It is also known as constitutional hepatic dysfunction, and familial nonhemolytic jaundice.
The condition is harmless, and patients do not need treatment.
In the United States (U.S.), between 3 and 7 percent of people are thought to have Gilbert syndrome, but most do not realize they have it.
Signs and symptoms
Mild jaundice is the only sign that a person has Gilbert syndrome.
Many people with Gilbert syndrome have no symptoms. Around 30 percent find out they have it by chance through routine tests.
Bilirubin is made when the body breaks down red blood cells.
In Gilbert syndrome, the liver does not process bilirubin effectively, due to an inherited genetic abnormality. This causes it to build up in the body.
If a person has too much bilirubin, they will have jaundice, a yellow tinge to the whites of the eyes. The skin, too, can take on a yellowish tinge, if levels rise further.
Extremely high levels of bilirubin can cause itching, but this does not occur in Gilbert's syndrome, because the levels of bilirubin are not that high.
Factors that may result in a mild rise in bilirubin levels and make symptoms more obvious include:
Bilirubin levels do not reach very high levels with Gilbert's syndrome, but the jaundice can be disturbing.
A person with Gilbert's syndrome is unlikely to have specific symptoms, beyond some yellowing of the eyes.
A person is born with Gilbert syndrome, when the gene is passed on from a parent, or parents. An individual is more likely to have it if both parents pass on the gene.
The gene causes hyperbilirubinemia, or elevated blood levels of bilirubin.
This happens because of reduced activity by the enzyme glucuronyltransferase, which conjugates, or converts, bilirubin to a water soluble form after it is released from red blood cells at the end of their 120 day life span.
When the bilirubin becomes water-soluble, the body excretes it in the bile into the duodenum and eventually out of the body in the stool.
A blood test can detect whehter bilirubin levels are higher than usual.
Persons with Gilbert syndrome are usually diagnosed in their late teens or early twenties.
Diagnosis based on the presence of mildly elevated conjugated bilirubin levels in the blood and the proper clinical situation.
Genetic testing is usually not required.
Diagnosis can be confirmed by giving phenobarbital, which lowers bilirubin levels, and intravenous nicotinic acid, which will raise bilirubin levels.
The elevated bilirubin level is either noticed on routine lab tests in patients who have no symptoms or a liver profile is ordered because the patient has jaundice.
If test results show that water-insoluble bilirubin levels are high, but other tests are normal, Gilbert's syndrome is the most likely diagnosis.
A doctor may want to do further tests to make sure the patient does not have another cause of elevated bilirubin. Some of the other causes are more serious than others.
Gilbert's syndrome does not need treatment, but, again, it is important to make sure that the person does not have another, more serious, condition.
Other reasons why bilirubin levels might be high
Other causes of elevated bilirubin include:
Acute inflammation of the liver: Thich could be related to viral infection, prescription drugs, alcohol, or fatty liver.
Inflammation or infection of the bile duct: This is known as cholangitis, and it can be serious,
Hemolytic anemia: Bilirubin levels increases when red blood cells are are destroyed prematurely.
Crigler-Najjar syndrome: This inherited condition impairs the specific enzyme responsible for processing bilirubin, resulting in an excess of bilirubin.
Dubin-Johnson syndrome: an inherited form of chronic jaundice that prevents conjugated bilirubin from being secreted out of the liver's cells.
Pseudojaundice: a harmless form of jaundice in which the yellowing of the skin results from an excess of beta-carotene, not from an excess of bilirubin; usually from eating lots of carrots, pumpkin, or melon.
Tests for these conditions may include:
- an ultrasound scan of the liver
- CT scan of the abdomen
- nuclear medicine scan of the liver and gallbladder
- endoscopic examination of the duodenum
- MRI of the abdomen
- fasting for 24 hours to see if bilirubin levels rise
- genetic testing
Gilbert syndrome is considered harmless, because it does not usually cause any health problems. As a result, no treatment is required.
The symptoms of jaundice may be unsettling, but they are intermittent and nothing to worry about, and long-term monitoring is not typically needed.
If symptoms worsen, the individual should talk to their doctor so that they can rule out any other condition that may have developed.
Gilbert syndrome will not damage the liver. Apart from jaundice, there are no known complications.
Managing Gilbert syndrome
Gilbert syndrome cannot be prevented, as it is an inherited disorder.
People with the condition should make sure their doctor knows they have it, as the additional bilirubin in the system can interfere with some medications.
Drugs that should be avoided, if possible, are:
- Atazanavir and indinavir, used to treat HIV infection
- Gemfibrozil, for lowering cholesterol
- Statins, also used for reducing cholesterol, when taken with gemfibrozil
- Irinotecan, used to treat advanced bowel cancer
- Nilotinib, for the treatment of some blood cancers
Choosing a healthy lifestyle with healthful food and plenty of exercise can help.
Exercise can also help manage stress, reducing the risk of a flareup. Alcohol can make the condition worse.