Urinary tract infections are a serious health problem affecting millions of people each year. Infections of the urinary tract are common — only respiratory infections occur more often.
Each year, urinary tract infections (UTI’s) account for about eight million doctor visits. Women are especially prone to UTI’s. One woman in five will develop a UTI during her lifetime.
The Urinary Tract
The urinary system is made up of the kidneys, ureters, bladder, and urethra. The key players in the system are the kidneys, a pair of purplish-brown organs located below the ribs toward the middle of the back. The kidneys:
- remove liquid waste from the blood, as urine
- keep a stable balance of salts and other substances in the blood, and
- produce a hormone that aids in the formation of red blood cells.
Narrow tubes, called ureters, carry urine from the kidneys to the bladder, a triangle-shaped chamber in the lower abdomen. Urine is stored in the bladder and emptied out of the body through the urethra.
The average adult passes about a quart and a half of urine each day. The amount of urine varies, depending on the fluids and foods a person eats and drinks. The volume of urine produced at night is about half that produced in the daytime.
Causes of UTI
Normal urine is sterile. It contains fluids, salts, and waste products, but it is free of bacteria, viruses, and fungi. An infection occurs when microorganisms, usually bacteria from the digestive tract, cling to the opening of the urethra and begin to multiply. Most UTIs arise from one specific type of bacteria, Escherichia coli or E. coli, which normally lives in the colon.
In most cases, bacteria start growing in the urethra. An infection that is limited to the urethra is called urethritis. From the urethra bacteria often move to the bladder, causing a bladder infection, called cystitis. If the infection is not treated right away, bacteria then goes up the ureters and infects the kidneys, called pyelonephritis.
Microorganisms called chlamydia and strong>mycoplasma can also cause UTI’s in both men and women. However, these type infections tend to remain in the urethra and reproductive system. Unlike E. coli, chlamydia and mycoplasma can be transmitted. Infections caused by chlamydia or mycoplasma require treatment of both partners.
The urinary system is structured in a way that helps prevent infection. The ureters and bladder normally prevent urine from backing up toward the kidneys. The flow of urine from the bladder helps wash bacteria out of the body. In men, the prostate gland produces secretions that slow bacterial growth. Immune defenses also prevent infection in both men and women. Despite your body’s safeguards, infections can still occur.
Who is at Risk for UTI
Some people are more prone to getting a UTI than others. Any abnormality of the urinary tract that obstructs the flow of urine, for example a kidney stone, sets the stage for an infection. An enlarged prostate gland can slow the flow of urine and increase the risk of UTI.
A common source of UTI is catheters, or tubes, placed in the bladder. Someone who cannot urinate, is in a coma, or is critically ill, often needs a catheter that must remain in the bladder for a long time. Some people, especially the elderly or those with nervous system disorders who lose bladder control, may need a catheter for life. Bacteria on the catheter can cause infection in the bladder.
People with diabetes have a higher risk of a UTI because of changes in their immune
system caused by their diabetes. Any disorder that suppresses the immune system raises the risk of a urinary tract infection.
UTI’s may occur in babies born with abnormalities of the urinary tract and may need to be corrected with surgery. UTI’s rarely happen in boys and young men. In women, though, the rate of UTI’s gradually increases with age. Scientists are not sure why women have more urinary infections than men. One factor may be that a woman’s urethra is shorter than a male’s. This allows bacteria quicker access to the into the bladder. Also, a woman’s urethral opening, called the meatus, is near the anus and vagina, both are sources of bacteria. Also, for many women, intimate relations seems to trigger an infection, although the reasons 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.
Recurrent Urinary Tract Infections
Many women suffer from frequent UTI’s. Nearly 20 percent of women who have a UTI will
have another; thirty percent of those will have yet another. Of the last group, 80 percent will have recurrences.
Usually, each infection is caused by type of bacteria that is different from the infection before, indicating a separate infection. Even when there are several UTI’s in a row caused by e. coli, slight differences in the bacteria indicate separate, distinct infections.
Studies suggests that one factor behind recurrent UTI’s may be the ability of bacteria to attach to cells lining the urinary tract. A recent study has also shown that women with recurrent UTI’s tend to have certain blood types. Some scientists speculate that women with these blood types are more prone to UTI’s because the cells lining the vagina and urethra may allow bacteria to attach more easily. Further research will show whether this association is correct and may prove useful in identifying those women who are at high risk for UTI’s.
Urinary Tract Infections in Pregnancy
Pregnant women do not seem to be more prone to UTI’s than other women. However, when a UTI does occur, it is more likely to travel to the kidneys. According to some reports, about 2 to 4 percent of pregnant women develop a urinary infection. Scientists think that hormonal changes and shifts in the position of the urinary tract during pregnancy make it easier for bacteria to travel up the ureters to the kidneys. For this reason, many doctors recommend periodic testing of urine during pregnancy.
Symptoms of Urinary Tract Infection
Not everyone with a UTI has symptoms, but most people have some. Symptoms can include a frequent urge to urinate and a painful, burning feeling in the area of the bladder or urethra during urination. It is not unusual to feel bad all over — such as tired, shaky, or “washed out” — and to feel pain even when not urinating. Often, women feel an uncomfortable pressure above the pubic bone. Some men experience a fullness in the rectum. It is common for a person with a urinary infection to complain that, despite the urge to urinate, only a small amount of urine is passed. The urine itself may look milky or cloudy, even reddish if blood is present. A fever may mean that the infection has reached the kidneys. Other symptoms of a kidney infection include pain in the back or side just below the ribs, nausea, or vomiting.
In children, the symptoms of a urinary infection may be overlooked or attributed to another disorder. A UTI should be considered a possibility when a child or infant seems irritable, is not eating normally, has an unexplained fever that does not go away, has leaking urine or loose bowels, or is not growing properly. The child should be seen by a doctor if there are any of these symptoms; especially if there is a change in the child’s urinary pattern.
