Hepatitis A (picornavirus) and E (hepevirus) are highly infectious viruses that are spread by the faeco-oral route. Given their similar clinical features and method of spread, they will be considered together for this article
Hepatitis A is the most common viral hepatitis worldwide and often appears in endemics. It is spread from contaminated food, such as shellfish.
Hepatitis E is endemic to India and the Middle East. Dogs and rodents and major reservoirs for the virus, although pork has become a major route of transmission in recent years.
Mechanism of spread
Faeco-oral route, usually from infected food.
Viraemia initially causes patients to feel unwell with non-specific symptoms, such as nausea, anorexia and myalgia. After 1-2 weeks, some patients become jaundiced. As jaundice deepens, urine becomes darker and stools turn pale due to intrahepatic cholestasis. Abdominal discomfort and pruritus are common features at this point. The liver may be tender and the spleen enlarged.
The illness usually lasts for 3-6 weeks.
Blood tests are all that are required to confirm the diagnosis. These primarily look at:
- LFTs: raised bilirubin and ALT in the icteric stage. The prodromal stage will have normal bilirubin levels
- FBC: leucopaenia, raised ESR
- Viral markers: Increased anti-viral IgM levels (note that IgG levels are of no diagnostic value as they persist for years following infection)
No other investigations are necessary if anti-viral IgM is detected. Liver biochemistry tests should be repeated after symptoms resolve to confirm return to normal levels.
No specific treatment is available. General advice include rest, dietary measures and avoiding alcohol.
Rare but include:
- Acute liver failure
- Cholestatic hepatitis
- Aplastic anaemia
Active and passive immunisation strategies are available for hepatitis A infections, although no strategies have yet been developed for hepatitis E.
Active immunisation: Vaccination
Passive immunisation: Immune serum globulin. Protective if given soon after exposure.
Prognosis is excellent. However, death can occur if fulminant hepatic necrosis develops.