Jaundice

What is jaundice?

Jaundice is not a disease but rather a sign that can occur in many different diseases. Jaundice is the yellowish staining of the skin and sclerae (the whites of the eyes) that is caused by high levels in blood of the chemical bilirubin. The color of the skin and sclerae vary depending on the level of bilirubin. When the bilirubin level is mildly elevated, they are yellowish. When the bilirubin level is high, they tend to be brown.

What causes jaundice?

Bilirubin comes from red blood cells. When red blood cells get old, they are destroyed. Hemoglobin, the iron-containing chemical in red blood cells that carries oxygen, is released from the destroyed red blood cells after the iron it contains is removed. The chemical that remains in the blood after the iron is removed becomes bilirubin.

The liver has many functions. One of the liver's functions is to produce and secrete bile into the intestines to help digest dietary fat. Another is to remove toxic chemicals or waste products from the blood, and bilirubin is a waste product. The liver removes bilirubin from the blood. After the bilirubin has entered the liver cells, the cells conjugate (attaching other chemicals, primarily glucuronic acid) to the bilirubin, and then secrete the bilirubin/glucuronic acid complex into bile. The complex that is secreted in bile is called conjugated bilirubin. The conjugated bilirubin is eliminated in the feces. (Bilirubin is what gives feces its brown color.) Conjugated bilirubin is distinguished from the bilirubin that is released from the red blood cells and not yet removed from the blood which is termed unconjugated bilirubin.

Jaundice occurs when there is 1) too much bilirubin being produced for the liver to remove from the blood. (For example, patients with hemolytic anemia have an abnormally rapid rate of destruction of their red blood cells that releases large amounts of bilirubin into the blood), 2) a defect in the liver that prevents bilirubin from being removed from the blood, converted to bilirubin/glucuronic acid (conjugated) or secreted in bile, or 3) blockage of the bile ducts that decreases the flow of bile and bilirubin from the liver into the intestines. (For example, the bile ducts can be blocked by cancers, gallstones, or inflammation of the bile ducts). The decreased conjugation, secretion, or flow of bile that can result in jaundice is referred to as cholestasis: however, cholestasis does not always result in jaundice.

What problems does jaundice cause?



Jaundice or cholestasis, by themselves, causes few problems (except in the newborn, and jaundice in the newborn is different than most other types of jaundice, as discussed later.) Jaundice can turn the skin and sclerae yellow. In addition, stool can become light in color, even clay-colored because of the absence of bilirubin that normally gives stool its brown color. The urine may turn dark or brownish in color. This occurs when the bilirubin that is building up in the blood begins to be excreted from the body in the urine. Just as in feces, the bilirubin turns the urine brown.



Besides the cosmetic issues of looking yellow and having dark urine and light stools, the symptom that is associated most frequently associated with jaundice or cholestasis is itching, medically known as pruritus. The itching associated with jaundice and cholestasis can sometimes be so severe that it causes patients to scratch their skin "raw," have trouble sleeping, and, rarely, even to commit suicide.

It is the disease causing the jaundice that causes most problems associated with jaundice. Specifically, if the jaundice is due to liver disease, the patient may have symptoms or signs of liver disease or cirrhosis.

If the jaundice is caused by blockage of the bile ducts, no bile enters the intestine. Bile is necessary for digesting fat in the intestine and releasing vitamins from within it so that the vitamins can be absorbed into the body. Therefore, blockage of the flow of bile can lead to deficiencies of certain vitamins. For example, there may be a deficiency of vitamin K that prevents proteins that are needed for normal clotting of blood to be made by the liver, and, as a result, uncontrolled bleeding may occur.

What diseases cause jaundice?

Increased production of bilirubin
There are several uncommon conditions that give rise to over-production of bilirubin. These conditions include: 1) rapid destruction of red blood cells (referred to as hemolysis), 2) a defect in the formation of red blood cells that leads to the over-production of hemoglobin in the bone marrow (called ineffective erythropoiesis), or 3) absorption of large amounts of hemoglobin when there has been much bleeding into tissues (e.g., from hematomas, collections of blood in the tissues).