Diagnosis of Urinary Tract Infection
To find out whether or not you have a UTI, your doctor will test a sample of urine for pus and bacteria. You will be asked to give a “clean catch” urine sample.
How to do a clean catch urine specimen
Wash the genital area and collect a “midstream” sample of urine in a sterile container. Catching urine this way helps prevent bacteria from the genital area from getting into the sample.
The sample is usually sent to a laboratory. However, some doctors’ offices are able to do the testing. The urine is checked for both white and red blood cells, and bacteria. The bacteria are grown in a culture, and tested against different antibiotics to see which medicine works best to kill the bacteria.
Some microbes, like chlamydia and mycoplasma, can only be detected with special bacterial cultures. A doctor suspects one of these infections if you have the symptoms of a UTI and pus in the urine, but a standard culture fails to grow bacteria.
When an infection does not clear up with treatment and is traced to the same strain of
bacteria, the doctor will order other tests to take pictures of the urinary tract. One of these tests is an intravenous pyelogram, which is an x-ray of the bladder, kidneys, and ureters. A dye that can be seen with an x-ray is injected into a vein, and several x-rays are taken. The xray shows an outline of the urinary tract, and any small changes in the structure of the urinary tract.
If you have recurrent UTI, your doctor may recommend an ultrasound,
which is a test that shows pictures of the urinary tract using sound waves. Another useful test is cystoscopy. A cystoscope is an instrument made of a hollow tube with several lenses and a light source. A cystoscope allows the doctor to actually look inside the bladder.
Treatment Of Urinary Tract Infection
UTI’s are treated with antibacterial medicines. The type of medicine and how long the treatment lasts depends on your health history and the results of the urine tests. The sensitivity test is very useful in helping the doctor choose the most effective medicine. The medicines used most often to treat routine, uncomplicated UTI’s are trimethoprim (Trimpex), trimethoprim/sufamethoxazole (Bactrim, Septra, Cotrim), amoxicillin (Amoxil, Trimox, Wymox), nitrofurantoin (Macrodantin, Furadantin), and ampicillin.
A UTI can often be cured with 1 or 2 days of treatment if the infection is not complicated by an obstruction or nervous system disorder. Still, many doctors ask their patients to take antibiotics for a week or two to assure that the infection has been cured. Single-dose treatment is not recommended for some patients, for example, those who have waited before getting treatment and have signs of a kidney infection, patients with diabetes or structural abnormalities, or men who have prostate infections. Longer treatment may also needed by patients with infections caused by mycoplasma or chlamydia, which are usually treated with tetracycline, trimethoprim/sulfamethoxazole (TMP/SMZ), or doxycycline. A follow-up urinalysis helps to confirm that the urinary tract infection has been cured. It is important to take all of the medicine prescribed even though the symptoms may go away before the infection is completely cured.
Patients who are very sick with kidney infections may be hospitalized until they can drink fluids and take needed medicines by themselves. Kidney infections often require several weeks of antibiotic treatment.
Various medicines are available to relieve the pain of a UTI. A heating pad or a warm bath may also help. Most doctors suggest drinking plenty of water to help cleanse the urinary tract of bacteria. It is best to avoid coffee, alcohol, and spicy foods if you have a UTI. One of the best things a smoker can do for the bladder is to quit smoking. Smoking is the major known cause of bladder cancer.
Recurrent Infections in Women
About 4 out of 5 women who have a UTI get another within 18 months; many women have them more often. A woman who has frequent three or more UTIs each year should ask her doctor about one of the following treatment options:
- Low doses of an antibiotic such as TMP/SMZ or nitrofurantoin daily for 6 months or longer. If taken at bedtime, the drug remains in the bladder longer and may be more effective.
- A single dose of an antibiotic after intimate relations.
- A short course, 1 or 2 days, of antibiotics whenever symptoms appear.
Dipsticks that change color when there in an infection present are now available without prescription. The strips detect nitrite, which is formed when bacteria change urine to nitrate. The test can detect about 90 percent of UTI’s and may be useful for women who have recurrent infections.
Doctors suggest some added steps that women can take to avoid infection:
- Drink plenty of water every day. Some doctors suggest drinking cranberry juice, which in large amounts inhibits the growth of some bacteria by acidifying the urine. Vitamin C supplements have the same effect.
- Urinate when you feel the need
- 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 intimate relations;
- Avoid using feminine hygiene sprays and scented douche, which may irritate the urethra.
Urinary Tract Infections During Pregnancy
A pregnant woman who develops a UTI should be treated promptly to avoid premature birth of her baby and other risks such as high blood pressure. Some antibiotics are not safe to take during pregnancy. Your doctor will consider various factors such as the drug’s effectiveness, the stage of pregnancy, the mother’s health, and potential effects on the fetus when selecting the best treatment.
Complicated Urinary Tract Infections
Curing infections that come from a urinary obstruction or nervous system disorder depends on finding and correcting the underlying problem, sometimes with surgery. If the underlying cause goes untreated, you may be at risk of kidney damage. Also, such infections tend to come from a wider range of bacteria, and sometimes from more than one type of bacteria at a time.
UTI’s are unusual in men. They usually stem from an obstruction — for example, a urinary stone or enlarged prostate — or a medical procedure that requires a catheter. The first step is to identify the infecting organism and the medicine which will kill it. Doctors often recommended longer therapy in men than in women, in part to prevent infections of the prostate gland. Prostate infections, called prostatitis, are harder to cure because antibiotics are unable to penetrate infected prostate tissue effectively. Therefore, men with prostatitis often need long-term treatment with a carefully selected antibiotic for a UTI.