Skip to content

BASICS

Description

  • Caused by hepatitis A virus (HAV), a small, nonenveloped, single-stranded RNA virus.
  • Infection primarily involves hepatocytes and macrophages.
  • Transmission mainly fecal-oral; also via sexual contact (anal-oral), intravenous drug use.
  • Incubation period 2–6 weeks (mean 4 weeks).
  • Disease course: prodromal symptoms followed by jaundice/convalescent phase.
  • Virus shed in bile and stool; highly infectious 2 weeks before symptoms.

Epidemiology

  • ~1.5 million cases globally annually.
  • HAV vaccine introduction (1995) decreased incidence in US.
  • Half of US infections acquired during travel to endemic regions.
  • Seroprevalence declining in developed countries, remains high in developing regions.
  • Children often asymptomatic or mild illness; severity increases with age.
  • Vertical transmission rare; breastfeeding safe.

ETIOLOGY AND PATHOPHYSIOLOGY

  • HAV is a Picornaviridae family enterovirus infecting liver cells.
  • Stable in water and on surfaces; inactivated by heat (>185°F for 60s) and chlorine.
  • Humans are sole reservoir.
  • Autoimmune hepatitis may rarely follow HAV infection (HLA-DR3/DR4 associations).

RISK FACTORS

  • Close personal contact, especially anal-oral sex.
  • Institutional/residential outbreaks.
  • Travel to endemic areas (Africa, Central/South America, Asia).
  • Consumption of contaminated food/water or raw shellfish.
  • Injection drug use.
  • Healthcare and childcare workers.
  • Immunocompromised and chronic liver disease patients.

PREVENTION

  • Active immunization: HAV vaccines (Havrix, Vaqta, Twinrix).
  • Vaccination recommended for:
  • All children 12–23 months; catch-up until 18 years.
  • Travelers to endemic areas.
  • Men who have sex with men.
  • Injection/noninjection drug users.
  • Healthcare workers, daycare personnel.
  • Persons with chronic liver disease or HIV.
  • Contacts of adoptees from endemic areas.
  • Persons experiencing homelessness or during outbreaks.
  • Hygiene: handwashing, safe food handling, sanitation.
  • Vaccine provides >20 years protection.

DIAGNOSIS

Clinical Criteria

  • Acute illness with discrete onset of hepatitis symptoms (fever, malaise, nausea, vomiting, dark urine).
  • Jaundice or bilirubin ≥3 mg/dL or ALT >200 IU/L.
  • Absence of more likely diagnosis.

Laboratory

  • Anti-HAV IgM positive (sensitivity and specificity >95%) diagnostic of acute infection.
  • Anti-HAV IgG appears after IgM; indicates past infection or vaccination.
  • Elevated AST/ALT (~500–5000 IU/L, ALT > AST).
  • Mildly elevated alkaline phosphatase.
  • Bilirubin elevated (conjugated and unconjugated).
  • Coagulation normal unless acute liver failure.
  • CBC: mild leukocytosis; thrombocytopenia may predict severity.
  • Ultrasound if cholestatic pattern or to exclude biliary pathology.

HISTORY AND PHYSICAL EXAM

  • Abrupt onset: nausea, vomiting, diarrhea, headache.
  • Older patients: jaundice, malaise, pruritus, right upper quadrant pain.
  • Fever variable.
  • Hepatomegaly common; splenomegaly less so.
  • Rare lymphadenopathy, arthritis, rash.
  • Asterixis suggests acute hepatic failure.

DIFFERENTIAL DIAGNOSIS

  • Other viral hepatitis (B, C, D, E).
  • Drug/toxin-induced hepatitis.
  • Alcoholic hepatitis.
  • Autoimmune hepatitis.
  • Hemochromatosis, Wilson disease.
  • Malaria, adenovirus, EBV, CMV.
  • Hepatic malignancy.
  • Ischemic hepatitis, Budd-Chiari syndrome.

TREATMENT

General Measures

  • Supportive care: hydration, nutrition.
  • Avoid alcohol and hepatotoxic drugs (acetaminophen limit ≤2 g/day).
  • Universal precautions to prevent transmission.
  • Monitor coagulation, electrolytes, renal function.
  • Refer fulminant hepatic failure for liver transplant evaluation.
  • Report cases to public health authorities.

Medication

  • No antivirals indicated; spontaneous recovery in ~99% cases.
  • Symptom management; antiemetics and IV fluids for dehydration.
  • Pruritus: diphenhydramine; cholestyramine for cholestasis.

Vaccination

  • Preexposure vaccination per guidelines.
  • Postexposure prophylaxis with vaccine and/or immunoglobulin within 14 days.

ISSUES FOR REFERRAL

  • Hepatic failure or complications.
  • Liver transplant centers in fulminant cases.

ONGOING CARE

  • Usually outpatient.
  • Isolation unnecessary; hygiene critical.
  • Return to work/school after 10–14 days of symptom onset.

PATIENT EDUCATION

  • Importance of hygiene and vaccination.
  • Food handlers with HAV should be segregated.
  • HAV immunity is lifelong post-infection.

PROGNOSIS

  • Excellent in children and healthy adults.
  • Case-fatality increases with age and chronic liver disease.
  • Relapsing hepatitis and prolonged cholestasis possible.
  • Rare autoimmune hepatitis post-HAV.

COMPLICATIONS

  • Fulminant hepatic failure (rare).
  • Relapsing hepatitis (up to 12 months).
  • Prolonged cholestasis (>3 months).
  • Autoimmune hepatitis post-infection.

REFERENCES

  1. Centers for Disease Control and Prevention. Hepatitis A questions and answers for health professionals. https://www.cdc.gov/hepatitis/hav/havfaq.htm. Accessed October 30, 2023.

  2. Desai AN, Kim AY. Management of hepatitis A in 2020-2021. JAMA. 2020;324(4):383-384.

  3. Pati I, Cruciani M, Candura F, et al. Hyperimmune globulins for the management of infectious diseases. Viruses. 2023;15(7):1543.

ADDITIONAL READING

  • Yang J, Wang D, Li Y, et al. Metabolomics in viral hepatitis: advances and review. Front Cell Infect Microbiol. 2023;13:1189417.