Hepatitis A
Summary
Hepatitis A is an acute, self-limiting viral hepatitis caused by the Hepatitis A Virus (HAV), a non-enveloped RNA virus. It is transmitted via the faecal-oral route, typically through contaminated water, food (especially shellfish), or close contact. Unlike hepatitis B and C, hepatitis A does NOT cause chronic infection. Most cases are mild and self-limiting, particularly in children. Symptomatic infection is more common and more severe in adults. Diagnosis is confirmed by IgM anti-HAV antibody. Treatment is supportive. Vaccination is highly effective for prevention and is recommended for travellers to endemic areas.
Key Facts
- Virus: Hepatitis A Virus (HAV) - RNA picornavirus
- Transmission: Faecal-oral (contaminated food/water, shellfish, close contact)
- Chronicity: NEVER chronic - always acute, self-limiting
- Incubation: 15-50 days (average 28 days)
- Diagnosis: IgM anti-HAV (acute); IgG anti-HAV (past infection/immunity)
- Treatment: Supportive (no specific antiviral)
- Prevention: Highly effective vaccine
Clinical Pearls
"Hepatitis A = Acute Only": Unlike Hep B and C, Hepatitis A NEVER causes chronic infection. One episode confers lifelong immunity.
"Sicker Adults, Mild Kids": Children often have asymptomatic or mild infection. Adults are more likely to have icteric hepatitis and take longer to recover.
"Shellfish and Travellers": Classic epidemiological clues - ask about recent travel to endemic regions and raw shellfish consumption.
"Fulminant Hepatitis is Rare": <0.5% develop acute liver failure, but risk increases with age and pre-existing liver disease.
Global Burden
- 1.4 million cases annually worldwide
- Highly endemic in developing countries
- Low endemicity in developed countries
Demographics
- All ages; severity increases with age
- Equal M:F
- High seroprevalence in endemic regions (>90% by adulthood)
Risk Factors
| Factor | Mechanism |
|---|---|
| Travel to endemic areas | Africa, Asia, Central/South America |
| Contaminated food/water | Poor sanitation |
| Shellfish consumption | Filter feeders concentrate virus |
| MSM | Close contact transmission |
| IVDU | Shared needles (rare) |
| Close contacts of cases | Household transmission |
| Childcare workers | Faecal-oral in nurseries |
UK Context
- Rare (imported cases, outbreaks)
- Travel-related or MSM outbreaks
Virology
- Hepatitis A Virus (HAV)
- Picornaviridae family
- Non-enveloped RNA virus
- Single serotype (only one genotype clinically relevant)
Transmission
- Faecal-oral route
- Contaminated water, food (raw shellfish), person-to-person
- Viral shedding peaks 2 weeks before symptoms onset
Pathogenesis
- Ingestion of contaminated food/water
- Intestinal uptake → Viraemia
- Hepatocyte infection → Viral replication
- Immune response → Hepatocyte destruction (T-cell mediated)
- Recovery → Viral clearance, lifelong immunity
Why Self-Limiting?
- Robust immune response clears virus
- No viral integration into host DNA
- No persistence mechanism
Phases
| Phase | Duration | Features |
|---|---|---|
| Incubation | 15-50 days | Asymptomatic |
| Prodrome | 1-7 days | Flu-like: Fever, malaise, fatigue, anorexia, nausea |
| Icteric phase | 2-4 weeks | Jaundice, dark urine, pale stools, RUQ discomfort |
| Convalescence | Weeks-months | Gradual recovery |
Symptoms
| Feature | Frequency |
|---|---|
| Fatigue/malaise | 80%+ |
| Nausea/vomiting | 70% |
| Anorexia | 70% |
| Abdominal pain (RUQ) | 60% |
| Jaundice | 70% adults, <10% children |
| Fever | 60% |
| Dark urine | 80% |
| Pale stools | 50% |
Age-Related Severity
General
- Jaundice (scleral icterus, skin)
- Mild fever
- Dehydration (if vomiting)
Abdominal
- Hepatomegaly (tender)
- RUQ tenderness
- Splenomegaly (occasionally)
- No ascites (acute infection)
Signs of Severe Disease
- Encephalopathy (confusion, asterixis)
- Coagulopathy (bruising, bleeding)
- Signs of hepatic decompensation
First-Line Tests
| Test | Finding |
|---|---|
| IgM anti-HAV | Positive = Acute infection (diagnostic) |
| IgG anti-HAV | Positive = Past infection or vaccination (immunity) |
| LFTs | ALT/AST markedly elevated (>000); Bilirubin elevated |
| FBC | Usually normal; mild lymphocytosis |
| Coagulation | INR usually normal; elevated = severe |
Serology Interpretation
| IgM | IgG | Interpretation |
|---|---|---|
| + | - | Acute infection |
