Health Library

Ulcerative colitis is a type of inflammatory bowel disease (IBD) that affects the lining of the large intestine (colon) and rectum. See also:

An ulcer is a crater-like lesion on the skin or of the mouth, stomach, and other body areas.

Ulnar nerve dysfunction is a problem with the ulnar nerve, which travels from the shoulder to the hand and allows movement or sensation in the wrist or hand.

Ultrasound involves the use of high-frequency sound waves to create images of organs and systems within the body.

A catheter is a long, soft, hollow tube. Catheters vary in size. An umbilical catheter is used for different reasons. An umbilical artery catheter (UAC) allows blood to be taken from an infant at different times, without repeated needle sticks. It can be used to continuously monitor your ...

An umbilical hernia is an outward bulging (protrusion) of the abdominal lining or part of the abdominal organ(s) through the area around the belly button.

Umbilical hernia repair is surgery to repair an . An umbilical hernia is a sac (pouch) formed from the inner lining of your belly (abdominal cavity) that pushes through a hole in the abdominal wall at the belly button.

Unconsciousness is when a person is unable to respond to people and activities. Often, this is called a coma or being in a comatose state. Other changes in awareness can occur without becoming unconscious. Medically, these are called “altered mental status” or “changed mental ...

Undescended occurs when one or both testicles fail to move into the before birth.

Undescended testicle repair is surgery to correct testicles that have not dropped down into the correct position in the scrotum. See also:

Unicompartmental knee arthroplasty (UKA) is surgery to replace either the inside (medial) or outside (lateral) compartments of the knee. Because only one part of the damaged knee is replaced, it is often called a partial knee replacement. See also:

Unilateral hydronephrosis is swelling of one kidney due to a backup of urine. See also:

Unstable angina is a condition in which your heart doesn’t get enough blood flow and oxygen. It may be a prelude to a heart attack. Angina is a type of chest discomfort caused by poor blood flow through the blood vessels (coronary vessels) of the heart muscle (myocardium). See also:

Ureteropelvic junction (UPJ) obstruction is a blockage in the area that connects the renal pelvis (part of the kidney) to one of the tubes (ureters) that move urine to the bladder.

Upper airway biopsy is surgery in which a small piece of tissue is removed from the upper airway (nose, mouth, throat) for examination.

An upper GI and small bowel series is a set of taken to examine the esophagus, stomach, and small intestine. See also:

Urine urea nitrogen is a measure of protein breakdown in the body. A test can be done to measure the amount of urea in the urine.

Ureteral retrograde brush biopsy is a procedure in which tissue from the kidney or ureter (tube that connects a kidney to the bladder) is removed for examination.

A ureterocele is a swelling at the bottom of one of the tubes (ureters) that carry urine from the kidney to the bladder. The swollen area can block urine flow. A ureterocele is a birth defect.

Urethral discharge culture is a laboratory test done on men and boys to identify organisms in the urethra (the tube that drains urine from the bladder) and genital tract that cause infection.

Urethral stricture is an abnormal narrowing of the tube that carries urine out of the body from the bladder (urethra).

Urethritis is swelling and irritation (inflammation) of the urethra. The urethra is the tube that carries urine from the body.

Urge incontinence is the strong, sudden need to urinate due to bladder spasms or contractions.

Uric acid is a chemical created when the body breaks down substances called purines. Purines are found in some foods and drinks, such as liver, anchovies, mackerel, dried beans and peas, beer, and wine. Most uric acid dissolves in blood and travels to the kidneys, where it passes out in urine. If ...

Uric acid is a chemical created when the body breaks down substances called purines. Purines are found in some foods and drinks, such as liver, anchovies, mackerel, dried beans and peas, beer, and wine. Purines are also a part of normal body substances, such as DNA. Most uric acid dissolves in ...

Urinalysis is the physical, chemical, and microscopic examination of urine. It involves a number of tests to detect and measure various compounds that pass through the urine.

Urinary casts are tiny tube-shaped particles made up of white blood cells, red blood cells, or kidney cells. They form in kidney structures called tubules. Casts are held together by a protein released by the kidney. The content of a cast can tell your health care provider whether your urine is ...

A urinary catheter is a small, soft tube placed in the bladder. WHY IS A URINARY CATHETER USED? A catheter may be needed if your baby is making only small amounts of urine. This could be due to your baby being very ill with low blood pressure, an abnormally developed urinary system, the use of a ...

A urinary catheter is any tube system placed in the body to drain and collect urine from the bladder.

Urinary (or bladder) incontinence is when you are not able to keep urine from leaking from your urethra, the tube that carries urine out of your body from your bladder. It can range from an occasional leakage of urine, to a complete inability to hold any urine. The three main types of urinary ...

