Urinary tract infection (UTI)

What is it?

A UTI is an infection of one or more parts of the urinary tract. The urinary tract consists of two kidneys, two ureters, a bladder, and a urethra. The kidneys are bean-shaped organs found in the lower back below the ribcage. They filter waste out of the blood and produce urine to carry the waste and excess water out of the body. The urine is carried through the ureters (tubes) from the kidneys to the bladder.

The bladder is a hollow muscular organ that stores urine for a short time period. The bladder stretches as urine accumulates and at a certain point it signals to the body that it needs to relieve the growing pressure. A muscular valve (sphincter) at the opening of the bladder is relaxed and the bladder contracts to send urine through the urethra (a tube linking the bladder to the external surface of a persons skin) and out of the body.

A UTI is sometimes referred to by the part of the urinary tract affected. Inflammation of the urethra (usually due to an infection but sometimes due to irritation), is called urethritis. If the bladder becomes involved it is referred to as cystitis, and if the kidneys are inflamed it is called pyelonephritis. Frequently, the blanket term UTI will be used by your doctor, because there is not a simple test that can tell exactly how much of the urinary tract is infected.