Elevated liver enzymes are a marker of inflammation or damage to liver cells. Inflamed or injured liver cells cause the liver enzymes alanine transaminase (ALT) and aspartate transaminase (AST) to leak into the bloodstream. Mild elevations of ALT and AST are commonly discovered in individuals with no symptoms during routine blood work. In general, normal ranges for ALT are 7 to 56-units per liter, while normal ranges for AST are 10 to 40-units per liter. Mild elevations of both liver enzymes are 2 to 3-times higher than normal range. Causes of elevated liver enzymes include…
1. Nonalcoholic Fatty Liver Disease. Nonalcoholic fatty liver disease (NAFLD) is the diagnosis used to describe an abnormal accumulation of fat in the liver of individuals who drink little or no alcohol. The disease is common and most individuals with the diagnosis show no signs or symptoms and have no complications. It is the most common cause of elevated liver enzymes. Risk factors for the development of NAFLD include obesity and type 2 diabetes.
2. Alcoholic Liver Disease. Alcoholic liver disease (ALD) represents injury to the liver as a result of alcohol abuse. Acetaldehyde is a toxic chemical produced by the breakdown of alcohol. All scientists agree that acetaldehyde damages the liver. The disease occurs after years of heavy drinking, but not all heavy drinkers go on to develop alcoholic liver disease. The amount of alcohol consumed is the most important risk factor for the development of ALD.
3. Medication-Associated Liver Injury. Many medications have been associated with liver injury and the elevation of liver enzymes. The most common cause of medication-associated liver injury is the over-the-counter pain reliever acetaminophen (Tylenol). Other pain relievers including aspirin, ibuprofen (Advil, Motrin), and naproxen (Aleve) can cause liver injury. Antibiotics can cause medication-associated liver injury.
4. Viral Hepatitis. Viral hepatitis describes inflammation of the liver due to a virus. In the United States, viral hepatitis is most commonly attributed to the hepatitis A virus (HAV), hepatitis B virus (HBV), and hepatitis C virus (HCV). It is estimated that 3.2-million in the United States have chronic hepatitis C, and 1.2-million have chronic hepatitis B. Individuals with chronic hepatitis are at increased to develop both cirrhosis and liver cancer.
5. Hemochromatosis. Hemochromatosis is an inherited disorder of iron metabolism. It is the most common cause of severe iron overload. Excess iron may be deposited into the liver. The abnormal accumulation of iron in the liver causes damage. As a result, levels of liver enzymes begin to elevate, especially AST and ALT. The three types of hemachromatosis are primary hemochromatosis, also known as hereditary hemochromatosis; secondary hemochromatosis; and neonatal hemochromatosis.