Urinary Tract Infections in Women

Urinary tract infections (UTI) are a serious health issue that affects millions of women each year. For this reason, women with a UTI should understand the causes and treatments for urinary tract infections.

The cause of most urinary tract infections is bacteria. Any part of your urinary tract can become infected which includes the kidneys, ureters, bladder and urethra. Bladder and urethra infections are the most common among women.

Urinary tract infections rank as the second most common in all types of infection in the human body. Urinary tract infections (UTI) account for approximately 8.3 million doctor visits each year.*

Women are especially prone to urinary tract infections for reasons that aren’t yet clear. One in five women develops a UTI during their lifetimes. Urinary tract infections are not as common in men as they are in women but they can be very serious when they do occur.

The causes of UTIs in women

Normally, urine is sterile and free of any bacteria, viruses, and fungi, but does comprise of some fluids, salts, and waste products. An infection occurs when tiny organisms, usually bacteria from the digestive tract, adhere to the opening of the urethra and begin to reproduce. The urethra is the tube that carries urine from the bladder to be expelled outside the body. Most infections are caused by Escherichia coli (E. coli) bacteria from the colon.

The typical case occurs when bacteria first travels to the urethra. When this bacteria multiples, an infection can occur. An infection confined to the urethra is urethritis. If the infection moves to the bladder (a bladder infection), it is called cystitis. If the infection is not treated immediately, bacteria could travel further up the ureters to infect the kidneys, which results in a kidney infection called pyelonephritis.

Chlamydia and Mycoplasma, both microorganisms, can also cause urinary tract infections in women but the trend of these types of infections is to remain limited to the urethra and reproductive system. Unlike E. coli, Chlamydia and Mycoplasma can be sexually transmitted and infections require treatment of both male and female partners.

The urinary system is biologically structured to help ward off infection. The ureters and bladder are supposed to prevent urine from backing up toward the kidneys, and the flow of urine from the bladder is designed to wash bacteria out of the body. Despite these safeguards, infections can still occur.

During menopause, the drop in estrogen levels can affect the urinary system. Like the vaginal wall, the urethra (the tube that drains the bladder and is used for urination) undergoes changes as estrogen levels drop. The urethra’s changes can lead to various urinary symptoms, including an increased susceptibility to urinary tract infections.

Pregnant women are not more prone to urinary tract infections than other women. However, when a UTI does occur during pregnancy, the infection is more likely to travel to the kidneys. Some reports say that about 2 - 4% of pregnant women develop a urinary infection. Some research suggests that hormonal changes and shifts in the position of the urinary tract during pregnancy make it easier for bacteria to travel through the ureters to the kidneys. Because of this, many doctors recommend periodic testing of urine during pregnancy. A pregnant woman who develops a UTI should be treated immediately to avoid premature delivery of her baby and other risks such as high blood pressure. Some antibiotics are not safe to take during pregnancy. In selecting the best treatment, doctors consider various factors such as the drug's effectiveness, the stage of pregnancy, the mother's overall health, and the potential effect on the fetus.

The Risk Factor for Woman

Some women are more prone to getting a urinary tract infection than others. Any anomaly of the urinary tract that obstructs the flow of urine (i.e., a kidney stone) increases the risk factor for an infection. A common source of infection is catheters, or tubes, placed in the urethra and bladder. A woman who cannot void or who is unconscious or critically ill might need a catheter that stays in place for a prolonged period. Some women, especially the elderly and those with nervous system disorders that cause loss of bladder control, may need a catheter for life.

Women with diabetes have a higher risk of a UTI because of changes in the immune system. Any other disorder that suppresses the immune system raises the risk of a urinary infection. Urinary tract infections may occur in infant girls who are born with abnormal urinary tracts which sometimes need to be corrected with surgery. The rate of UTI’s increases with age in women, however scientists can’t pinpoint why women have more urinary infections than men. One factor may be that a woman's urethra is shorter, increasing the risk of bacteria quickly accessing the bladder. A woman's urethral opening is near sources of bacteria from the anus and vagina. For many women, sexual intercourse seems to trigger an infection, although the reasons for this linkage are unclear.

