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Hepatitis A

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Overview

The hepatitis A virus (HAV) is an RNA virus spread through the faecal-oral route that typically leads to self-limiting inflammation of the liver and unlike hepatitis B and C, it is not associated with chronic liver disease.

The incubation period (the time taken for symptoms to develop after contracting a pathogen) of hepatitis A is around 2 weeks.

Epidemiology

  • Hepatitis A is less common in the developed world
  • Hepatitis A is the most common form of acute viral hepatitis worldwide, particularly in countries that are resource-limited and have poor sanitation

Risk Factors

  • Close contact with an infected person
  • Living in or travelling to an endemic region
  • Eating and drinking in places with poor sanitation

Presentation

Patients tend to have a flu-like prodrome and may have:

  • Fever
  • Jaundice
  • Malaise
  • Nausea and vomiting
  • Tender hepatomegaly
  • Dark urine and pale stools
    • Due to bilirubin excretion in the urine instead of the gastrointestinal tract, see Jaundice.

Differential Diagnoses

Hepatitis E

  • Both have similar risk factors as they are both spread through the faecal-oral route
  • Hepatitis E is more common and severe in pregnant people

Investigations

  • Hepatitis A serology – either hepatitis RNA PCR or hepatitis immunoglobulin tests:
    • HAV-IgM positive, HAV-IgG positive: acute hepatitis A likely
    • HAV-IgM positive, HAV-IgG negative: false positive may be possible
    • HAV-IgM negative, HAV-IgG positive: suggests previous infection or vaccination
    • See Hepatitis Serology Testing for more detail on interpreting antibody and antigen testing in viral hepatitis.
  • Liver function tests (LFTs):
    • Bilirubin – increased (usually >85 µmol/L)
    • ALT, AST – increased (usually 500 – 10,000 IU/L) and ALT > AST
    • ALP – may be raised to up to 2 times the upper limit of normal

Management

Overview

  • 1st-line: symptom management and analgesia + notify Public Health England
    • All viral hepatitides are notifiable diseases
    • Most cases of hepatitis A are mild and self-limiting
    • Any severely unwell patient should be admitted to hospital

Immunisation

Immunisation involves 2 doses 6-12 months apart and is offered to:

  • Patients travelling to high-risk areas if >1 year old
  • Men who have sex with men
  • People who inject drugs
  • People with chronic liver disease
  • People who have occupational risks (e.g. working in a lab)

Monitoring

  • Patients should be followed up every 1-2 weeks with repeat liver function tests until AST and/or ALT are within normal levels.

Patient Advice

  • Patients should avoid work or school for 7 days after the onset of symptoms

Complications

  • Complications are very rare, however, 15% of patients may experience a relapsing course persisting for several months.

Prognosis

  • Around 85% of patients make a full recovery within 3 months and almost all people fully recover within 6 months.

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