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ACUTE VIRAL HEPATITIS
This is a common worldwide disease, which occurs sporadically and in epidemics with outbreaks, most commonly in institutions, in rural areas and in military forces during wars. Incidence is the highest in autumn and early winter.
There are two types of hepatitis with distinctive clinical, epidemiological and immunological features. The two types of disease are caused by two different viruses. The disease associated with virus A is the classical type of mfectious hepatitis, in former years it was also known as epidemic jaundice and acute jaundice. The disease associated with virus В resembles serum hepatitis, post-transfusion hepatitis and postvaccinal hepatitis. Detection of the infection depends on the demonstration of an antigen, hepatitis В
antigen (HBAg or Australia antigen) or its antibody (HBAb) in the serum of exposed individuals.
It is well recognized that viral A hepatitis is a contagious disease and that the most common mode of transmission is by the intestinal-oral route. Man is a reservoir and source of infection.
Virus В is mainly transmitted parenterally. Transfusion of contaminated blood or blood products is a usual source of infection, although the use of needles by drug abusers is also responsible for the infection. Nonparenteral spread can also occur.
Virus A infection has an incubation period of 2 to б weeks, virus В — about 6 to 25 weeks. All age groups are affected.
The prodromal phase begins suddenly with malaise, nausea, vomiting and fever. Jaundice reaches a peak within 1 to 2 weeks. Then the recovery phase begins. The liver is usually enlarged and tender.
High values of transaminase appear early in the prodromal stage and slowly fall during the recovery phase. Urinary bile appears before jaundice; its early detection provides a valuable clue to the diagnosis. The WBC count is usually low — normal and blood smear often shows a few atypical lymphocytes. In the prodromal phase hepatitis mimics a variety of illnesses and is difficult to diagnose. Where the diagnosis is uncertain, liver biopsy usually helps.
A favourable prognosis in hepatitis В is less certain than in virus A infection, especially in elderly people where mortality is 10 to 15%.
Personal hygiene helps to prevent spread of hepatitis A with a particular emphasis on disposal of feces. Globulin provides' protection against hepatitis A and should be given to close contacts.
Hepatitis В is minimized by proper technical procedures to prevent transmission by blood from an infected donor or through the use of properly sterilized syringes and needles. High immune serum globulin against virus В provides partial protection but is not yet available.
In most cases no special treatment is required. Appetite usually returns to normal after the first few days and the patient need not be confined to bed. Restrictions on diet or activity are unnecessary and have no scientific basis. Vitamin supplements are rarely required. Corticosteroids are contraindicated in ordinary cases. Most patients can safely return to work before jaundice completely resolves and before transaminases are normal.