What Is It?
Most urinary tract infections are caused by a variety of bacteria, including Escherichia coli (E. coli), found in feces. Because the openings of the bowel, vagina and urethra are close together, it's easy for the bacteria to spread to the urethra and travel up the urinary tract into the bladder and sometimes the kidneys.
Urinary tract infections result in eight to 10 million doctors' office visits each year in the United States, and at least 50 percent of women will have at least one urinary tract infection at some point in their lives.
Luckily, most urinary tract infections are not serious and can be easily treated with antibiotic medications. The symptoms of a urinary tract infection can be stubborn and can persist after treatment. Sometimes an infection recurs a few weeks after treatment. Nearly 20 percent of women who have a urinary tract infection will have another, and 30 percent of those who have had two will have a third. About 80 percent of those who have had three will have a fourth. If left untreated, urinary tract infections can lead to other more complicated health problems so they should not be ignored.
How the Urinary Tract Works
Your urinary tract includes two kidneys, two ureters, the bladder and the urethra. Your kidneys remove waste and water from your blood to produce urine. Urine travels through muscular tubes, called the ureters, to the bladder. The bladder is a balloon-like organ composed of muscle, connective tissue and nerves that swells as it fills with urine. Urine is stored in the bladder until it is released from the body through another tube, called the urethra. Two muscle groups, the pelvic floor muscles and the urinary sphincters, control the activity of the urethra and bladder neck. These muscles must work together to hold urine in the bladder most of the time and allow the bladder to empty when appropriate.
Cause of Urinary Tract Infection: Bacteria
Most urinary tract infections are caused by a variety of bacteria, including Escherichia coli (E. coli), found in feces. Because the openings of the bowel, vagina and urethra are very close together, it's easy for the bacteria to spread to the urethra and travel up the urinary tract into the bladder and sometimes up to the kidneys.
Untreated Urinary Tract Infections: Bladder & Kidney Infections
Infection occurs when the bacteria cling to the opening of the urethra and multiply, producing an infection of the urethra, called urethritis. The bacteria often spread up to the bladder, causing a bladder infection, called cystitis. Untreated, the infection can continue spreading up the urinary tract, causing infection in the kidneys, called pyelonephritis. Pyelonephritis can also occur without a preceding bladder infection.
A kidney infection that is not treated can result in the bacteria entering the bloodstream (this is known as urosepsis), which can be a life-threatening infection requiring hospitalization and intravenous antibiotics.
The first sign of a bladder infection may be a strong urge to urinate or a painful burning sensation when you urinate. You may feel the urge to go frequently, with little urine eliminated each time. At times, the urge to urinate may be hard to control and you may have urinary leakage. You may also have soreness in your lower abdomen, in your back or in the sides of your body. Your urine may look cloudy or have a reddish tinge from blood. It may smell foul or strong. You also may feel tired, shaky and washed out.
If the infection has spread to the kidneys, you may have fever, chills, nausea, vomiting and back pain, in addition to the frequent urge to urinate and painful urination.
Common Causes of UTIs
Some women are more prone to urinary tract infections than others because the cells in their vaginal areas and in their urethras are more easily invaded by bacteria. Women with mothers or sisters who have recurring urinary tract infections also tend to be more susceptible. Your risk of urinary tract infection also is greater if you're past menopause. Thinning of the tissues of the vagina, bladder and urethra, as well as change in the vaginal environment after menopause, may make these areas less resistant to bacteria and cause more frequent urinary tract infections.
Irritation or injury to the vagina or urethra caused by sexual intercourse, douching, tampons or feminine deodorants can give bacteria a chance to invade. Using a diaphragm can cause irritation and can interfere with the bladder's ability to empty, giving bacteria a place to grow.
Any abnormality of the urinary tract that blocks the flow of urine, such as a kidney stone or significant prolapse of the uterus or vagina, also can lead to an infection or recurrent infections. Illnesses that affect the immune system, such as diabetes, AIDS and chronic kidney diseases, increase the risk of urinary tract infections. A weak bladder can also make it difficult to empty completely, allowing bacteria to grow. Lengthy use of an indwelling catheter, a soft tube inserted through the urethra into the bladder to drain urine, is a common source of urinary tract infections. Intermittent catheterization (where a person empties the bladder several times a day but the catheter is removed immediately) actually is used to prevent recurrent infections in some patients.
