Liver function tests 287

suggested that the liver is an important site of HIV replication, too. There have been well-documented cases of liver inflammation during primary HIV infection, the initial flulike syndrome that often precedes seroconversion, and this is a strong indication that HIV attacks liver cells directly.

Liver cancer is not commonly found in any population, but it is increased in HIV positive people. Particularly with the advent of haart, people are living longer and they must also handle the infections that can lead to liver cancer, such as hepatitis B or hepatitis C. Up to one-third of people with Kaposi's sarcoma will have some involvement in the liver, but this generally remains asymptomatic, being found only at autopsy. In lymphoma, the gastrointestinal tract and liver are the most common sites of involvement outside of the lymph nodes. Since the liver processes toxic compounds absorbed by the body, its cells are particularly sensitive to the side effects of medications. Many drugs used in AIDS therapy induce changes in liver enzymes or cause other impairments of liver function. Some common ones that may cause hepato-toxicity are Bactrim, Efavirenz, tuberculosis drugs, NNRTIs, and protease inhibitors.

Naturopaths recommend taking milk thistle, N-acetyl Cysteine (NAC), and other food supplements, to reduce liver toxicity. Although benefits of these are not established, it has been established that milk thistle is not toxic to patients and does not interfere with HAART. NAC is used in medical therapy to reduce toxicities seen in overdoses of acetaminophen, so it too may be helpful in reducing liver toxicity.

liver function The liver has many critical functions, including filtering blood, eliminating toxins, secreting bile (a fluid that helps absorb and digest fat), and making clotting factors. It also converts sugar into triglycerides (lipids) and glycogen (a carbohydrate) to be stored for energy and, between meals, converts triglycerides, glycogen, and amino acids into blood sugar to meet the body's immediate energy needs. The work of the liver is particularly critical to the brain and central nervous system. These tissues receive their energy supply only from sugar, and so are extremely vulnerable to liver failure.

Various tests are available for liver disorders. These include tests for liver function and viral hepatitis. computerized axial tomography (the familiar CAT, or CT, scan) and ultrasound sonograms may also frequently be useful. Liver chemistry tests are an initial means for measuring the liver's condition. High blood levels of two common liver enzymes involved in amino acid breakdown (AST and ALT, also designated as serum glutamic-oxaloacetic transaminase [SGOT] and serum glutamic pyruvic transaminase [SGPT] in lab reports) are a sign of acute liver cell injury. Such damage to cell integrity allows these chemicals to escape from the cells and is associated with viral hepatitis and the toxic effects of drugs and poisons.

Some specialists recommend a liver biopsy for HIV-positive patients with unexplained fever or abnormal liver tests. In this procedure, a segment of tissue is removed with a needle inserted through the skin. The tissue is then examined microscopically.

liver function tests This is a group (a panel) of blood tests that indicates some component of liver function. Several are listed below, as well as the reasoning for taking them.

Alanine aminotransferase (ALT): ALT is an enzyme produced within the cells of the liver. Any form of liver damage can result in an elevation in the ALT. The ALT level may or may not correlate with the degree of damage or inflammation. ALT is the most sensitive and commonly used marker for liver cell damage. Aspartate aminotransferase (AST): AST is not as specific for liver function as the ALT; ratios between ALT and AST are useful to physicians in assessing the possible cause of liver enzyme abnormalities. Gamma glutamic transpeptidase (GGT): Certain GGT levels, as an isolated finding, reflect rare forms of liver disease. Medications commonly cause GGT to be elevated. It is an enzyme that is also produced by the bile ducts, so it may reflect problems there. Alkaline phosphatase: This is an enzyme that is associated with the biliary tract. If the alkaline phosphatase is elevated, biliary tract damage and inflammation should be considered.

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