Acute inflammation of the liver
Any condition in which the liver becomes inflamed can reduce the ability of the liver to conjugate (attach glucuronic acid to) and secrete bilirubin. Common examples include acute viral hepatitis, alcoholic hepatitis, and Tylenol-induced liver toxicity.

Chronic liver diseases
Chronic inflammation of the liver can lead to scarring and cirrhosis, and can ultimately result in jaundice. Common examples include chronic hepatitis B and C, alcoholic liver disease with cirrhosis, and autoimmune hepatitis.

Infiltrative diseases of the liver
Infiltrative diseases of the liver refer to diseases in which the liver is filled with cells or substances that don't belong there. The most common example would be metastatic cancer to the liver, usually from cancers within the abdomen. Uncommon causes include a few diseases in which substances accumulate within the liver cells, for example, iron (hemochromatosis), alpha-one antitrypsin (alpha-one antitrypsin deficiency), and copper (Wilson's disease).

Inflammation of the bile ducts
Diseases causing inflammation of the bile ducts, for example, primary biliary cirrhosis or sclerosing cholangitis and some drugs, can stop the flow of bile and elimination of bilirubin and lead to jaundice.

Blockage of the bile ducts
The most common causes of blockage of the bile ducts are gallstones and pancreatic cancer. Less common causes include cancers of the liver and bile ducts.

Drugs
Many drugs can cause jaundice and/or cholestasis. Some drugs can cause liver inflammation (hepatitis) similar to viral hepatitis. Other drugs can cause inflammation of the bile ducts, resulting in cholestasis and/or jaundice. Drugs also may interfere directly with the chemical processes within the cells of the liver and bile ducts that are responsible for the formation and secretion of bile to the intestine. As a result, the constituents of bile, including bilirubin, are retained in the body.

Genetic disorders
There are several rare genetic disorders present from birth that give rise to jaundice. Crigler-Najjar syndrome is caused by a defect in the conjugation of bilirubin in the liver due to a reduction or absence of the enzyme responsible for conjugating the glucuronic acid to bilirubin. Dubin-Johnson and Rotor's syndromes are caused by abnormal secretion of bilirubin into bile.

The only common genetic disorder that may cause jaundice is Gilbert's syndrome which affects approximately 7% of the population. Gilbert's syndrome is caused by a mild reduction in the activity of the enzyme responsible for conjugating the glucuronic acid to bilirubin.

Developmental abnormalities of bile ducts
There are rare instances in which the bile ducts do not develop normally and the flow of bile is interrupted. Jaundice frequently occurs. These diseases usually are present from birth though some of them may first be recognized in childhood or even adulthood. Cysts of the bile duct (choledochal cysts) are an example of such a developmental abnormality. Another example is Caroli's disease.

Jaundice of pregnancy
Most of the diseases discussed previously can affect women during pregnancy, but there are some additional causes of jaundice that are unique to pregnancy.

Pre-eclampsia. Pre-eclampsia, previously called toxemia of pregnancy, is a disease that occurs during the second half of pregnancy and involves several systems within the body, including the liver. It may result in high blood pressure, fluid retention, and damage to the kidneys as well as anemia and reduced numbers of platelets due to destruction of red blood cells and platelets. It often causes problems for the fetus.

Acute fatty liver of pregnancy. Acute fatty liver of pregnancy (AFLP) is a very serious complication of pregnancy of unclear cause that often is associated with pre-eclampsia. It occurs late in pregnancy and results in failure of the liver. It can almost always be reversed by immediate delivery of the fetus.

How is the cause of jaundice diagnosed?

Many tests are available for determining the cause of jaundice, but the history and physical examination are important as well.

