Fatty liver disease, also known as hepatic steatosis, is most often associated with alcoholism, but it may occur in patients who are not heavy drinkers. In these individuals, common causes include obesity, diabetes, elevated triglycerides, endocrine diseases such as Cushing syndrome, and medications such as steroids. Symptoms are usually mild, with or without liver enlargement and elevated liver enzymes.
Most patients with fatty infiltration of the liver do not have symptoms or may experience mild discomfort. The discomfort is usually described as dull or achy and is most commonly located in the right upper quadrant of the abdomen, or the space above and to the right of the navel and below the rib cage. This corresponds to the liver's location.
Hepatomegaly, or liver enlargement, is the most common sign associated with fatty liver disease. A physician can assess the liver's size by means of a physical exam. Enlargement may also be demonstrated by the use of various imaging modalities, including ultrasound, CT or MRI. However, these modalities do not distinguish fatty inflitration from other causes of liver enlargement, such as hepatitis. Liver biopsy may be required in cases where the diagnosis is unclear.
Laboratory studies may show mildly elevated levels of liver enzymes, which indicate damage to the liver and the release of cellular contents. Most frequently the aminotransferases, ALT and AST, are mildly elevated; however, laboratory values may be normal in up to 80 percent of persons with fatty liver disease not caused by alcohol. Alcoholics, on the other hand, almost always show an elevation of ALT greater than AST.