The bladder, urethra, ureters and kidneys make up the urinary system. Also called the urinary tract, this system produces, stores and eliminates urine. However, it is prone to infection. Such infections are called cystitis or urinary tract infections (UTIs).
Cystitis is an infection of the bladder. Although any part of the system can become infected, cystitis is the most common type of UTI. It is much more common in women than in men, and as many as half of women will experience cystitis at least once.
In cystitis, bacteria infect the urine in the bladder. Bacteria, usually from the rectum, move to the vagina and urethra (the tube from the bladder to the outside of the body). Once bacteria grow here, they may enter the urethra and move to the bladder. There, they stick to and infect cells lining the bladder. Bacteria called E. coli cause up to 85 per cent of cystitis cases.
The urinary tract is normally protected from infection in a number of ways. Urine itself is usually produced free from infection. It flows away from the kidneys and out of the body, helping to wash bacteria out of the urinary tract. The body’s immune (defence) system and the lining of the bladder also help fight infection. In women, bacteria normally found in the vagina provide some protection. Secretions from the prostate gland help to protect men.
Symptoms that suggest a bladder infection can include:
Bacteria in the urine do not always cause symptoms. If the amount of bacteria is low, there may be no symptoms. It is also possible to have large amounts of bacteria in the urine without having symptoms. This is called asymptomatic bacteruria. It is found in about four percent of the population, but elderly females are at higher risk. It is not usually treated with antibiotics except under certain conditions, including pregnancy, kidney transplants, or when the flow of urine is blocked.
Treating bladder infections promptly reduces the chance of spread to the kidneys (called pyelonephritis). Infection can significantly damage the kidney.
If infection reaches the kidneys, symptoms may include:
Women are more likely to develop cystitis than are men. See sidebar for some common risk factors. In women, the urethra and vagina are close to the rectum. This source of bacteria can be harmful to the urinary tract. Since women have shorter urethras than men, bacteria can reach the bladder more easily. Frequent sexual activity or a new sexual partner increases the chance of spreading bacteria from the rectum to the vagina and the opening of the urethra.
The choice of birth control method also influences a woman’s risk. Studies have found that using spermicide or a diaphragm make bladder infection more likely.
After menopause, reduced estrogen levels can put women at risk. Less estrogen makes the vagina drier and susceptible to damage. Possible trauma during intercourse can then lead to cystitis. Changes in the normal bacteria of the vagina may mean that the natural protective effect is lost.
An abnormal structure or blockage of the urinary tract, or any condition interfering with the normal flow of urine, can lead to cystitis.
Another risk is using a catheter, a tube that drains urine from the bladder. Diabetes, procedures involving the urinary tract, and recent antibiotic use are also linked.
If your doctor believes that you have cystitis, a physical exam can assess your abdomen, genital area and urinary system. This helps rule out other medical conditions with similar symptoms. Such conditions include vaginal infections, sexually transmitted infections, or other bladder problems.
Your doctor may ask you to provide a urine sample. A dipstick test, done in the office, can easily check for signs of infection like white blood cells, red blood cells or nitrites. Your doctor may also ask the lab to do a urinalysis and a urine culture. Urine cultures are used to grow and identify specific bacteria infecting the urine. This helps to determine the most effective antibiotic treatment. However, if your symptoms clearly indicate bladder infection, you may be treated without testing.
A number of antibiotics are effective in treating cystitis. Your doctor will decide which to use, considering the severity of your infection, allergies, medical conditions, and if you are experiencing a repeat infection. Three days of antibiotics is usually enough, but your doctor may prescribe antibiotics for seven days. If urination is very painful, your doctor can give you medication to help. Since antibiotic treatment usually clears up symptoms, following up with your family doctor is not necessary. However, go back if you still have symptoms after taking all of your antibiotics. You may need a different antibiotic and more tests, such as a urine culture.
Though we all need to drink enough fluid every day, it is essential when you have a bladder infection. Passing urine more often flushes bacteria out of the urinary tract. Drinking at least 10 ounces (280 mL) per day of cranberry juice may clear mild cases of cystitis.
Bladder infections do not usually last long when treated with antibiotics, but sometimes they return. About a quarter of women experience recurring infections, usually several weeks after a previous infection. This is usually another infection that has emerged after the first has been successfully treated. Less commonly, recurring infections can mean that the treatment has failed. Relapses usually occur within a few weeks of the previous infection.
If you have recurring cystitis, see your family doctor. You may need further tests, such as urine tests or imaging tests. Imaging tests, such as x-rays, ultrasound and CT scans, look at the structure of the urinary tract. You may also be referred to an urologist, a doctor who specializes in problems of the urinary tract. In general, women who have had three episodes of cystitis and men who have had their first should be checked.
Treatment for recurrent cystitis includes taking a preventive dose of antibiotics every day, or treating each infection with a course of antibiotics. Your family doctor will help you decide which option is best for you. If you suffer from recurrent cystitis related to sexual activity, one dose of antibiotics taken after intercourse can reduce the chance of developing a bladder infection. Again, drinking cranberry juice may also help.
Search for cystitis in the health information section
The Cochrane Collaboration
Information on the effectiveness of cranberries
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Other than preventive antibiotics, few strategies for preventing cystitis have been proven (see sidebar at left). In general, drinking lots of fluid and passing urine regularly helps. Women should always clean the urinary and genital area from front to back. Avoid products and chemicals that irritate these areas.
Sexually active women who have problems with bladder infections should avoid using spermicide or a diaphragm, and reduce the number of sexual partners. Passing urine before and after intercourse is recommended. After menopause, women may want to talk with their family doctor about using vaginal estrogen. Studies have shown that it can lower the risk of recurrent cystitis.
Recent studies have shown that cranberry juice (or tablets) can reduce the chance of cystitis by about 35 per cent. Be sure that the product you try is 100 per cent cranberry juice, as cranberry juice cocktails contain lower concentrations of cranberry.
Cystitis is the most common type of urinary tract infection. If you have symptoms, see your family doctor. Recurrent bladder infections should be investigated and treated. You may also want to consider prevention strategies that do not involve medication.