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Hepatitis
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What is Hepatitis ? H epatitis is an inflammation of the liver. The word comes from a combination of two Greek words: "Hepatos-" ("liver"), and "-itis" ("inflammation"). The inflammation of the liver (hepatitis) can be caused by several factors: - viruses - viral hepatitis is caused by several viruses that attack mainly the liver. The viruses identified until now have been named as A, B, C, D, E, and G, from which A and E are contagious. - toxic agents - alcohol, drugs or other chemicals. - auto-immune disorders. Chronic Hepatitis If inflammation and necrosis of hepatocytes persist for more than 6 months we are dealing with chronic hepatitis. Based on histological criteria, chronic hepatitis classification is as follows: · chronic persistent; · chronic lobular and · chronic active hepatitis. A) Chronic Persistent Hepatitis and Chronic Lobular Hepatitis They usually follow acute hepatitis B or C. These disorders may persist for years, but are mild and rarely progress to chronic active hepatitis or cirrhosis. Clinical features for both are : · vague or no symptoms (anorexia, weakness and nausea) · clinical signs are absent. Sometimes liver enlargement can be detected · persistently high transaminase values Liver biopsy shows: · Chronic Persistent Hepatitis: portal mononuclear inflammation (portal hepatitis) without significant fibrosis or acinar disarray (signs of evolution into cirrhosis). · Chronic Lobular Hepatitis: diffuse lobular inflammation, with features of persisting acute hepatitis. There is low portal infiltrate. No signs of evolution into cirrhosis. Treatment is not necessary and natural recovery is usual. However, periodic controls are recommended. B) Chronic Active Hepatitis It's a serious disorder that has a general tendency to progress to hepatic cirrhosis and possibly even primary liver cancer. Histologically it's characterized by: a) Inflammation - Initially a lymphocytic portal reaction is present and lymphocytes infiltrate progressively the acini, causing considerable necrosis of hepatocytes (spotty and confluent necrosis). b) Fibrosis Necrosis of hepatocytes causes collapse of the reticular strome that supports liver cells. Then an irreversible deposition of collagen (fibrosis) occurs. Zones of collapse, fibrosis and abnormal hepatocellular regeneration (nodular regeneration) lead to distortion of the acinar architecture, which is characteristic for liver cirrhosis. The histological activity of Chronic Active Hepatitis is a concept that takes into account both inflammatory infiltration and hepatocellular damage that lead to fibrosis. Inflammatory activity defines grade (mild, moderate or severe) of Chronic Active Hepatitis, and therefore its prognosis (probability of evolution into cirrhosis), and is to a great extent reversible with therapy. The degrees of fibrosis express the stage reached by Chronic Active Hepatitis into its evolution to cirrhosis. It is irreversible, but therapy, reducing inflammation, can lessen or stop its progression.
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