| + | + | Acute infection (recent) |
| - | + | Past infection or vaccination (immune) |
| - | - | Susceptible |
Additional Tests
- Ultrasound abdomen: Exclude biliary obstruction, assess liver
- Blood glucose: Hypoglycaemia in liver failure
Supportive Care
┌──────────────────────────────────────────────────────────┐
│ HEPATITIS A MANAGEMENT │
├──────────────────────────────────────────────────────────┤
│ │
│ MOST CASES: SUPPORTIVE CARE (Outpatient) │
│ • Rest │
│ • Adequate hydration │
│ • Antiemetics (if needed) │
│ • Avoid alcohol (hepatotoxic) │
│ • Avoid paracetamol if liver severely affected │
│ • No specific antiviral therapy │
│ │
│ MONITORING: │
│ • Check LFTs weekly until improving │
│ • INR if severe symptoms │
│ • Warn about signs of deterioration │
│ │
│ ADMISSION CRITERIA: │
│ • Unable to tolerate oral fluids │
│ • INR >1.5 or encephalopathy (fulminant hepatitis) │
│ • Elderly or pre-existing liver disease │
│ │
│ FULMINANT HEPATITIS (RARE): │
│ • Liver transplant centre referral │
│ • ICU care, N-acetylcysteine, transplant evaluation │
│ │
└──────────────────────────────────────────────────────────┘
Public Health
- Notifiable disease in UK
- Contact tracing
- Vaccination/immunoglobulin for close contacts within 14 days
- Hygiene advice (handwashing, food safety)
Return to Work
- Exclude food handlers for 7 days after jaundice onset
- Children: Exclude from school/nursery for 7 days after jaundice
Rare Complications
- Fulminant hepatitis/acute liver failure (<0.5%)
- Prolonged cholestasis (>3 months)
- Relapsing hepatitis (10-15%)
- Post-hepatitic syndrome (prolonged fatigue)
Risk Factors for Severe Disease
- Age >50
- Pre-existing chronic liver disease (especially Hep B/C)
- Immunosuppression
No Chronic Sequelae
- No chronic hepatitis, cirrhosis, or hepatocellular carcinoma
Natural History
- Self-limiting in >99% of cases
- Complete recovery expected
- No chronic carrier state
Recovery Timeline
- Symptoms resolve: 2-6 weeks
- LFTs normalise: 2-3 months
- Full recovery: 3-6 months (adults may take longer)
Mortality
- Overall: <0.3%
- Age >50 or chronic liver disease: Up to 1-2%
- Fulminant hepatitis: High mortality without transplant
Key Guidelines
- EASL: Hepatitis A Guidelines
- Green Book: Immunisation Against Infectious Disease (UK)
- CDC: Hepatitis A Prevention
Key Evidence
Vaccination
- Highly effective (95%+ protection after 2 doses)
- Long-lasting immunity (possibly lifelong)
Post-Exposure Prophylaxis
- Vaccine effective if given within 14 days of exposure
- Immunoglobulin for immunocompromised or >40 years
What is Hepatitis A?
Hepatitis A is a liver infection caused by a virus. It's spread by eating or drinking something contaminated with the virus, often from poor sanitation or raw shellfish. It causes a short illness and then gets better completely - unlike some other types of hepatitis, it does NOT cause long-term liver damage.
What Are the Symptoms?
- Feeling tired and unwell
- Loss of appetite, nausea
- Stomach ache (right side)
- Yellowing of the skin and eyes (jaundice)
- Dark urine, pale poo
Is it Serious?
For most people, hepatitis A is mild and you recover fully within a few weeks to months. Very rarely, it can cause serious liver problems, especially in older people or those with existing liver disease.
How is it Treated?
There's no specific medicine - your body fights off the virus on its own. Treatment is rest, fluids, and avoiding alcohol. Most people recover at home.
How Can I Prevent It?
- Wash hands thoroughly after using the toilet and before eating
- Avoid raw/undercooked shellfish in high-risk areas
- Get vaccinated before travelling to endemic countries
- Drink bottled or boiled water in high-risk areas
Is There a Vaccine?
Yes! The hepatitis A vaccine is very effective. It's recommended for travellers to Africa, Asia, South America, and other high-risk regions.
Primary Guidelines
- European Association for the Study of the Liver. EASL Clinical Practice Guidelines on Hepatitis A.
- Public Health England. Immunisation Against Infectious Disease (Green Book). Chapter 17: Hepatitis A.
Key Studies
- Jacobsen KH, Wiersma ST. Hepatitis A virus seroprevalence by age and world region, 1990 and 2005. Vaccine. 2010;28(41):6653-6657. PMID: 20723630
- Fiore AE. Hepatitis A transmitted by food. Clin Infect Dis. 2004;38(5):705-715. PMID: 14986256