简体 | 繁体
loading...
海外博客
    • 首页
    • 新闻
    • 读图
    • 财经
    • 教育
    • 家居
    • 健康
    • 美食
    • 时尚
    • 旅游
    • 影视
    • 博客
    • 群吧
    • 论坛
    • 电台
  • 热点
  • 原创
  • 时政
  • 旅游
  • 美食
  • 家居
  • 健康
  • 财经
  • 教育
  • 情感
  • 星座
  • 时尚
  • 娱乐
  • 历史
  • 文化
  • 社区
  • 帮助
您的位置: 文学城 » 博客 »6

6

2005-06-02 19:08:17

人生随缘 看不惯别人是自寻烦恼 .可以不拥有任何东西,除了对生活的激情。好好生活,你的生命是一次性的。
首页 文章页 文章列表 博文目录
给我悄悄话
打印 被阅读次数

Tests That Measure Biosynthetic Function of the Liver

Serum Albumin

Serum albumin is synthesized exclusively by hepatocytes. Serum albumin has a long half-life: 15 to 20 days, with approximately 4% degraded per day. Because of this slow turnover, the serum albumin is not a good indicator of acute or mild hepatic dysfunction; only minimal changes in the serum albumin are seen in acute liver conditions such as viral hepatitis, drug-related hepatoxicity, and obstructive jaundice. In hepatitis, albumin levels <3 g/dL should raise the possibility of chronic liver disease. Hypoalbuminemia is more common in chronic liver disorders such as cirrhosis and usually reflects severe liver damage and decreased albumin synthesis. One exception is the patient with ascites in whom synthesis may be normal or even increased, but levels are low because of the increased volume of distribution. However, hypoalbuminemia is not specific for liver disease and may occur in protein malnutrition of any cause, as well as protein-losing enteropathies, nephrotic syndrome, and chronic infections that are associated with prolonged increases in levels of serum interleukin 1 and/or tumor necrosis factor, cytokines that inhibit albumin synthesis. Serum albumin should not be measured for screening in patients in whom there is no suspicion of liver disease. A general medical clinic study of consecutive patients in whom no indications were present for albumin measurement showed that while 12% of patients had abnormal test results, the finding was of clinical importance in only 0.4%.

Serum Globulins

Serum globulins are a group of proteins made up of gamma globulins (immunoglobulins) produced by B lymphocytes and alpha and beta globulins produced primarily in hepatocytes. Gamma globulins are increased in chronic liver disease, such as chronic hepatitis and cirrhosis. In cirrhosis, the increased serum gamma globulin concentration is due to the increased synthesis of antibodies, some of which are directed against intestinal bacteria. This occurs because the cirrhotic liver fails to clear bacterial antigens that normally reach the liver through the hepatic circulation.

Increases in the concentration of specific isotypes of gamma globulins are often helpful in the recognition of certain chronic liver diseases. Diffuse polyclonal increases in IgG levels are common in autoimmune hepatitis; increases >100% should alert the clinician to this possibility. Increases in the IgM levels are common in primary biliary cirrhosis, while increases in the IgA levels occur in alcoholic liver disease.

Coagulation Factors

With the exception of factor VIII, the blood clotting factors are made exclusively in hepatocytes. Their serum half-lives are much shorter than albumin, ranging from 6 h for factor VII to 5 days for fibrinogen. Because of their rapid turnover, measurement of the clotting factors is the single best acute measure of hepatic synthetic function and helpful in both the diagnosis and assessing the prognosis of acute parenchymal liver disease. Useful for this purpose is the serum prothrombin time, which collectively measures factors II, V, VII, and X. Biosynthesis of factors II, VII, IX, and X depends on vitamin K. The prothrombin time may be elevated in hepatitis and cirrhosis as well as in disorders that lead to vitamin K deficiency such as obstructive jaundice or fat malabsorption of any kind. Marked prolongation of the prothrombin time, >5 s above control and not corrected by parenteral vitamin K administration, is a poor prognostic sign in acute viral hepatitis and other acute and chronic liver diseases.

Coagulation Factors

With the exception of factor VIII, the blood clotting factors are made exclusively in hepatocytes. Their serum half-lives are much shorter than albumin, ranging from 6 h for factor VII to 5 days for fibrinogen. Because of their rapid turnover, measurement of the clotting factors is the single best acute measure of hepatic synthetic function and helpful in both the diagnosis and assessing the prognosis of acute parenchymal liver disease. Useful for this purpose is the serum prothrombin time, which collectively measures factors II, V, VII, and X. Biosynthesis of factors II, VII, IX, and X depends on vitamin K. The prothrombin time may be elevated in hepatitis and cirrhosis as well as in disorders that lead to vitamin K deficiency such as obstructive jaundice or fat malabsorption of any kind. Marked prolongation of the prothrombin time, >5 s above control and not corrected by parenteral vitamin K administration, is a poor prognostic sign in acute viral hepatitis and other acute and chronic liver diseases.