Because the uterus sits directly on the bladder during pregnancy and can block the drainage of urine from the bladder, UTIs are more common in pregnant women. And when women develop urinary tract infections during pregnancy, the bacteria are more likely to affect the kidneys. Hormonal changes and repositioning of the urinary tract during pregnancy may make it easier for bacteria to invade the kidneys. Such infections in pregnant women can lead to urosepsis, kidney damage, high blood pressure and premature delivery of the baby. All pregnant women should have their urine tested periodically during pregnancy. Pregnant women with a history of frequent urinary tract infections should have their urine tested often.
Most antibiotic medications are safe to take during pregnancy, but your health care professional will consider the drug's effectiveness, how far your pregnancy has progressed and the potential side effects on the fetus when determining which medication is right for you and how long you should take it.
Your health care professional will determine whether you have a urinary tract infection based on your symptoms, a physical examination and the result of a laboratory test of your urine. You will be asked to urinate into a small cup. The urine will be examined under a microscope for bacteria and for a large amount of white blood cells, which fight infection. A urine culture may be done in which the bacteria in the urine are encouraged to grow. The bacteria can then be identified and may be tested to see which antibiotic best kills them.
If you are having recurrent symptoms of infections despite treatment, it is important that your urine be cultured before you are placed on antibiotics. Repeated treatment of presumed infections without urine culture should be avoided.
Some bacteria, such as chlamydia, can only be found with special urine cultures. A health care professional may suspect these infections when a woman has urinary tract infection symptoms, but a standard culture doesn't grow the bacteria.
If you have recurring urinary tract infections, your health care professional may suggest other tests to look for obstructions or other problems that might trap urine in the tract and cause infection:
- Intravenous pyelogram (IVP) is an X-ray exam of the urinary tract using a dye that is injected into a vein and then enters the kidneys, ureters and bladder. This test is not commonly used alone anymore.
- A computed tomography scan (CT scan), also known as a CT urography, is a type of X-ray test used to capture images of different structures in the body. The CT scan is usually given with an intravenous dye similar to that used in an IVP (see above). The dye allows your doctor to better see your kidneys, ureters and bladder. Newer CT scanners use much less radiation.
- Ultrasound uses sound waves to produce images of the urinary tract. No radiation is involved in this test.
- Cystoscopy is a test using a thin telescope-like instrument that allows your health care professional to see inside the urethra and bladder and examine them for problems.
Urinary tract infections are treated with medications that kill the bacteria causing the infection. Your health care professional will determine which medication to prescribe and how you should take it, based on your medical history and condition and the results of the urine tests. Many medications can have side effects, so talk to your health care professional about what to expect. Also, medications can interact with other prescriptions and over-the-counter drugs, so make sure you tell your health care professional what drugs you are taking.
The antibiotics most often used to treat urinary tract infection are pills typically taken for three days. More complicated infections are usually treated with seven to 10 days or more of antibiotics, depending on the bacteria causing the infection, the drug used and your medical history. The most frequently prescribed drugs include:
- ciprofloxacin (Cipro)
- levofloxacin (Levaquin)
- nitrofurantoin (Macrobid, Furadantin)
- norfloxacin (Noroxin)
- fosfomycin (Monurol)
- trimethoprim/sulfamethoxazole (Bactrim, Septra)
Note: Fluoroquinolones, which include the antibiotics ciprofloxacin, gatifloxacin, levofloxacin and norfloxacin, have been associated with an increased risk of tendonitis and tendon rupture. If you are prescribed one of these medications for a urinary tract infection, discuss this risk with your health care professional.
Urinary tract infections caused by microorganisms, such as chlamydia, may be treated with the antibiotics azithromycin, tetracycline or doxycycline.
Although your symptoms may be relieved in a day or two after starting the medication, you must take all the medication your health care professional prescribes. Otherwise, you run the risk of a recurrence. That is, some bacteria may survive and cause your infection to return or cause reinfection with a new or different organism.
To help ease your discomfort until the antibiotics kick in, you can take a prescription medication called phenazopyridine (Pyridium). A similar medication, called Uristat, is available over the counter. However, keep in mind that these medications only ease symptoms; they do not treat the infection. They also change the color of your urine, can interfere with laboratory testing and shouldn't be taken for more than 48 hours unless told differently by your health care provider.
