Hepatitis can be caused by the hepatitis viruses A, B, C, D, or E. The D and E forms are rare in the United Kingdom. A large proportion of infections with hepatitis viruses of all types are asymptomatic or result in anicteric illnesses that may not be diagnosed as hepatitis. Hepatitis A virus causes a typically minor illness in childhood, with more than 80% of cases being asymptomatic. In adult life infection is more likely to produce clinical symptoms, although only a third of patients with acute hepatitis A infections are jaundiced. Infections with hepatitis B and C viruses are also usually asymptomatic except in intravenous drug users, in whom 30% of hepatitis B infections are associated with jaundice.
Common symptoms of acute viral hepatitis
- Nausea and vomiting
- Fatigue and malaise
- Change in sense of smell or taste
- Right upper abdominal pain
- Coryza, photophobia, headache
- Diarrhoea (may have pale stools and dark urine)
Types and modes of transmission of human hepatitis viruses
|Virus type||Picorna- viridae||Hepadna- viridae||Flavi- viridae||Delta- viridae||Calci- viridae|
|Mean (range) incubation period (days)||30 (15-50)||80 (28-160)||50 (14-160)||Variable||40 (15-45)|
|Mode of transmission:|
In the preicteric phase, patients often have non-specific systemic symptoms together with discomfort in the right upper quadrant of the abdomen. An illness resembling serum sickness occurs in about 10% of patients with acute hepatitis B infection and 5-10% of patients with acute hepatitis C infection. This presents with a maculopapular rash and arthralgia, typically affecting the wrist, knees, elbows, and ankles. It is due to formation of immune complexes, and patients often test positive for rheumatoid factor. It is almost always self limiting, and usually settles rapidly after the onset of jaundice.
Other biochemical or haematological abnormalities seen in acute hepatitis
- Leucopenia is common (<5×109/l in 10% of patients)
- Anaemia and thrombocytopenia
- Immunoglobulin titres may be raised
Rarely, patients with acute hepatitis B infection present with acute pancreatitis. Up to 30% of patients have raised amylase activity, and postmortem examinations in patients with fulminant hepatitis B show histological changes of pancreatitis in up to 50%. Myocarditis, pericarditis, pleural effusion, aplastic anaemia, encephalitis, and polyneuritis have all been reported in patients with hepatitis.