Bilirubin and Liver Disease/Hepatitis
Bilirubin is the yellow-colored pigment that the liver produces when it recycles worn-out red blood cells. Normal bilirubin levels are less than 1 mg/dl (milligram per deciliter). When levels become elevated, eyes and skin may turn yellow (jaundice), urine may appear a dark-tea color, and stools may look like light colored clay. Elevated bilirubin, while not the most common abnormality in blood tests pertaining to the liver, is quite obvious on a physical exam, and it is the liver-related abnormality most familiar to the general public.
A phrase doctors often hear from their patients is, “I can’t have liver disease, I’m not yellow.” People are often surprised to discover that most people with liver disease will never become yellow. In fact, many bilirubin elevations are not even related to liver disease at all. Bilirubin metabolism is very complex and consists of many steps. A problem with any one of these steps results in an abnormally high level of bilirubin. As it pertains to the liver, an elevated bilirubin level is usually associated with worsening liver disease or with bile duct blockage (cholestasis). Some possible causes of a high bilirubin level include the following:
• Primary biliary cirrhosis
• Primary sclerosing cholangitis
• Alcoholic hepatitis
• Hemolysis—red blood cell (RBC) destruction
• Drug-induced liver disease
• Choledocholithiasis (gallstones in the bile duct)
• Liver failure or general worsening of liver disease
• Tumors affecting the liver, bile ducts, or gallbladder
• Viral hepatitis
• Benign familial disorders of bilirubin metabolism, such as Gilbert’s syndrome (see below)
Bilirubin elevations are often associated with GGT and AP level elevations (discussed in my book). When elevated levels of bilirubin and GGT and AP occur concurrently, a person is referred to as being cholestatic. However, if the bilirubin level remains normal and the GGT and AP remain elevated, the person is known as having anicteric cholestasis. Diseases marked by elevations of bilirubin, GGT, and AP are known as cholestatic liver diseases.
A Word About Gilbert’s Syndrome
Gilbert’s syndrome is a very common, albeit benign, inherited disorder of bilirubin breakdown (metabolism). It occurs in approximately 4-9 percent of the population. It is characterized by intermittently elevated bilirubin levels. The presence of Gilbert’s syndrome is usually discovered when blood tests are routinely performed, or when they are performed for the evaluation of an unrelated problem, or for preemployment or preinsurance screening. Bilirubin levels usually rise to about 3 mg/dl, but rarely do they go any higher than 5 mg/dl. Levels typically increase during periods of fasting, stress, menstruation, or during the course of an unrelated illness or infection. Jaundice is the only abnormality found on physical exam. Some people complain of nonspecific symptoms such as abdominal discomfort, nausea or fatigue. However, some experts feel that these symptoms are due to anxiety. All other LFTs are normal. Imaging studies, such as a liver sonogram and liver biopsy are not indicated. However, they should be normal if performed. No long-term complications arise from this harmless syndrome, and no therapy is required.
All contents of this article are Copyright © Melissa Palmer, MD
Melissa Palmer, MD is the author of " Dr. Melissa Palmer's Guide of Hepatitis and Liver Disease". (Published 2004. Penguin Putnam).
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