According to several studies, women who use a diaphragm are more likely to develop a UTI than women who use other forms of birth control. Recently, researchers found that women whose partners use a condom with spermicidal foam also tend to have growth of E. coli bacteria in the vagina.

The Symptoms of UTI

Not every woman with a UTI is symptomatic but most women display at least a couple of symptoms. Symptoms may include a frequent urge to urinate and a painful, burning feeling in the vicinity of the bladder or urethra during the urination process. It is not unusual to generally feel tired, shaky, washed out and to feel pain even when not urinating. Women often feel an uncomfortable pressure just above the pubic bone. It is common for a woman with a urinary infection to, despite the urge to urinate, pass only a small amount of urine. The urine itself may look cloudy or milky or even reddish if blood is present. Normally, a UTI does not cause fever if it is in the urethra or bladder. A fever may indicate that the infection has spread to the kidneys. Other symptoms of a kidney infection include pain in the back or side below the ribs, nausea, or vomiting.

UTI Diagnosis

To find out whether your urinary tract has been infected, your doctor will test a sample of your urine for bacteria and pus. The general practice is to ask for a "clean catch" urine sample by washing the genital area and collecting a "midstream" sample in a sterile container. This method of collecting urine prevents bacteria around the genital area from getting into the sample and complicate the test results. The urine sample is then sent to a laboratory if the doctor’s office is not equipped to perform the testing.

In the urinalysis test, the urine is tested for red and white blood cells and bacteria. If found, the bacteria is then grown in a culture and tested against different antibiotics to see which drug is most effective against it.

Some microbes, like Mycoplasma and Chlamydia, can be detected only with specific bacterial cultures. A doctor suspects a microbial infection when a woman displays symptoms of a UTI but a standard culture doesn’t display any bacterial growth.

When treatment does not clear up infection and is traced to the same strain of bacteria, the doctor may order more tests to help determine if your system is normal. One of such tests is an intravenous pyelogram, which allows for x-ray images of the kidneys, bladder and ureters. An opaque dye visible on x-ray film is injected into a vein and a series of x-rays are taken. The film maps the urinary tract, revealing even the slightest changes in the structure of the tract.

If infections recur, your doctor also may recommend an ultrasound exam, which images from the echo patterns of sound waves reflected from internal organs. Another useful test is a cystoscopy. A cystoscope is an instrument made of a hollow tube with several lenses and a light source, which allows the doctor to see the inside of the bladder via the urethra.

UTI Treatment

The general treatment of urinary tract infections is the use of antibacterial drugs. The length of treatment and choice of drug depend on the patient's medical history and the “mid-stream” urine tests that help identify the offending bacteria. The drugs most often used to treat routine, uncomplicated UTIs are trimethoprim/sulfamethoxazole (Bactrim, Septra, Cotrim), trimethoprim (Trimpex), nitrofurantoin (Macrodantin, Furadantin), ampicillin (Omnipen, Polycillin, Principen, Totacillin) and amoxicillin (Amoxil, Trimox, Wymox). A class of drugs called quinolones includes four drugs approved in recent years for treating UTI. These drugs include ciprofloxacin (Cipro), ofloxacin (Floxin), norfloxacin (Noroxin) and trovafloxin (Trovan).

A UTI can be cured within 1 or 2 days of treatment if the infection is not complicated by an obstruction or other disorder. As a precaution, many doctors ask their patients to continue antibiotics for a week or more to make sure that the infection has been halted. Single-dose treatment is not recommended for some patients, for example, those who neglected immediate treatment or display signs of kidney infection, diabetic patients, or patients with structural abnormalities. Longer treatment is also needed for women with infections caused by Chlamydia or Mycoplasma, which are generally treated with tetracycline, trimethoprim/sulfamethoxazole (TMP/SMZ), or doxycycline. A follow-up urinalysis test confirms that the urinary tract is infection-free. Symptoms may disappear before the infection is fully cleared so it is important to take the full course of treatment.