If you are menopausal, you may experience more frequent urinary tract infections because thinning of the tissues of the vagina and urethra following menopause may make these areas less resistant to bacteria. Hormone replacement (either systemic or vaginal) may help. Vaginal estrogen has fewer health risks than systemic estrogen (such as in birth control pill and patches) because only a small amount is absorbed into the bloodstream. Vaginal estrogen is available as a cream (Estrace), a tablet (Vagifem, Premarin) and a flexible plastic ring (Estring). Femring is another vaginal estrogen product, but it has higher doses of estrogen and is primarily recommended for hot flashes; women with a uterus who use Femring should take progestin to minimize their risk of uterine cancer.
Discuss these treatment options and the latest research about their risks and benefits with your health care professional, keeping your personal health history and needs in mind. If you decide to take hormone replacement therapy, you should take the lowest dose that helps for the shortest time possible. You and your doctor should also reevaluate every six months whether or not you should be taking hormones.
Severe kidney infections may require hospitalization and treatment with intravenous antibiotics, especially if nausea, vomiting and fever increase the risk of dehydration and prevent the ability to swallow pills. Kidney infections usually require two weeks of antibiotic therapy, although treatment may extend as long as six weeks (this extended course usually is prescribed for men whose infections are due to prostatitis, however).
In addition to taking your medication, your health care professional may recommend drinking plenty of fluid (the equivalent of six to eight 8-ounce glasses a day) to help flush the urinary tract and avoiding foods and beverages that can irritate the urinary tract, such as coffee and alcohol. A heating pad may help to temporarily relieve pain.
After you've completed your course of medication, your health care professional may suggest a follow-up urine test to make sure the infection is gone.
There are several simple, do-it-yourself techniques that may prevent a urinary tract infection. Some may work some of the time or only in some women. But, because they carry no side effects, they certainly are worth trying to prevent the often painful and bothersome symptoms the infection can bring:
- Drink plenty of fluid––the equivalent of six to eight 8-ounce glasses––every day to flush bacteria out of your urinary system. Water is the ideal fluid because it is readily available, inexpensive and noncaloric, but other beverages also count toward your fluid intake, including juices, milk and herbal teas. Even alcoholic beverages such as beer and wine and caffeinated beverages such as coffee and colas help replenish your fluids, but don't rely heavily on them because they have diuretic properties. Additionally, alcohol and caffeine, as well as spicy foods, are among the substances that may irritate the bladder and, thus, should be avoided.
- Make sure you're getting vitamin C in your diet, either through diet or supplements. Vitamin C, or ascorbic acid, makes your urine acidic, which discourages the growth of bacteria. Drinking cranberry juice may also produce the same effect. Cranberry supplements are a more concentrated form of cranberry juice without the sugar content.
- Urinate frequently and when you feel the urge; don't hold it in. Keeping urine in your bladder for long periods gives bacteria a place to grow.
- Avoid using feminine hygiene sprays and scented douches. They may irritate the urethra.
- If you wear a pad for urinary leakage, you should change it often. Wet pads provide an environment for bacteria to grow.
If you suffer from urinary tract infections more than three times a year, your health care professional may suggest one of the following therapies to try to prevent another recurrence:
- a low dosage of an antibiotic medication such as trimethoprim/sulfamethoxazole or nitrofurantoin, taken daily for six months or longer
- a single dose of an antibiotic medication taken after sexual intercourse if it is determined that your UTIs are related to sex
- a short, one- or two-day course of antibiotic medication taken when symptoms appear
- Use of preventive medications that change the bladder environment, such as methanamine.
If you experience recurring UTIs, home urine tests, which involve dipping a test stick into a urine sample, may be helpful.
Some research suggests that a woman's blood type may play a role in her risk of recurrent UTIs. Bacteria may be able to attach to cells in the urinary tract more easily in those with certain blood factors. Additional research will determine if such an association exists and whether it could be useful in identifying people at risk of developing recurrent UTIs.
Vaccines are being developed to help patients build up their own natural infection-fighting powers. Vaccines that are prepared using dead bacteria do not spread like an infection; instead, they prompt the body to produce antibodies that can later fight live organisms. Researchers are currently looking into vaccines that can be administered orally, by way of a vaginal suppository and through the nose.
Facts to Know
- Urinary tract infections result in eight to 10 million doctors' office visits each year in the United States, and at least 50 percent of women will have at least one urinary tract infection at some point in their lives.
- Nearly 20 percent of women who have one urinary tract infection will have another, and 30 percent of those who have had two will have a third. About 80 percent of those who have had three will have a fourth. Four out of five such women get another infection within 18 months of the last one.
