Banishing urinary tract infections

Prompt treatment reduces the risk of complications. And some simple lifestyle strategies can help prevent a recurrence.

Many women -- up to half of us -- are intimately familiar with the pain and urgency of a urinary tract infection (UTI). What many women may not know is why they get UTIs and how to avoid them.

The urinary tract is particularly vulnerable to infection in women because the opening of the urethra (the tube that carries urine from the bladder to the outside) is so close to the bacteria-rich area around the anus. UTIs occur most often when bacteria -- usually Escherichia coli (E. coli), a normal inhabitant of the gut -- re-enter the body by way of the urethra and infect tissues in the lower or upper urinary tract.

Anatomy is destiny
UTIs are more common in women than in men. One reason is that women have a shorter urethra, which allows bacteria quicker access to the bladder. In men, the penis and scrotum help isolate the urethra from the anus.

Bacteria reach the urethra in several ways, including sexual activity. Intercourse can spread bacteria from the genital area to the urethra. Rubbing during intercourse can also inflame the urethra and predispose it to infection. Bacteria from bowel movements may spread to the urethra if a woman wipes from back to front. A medical procedure that requires insertion of a catheter into the urethra also increases the chance of infection.

Women who use a diaphragm for birth control are at a slightly increased risk for a UTI. A diaphragm may make it more difficult to empty the bladder completely, so bacteria remain in the bladder and multiply. The creams and gels used with the diaphragm can also irritate the urethra by interfering with normal bacterial levels in the urogenital area. The physical act of inserting and removing the diaphragm is another source of irritation and possible infection.

In postmenopausal women, a drop in estrogen levels may shift the balance of microorganisms in the vagina and encourage bacterial growth that causes a UTI. Increased risk for UTIs is also associated with conditions more common in older women--diabetes, atrophy of the urethral lining, and urge incontinence.

Signs and symptoms
Most UTIs involve the bladder and urethra. Symptoms include an intense need to urinate, though often only a few drops at a time, and a severe, burning pain during urination (dysuria). The urge to urinate may even disturb sleep (nocturia). Some women experience pressure or tenderness in the lower abdomen, incontinence, bedwetting, or blood in the urine. Infected urine may be cloudy and have a strong odor.

If diagnosed and treated promptly, a lower UTI is usually short-lived and seldom a health threat. But a delayed diagnosis gives bacteria a chance to migrate to the upper urinary tract and infect the kidneys. In addition to the symptoms of a lower UTI, a kidney infection may produce fever, chills, nausea and vomiting, and back pain, usually on one side. Antibiotics, rest, and plenty of fluids will cure most cases, but a woman with severe vomiting may need to receive intravenous fluids and antibiotics in the hospital.

Getting a diagnosis
Diagnosing a UTI requires a simple urine analysis. Your clinician will ask for a "clean-catch" sample to prevent contamination from genital-area bacteria. You wash your genital area and then collect some urine in a cup midstream as you urinate.

To evaluate frequent recurrences, your doctor may recommend either an ultrasound or computed tomography (CT) scan of the upper urinary tract (ureters and kidneys), or cystoscopy to examine the lower urinary tract. During cystoscopy, a doctor inserts a lighted tube through the urethra to view the inside of the urethra and bladder.

If antibiotics don't clear up the infection, you may need an intravenous pyelogram. The doctor will inject contrast fluid into a vein to make the bladder, ureters, and kidneys visible on an x-ray. This procedure can help locate kidney stones, tumors, and other obstructions that might cause recurrent UTIs or blood in the urine.

Treating UTIs
Curing a lower UTI usually takes three days or less of antibiotic treatment. The appropriate drug (see chart) and course of treatment depend on factors such as a woman's age, her previous experience with UTIs, where she lives (E. coli has developed antibiotic resistance in some areas of the country), and whether she's pregnant or has other medical conditions. For example, diabetics are more vulnerable to kidney infections, and they may need to take antibiotics longer.

New research suggests that a single dose of antibiotics may be as effective as a three-day course. A study in the March 2002 Urology investigated the effects of shorter and longer courses of two types of antibiotics in more than 1,300 women with UTIs. Women took either a single 400-mg dose of gatifloxacin, a three-day treatment with 200 mg daily of gatifloxacin, or a three-day treatment with 200 mg of ciprofloxacin in two daily doses. The cure rate for all three treatments was 90%-95%. Upper UTIs are more difficult to treat and may require several weeks of antibiotics.