Severely ill women with kidney infections may be hospitalized until they can take fluids and necessary drugs on their own. Kidney infections typically require several weeks of antibiotic treatment. Researchers at the University of Washington found that 2-week therapy with TMP/SMZ was as effective as 6 weeks of treatment with the same drug in women with kidney infections that did not involve an obstruction or nervous system disorder. In such cases, kidney infections rarely lead to kidney damage or kidney failure unless untreated.

Several drugs are available to help relieve the pain of a UTI. A heating pad may help. Most doctors suggest that the act of drinking more water helps purify the urinary tract of lingering bacteria. While undergoing treatment, it helps to avoid alcohol, coffee, and spicy foods. One of the most beneficial things a smoker can do for his bladder is to quit smoking. Smoking is one of the major causes of bladder cancer.

Curing infections caused by a urinary obstruction or other systemic disorder depends on diagnosing and fixing the underlying problem, sometimes even surgically. If the root cause is untreated, there is an increased risk of kidney damage. Such infections tend to stem from a wider range of bacteria, and sometimes infections can occur from more than one type of bacteria at a time.

Recurrent Infections in Women

Approximately 50% of all women will incur at least one urinary tract infection in her lifetime, with many women suffering several infections throughout their lifetimes. Many women suffer from frequent UTI’s. Nearly 20% of women who have a UTI will have another, and 30% of those will have yet another. Of the last group, 80% will have even more recurrences. Women who have had three urinary tract infections are likely to continue having them. Four out of five such women get another within 18 months of the last UTI.

The latest infection usually stems from a strain or type of bacteria that is different from the infection before it, indicating a separate infection. Even when several UTI’s in a row are due to E. coli, slight differences in the bacteria indicate distinct infections.

A woman who has frequent recurrences (three or more a year) can ask her doctor about one of the following treatment options:

• Take low doses of an antibiotic such as nitrofurantoin or TMP/SMZ daily for six months or longer. If taken at bedtime, the drug remains in the bladder longer and may be more effective. NIH-supported research at the University of Washington has shown this therapy to be effective without causing any serious side effects.
• Take a single dose of an antibiotic after sexual intercourse.
• Take a short course (1 or 2 days) of antibiotics when symptoms appear.

Dipsticks that change color when an infection is present are now available without a prescription. The strips detect nitrite, which is formed when bacteria change nitrate in the urine to nitrite. The test detects approximately 90% of UTI’s when used with the first morning urine specimen and may be very useful for women who suffer from recurrent infections.

Research funded by the National Institutes of Health (NIH) suggests that one factor behind recurrent UTIs may be the ability of bacteria to attach to cells lining the urinary tract. A recent study found that bacteria created a protective film on the inner lining of the bladder in mice. If a similar occurrence can be demonstrated in humans, the discovery may lead to new treatments that will be able to prevent recurrent UTIs. Another line of research indicates that women who are "non-secretors" of certain blood group antigens may be more prone to recurrent urinary tract infections. The cells lining the urethra and vagina may allow bacteria to attach more easily. Further research will help show whether this association is sound and proves useful in identifying women with an increased risk for UTIs.

Doctors suggest some additional steps that a woman can take on her own, to avoid an infection:

• Drink plenty of water every day.
• Urinate when you feel the need; don't resist the urge to urinate.
• Wipe from front to back to prevent bacteria around the anus from entering the vagina or urethra.
• Take showers instead of tub baths.
• Cleanse the genital area before sexual intercourse.
• Avoid the use of feminine hygiene sprays and scented douches, which may irritate the urethra.
• Some doctors suggest drinking cranberry juice.

Complicated Infections

Curing infections that stem from a urinary obstruction or other systemic disorders depend on finding and correcting the underlying problem, sometimes with surgery. If the root cause goes untreated, this group of patients is at risk of kidney damage. Also, such infections tend to arise from a wider range of bacteria, and sometimes from more than one type of bacteria at a time.

Source

The National Institute of Health
*Ambulatory Care Visits to Physician Offices, Hospital Outpatient Departments, and Emergency Departments: United States, 1999-2000. Vital and Health Statistics. Series 13, No. 157. Hyattsville, MD: National Center for Health Statistics, Centers for Disease Control and Prevention, U.S. Dept. of Health and Human Services; September 2004.