Diseases & Conditions

Gilbert syndrome

Gilbert (zheel-BAYR) syndrome is a common, mild liver disorder in which the liver doesn't properly process a substance called bilirubin. Bilirubin is produced by the breakdown of red blood cells. Also known as constitutional hepatic dysfunction, unconjugated benign bilirubinemia and familial nonhemolytic jaundice, Gilbert syndrome typically doesn't require treatment or pose serious complications.

In fact, Gilbert syndrome is usually not considered a disease because of its benign nature. You most often find out you have the disorder by accident, when you have a blood test that shows elevated bilirubin levels.

Gilbert syndrome affects 3 percent to 7 percent of the U.S. population. Worldwide estimations vary, and no good measure exists. More males than females have the condition.

If you have Gilbert syndrome, you have inherited an abnormal gene that controls the enzyme that helps break down bilirubin. Bilirubin is a yellowish pigment and is a normal waste product from the breakdown of old red blood cells. Bilirubin travels through your bloodstream to the liver. Normally an enzyme in liver cells breaks down the bilirubin and removes it from the bloodstream. The bilirubin passes from the liver into the intestines with bile. It's then excreted in stool. A small amount of bilirubin remains in the blood.

When you have Gilbert syndrome, you have a lower level of the enzyme that breaks down bilirubin. Consequently, excessive amounts of a form of bilirubin called unconjugated bilirubin can build up in your blood.

If you notice a yellowish tinge to your skin or the normally white portions of your eyes, let your doctor know as soon as possible. A variety of conditions other than Gilbert syndrome can cause jaundice, and medical tests and exams can rule out serious illnesses.

Check with your doctor before taking new medications and take care not to consume higher than recommended doses of acetaminophen (Tylenol, others). You may be at greater risk of liver side effects for these or other drugs.

Often found by accident or if you have jaundice
If you have jaundice, your doctor may suspect that you have Gilbert syndrome or perhaps another condition. Often, though, Gilbert is found purely by accident when you have blood tests for other health reasons. Although it's present from birth, Gilbert syndrome usually isn't diagnosed until puberty or later, when bilirubin production increases.

Blood tests
Your doctor may do a physical exam and order additional blood tests. With Gilbert syndrome, unless you have an episode of jaundice, there are no physical signs or symptoms.

Common blood tests include:

• Complete blood count (CBC)
• Liver function tests

A diagnosis of Gilbert syndrome can usually be made from blood tests. With Gilbert syndrome, all of the results will typically be normal except for the mildly increased level of unconjugated bilirubin.

When you have Gilbert syndrome, the level of bilirubin in your blood may fluctuate. It's not always higher than the normal range. If your initial blood test shows a normal level of bilirubin, your doctor may suggest repeating the tests a couple of times.

Tests that help rule out other conditions
Rarely, your doctor may suggest other tests, including:

• An ultrasound of your liver
• Fasting for a 24-hour period to see if that increases bilirubin levels
• Genetic testing, which is not widely available, to check for the abnormal gene that causes Gilbert syndrome

When you have jaundice or a high bilirubin level, it's important to ensure that you don't have a more serious liver condition such as hepatitis or an obstructed bile duct. Your doctor may recommend other tests to check for such conditions.

Jaundice
Gilbert syndrome can cause episodes of jaundice. However, the jaundice is usually mild and goes away on its own. There are no other known complications of the condition, and it won't damage your liver.

More side effects with certain medications
The low level of the bilirubin-processing enzyme may cause increased side effects with certain medications because this enzyme helps eliminate these medications. In particular, irinotecan (Camptosar), a medication used to treat colon cancer, can reach toxic levels if you have Gilbert syndrome, causing severe diarrhea. Because of this potential effect with certain medications, talk to your doctor before taking any new medications if you have Gilbert syndrome.

Because Gilbert syndrome is essentially a mild, harmless condition, it doesn't require treatment. The level of jaundice associated with Gilbert syndrome is typically harmless as well, and goes away on its own.

If you have Gilbert syndrome, you don't typically need long-term monitoring of your condition or repeat blood tests. But consult your doctor if you notice worsening jaundice or other symptoms.

If you're concerned about jaundice, the barbiturate medication phenobarbital may reduce bilirubin levels but can have side effects such as sedation and lightheadedness.