Other Diagnostic Tests

While tests may direct the physician to a category of liver disease, additional radiologic testing and procedures are often necessary to make the proper diagnosis, as shown in Fig. 283-1. The two most commonly used ancillary tests are reviewed here.

Percutaneous Liver Biopsy

Percutaneous biopsy of the liver is a safe procedure that can be easily performed at the bedside with local anesthesia. Liver biopsy is of proven value in the following situations: (1) hepatocellular disease of uncertain cause, (2) prolonged hepatitis with the possibility of chronic active hepatitis, (3) unexplained hepatomegaly, (4) unexplained splenomegaly, (5) hepatic filling defects by radiologic imaging, (6) fever of unknown origin, (7) staging of malignant lymphoma. Liver biopsy is most accurate in disorders causing diffuse changes throughout the liver and is subject to sampling error in focal infiltrative disorders such as hepatic metastases. Liver biopsy should not be the initial procedure in the diagnosis of cholestasis. The biliary tree should first be assessed for signs of obstruction.

Ultrasonography

Ultrasonography is the first diagnostic test to use in patients whose liver tests suggest cholestasis, to look for the presence of a dilated intrahepatic or extrahepatic biliary tree or to identify gallstones. In addition, it shows space-occupying lesions within the liver, enables the clinician to distinguish between cystic and solid masses, and helps direct percutaneous biopsies. Ultrasound with Doppler imaging can detect the patency of the portal vein, hepatic artery, and hepatic veins and determine the direction of blood flow. This is the first test ordered in patients suspected of having Budd-Chiari syndrome.

登录后才可评论.
  • 文学城简介
  • 广告服务
  • 联系我们
  • 招聘信息
  • 注册笔名
  • 申请版主
  • 收藏文学城

WENXUECITY.COM does not represent or guarantee the truthfulness, accuracy, or reliability of any of communications posted by other users.

Copyright ©1998-2025 wenxuecity.com All rights reserved. Privacy Statement & Terms of Use & User Privacy Protection Policy

今日热点

  • 武汉封城市长周先旺被抓雅美之途
  • 几十年后我还在玩的DOS游戏硅谷居士
  • 陈立仁案为何会牵扯出前女友?小雨如酥
  • 退休生活的一抹风景:抱团旅行的温暖与快乐远远的雾
  • 马克谈天下(511) 为什么我依然对美国有信心markyang
  • 我的生活处于一个非常奇怪的状态,如何选择?来来往往2020
  • 特朗普关税战将如何落幕?朱头山
  • 怕儿媳的婆婆 & 失而复得的闺蜜(图)——母亲节非甜品 (7)悉采心
  • 纽约琐事(六十六)保姆跑了Miken
  • 不低头的硬汉,怀念北京大学数学系程庆民先生秋立
  • 送别章立凡:一个亲属眼中的复杂身影Spring_北美08
  • 再论毛泽东感谢日本侵华金笔
  • 不是你的问题,是 ZIP Code 的锅徐徐道来
  • 读书改变命运我爱丁二酸钠

一周热点

  • 我家后院子的花草瓜菜都长疯了!mychina
  • 2025年回国感想九月红豆
  • 2025上半年三地股市见闻: 投资与做人康赛欧
  • 从移民到总统, 祝你生日快乐BeijingGirl1
  • 又参观了一个老人公寓帕格尼尼
  • 人间清醒与人间糊涂多伦多橄榄树
  • 吃得就是任性!国庆节挑战105磅巨无霸汉堡爪四哥
  • 进攻伊朗犯了战略错误朱头山
  • 伊朗女生、韩国女生、加拿大女生:做爱彼迎民宿教育了我SUDreamers
  • BeijingGirl1真的被封号了吗?硅谷居士
  • 以色列——被逐出欧洲家园犹太人的无奈归宿(一)橡溪
  • 国庆,《大而美法案》后的税务变化有哪些?(图)菲儿天地
  • 终究被女儿嫌弃了广陵晓阳
  • 美国梦碎:精英女儿出圈了。。。岸沚汀兰
6
切换到网页版

6

(2005-06-02 19:08:17) 评论 (1)

Tests That Measure Biosynthetic Function of the Liver

Serum Albumin

Serum albumin is synthesized exclusively by hepatocytes. Serum albumin has a long half-life: 15 to 20 days, with approximately 4% degraded per day. Because of this slow turnover, the serum albumin is not a good indicator of acute or mild hepatic dysfunction; only minimal changes in the serum albumin are seen in acute liver conditions such as viral hepatitis, drug-related hepatoxicity, and obstructive jaundice. In hepatitis, albumin levels <3 g/dL should raise the possibility of chronic liver disease. Hypoalbuminemia is more common in chronic liver disorders such as cirrhosis and usually reflects severe liver damage and decreased albumin synthesis. One exception is the patient with ascites in whom synthesis may be normal or even increased, but levels are low because of the increased volume of distribution. However, hypoalbuminemia is not specific for liver disease and may occur in protein malnutrition of any cause, as well as protein-losing enteropathies, nephrotic syndrome, and chronic infections that are associated with prolonged increases in levels of serum interleukin 1 and/or tumor necrosis factor, cytokines that inhibit albumin synthesis. Serum albumin should not be measured for screening in patients in whom there is no suspicion of liver disease. A general medical clinic study of consecutive patients in whom no indications were present for albumin measurement showed that while 12% of patients had abnormal test results, the finding was of clinical importance in only 0.4%.

