n. inflammation of the liver caused by viruses, toxic substances (including alcohol), autoimmune disease, metabolic disease, or the excess deposition of fat (see nonalcoholic fatty liver disease). Infectious hepatitis is caused by viruses, several types of which have been isolated. These include hepatitis A, hepatitis B, hepatitis C, hepatitis D, and hepatitis E. Other viral causes of hepatitis include *Epstein-Barr virus, *cytomegalovirus, and rarely *herpes simplex virus. Hepatitis A is transmitted by food or drink contaminated by a carrier or patient and commonly occurs where sanitation is poor. After an incubation period of 15–40 days, the patient develops fatigue, anorexia, nausea, vomiting, arthralgia, and fever. Yellow discoloration of the skin (see jaundice) appears about a week later and persists for up to three weeks. The patient may be infectious throughout this period. Serious complications are unusual and an attack often confers immunity. Injection of *gammaglobulin provides temporary protection, but active immunization is preferable.
Hepatitis B (formerly known as serum hepatitis) is transmitted by infected blood or blood products contaminating hypodermic needles, blood transfusions, or tattooing needles, by unprotected sexual contact, or (rarely) by contact with any other body fluid. It often occurs in drug users. Symptoms, which develop suddenly after an incubation period of 1–6 months, include headache, fever, chills, general weakness, and jaundice. Treatment includes *interferon alfa and other oral antivirals (e.g. *lamivudine, *adefovir dipivoxil, entecavir). Most patients make a gradual recovery but the mortality rate is 5–20%. A vaccine is available.
Hepatitis C (formerly known as non-A, non-B hepatitis) has a mode of transmission similar to that of hepatitis B (predominantly intravenous drug abuse). Treatment is with interferon alfa, peginterferon alfa, ribavirin, telaprevir, and boceprevir.
Hepatitis D is a defective virus that can only proliferate when there is infection with hepatitis B. Patients with D virus usually have severe chronic hepatitis.
Hepatitis E is transmitted by infected food or drink and can cause acute hepatitis; it is especially severe in a pregnant patient.
Chronic hepatitis continues for months or years, eventually leading to *cirrhosis and possibly to malignancy (see hepatoma). It is usually caused by chronic viral hepatitis, alcohol, or autoimmune disease.... hepatitis
Health Encyclopedia