Hepatitis
Contact Precautions
Viral hepatitis is a fairly common systemic disease. It is marked by hepatic cell destruction, necrosis, and autolysis leading to anorexia, jaundice, and hepatomegaly. In most patients, hepatic cells eventually regenerate with little or no residual damage, allowing complete recovery. However, old age and serious underlying disorders make complications more likely. The prognosis is poor if edema and hepatic encephalopathy develop.
Today, six types of viral hepatitis are recognized:
Type A (infectious or short-incubation hepatitis) is on the rise in homosexuals and in people with immunosuppression related to human immunodeficiency virus (HIV) infection. It’s usually self-limiting and without a chronic form.
Type B (serum or long-incubation hepatitis) is also increasing among HIV-positive individuals. Hepatitis B is considered a sexually transmitted infection because of the high incidence and rate of transmission by this route. Routine screening of donor blood for hepatitis B surface antigen (HBsAg) has decreased the incidence of posttransfusion-related cases, but transmission via needles shared by drug abusers remains a major problem.
Type C hepatitis accounts for about 20% of all viral hepatitis cases and is transmitted primarily through blood and body fluids or during tattooing.
Type D (delta hepatitis) is confined to people who are frequently exposed to blood and blood products, such as I.V. drug users and hemophiliacs. It’s transmitted parenterally and, less commonly, sexually. It occurs only in those who have hepatitis B virus.
Types C and E hepatitis occur primarily in people who have recently returned from an endemic area (such as India, Africa, Asia, or Central America).
Type G is a newly discovered form of hepatitis. Transmission is by the bloodborne route, and it occurs more commonly in those who receive blood transfusions.
Causes
The six major forms of viral hepatitis—A, B, C, D, E, and G—result from infection with causative viruses.
Type A hepatitis is highly contagious and is usually transmitted by the fecal-oral route, commonly within institutions or families. However, it may also be transmitted parenterally. Hepatitis A usually results from ingestion of contaminated food, milk, or water. Outbreaks of this type are often traced to ingestion of seafood from polluted water.
Type B hepatitis is transmitted by the direct exchange of contaminated blood as well as by contact with contaminated human secretions and stools. Transmission of hepatitis B also occurs during intimate sexual contact and through perinatal transmission.
Type C hepatitis is a blood-borne illness transmitted primarily via sharing of needles by I.V. drug users, through unsanitary tattooing, and through blood transfusions. People with chronic hepatitis C are considered infectious.
Type D hepatitis is found only in patients with an acute or a chronic episode of hepatitis B. Type D infection requires the presence of HBsAg; the type D virus depends on the double-shelled type B virus to replicate. For this reason, type D infection can’t outlast a type B infection.
Type E hepatitis is transmitted enterically and is usually waterborne, much like type A. Because this virus is inconsistently shed in stools, detection is difficult. Outbreaks of type E hepatitis have occurred in developing countries. Hepatitis G is thought to be blood-borne, with transmission similar to that of hepatitis C.
Complications
Life-threatening fulminant hepatitis—the most feared complication—develops in about 1% of patients. Fulminant hepatitis
causes unremitting liver failure with encephalopathy, progresses to coma, and commonly leads to death within 2 weeks.
causes unremitting liver failure with encephalopathy, progresses to coma, and commonly leads to death within 2 weeks.
Other complications may be specific to the type of hepatitis:
Chronic active hepatitis may occur as a late complication of hepatitis B.
During the prodromal stage of acute hepatitis B, a syndrome resembling serum sickness, characterized by arthralgia or arthritis, rash, and angioedema, may occur. This syndrome can lead to misdiagnosis of hepatitis B as rheumatoid arthritis or lupus erythematosus.
Primary liver cancer may develop after infection with hepatitis B or C.Related posts:
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