Alanine aminotransferase, or ALT, and aspartate aminotransferase, AST, are the liver enzymes. ALT is mainly found in the liver, while AST is found in the liver and other tissues, organs and cells. These two enzymes are also normally in the bloodstream in small amounts, but are elevated whenever there is damage in the liver cells.
Alcohol
Approximately 45 to 50 percent of American adults drink alcohol, while an estimated seven to 10 percent abuse its use, according to Patrick O'Connor, M.D., Chief of the Section of General Internal Medicine at Yale University School of Medicine in "The Merck Manual for Healthcare Professionals." The long-term use of large amounts of alcohol can damage the liver and cause alcoholic hepatitis, fatty liver or cirrhosis of the liver. Alcoholic hepatitis is the inflammation of the liver due to alcohol. Fatty liver is a disorder where fats accumulate in the liver, and it is usually caused by alcohol. Cirrhosis is the final stage of a damaged liver.
Viral Hepatitis
Viral hepatitis is liver inflammation due to a viral infection. Five main viruses cause this disease, with the names of hepatitis A virus through the hepatitis E virus. The hepatitis A virus spreads through poor sanitation and through eating contaminated seafood. Since the vaccine was first introduced, the infection has decreased by 76 percent, per Lawrence Friedman, M.D., Assistant Chief of Medicine at Massachusetts General Hospital in "Current Medical Diagnosis & Treatment." The hepatitis B and C viruses can transmit through the needles of IV drug users. Hepatitis B can also be sexually transmitted, while hepatitis C can also be transmitted through tattoos and body piercing. Only those with hepatitis B can contract the hepatitis D virus. Hepatitis E is rare in America.
Medications
Thirty-one to 44 percent of the people who take four grams of acetaminophen every day for 14 days have elevated liver enzymes, writes Jules Dienstag, M.D., Professor of Medicine at Harvard Medical School in "Harrison's Principles of Internal Medicine." Four grams is the maximum recommended dose. Acetaminophen is primarily broken down and detoxified in the liver and when the liver is overwhelmed, liver damage occurs. Approximately one to two percent of those who take statin medications have elevated liver enzyme levels. Statins are taken to lower the LDL cholesterol levels. Dr. Dienstag writes that an additional number of people have small increases in the first weeks of taking this medication.
Hemochromatosis
Hemochromatosis is a hereditary disease and more than 80 percent of the cases are due to a gene mutation, according to Eugene Frenkel, M.D., Professor of Internal Medicine and Radiology at the University of Texas Southwestern Medical Center in "The Merck Manual for Healthcare Professionals." In this disease, too much iron is absorbed in the small intestines. The increased amount of iron is then deposited in the heart, kidneys, testes, joints, adrenal glands, pituitary gland, skin, pancreas and liver. Dr. Frenkel writes that liver damage is the main complication and the number one cause of death. Some of those with liver damage will develop cirrhosis and liver cancer.
References
- "Current Medical Diagnosis & Treatment 2011"; Stephen McPhee, M.D., Maxine Papadakis, M.D.; 2011
- "Harrison's Principles of Internal Medicine"; Anthony Fauci, M.D., Dennis Kasper, M.D., Dan Longo, M.D. et al.; 2008
- The Merck Manual for Healthcare Professionals: Alcohol
- The Merck Manual for Healthcare Professionals: Primary Hemochromatosis
