hepatitis

n.

inflammation of the liver caused by viruses, toxic substances, or immunological abnormalities. Infectious hepatitis is caused by viruses, several types of which have been isolated as specific causes of the disease and can be detected by blood tests, including hepatitis A, hepatitis B, hepatitis C, hepatitis D, and hepatitis E. Other viral causes of hepatitis include the Epstein-Barr virus. See also Entamoeba.

Hepatitis A (epidemic hepatitis) 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 fever and sickness. 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 sexual contact, or by contact with any other body fluid (e.g. milk, sweat); it often occurs in drug addicts. Symptoms, which develop suddenly after an incubation period of 1–6 months, include headache, fever, chills, general weakness, and jaundice. Treatment includes interferon alfa. 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; symptoms include fatigue, sore bones, and dryness of the eyes. Treatment is with interferon alfa, peginterferon alfa, and ribavirin. Hepatitis D is a defective virus and occurs only with or after 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.

Chronic hepatitis continues for months or years, eventually leading to cirrhosis (see also hepatoma). It may be caused by persistent infection with a hepatitis virus (usually hepatitis B, C, or D), which may respond to treatment with interferon, or by autoimmune disease, treated by corticosteroids or immunosuppressant therapy.