Acute Viral Hepatitis A and E
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Direct answer
Acute viral hepatitis A and E are self-limiting enteric infections caused by hepatitis A virus and hepatitis E virus, both spread by the faecal-oral route. Neither usually causes chronic hepatitis in immunocompetent people, but hepatitis E in pregnancy, particularly in the third trimester, carries a high risk of fulminant liver failure. Diagnosis rests on IgM antibody to the relevant virus.
What you must remember
- Transmission: Hepatitis A spreads through contaminated food and water; hepatitis E spreads mainly through contaminated drinking water and causes outbreaks in India, especially in the monsoon.
- Incubation: Hepatitis A takes about 15 to 50 days to appear, and hepatitis E about 15 to 60 days.
- Serology: Anti-HAV IgM and anti-HEV IgM confirm acute infection; anti-HAV IgM can stay positive for a few months.
- Chronicity: Hepatitis A never becomes chronic, while hepatitis E can persist in immunosuppressed patients, mainly with genotype 3.
- Pregnancy: Hepatitis E in late pregnancy carries a much higher mortality from fulminant failure than hepatitis A does.
- Prevention: Hepatitis A vaccine (two doses of inactivated vaccine; one dose of live attenuated vaccine in India) and immunoglobulin within two weeks of exposure; hepatitis E vaccine is not part of routine national programmes in India.
- Management: Supportive care, avoidance of alcohol and hepatotoxic drugs, and monitoring of clotting and glucose; no specific antiviral for acute infection.
A worked scenario: jaundice in the third trimester
A 26-year-old woman at 32 weeks of pregnancy presents with jaundice, vomiting and drowsiness. Two weeks earlier, several people in her village fell ill after drinking from a shared open tank.
Her transaminases are in the thousands, bilirubin is raised and the prothrombin time is prolonged.
- Test for hepatitis E: IgM anti-HEV and HEV RNA are sent first, and a positive IgM supports hepatitis E.
- Exclude the mimics: the clinician also excludes paracetamol overdose and acute fatty liver of pregnancy, which also occurs in the third trimester.
- Grade severity: encephalopathy, a rising bilirubin and a worsening prothrombin time define acute liver failure.
- Manage as a team: management is multidisciplinary, with obstetric input, close monitoring of coagulation and glucose, and early referral to a unit able to manage acute liver failure.
- Trace the source: because hepatitis E usually travels in a shared water supply, the clinician asks about household and village contacts. A cluster of cases points to a contaminated source, which must be fixed to stop further spread, and the local public health team is informed.
Supportive care is the mainstay, and no antiviral is routinely used for acute hepatitis E.
Where the exam tries to catch you
The classic confusion is between hepatitis A and E, because both are enteric and both are self-limiting.
- Trap: treating hepatitis A and E as interchangeable. Correct: the pregnancy scenario separates them, since hepatitis E carries the fulminant risk, and chronicity does too, as only hepatitis E can persist, mainly in immunosuppressed patients.
- Trap: reading IgM as proof of current infection. Correct: IgM anti-HAV can remain positive for several months, so it indicates recent rather than strictly current infection.
- Trap: choosing immunoglobulin after hepatitis E exposure. Correct: immunoglobulin protects against hepatitis A after exposure but has no role after hepatitis E exposure.
Frequently asked questions
Which hepatitis virus causes fulminant hepatitis in pregnancy?
Hepatitis E virus causes the most serious outcome in pregnancy, with fulminant hepatitis and high maternal mortality, particularly in the third trimester. Hepatitis A is generally mild in pregnancy and does not carry the same risk.
Which serological test confirms acute hepatitis A infection?
Detection of IgM antibody to hepatitis A virus confirms acute hepatitis A infection, because IgM appears early and falls over a few months. IgG anti-HAV alone indicates past infection or vaccine-induced immunity, not acute disease.
Is hepatitis E vaccine part of routine immunisation in India?
Hepatitis E vaccine is not part of the routine national immunisation schedule in India, so prevention relies on safe drinking water, sanitation and hygiene. A licensed vaccine exists in some other countries, but it is not in the routine national programme here.
Can hepatitis E become chronic in an adult?
Chronic hepatitis E is rare in immunocompetent adults and is mainly recorded in patients on immunosuppressive therapy, including transplant recipients, usually with genotype 3. Hepatitis A never becomes chronic, which is one of the main differences between the two infections.
What immunoglobulin is given after hepatitis A exposure?
Immunoglobulin given within two weeks of exposure provides short-term passive protection against hepatitis A in close contacts such as household members. Active vaccination is also given, and immunoglobulin has no established role after hepatitis E exposure.