Glossary

Find definitions for thousands of medical terms, treatments, and tests -- even health-related abbreviations, prefixes, and suffixes.

Filter by First Letter
A B C D E F G H I J K L M N O P Q R S T U V W X Y Z

J

Jaundice is a condition in which the skin and whites of the eyes appear yellow because of the buildup of a yellow-brown pigment called bilirubin in the blood and skin.

Bilirubin is produced by the breakdown of red blood cells. The liver normally gets rid of bilirubin in bile (a fluid that helps the body digest fats).

Excess amounts of bilirubin can build up because of rapid destruction of red blood cells, liver diseases (such as hepatitis), blockage of the bile ducts leading from the gallbladder to the small intestine, or other problems. Bilirubin can be measured in the blood, where it is one indicator of a person's liver function.

Other symptoms that may occur as a result of excess bilirubin include dark urine, light-colored or whitish stools, and itching of the skin (pruritis).

If successful, treatment for the underlying cause of jaundice may cause the skin, eyes, urine, and stools to return to their normal color.

Last Revised: July 6, 2011

Author: Healthwise Staff

Medical Review: E. Gregory Thompson, MD - Internal Medicine & W. Thomas London, MD - Hepatology

Jaundice in newborns (also called hyperbilirubinemia) is a condition in which the skin and the whites of a baby's eyes appear yellow because of a buildup of bilirubin in the blood. Bilirubin is a yellow-brown substance produced by the breakdown of red blood cells.

During pregnancy, the mother's liver gets rid of fetal bilirubin. After birth, babies must eliminate bilirubin on their own. But many newborns cannot get rid of bilirubin as fast as they make it. Bilirubin then builds up in the baby's body, causing jaundice.

Although jaundice should be monitored, it usually does not require medical treatment. Phototherapy, in which a baby is placed under special lights or fiber-optic blankets, may be used if bilirubin levels reach a high enough level. On rare occasions blood transfusions are needed.

In rare cases, jaundice in a newborn may be a sign of another condition, such as infection, a digestive system problem, or blood-type incompatibility with the mother.

Last Revised: May 11, 2012

Author: Healthwise Staff

Medical Review: John Pope, MD - Pediatrics & Chuck Norlin, MD - Pediatrics

A joint is the point at which two bones are connected. Many joints provide support and stability and allow movement, although some, such as those of the pelvis, are not movable.

Joints contain bones, cartilage, and a lining called synovium, which produces a lubricating fluid. Most joints are held together by muscles, tendons, and ligaments and are often cushioned by fluid-filled sacs called bursae.

There are several types of joints, including:

  • Hinge joints, such as the elbows and knees.
  • Ball-and-socket joints, such as the hips and shoulders.
  • Pivot joints, which allow rotation. For example, the joints in the neck allow the head to turn from side to side.
  • Condyloid joints, such as the wrist, which allow movement in many different directions.

Last Revised: June 5, 2012

Author: Healthwise Staff

Medical Review: Anne C. Poinier, MD - Internal Medicine & Nancy Ann Shadick, MD, MPH - Internal Medicine, Rheumatology