INFECTIOUS MONONUCLEOSIS. This is due to the Epstein-Barr virus. Mild jaundice associated with minor abnormalities of liver biochemistry is extremely common but ‘clinical’ hepatitis is rare. Hepatic histological changes occur within 5 days of onset; the sinusoids and portal tracts are infiltrated with large mononuclear cells but the liver architecture is preserved. A Paul-Bunnell or Monospot test is usually positive and atypicallymphocytes are present in the peripheral blood. Treatment is symptomatic.
CYTOMEGALOVIRUS. This can cause acute hepatitis, particularly in patients with poor immune responses. The virus may be isolated from the urine. The liver biopsy shows intranuclear inclusions and giant cells.
YELLOW FEVER. This viral irIfection is carried by the mosquito Aedes aegypti and causes acute hepatic necrosis. There is no specific treatment.
HERPES SIMPLEX. Very occasionally the herpes simplex virus causes a generalized acute infection, particularly in the immunosuppressed patient. Liver biopsy shows extensive necrosis. Acyclovir is used for treatment.
OTHER INFECTIOUS AGENTS. Abnormal liver biochemistry is frequently found in a number of acute infections. The abnormalities are usually mild and have no clinical significance.
TOXOPLASMOSIS. Produces a similar clinical picture to infectious mononucleosis with abnormal liver biochemistry but the Paul-Bunnell test is negative.