History
The history can suggest possible reasons for the jaundice. For example, heavy use of alcohol suggests alcoholic liver disease, whereas use of illegal, injectable drugs suggests viral hepatitis. Recent initiation of a new drug suggests drug-induced jaundice. Episodes of abdominal pain associated with jaundice suggests blockage of the bile ducts usually by gallstones.

Physical examination
The most important part of the physical examination in a patient who is jaundiced is examination of the abdomen. Masses (tumors) in the abdomen suggest cancer infiltrating the liver (metastatic cancer) as the cause of the jaundice. An enlarged, firm liver suggests cirrhosis. A rock-hard, nodular liver suggests cancer within the liver.

Blood tests
Measurement of bilirubin can be helpful in determining the causes of jaundice. Markedly greater elevations of unconjugated bilirubin relative to elevations of conjugated bilirubin in the blood suggest hemolysis (destruction of red blood cells). Marked elevations of liver tests (aspartate amino transferase or AST and alanine amino transferase or ALT) suggest inflammation of the liver (such as viral hepatitis). Elevations of other liver tests, e.g., alkaline phosphatase, suggest diseases or obstruction of the bile ducts.

Ultrasonography
Ultrasonography is a simple, safe, and readily-available test that uses sound waves to examine the organs within the abdomen. Ultrasound examination of the abdomen may disclose gallstones, tumors in the liver or the pancreas, and dilated bile ducts due to obstruction (by gallstones or tumor).

Computerized tomography (CT or CAT scans)
Computerized tomography or CT scans are scans that use x-rays to examine the soft tissues of the abdomen. They are particularly good for identifying tumors in the liver and the pancreas and dilated bile ducts, though they are not as good as ultrasonography for identifying gallstones.

Magnetic resonance imaging (MRI)
Magnetic Resonance Imaging scans are scans that utilize magnetization of the body to examine the soft tissues of the abdomen. Like CT scans, they are good for identifying tumors and studying bile ducts. MRI scans can be modified to visualize the bile ducts better than CT scans (a procedure referred to as MR cholangiography), and, therefore, are better than CT for identifying the cause and location of bile duct obstruction.

Endoscopic retrograde cholangiopancreatography (ERCP) and endoscopic ultrasound

Endoscopic retrograde cholangiopancreatography (ERCP) provides the best means for examining the bile duct. For ERCP an endoscope is swallowed by the patient after he or she has been sedated. The endoscope is a flexible, fiberoptic tube approximately four feet in length with a light and camera on its tip. The tip of the endoscope is passed down the esophagus, through the stomach, and into the duodenum where the main bile duct enters the intestine. A thin tube then is passed through the endoscope and into the bile duct, and the duct is filled with x-ray contrast solution. An x-ray is taken that clearly demonstrates the contrast-filled bile ducts. ERCP is particularly good at demonstrating the cause and location of obstruction within the bile ducts.
Ultrasonography can be combined with ERCP by using a specialized endoscope capable of doing ultrasound scanning. Endoscopic ultrasound is excellent for diagnosing small gallstones in the gallbladder and bile ducts that can be missed by other diagnostic methods such as ultrasound, CT, and MRI. It also is the best means of examining the pancreas for tumors and can facilitate biopsy through the endoscope of tumors within the pancreas.

Liver biopsy
Biopsy of the liver provides a small piece of tissue from the liver for examination under the microscope. The biopsy most commonly is done with a long needle after local injection of the skin of the abdomen overlying the liver with anesthetic. The needle passes through the skin and into the liver, cutting off a small piece of liver tissue. When the needle is withdrawn, the piece of liver comes with it. Liver biopsy is particularly good for diagnosing inflammation of the liver and bile ducts, cirrhosis, cancer, and fatty liver.

How is jaundice treated?

With the exception of the treatments for specific causes of jaundice mentioned previously, the treatment of jaundice usually requires a diagnosis of the specific cause of the jaundice and treatment directed at the specific cause, e.g., removal of a gallstone blocking the bile duct.