Antibiotics kill the bacteria causing the UTI, but they also kill "good bacteria" that maintain the balance in the vagina. This may lead to overgrowth of the resident yeast (Candida), causing a yeast infection. For this reason, doctors will often recommend that women use an over-the-counter yeast infection preparation as soon as they start taking antibiotics.

An unwelcome encore
Roughly 33% of women who have had one UTI will have another. If you've had two within six months, or three within one year, talk to your clinician about prophylactic (preventive) treatment. You may be able to reduce your risk with a low daily dose of antibiotics for six months or longer, or a single dose after sexual intercourse.

Women may soon have another option: a vaccine. Researchers at the University of Wisconsin Medical School are studying an experimental vaccine, in vaginal suppository form, made of several strains of bacteria. A recent test of the vaccine in women with recurrent UTIs suggests that a dosing schedule that includes periodic boosters may be effective in preventing new infections.

This approach clearly warrants further study. Preventing UTI recurrence without antibiotics could reduce the likelihood that bacteria will become resistant to certain drugs. And a vaccine could offer relief to women who develop yeast infections from taking antibiotics for recurrent UTIs.

How to prevent UTIs
Several simple strategies can help prevent UTIs.

• Visit the bathroom frequently. This will help prevent urine from stagnating in the bladder, which can foster bacterial growth and infection.

• Urinate after sexual intercourse. Urine flushes away bacteria that can creep up the urethra and cause infection. Also, wash the genital area before and after intercourse.

• Avoid using products that contain the spermicide nonoxynol-9. It can irritate the urethra and leave it vulnerable to infection.

• Use vaginal estrogen if you're postmenopausal. Estrogen promotes the growth of "friendly" bacteria that help protect against UTIs.

• Drink plenty of water. Urinating helps flush bacteria from the urethra.

• Wipe from front to back after a bowel movement.

• Avoid feminine hygiene sprays and douches. They may irritate the urethra.

Does cranberry juice really help?
Although there are few large studies on the effectiveness of cranberry juice against UTIs, for years many women have used it as a preventive. In 1994, a small Harvard University study found that 10 ounces of cranberry juice a day reduced the risk of a lower UTI when compared with an identical-tasting placebo.

Recent research suggests a mechanism for this protection. Certain parts of cranberries (and possibly blueberries) -- fructose, glycoproteins, and tannins -- help prevent bacteria from sticking to cells in the urinary tract. Once a UTI develops, however, cranberry juice doesn't take the place of medical care and antibiotic treatment.

Urinary tract infections
Although urinating flushes away most bacteria, some may adhere to the surface of the urethra, multiply, and invade the bladder. From there, they may move up the ureters to infect the kidneys. A UTI of the lower urinary tract, involving only the bladder, is called cystitis. Pyelonephritis is an upper urinary tract infection that extends to the kidneys.

Antibiotics for urinary tract infections
Legend for Chart:

A - Medication (brand name)
B - Length of treatment
C - Side effects/comments

A B
C

ciprofloxacin (Cipro) 3 days

Nausea; avoid if pregnant;
expensive(*)

fosfomycin (Monurol) 1 dose

Diarrhea, headache, nausea

gatifloxacin (Tequin) 3 days

Avoid if pregnant; expensive(*)

levofloxacin (Levaquin) 3 days

Avoid if pregnant; expensive(*)

nitrofurantoin (Furadantin,
Macrobid, Macrodantin) 7 days

Nausea, vomiting; avoid in
late pregnancy

norfloxacin (Noroxin) 3 days

Avoid if pregnant; expensive(*)

ofloxacin (Floxin) 3 days

Avoid if pregnant; expensive(*)

trimethoprim
(Proloprim, Trimpex) stomach 3 days

Diarrhea, vomiting, upset

trimethoprim-
sulfamethoxazole (Bactrim) 3 days

Nausea, hives, rash

(*) May cost more than $40 for a 3-day course of treatment

Sources: Fitzgerald, M, and D Lie, "Urinary Tract Infection:
Providing the Best Care," Clinical Update CME, www.medscape.com;
PDR Pocket Guide to Prescription Drugs (Simon and Schuster, New
York, 2002).
DIAGRAM: Urinary tract infections

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