Serum Globulins

Serum globulins are a group of proteins made up of gamma globulins (immunoglobulins) produced by B lymphocytes and alpha and beta globulins produced primarily in hepatocytes. Gamma globulins are increased in chronic liver disease, such as chronic hepatitis and cirrhosis. In cirrhosis, the increased serum gamma globulin concentration is due to the increased synthesis of antibodies, some of which are directed against intestinal bacteria. This occurs because the cirrhotic liver fails to clear bacterial antigens that normally reach the liver through the hepatic circulation.

Increases in the concentration of specific isotypes of gamma globulins are often helpful in the recognition of certain chronic liver diseases. Diffuse polyclonal increases in IgG levels are common in autoimmune hepatitis; increases >100% should alert the clinician to this possibility. Increases in the IgM levels are common in primary biliary cirrhosis, while increases in the IgA levels occur in alcoholic liver disease.

Coagulation Factors

With the exception of factor VIII, the blood clotting factors are made exclusively in hepatocytes. Their serum half-lives are much shorter than albumin, ranging from 6 h for factor VII to 5 days for fibrinogen. Because of their rapid turnover, measurement of the clotting factors is the single best acute measure of hepatic synthetic function and helpful in both the diagnosis and assessing the prognosis of acute parenchymal liver disease. Useful for this purpose is the serum prothrombin time, which collectively measures factors II, V, VII, and X. Biosynthesis of factors II, VII, IX, and X depends on vitamin K. The prothrombin time may be elevated in hepatitis and cirrhosis as well as in disorders that lead to vitamin K deficiency such as obstructive jaundice or fat malabsorption of any kind. Marked prolongation of the prothrombin time, >5 s above control and not corrected by parenteral vitamin K administration, is a poor prognostic sign in acute viral hepatitis and other acute and chronic liver diseases.

Coagulation Factors

With the exception of factor VIII, the blood clotting factors are made exclusively in hepatocytes. Their serum half-lives are much shorter than albumin, ranging from 6 h for factor VII to 5 days for fibrinogen. Because of their rapid turnover, measurement of the clotting factors is the single best acute measure of hepatic synthetic function and helpful in both the diagnosis and assessing the prognosis of acute parenchymal liver disease. Useful for this purpose is the serum prothrombin time, which collectively measures factors II, V, VII, and X. Biosynthesis of factors II, VII, IX, and X depends on vitamin K. The prothrombin time may be elevated in hepatitis and cirrhosis as well as in disorders that lead to vitamin K deficiency such as obstructive jaundice or fat malabsorption of any kind. Marked prolongation of the prothrombin time, >5 s above control and not corrected by parenteral vitamin K administration, is a poor prognostic sign in acute viral hepatitis and other acute and chronic liver diseases.

Other Diagnostic Tests

While tests may direct the physician to a category of liver disease, additional radiologic testing and procedures are often necessary to make the proper diagnosis, as shown in Fig. 283-1. The two most commonly used ancillary tests are reviewed here.

Percutaneous Liver Biopsy

Percutaneous biopsy of the liver is a safe procedure that can be easily performed at the bedside with local anesthesia. Liver biopsy is of proven value in the following situations: (1) hepatocellular disease of uncertain cause, (2) prolonged hepatitis with the possibility of chronic active hepatitis, (3) unexplained hepatomegaly, (4) unexplained splenomegaly, (5) hepatic filling defects by radiologic imaging, (6) fever of unknown origin, (7) staging of malignant lymphoma. Liver biopsy is most accurate in disorders causing diffuse changes throughout the liver and is subject to sampling error in focal infiltrative disorders such as hepatic metastases. Liver biopsy should not be the initial procedure in the diagnosis of cholestasis. The biliary tree should first be assessed for signs of obstruction.

Ultrasonography

Ultrasonography is the first diagnostic test to use in patients whose liver tests suggest cholestasis, to look for the presence of a dilated intrahepatic or extrahepatic biliary tree or to identify gallstones. In addition, it shows space-occupying lesions within the liver, enables the clinician to distinguish between cystic and solid masses, and helps direct percutaneous biopsies. Ultrasound with Doppler imaging can detect the patency of the portal vein, hepatic artery, and hepatic veins and determine the direction of blood flow. This is the first test ordered in patients suspected of having Budd-Chiari syndrome.