- Some women are more prone to the infection than others. Women at higher risk include those who are past menopause, who have diabetes or who use a diaphragm. If your mother or sister had frequent urinary tract infections, you are more likely to have one. Recently, researchers found that women who use spermicides as contraception—particularly if they use them with diaphragms—are also at a greater risk for recurrent UTIs.
- About 2 percent to 7 percent of pregnant women develop a urinary tract infection. Pregnant women are more likely to have UTIs and the infection is more likely to spread to the kidneys. UTIs during pregnancy need prompt attention by a health care professional to avoid a premature birth. Pregnant women may have no symptoms associated with an infection so regular urine tests are important.
- One type of bacteria––Escherichia coli (E. coli), which lives in the digestive system and spreads to the urinary tract––causes most urinary tract infections.
- Urinaryurgency, urge incontinence and pain with urination can be early symptoms of urinary tract infection. Urinary urgency is characterized by frequent overwhelming urges to urinate. Urgency incontinence is urine leakage resulting from not getting to a toilet in time.
- Urinary tract infections usually are not serious and are easily treated by taking antibiotics. Kidney infection is the most common complication and can produce fever, chills, nausea, vomiting and back pain.
- Although urinary tract infections do occur in men, women are at greater risk because of their anatomy. The female urethra is short, and the rectum, vagina and urethra are located closely together in women, making it easy to spread bacteria that live in the digestive tract to the urinary tract.
- Women who have more than three urinary tract infections in a year may benefit from preventive antibiotic therapy. Such therapy may involve taking a low dose of medication every day for six months or longer, taking a single dose after having sex or taking a dose for one or two days when symptoms begin to appear. If you experience recurring UTIs, home urine tests, which involve dipping a test stick into a urine sample, may be helpful.
- When being treated for a urinary tract infection, take all the antibiotic medication you have been given, even if your symptoms are gone before you finish your prescription. If you fail to complete the treatment, the infection may still be present, and your symptoms will return or another infection may arise in a short time.
Questions to Ask
Review the following Questions to Ask about urinary tract infection so you're prepared to discuss this important health issue with your health care professional.
- Am I at risk for a urinary tract infection?
- What can I do to prevent a urinary tract infection?
- What are the signs of a urinary tract infection?
- What tests are available to find the cause of my infection, and which one is right for me?
- What are the results of my urine tests, and what do they mean?
- What medication are you prescribing for my infection? How should I take it and for how long?
- What are the possible side effects of the antibiotic medication, and what should I do to avoid or lessen them? Will the antibiotic interact with any other medications I am taking?
- If I keep getting urinary tract infections, will I need more tests? Which ones? How will they be done and what can the results mean?
- Am I a candidate for preventive antibiotic therapy, and what treatment would be best for me? What is the medication, and when and how should I take it?
- How do you get a urinary tract infection?
The infection is most often caused by bacteria from the digestive tract being spread to the urethra and then traveling up the urinary tract to the bladder and sometimes the kidneys. It can also be caused by bacteria and microorganisms transmitted during sexual intercourse.
- Isn't it true that once you have a urinary tract infection, you'll never have another one?
No. In fact, once you have a urinary tract infection, you are more likely to have another. Nearly 20 percent of women who have a urinary tract infection will have another, and 30 percent of those who have had two will have a third. About 80 percent of those who have had three will have a fourth. Four out of five such women get another infection within 18 months of the last one.
- How can I tell if I have a urinary tract infection?
Symptoms of urinary tract infections may include frequent, urgent needs to urinate, but not making it to the toilet in time; a painful, burning sensation when urination occurs; cloudy or reddish-colored urine; urine that smells foul or strong; and soreness in the back, side or lower abdomen. If fever, chills, nausea, vomiting and/or back pain accompany the symptoms, you may have a kidney infection. See your health care professional promptly if you have any signs of a urinary tract infection.
- My urinary tract infection seems to be gone. Do I still need to take the rest of my antibiotic medication?
Yes, absolutely. Although your symptoms may disappear in one or two days after taking antibiotic medication, you must take all the medication to destroy the germs causing the infection. If you don't, your symptoms may return, or you may have another urinary tract infection in a short time.
- Will a urinary tract infection harm my baby or me when I'm pregnant?
