A bladder infection is a bacterial infection of the bladder. It is also sometimes known as a urinary tract infection because the urinary tract includes the bladder, urethra, ureters, and kidneys.
Bladder infections are much more common in women than in men. It is estimated that more than 50 percent of women will experience a bladder infection at least once in their lifetime. Most are uncomplicated infections typically caused by the Escherichia coli (E. coli) bacterium.
The term "uncomplicated" is used to describe infections that occur in healthy women as opposed to "complicated" bladder infections that happen to people with other conditions, such as catheters, urinary stents, diabetes, pregnancy, or other causes.
Although an uncomplicated bladder infection is often easily treated with a short course of antibiotics, it can be considerably uncomfortable for the person who has it.
Causes
Bladder infections often occur when bacteria get into the urethra, the tube that carries urine out of the body, and then move into the bladder.
Lady with bladder infection on the toilet
A bladder infection may be caused by frequent sexual intercourse and not urinating immediately after sexual intercourse.
Once in the bladder, the bacteria can stick to the lining of the bladder, causing it to become inflamed, a condition known as cystitis. The bacteria can also move from the bladder into the kidneys, resulting in a kidney infection.
There are a number of factors that can increase the risk of getting a bladder infection, including:
frequent sexual intercourse
having sexual intercourse with a new partner
using a diaphragm and a spermicide for birth control
not urinating immediately after sexual intercourse
having diabetes
having a bladder or kidney infection within the past 12 months
changes in the urinary system
Symptoms
The symptoms of a bladder infection can include:
pain or burning when urinating
urgent and frequent need to urinate, often passing small quantities of urine
discomfort in the lower abdomen
offensive-smelling urine
cloudy urine
blood in the urine
People with kidney infections have similar symptoms, but they may also have:
fever
back pain or pain in the side or groin
nausea or vomiting
A doctor can usually diagnose a bladder infection after discussing the symptoms a person is experiencing and doing a urinalysis. This is a urine test that looks for the presence of white blood cells in the urine, and signs of inflammation, which indicates an infection.
If a kidney infection is suspected, the doctor may recommend a urine culture. A urine culture is a laboratory test used to identify the different bacteria that may be present in a urine sample.
People with uncomplicated bladder infections are usually treated with a short course of antibiotics. Treatment options vary, but the following are the most common prescriptions for uncomplicated cystitis:
A single-dose treatment is also available, but it generally results in lower cure rates and more frequent recurrence.
Most people find that their symptoms begin to improve the day after beginning the treatment. Even if someone feels better, it is important that they take the full course of antibiotics in order to completely eliminate the infection. If they do not finish the whole dose, the infection may return, and it can be harder to treat the second time around.
If symptoms persist for more than 2 or 3 days after starting treatment, people should contact their doctor.
People with more complicated bladder infections will usually need to take antibiotics for 7-14 days. Complicated infections include those that occur during pregnancy, or in people who have diabetes or a mild kidney infection. It is also recommended that men with acute urinary infections take antibiotics for 7-14 days as well.
Less commonly, fluorocarbons and beta-lactam antibiotics are used to treat more invasive infections. These antibiotics are effective, but they are not recommended for initial treatment because of concerns about bacterial resistance.