Collagen implants are injections done to help control urine leakage that is caused by a weak urinary sphincter. The sphincter is a muscle that allows your body to hold the urine in the bladder. If your sphincter muscle stops working well you will have urine leakage. See also:

Retropubic suspension is surgery to help control urine leakage that can happen when you laugh, cough, sneeze, lift things, or exercise ( ). The surgery helps close your urethra (the tube that carries urine from the bladder to the outside) and the bladder neck (the part of the bladder that connects ...

Placement of tension-free vaginal tape is a procedure to help control , urine leakage that can happen when you laugh, cough, sneeze, lift things, or exercise. The procedure helps close your urethra (the tube that carries urine from the bladder to the outside) and the bladder neck (the part of the ...

Vaginal sling procedures help control , urine leakage that can happen when you laugh, cough, sneeze, lift things, or exercise. They help close your urethra (the tube that carries urine from the bladder to the outside) and the bladder neck (the part of the bladder that connects to the urethra). See ...

A urinary tract infection, or UTI, is an infection that can happen anywhere along the urinary tract. Urinary tract infections have different names, depending on what part of the urinary tract is infected. Bladder — an infection in the bladder is also called cystitis or a bladder ...

A urinary tract infection (UTI) is a bacterial infection of the urinary tract. This article discusses UTIs in children. The urinary tract includes the: Bladder Kidneys Ureters — the tubes that take urine from each kidney to the bladder Urethra — the tube that empties urine from the ...

Bed wetting (or enuresis) is when children wet the bed more than twice per month after age 5 or 6.

Difficulty starting or maintaining a urinary stream is called urinary hesitancy.

Excessive urination at night is a condition in which you wake up several times during the night to urinate. Waking up several times a night to urinate is called nocturia.

Excessive volume of urination means that you release abnormally large amounts of urine each day. The medical term for this condition is polyuria.

Painful urination describes any pain, discomfort, or burning sensation when passing urine.

Urine of an abnormal color appears different from the usual straw-yellow color. Abnormally-colored urine may be cloudy, dark, or blood-tinged. See also:

Blood in your urine, or hematuria, can be classified as microscopic or gross. Microscopic hematuria is when there is very little blood in the urine and it can only be seen with a microscope. Gross hematuria is when there is enough blood in the urine that you can see it with the naked eye. Usually it ...

The urine 24-hour volume test measures the amount of urine produced in a day.

Urine chemistry refers to a group of tests performed on a urine sample.

Urine collection is a method of getting a urine sample from an infant for testing purposes. It can be done at home.

A urine concentration test measures the ability of the kidneys to conserve or excrete water appropriately. See also:

Catheterized specimen urine culture is a test in which a urine sample is taken by inserting a catheter (a thin rubber tube) through the urethra into the bladder.

A clean catch is a method of collecting a urine sample for various tests, including urinalysis, cytology, and urine culture.

A urine drug screen is designed to detect illegal (and some prescription) drugs in the urine. See for information about specific drugs.

Urine melanin is a test to determine the abnormal presence of in the urine.

Urine odor refers to the scent of the fluid excreted during urination. Urine odor varies. However, if you drink enough fluids and are otherwise healthy, urine does not usually have a strong smell.

Decreased urine output is defined as producing less than 500 milliliters of urine in 24 hours.

A urine pH test measures the acidity of urine. See also:

Urine specific gravity is a laboratory test that measures the concentration of all chemical particles in the urine. See also:

Uroflowmetry is a test that measures the volume of urine released from the body, the speed with which it is released, and how long the release takes.

Urticaria pigmentosa is a skin disease that produces and intense . If you rub the lesions, hives may develop.

Uterine artery embolization (UAE) is a procedure to treat without surgery. Uterine fibroids are noncancerous (benign) tumors that develop in the uterus (womb). During the procedure, the blood supply of the fibroids is cut off, causing the fibroids to shrink.

Uterine fibroids are noncancerous (benign) tumors that develop in the uterus (womb), a female reproductive organ.

Uterine prolapse is falling or sliding of the uterus from its normal position in the pelvic cavity into the vaginal canal.

The uvea is the middle layer of the eye beneath the white part of the eye (the ). It consists of the , , and . These structures control many of the functions of the eye such as adjusting to different levels of light or different distances of objects.

Uveitis is swelling and irritation of the , the middle layer of the eye. The uvea provides most of the blood supply to the .

Uvulitis is inflammation of the uvula, the small tongue-shaped piece of tissue that hangs from the top of the back part of the mouth. It is usually associated with inflammation of other mouth parts, such as the palate, tonsils, or throat (pharynx). See also: