Viral hepatitis is inflammation of the liver caused by hepatotropic viruses — viruses with a particular affinity for liver cells. It is not one disease but a family: five distinct viruses, hepatitis A, B, C, D and E, produce a clinically similar illness through different virological and epidemiological routes. Before serological tests were available, the difference between the viral hepatitis caused by the different viruses was not obvious from the clinical and epidemiological features alone; only after serological tests became available could the different virological causes be distinguished.
The liver injury is immune-mediated rather than caused by the viruses killing hepatocytes directly. The acute form is defined as resolution of symptoms before 6 months. All five viruses can cause acute hepatitis; HBV, HCV and HDV can also cause chronic hepatitis in a proportion of cases, and HEV mostly causes an acute illness, though some of its genotypes can cause chronic disease.
Where to start
- Transmission and Epidemiology of Viral Hepatitis — how each of the five viruses spreads, which groups are at risk, and how common chronic infection is.
- Pathogenesis of Viral Hepatitis — why the viruses do not damage liver cells directly, and how the immune response decides whether infection clears or persists.
- Clinical Presentation of Viral Hepatitis — the incubation period of each virus and the prodromal, icteric and recovery phases of the acute illness.
- Laboratory Diagnosis of Viral Hepatitis — the general laboratory picture of liver injury: enzymes, bilirubin, blood count and clotting.
- Serology of Viral Hepatitis — the virus-specific tests that identify the responsible virus and separate acute from chronic infection.
- Complications of Viral Hepatitis — fulminant hepatitis and the rarer complications.
- Differential Diagnosis of Viral Hepatitis — the infections, drugs and other conditions that mimic viral hepatitis.
- Treatment of Viral Hepatitis — supportive care for the acute illness and drug treatment for chronic hepatitis B, C and D.
- Prevention of Viral Hepatitis — vaccines, post-exposure prophylaxis and the measures that interrupt transmission.