HEPATITIS

HEPATITIS

 

 is an inflammation of the liver and usually refers to the diseases caused

by a group of viruses identified as hepatitis A, B, C, D, and E.

A. Hepatitis A (infectious hepatitis) is caused by the hepatitis A virus (HAV).

1. Transmission. HAV is transmitted most commonly through the fecal-oral route and is

frequently seen in epidemics in areas with poor sanitation. Raw shellfish from contaminated

water can also transmit the disease.

2. Disease course. HAV infections are almost always acute and self-limiting. There is no

carrier state. Symptoms, if present, are vague and relatively nonspecific; patients may

complain of fatigue, malaise, and anorexia. Jaundice may be present, although most

patients are anicteric. Many cases are subclinical, especially those in children.

3. Laboratory diagnosis. Liver function test results, especially alanine aminotransferase

(ALT), are elevated. Total bilirubin levels may be elevated. Antibodies to HAV can be

detected by enzyme immunoassay (EIA) and RIA methods. IgM anti-HAV antibodies

develop during the acute phase of the disease and persist for 3 to 12 months after onset

of the disease. As IgM titers decrease, levels of IgG anti-HAV antibodies increase and

persist throughout life. These IgG antibodies confer lifelong immunity.

4. Prevention. Household and sexual contacts of infected persons should receive immune

globulin injections within 2 weeks of exposure. A recently developed vaccine against

HAV is now available.

B. Hepatitis B virus (HBV) was formerly known as the Australia or hepatitis-associated

antigen. Box 5–1 summarizes the order of appearance of HBV markers.

1. Transmission. HBV is transmitted parenterally or through sexual contact with infected

persons. Common parenteral routes include intravenous drug use, transfusion of contaminated

blood or blood products, and cutaneous or mucous membrane exposure (e.g.,

needlestick injuries; splashes in the eyes, nose, or mouth).

2. Disease course. The average incubation period is 2 to 3 months. HBV infections

may be acute, chronic, or fulminant, or the patient may be a chronic asymptomatic

carrier. Symptoms are similar to those seen in HAV infections. Jaundice may or may

not be present. Approximately 95% of all cases of hepatitis B are acute.