A urinary tract infection (UTI) can occur in any part of the
urinary tract. Bacteria cause the vast majority of UTIs. Fungi or viruses can
also cause UTIs.
UTIs are the second most common type of infection in humans.
The National Kidney & Urologic Diseases Information Clearinghouse (NKUDIC)
reports that UTIs account for over 8 million doctor visits annually.
What Is the Urinary
The urinary tract consists of the kidneys, ureters, bladder,
Your kidneys are two bean-shaped organs. They are located in
the abdomen on either side of the spine. The kidneys filter your blood to
remove excess water, salt, potassium, urea, and other substances. You then
excrete the waste products as urine.
The ureters are thin, spaghetti-shaped tubules. They carry
urine from the kidney to the bladder.
The bladder is a small, balloon-shaped organ located in the
pelvis. In women, the bladder is located in front of the uterus. In men, the
bladder is located just above the prostate gland.
The urethra is the tube through which urine exits the
bladder. The urethra in women is shorter than it is in men. In men, it has to
pass through the prostate and the penis.
UTIs can involve the urethra (urethritis), bladder
(cystitis), kidneys (pyelonephritis), or a combination of the three. When the
kidneys are involved, a UTI can be life-threatening.
UTI Risk Factors
Anything that reduces bladder emptying or irritates the
urinary tract can cause UTIs. Many factors can put you at risk of a UTI.
Blockages can make it difficult to empty the bladder and can
cause a UTI. Enlarged prostate, kidney stones, and certain forms of cancer can
Women are more likely to get UTIs. This is because the urethra
is shorter in women than it is in men. UTIs in men are less common but tend to
be more serious.
Pressure on the urinary tract during sex can move bacteria
from the colon into the bladder. Most women have bacteria in their urine after
intercourse. However, the body usually can get rid of these bacteria within 24
hours. Bowel bacteria may have properties that allow them to stick to the
Wiping from the back to the front after going to the
bathroom can lead to a UTI. This motion drags bacteria from the rectal area
towards the urethra.
Spermicides can increase UTI risk. They may cause skin
irritation in some women. This increases the risk of bacteria entering the
Latex condoms can cause increased friction during
intercourse. They may also irritate the skin. This may increase the risk of UTI
in some individuals. However, condoms are important for reducing the spread of
sexually transmitted infections.
Diaphragms may put pressure on the urethra. This can
decrease bladder emptying. Some studies have shown a higher risk of UTI in
women who use diaphragms.
Diabetes, especially if poorly controlled, may make it more
likely for someone to get a UTI.
Loss of Estrogen
After menopause, a loss of estrogen changes the normal
bacteria in the vagina. This can increase the risk of UTI.
Prolonged Use of
Catheters are used when someone cannot urinate normally.
These thin, flexible tubes are inserted into the bladder. They allow urine to
drain into a container. Long-term catheter use can increase the risk of UTI.
They may make it easier for bacteria to get into the bladder. Treatment for a
catheter-associated UTI may require removal of the device.
Symptoms of UTI
Symptoms of UTI depend on what part of the urinary tract is
Lower-tract UTIs affect the urethra and bladder. Symptoms of
a lower-tract UTI include:
- burning with urination
- increased frequency of urination without passing
- bloody urine
- cloudy urine
- urine that looks like cola or tea
- urine that has a strong odor
- pelvic pain (women)
- rectal pain (men)
Upper-tract UTIs affect the kidneys. These are potentially
life threatening if bacteria move from the infected kidney into the blood. This
condition is called urosepsis. Urosepsis can cause dangerously low blood
pressure, shock, and death. Symptoms of upper-tract UTI include:
- pain and tenderness in the upper back and sides
Women who are pregnant and have symptoms of UTI should see
their doctor right away. UTIs during pregnancy can cause high blood pressure
and premature delivery. UTIs during pregnancy are also more likely to spread to
Diagnosis of UTI
History and physical exam may suggest you have a lower or
The diagnosis of a UTI requires a “clean catch” urine
specimen. This is urine collected from the middle of the urinary stream. Your
doctor will explain to you how to get a clean catch. The goal of a clean catch is to avoid picking up bacteria from your skin.
Your doctor will look for a large number of white blood
cells in your urine. This signals an infection. Your doctor will also take a
culture of your urine to test for bacteria. A culture can identify the cause of
the infection. It can also help your doctor choose which treatment is right for
If an upper-tract UTI is suspected, you may also need a
complete blood count (CBC) and blood cultures. These can make certain your
infection hasn’t spread to the blood.
If you have repeated UTIs, you may need to be checked for an
obstruction. Some tests for this include:
- intravenous pyelogram (IVP), which shows the
doctor your entire urinary tract by using injected dye
- cystoscopy, which involves using a small camera
to examine the bladder
During a cystoscopy, your doctor may remove a small piece of
bladder tissue. This is called a biopsy. A biopsy can be used to rule out
Treatment of UTI
Antibiotics are used to treat UTIs. Your doctor can treat a
lower-tract UTI with oral antibiotics. Upper-tract UTIs require intravenous
antibiotics (antibiotics put directly into your veins).
Sometimes, bacteria develop resistance to antibiotics. Urine
cultures can help your doctor select an effective antibiotic treatment.
Researchers are trying to develop a vaccine to prevent
In the meantime, there are simple steps you can take to help
prevent UTIs. WomensHealth.gov recommends:
- wiping from front to back after urinating or
having a bowel movement
- drinking six to eight glasses of water daily
- drinking water after having sex
- not holding urine for long periods of time
- cleaning your vaginal and rectal areas daily
- taking showers instead of baths
- wearing pants that aren’t
too tight to avoid trapping moisture
- wearing underwear with a cotton crotch
- While these steps are useful, they don’t
guarantee that you won’t get a UTI. Contact your doctor whenever you have the symptoms
of a UTI. If you have recurrent UTIs and use spermicides or a diaphragm, your
doctor may recommend a different birth control.