If the infection is caught and treated early, generally not. However, pregnant women are more likely to have a urinary tract infection spread to their kidneys, which can cause kidney damage, high blood pressure and increased risk of premature delivery. If you're pregnant and suspect you have a urinary tract infection, see your health care professional right away.
- Isn't drinking cranberry juice to prevent urinary tract infection an old wives' tale?
Not necessarily. Cranberry juice and vitamin C make the urine more acidic, which makes it more difficult for bacteria that can cause urinary tract infections to grow. Cranberry juice also has another unique factor that helps prevent bacteria from adhering to the urinary tract walls.
- Why do I keep getting urinary tract infections?
Some women are more prone to urinary tract infections than others because the cells in their vaginal areas and in their urethras are more easily invaded by bacteria. Your risk of developing a urinary tract infection is also greater if you're past menopause because changes in your tissues after menopause may make the area less resistant to bacteria.Irritation or injury to the vagina or urethra caused by sexual intercourse, douching, tampons or feminine deodorants can give bacteria a chance to invade. Using a diaphragm can cause irritation and can interfere with the bladder's ability to empty, giving bacteria a place to grow.Any abnormality of the urinary tract that blocks the flow of urine, such as a kidney stone, also can lead to an infection. Illnesses that affect the immune system also increase the risk of urinary tract infections.Practicing good personal hygiene habits, including washing the areas around the bowel, vagina and urethra daily and wiping from front to back, can help prevent spreading bacteria to the urinary tract. Drinking plenty of water daily, urinating when you feel the need (rather than waiting) and urinating after sexual intercourse can help flush the system of bacteria.
- Are there any medications that can prevent my recurring infections?
If you have urinary tract infections three times a year or more, ask your health care professional about preventive antibiotic therapy. Taking a low dosage of antibiotics over an extended time or a single dose after sexual intercourse is often prescribed to head off infections. Or, you may take antibiotics for one or two days when you first notice signs of a urinary tract infection. Talk with your health care professional about which treatment may be best for you.
- Cranberry juice may help
There is some evidence that drinking cranberry juice or taking cranberry tablets may help prevent frequent bladder infections. This has not been proven, however.
- How to avoid urinary tract infections
To prevent your next urinary tract infection, be sure to drink the equivalent of at least eight glasses of fluid (water is best) throughout the day. That encourages frequent urination, which flushes bacteria from the bladder. And avoid substances that can irritate the bladder, such as alcohol and caffeine.
- UTIs may be harmful to unborn babies
If you develop a UTI while pregnant, be sure to take the medication exactly as directed by your health care professional. Pregnant women who fail to properly treat their UTIs incur a higher risk of high blood pressure, miscarriage and premature labor.
- Self-help for urinary tract infections
Although your health care professional can recommend a variety of drugs to relieve the pain of a UTI, there are things you can do on your own. Draping a heating pad over your lower pelvic area can help curb the symptoms, as can drinking plenty of water to help flush bacteria out of the urinary tract. Also, try to avoid coffee, alcohol and spicy foods that can irritate the lining of the urinary tract, particularly while you have a UTI.
Organizations and Support
For information and support on coping with Urinary Tract Infections, please see the recommended organizations, books and Spanish-language resources listed below.
American Urogynecologic Society
Address: 2025 M Street NW, Suite 800
Washington, DC 20036
American Urological Association
Address: 1000 Corporate Blvd.
Linthicum, MD 21090
Hotline: 1-800-RING-AUA (1-866-746-4282)
National Institute of Diabetes, Digestive and Kidney Diseases (NIDDK)
Address: Building 31, Room 9A06
31 Center Drive, MSC 2560
Bethesda, MD 20892
National Kidney and Urologic Diseases Information Clearinghouse
Address: 3 Information Way
Bethesda, MD 20892
National Kidney Foundation
Address: 30 East 33rd Street
New York, NY 10016
Society of Urologic Nurses and Associates
Address: East Holly Avenue, Box 56
Pittman, NJ 08071
The Interstitial Cystitis Survival Guide: Your Guide to the Latest Treatment Options and Coping Strategies
by Robert M. Moldwin
A Seat on the Aisle, Please! The Essential Guide to Urinary Tract Problems in Women
by Elizabeth Kavaler
Herbs for the Urinary Tract
by Michael Moore
Medline Plus: Urinary Tract Infection
Address: US National Library of Medicine
8600 Rockville Pike
Bethesda, MD 20894
UrologyHealth.org: American Urological Assocation Foundation
Address: National Urology Health Hotline
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