What is jaundice?

Causes and Symptoms

Jaundice is not a disease, but rather a common sign of various disorders in the
liver or the blood. Bilirubin is a pigment formed by the
breakdown of hemoglobin, the oxygen-carrying molecule in red blood cells.
Bilirubin is then transported to the liver, where it is processed into a
water-soluble form. This process is known as conjugation. Conjugated bilirubin is
secreted into the bile ducts and eventually excreted in feces. An increase in
red blood
cell breakdown, impairment in liver function, or blockage of
the bile ducts can all result in the buildup of bilirubin. The first visible
manifestation of this is often scleral icterus, a yellowing of the white part of
the eyes. When levels of conjugated bilirubin are abnormally high, it may be seen
in the urine as urobilinogen, which causes a darkening of the urine.

Once the bilirubin level in the blood exceeds 2.5 milligrams per deciliter, the yellow skin discoloration of jaundice can be seen. It is apparent first at the bottom of the tongue and later throughout the skin. Jaundice is sometimes associated with itching, presumably because of the deposition of bilirubin under the skin.

Treatment and Therapy

The treatment of jaundice depends on its cause. The first step is to determine
whether there is an excess of conjugated bilirubin or unconjugated bilirubin. High
levels of unconjugated bilirubin suggest an increase in red blood cell breakdown,
known as hemolysis. This condition can be confirmed by examination of
a peripheral blood smear and other laboratory studies. Most cases of hemolysis are
the result of another underlying cause, such as infection or drugs. Hemolysis can
also result from the body’s immune system attacking its own red blood cells.
Unconjugated bilirubin is also elevated in inherited disorders such as
Gilbert’s
syndrome and Crigler-Najjar syndrome. These disorders are
usually detected in early childhood.

Excess conjugated bilirubin, on the other hand, suggests a blockage in the biliary
tree, which can be attributable to gallstones or, less commonly, a tumor.
Gallstones can be confirmed with ultrasonography and may require surgery
if they cause symptoms. Rarer causes of blockage in the biliary tree include
strictures and sclerosing cholangitis. Disorders of the liver itself can also
result in high levels of conjugated bilirubin, but oftentimes both types of
bilirubin are elevated. Liver diseases include viral
hepatitis (hepatitis A, B, or C), as well as alcohol and
drug-induced hepatitis.

Bibliography

Arias, Irwin M., and
James L. Boyer, eds. The Liver: Biology and Pathobiology.
Hoboken: Wiley, 2009. Print.

Kasper, Dennis L., et
al., eds. Harrison’s Principles of Internal Medicine. 18th
ed. New York: McGraw-Hill, 2011. Print.

Manning, Donal, and Kevin
N. Ives. "What's New in Neonatal Jaundice." Infant 8.5
(2012): 137–41. Print.

Palmer, Melissa.
Dr. Melissa Palmer’s Guide to Hepatitis and Liver
Disease. Rev. ed. Garden City Park: Avery, 2004.
Print.

Sargent, Suzanne, and
Michelle Clayton. "Adult Jaundice—The Pathophysiology, Classification, and
Causes." Gastrointestinal Nursing 9.4 (2011): 34–40.
Print.