What Is It?

A urinary-tract infection is an infection involving the organs that produce urine and carry it out of the body. These structures include the kidneys, ureters (long, slender tubes connecting the kidneys with the bladder), bladder and urethra. Doctors often divide urinary-tract infections into two types, lower-tract infections and upper-tract infections:

• Lower-tract infections — These include cystitis (bladder infection) and urethritis (infection of the urethra). Bacteria normally found in the intestine are the main cause of lower-urinary-tract infections. These bacteria spread from the anus to the urethra and bladder where they grow, invade the tissue and cause infection.
• Upper-tract infections — These involve the ureters and kidneys. These infections are called pyelonephritis or kidney infection. Upper-urinary-tract infections usually occur because bacteria travel up from the bladder into the kidney. Sometimes, they occur when bacteria travel from other areas of the body through the bloodstream and settle in the kidney.

There are about 8 million cases of urinary-tract infections diagnosed each year in the United States. Women are affected more often than men, especially sexually active women because sexual intercourse can cause bacteria to spread upward into the bladder. Also, the use of contraceptive diaphragms and spermicides may change the normal bacterial environment around the urethra and make infection more likely. In pregnant women, temporary changes in the physiology and anatomy of the urinary tract make expectant mothers prime candidates for cystitis and pyelonephritis. Kidney and bladder infections can pose a serious risk to pregnant women and their unborn children, because they increase the risk of premature contractions or delivery and sometimes death of the fetus or newborn infant.

Urinary-tract infection can cause one or more of the following symptoms:

• Unusually frequent urination
• An intense urge to urinate
• Dysuria — pain, discomfort or a burning sensation during urination
• Pain, pressure or tenderness in the area of the bladder (midline, above or near the pubic area)
• Urine that looks cloudy, or smells foul or unusually strong
• Fever, with or without chills
• Nausea and vomiting
• Pain in the side or mid to upper back
• Nocturia — awakening from sleep to pass urine
• Onset of enuresis (bed-wetting) in a person who has usually been dry at night

Your doctor will ask you about your present symptoms and about any previous episodes of urinary-tract infection. To assess your risk factors, your doctor will ask you about your sexual history, including any history of sexually transmitted diseases for yourself and your partner, condom use, multiple partners, use of diaphragm and/or spermicides and the possibility of pregnancy. Your doctor also will ask if you have any other medical problems, such as diabetes, which can make you more likely to develop infections.

Your doctor will diagnose a urinary-tract infection based on your symptoms, the results of your physical examination, and whether a laboratory test of your urine shows bacteria in the urine. Your urine also may be sent for testing to identify the specific type of bacteria and the specific antibiotics that can be used to eliminate the bacteria.

In patients with frequent urinary-tract infections, additional testing may be needed, such as:

• An intravenous pyelogram (IVP), which shows an outline of your urinary tract on X-rays
• A computed tomography (CT) scan of your kidneys and urinary system
• An ultrasound exam
• Cystoscopy, an examination in which your doctor checks the inside of your bladder using a thin, hollow telescope-like instrument.

With proper treatment, most uncomplicated urinary-tract infections can be cured in two to three days.

To help prevent urinary-tract infections:

• Drink several glasses of water each day — Fluids discourage the growth of bacteria by flushing out your urinary tract. Drinking cranberry juice or taking vitamin C supplements also may deter bacterial growth by making your urine more acidic.
• Wipe from front to back — To prevent the spread of intestinal bacteria from the rectum to the urinary tract, women always should wipe toilet tissue from front to the back after having a bowel movement.
• Decrease the spread of bacteria during sex — If possible, cleanse the area around your genitals before having sex. Urinate after sexual intercourse to flush bacteria from your bladder.

Doctors treat simple urinary-tract infections with antibiotics. Culture and sensitivity testing can determine the best antibiotic for treatment. Most uncomplicated lower-tract infections are treated with a three-day course of antibiotics, although women who are pregnant, or who have diseases such as diabetes that suppress the immune system, usually need a longer course of antibiotics.

Patients with severe upper-tract infections may require hospital treatment with antibiotics given through a vein (intravenously ). This is especially true if nausea, vomiting and fever increase the risk of dehydration and prevent the patient from taking oral antibiotics.

Call your doctor whenever you have frequent urination, an intense urge to urinate, discomfort during urination or other symptoms of a urinary-tract infection. It is especially important for any pregnant woman who has symptoms of a urinary-tract infection to call her doctor immediately.

Once a woman has been cured of her first urinary-tract infection, she has a 20-percent chance of developing a second infection. After the second infection, she has a 30-percent risk of developing a third. If a woman has three or more urinary-tract infections within one year and the structure or anatomy of the urinary tract is normal, her doctor may prescribe a special antibiotic regimen to decrease the risk of future infections. Women with frequent infections also can monitor their urine with special dipsticks to detect the first signs of bacteria in the urine, even before symptoms of infection begin.

Diseases and Conditions Center

All ArmMed Media material is provided for information only and is neither advice nor a substitute for proper medical care. Consult a qualified healthcare professional who understands your particular history for individual concerns.