A dogmatic but true medical statement is that there are no trivial elevations of liver enzymes. In other words, every case of liver enzyme elevation needs to be explained. Causes of liver enzyme elevation can be sorted into disorders of cholestasis and disorders of hepatocellular (liver) injury. Cholestatic disorders, where bile is prevented from leaving the liver by a blockage of the common bile duct (gallstone in the duct, pancreatitis, or tumor), tend to cause elevations in alkaline phosphatase, bilirubin, and gamma-glutamyl transferase, or GGT. Hepatocellular injury (hepatitis) raises levels of alanine aminotransferase (ALT) and aspartate aminotransferase (AST). The most common causes of liver enzyme elevation are alcohol use and toxicity, medication side effects, and fatty liver disease. “Significant” alcohol consumption is defined as more than 21 drinks a week in men and more than 14 in women, over a period of two years or more. Consumption of alcohol within five days of a routine blood test may cause enzyme elevations.
When evaluating enzyme elevations, a detailed medication history must be obtained. Focus should be placed on recently-added medications, dosage changes, medication overuse, and non-prescription medications and herbal supplements. Medications that may cause enzyme elevations include statins (usually seen within three months of beginning therapy), non-steroidal anti-inflammatory drugs (NSAIDs like Motrin, Aleve, etc.), anti-seizure drugs, antibiotics, anabolic steroids (i.e. testosterone), and acetaminophen (Tylenol). Tylenol overdoses may be fatal because of liver failure. Risk factors for viral hepatitis should be investigated. These risk factors include IV drug use, blood transfusions, unprotected sexual contact, organ transplantation, a history of work in a medical facility, and a history of travel to areas where hepatitis A or E is endemic (i.e. Southeast Asia).
Fatty liver disease is extremely common in the U.S. Estimates are that one third of the U.S. population, or 100 million people, suffers from non-alcoholic fatty liver disease. It is more common in men than women and is present in 80 to 90 percent of obese adults, two thirds of adults with type 2 diabetes, and many people with hyperlipidemia (high cholesterol). It is also seen to some degree in 40 to 70 percent of obese children. Hereditary hemochromatosis, a disorder of iron overload, is the most common inherited liver disorder in adults of European descent. It causes cirrhosis but, if caught early, is very treatable. Diagnosing it can be challenging, however, as it causes no symptoms until late in the disease. It does cause liver enzyme elevations, even early in the disease process. Early symptoms may include severe fatigue, joint pains, and, in men, impotence. Later on, it causes the appearance of the classic triad, known as “bronze diabetes,” with cirrhosis, diabetes, and darkening of the skin.
When you visit your doctor for a routine checkup, as all adults should, be sure to ask the doctor to include a liver enzyme panel. But be sure to abstain from alcohol for at least three days beforehand so as not to cause an accidental and misleading enzyme elevation.