What Is Jaundice? What Causes Jaundice? What Is Icterus?
30 Sep 2009
Jaundice, also known as icterus, is a term used to describe a yellowish tinge to the skin and sclerae (the white part of the eye) that is caused by hyperbilirubinemia (an excess of bilirubin in the blood). Body fluids may also be yellow. The color of the skin and sclerae varies depending on levels of bilirubin; mildly elevated levels display yellow skin and sclerae, while highly elevated levels display brown.
Bilirubin (bil-ih-ROO-bin) is a yellow colored substance that is responsible for the yellowing of the skin and sclerae. Bilirubin is a waste product that remains in the bloodstream after the iron is removed from the hemoglobin, which is released from the degradation of erythrocytes (cells that contain hemoglobin and can carry oxygen to the body). When there is an excess of bilirubin it may leak out into surrounding tissues, saturating them with this yellow substance.
Bilirubin that is circulating freely in the blood is called unconjugated bilirubin. One of the liver's functions is to filter out waste, such as bilirubin, from the blood. Once it is in the liver, other chemicals latch on to the bilirubin, creating a substance called conjugated bilirubin, which is secreted in bile (a digestive juice released by the liver) and then excreted. Bilirubin is what gives feces its brown color.
The modern English word "jaundice" is derived from the middle French word jaunisse. Jaun means "yellow" and -isse means "-ness"; hence the middle French word jaunisse, which means "yellowness".
According to MediLexicon's medical dictionary, jaundice is:
"A yellowish staining of the integument, sclerae, deeper tissues, and excretions with bile pigments, resulting from increased levels in the plasma."
There are three main types of jaundice:
* Hepatocellular jaundice - a type of jaundice that occurs as a result of liver disease or injury.
* Hemolytic jaundice - a type of jaundice that occurs as a result of hemolysis (an accelerated breakdown of erythrocytes - red blood cells) leading to an increase in production of bilirubin.
* Obstructive jaundice - a type of jaundice that occurs as a result of an obstruction in the bile duct (a system of tubes that carries bile from the liver to the gallbladder and small intestine), which prevents bilirubin from leaving the liver.
Jaundice, not to be confused with infant jaundice, is usually a sign of an underlying disorder.
What causes jaundice?
Jaundice most often occurs as a result of an underlying disorder that either causes tissues to become over-saturated with bilirubin or prevents the liver from disposing of bilirubin.
Some underlying conditions that may cause jaundice are:
* Acute inflammation of the liver - may impair the ability of the liver to conjugate and secrete bilirubin, resulting in a buildup of bilirubin.
* Inflammation of the bile duct - may prevent the secretion of bile and removal of bilirubin, causing jaundice.
* Obstruction of the bile duct - prevents the liver from disposing of bilirubin, which results in hyperbilirubinemia.
* Hemolytic anemia - Production of bilirubin increases when large quantities of erythrocytes are broken down.
* Gilbert's syndrome - an inherited condition that impairs the ability of enzymes (biomolecules that provoke chemical reactions between substances) to process the excretion of bile.
* Cholestasis-a condition in which the flow of bile from the liver is interrupted. The bile containing conjugated bilirubin remains in the liver instead of being excreted.
More rare conditions that may cause jaundice include:
* Crigler-Najjar syndrome - an inherited condition that 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.
What are the signs and symptoms of jaundice?
The most pervasive sign of jaundice is a yellow tinge to the skin and sclerae (whites of the eyes). This usually starts at the head and spreads down the body.
Other symptoms of jaundice include:
* Pruritis (itchiness)
* Fatigue
* Abdominal pain - typically indicates a blockage of the bile duct.
* Weight loss
* Vomiting
* Fever
* Paler than usual stools
* Dark urine
How is jaundice diagnosed?
Doctors will most likely diagnose jaundice based on the patient's history and a physical exam, paying close attention to the abdomen. Doctors will be feeling for masses (tumors) in the abdomen and/or checking the firmness of the liver; a firm liver indicates cirrhosis, while a rock-hard liver indicates cancer.
The severity of jaundice is determined by several tests, the first of which is a liver function test to find out whether or not the liver is functioning properly.
If the cause of your symptoms cannot be identified, your doctor may require blood tests to check levels of bilirubin and evaluate the composition of the blood. Some of these tests include:
* Bilirubin tests - a high level of unconjugated bilirubin relative to levels of conjugated bilirubin indicate hemolysis (accelerated break down of erythrocytes)
* Full blood count (FBC), or complete blood count (CBC) - measures levels of erythrocytes (red blood cells), leukocytes (white blood cells), and thrombocytes (platelets).
* Hepatitis A, B, and C tests
If an obstruction of the liver is suspected, the liver's structure will be looked at with the help of imaging tests. Some of these tests include:
* Magnetic resonance imaging (MRI) - uses magnetic signals to create image "slices" of the soft tissues of the human body. MRIs can also be manipulated in such a way that the cause and location of a bile duct obstruction can be identified.
* Abdominal ultrasonography (ultrasound) - uses high frequency sound waves to create a two-dimensional image of the soft tissues inside the human body. It is especially useful in identifying gallstones, although tumors and dilated bile ducts may also show.
* Computerized tomography (CT) scan, or computerized axial tomography (CAT) scan - uses a thin X-ray beam to create image "slices" of soft tissues in the body. It is especially useful in identifying tumors and dilated bile ducts.
* Endoscopic retrograde cholangiopancreatography (ERCP) - the patient swallows an endoscope (a tube) that reaches down to the bile duct. An x-ray contrast solution is then secreted to reveal the contrast-filled bile duct in an x-ray. This imaging test is the most useful in identifying the cause and location of a bile duct obstruction.
A liver biopsy is particularly useful in checking for inflammation, cirrhosis, cancer, and fatty liver. This test involves injecting a needle through the skin and into the liver to obtain a sample of the tissue, which is examined under a microscope.
What are the treatment options for jaundice?
Treatment of jaundice typically requires a diagnosis of the specific cause in order to select suitable treatment options. Treatment would target the specific cause, rather than the jaundice itself.
Anemia-induced jaundice may be treated by increasing the amount of iron in the blood; either by taking iron-supplements or eating more iron-rich foods.
Hepatitis-induced jaundice may be treated with anti-viral or steroid medications.
Obstruction-induced jaundice may be treated via surgery to remove the obstruction.
Medication-induced jaundice is treated by selecting an alternative medication and by discontinuing medications that caused jaundice.
What complications could occur from jaundice?
The symptom pruritis (itching) can sometimes be so intense that patients scratch their skin raw, have insomnia, or even commit suicide.
Most complications that arise are a result of the underlying cause of jaundice, not from jaundice itself. For example, jaundice caused by a bile duct obstruction may lead to uncontrolled bleeding due to a deficiency of vitamins needed for normal blood clotting.
How can jaundice be prevented?
Jaundice is related to the function of the liver, so it is essential that you maintain this vital organ's health by eating a balanced diet, exercising at least 30 minutes five times a week, and refraining from exceeding recommended amounts of alcohol.
Written by Caroline Gillott
Copyright: Medical News Today