycare
    • serving in the military
    • eating raw or undercooked shellfish and vegetables
• Transmission
  • via the fecal-oral route 
• Pathogenesis
  • within the cytoplasm of a hepatocyte, the virus replicates
    • CD8+ T-cells and natural killer cells destroy the infected hepatocytes, leading to hepatocellular damage
      • when the immune response to the infected hepatocytes is severe, it can result in severe hepatitis
• Prognosis
  • typically a self-limited illness
• does not become a chronic condition

Presentation

• Symptoms
  • nausea and vomiting
  • anorexia
  • abdominal pain
  • dark urine
  • pale stools
• Physical exam
  • hepatomegaly
• jaundice and scleral icterus

Studies

• Serologic testing
  • anti-HAV IgM 
    • active infection is present
  • anti-HAV IgG
    • a previous infection was present
    • no active disease
    • the patient is protected against infection
• elevated aminotransferases

Differential

• Hepatitis B infection 
  • differentiating factors
    • presence of anti-hepatitis B antibodies in serological testing
• Hepatitis C infection
  • differentiating factor
• presence of anti-hepatitis C antibodies in serological testing

Treatment

• Medical
  • hepatitis A virus (HAV) vaccine
    • indication
      • all children at 1 year of age
      • all children between ages 2 and 18 who live in an area with a high disease incidence
      • people who travel or work in countries with a high disease incidence
      • men who have sex with men
      • illicit drug users
      • patients with chronic liver disease
    • comments
      • used to protect against exposure to the HAV
  • immune globulin
    • indication
      • in infants < 6 months of age
      • in travelers who have a contraindication to the vaccine (e.g., allergy)
    • comments
      • this provides passive immunization against the HAV
  • hepatitis A virus vaccine and immune globulin
    • indication
      • patients with chronic liver disease
• immunocompromised patients who are not able to mount an adequate immune response to the hepatitis A vaccine

Complications

• Cholestatic hepatitis
• Fulminant hepatitis (< 1% of cases)