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 Tract?
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. The waste products are then excreted 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 far 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), or kidneys (pyelonephritis). When the kidneys are involved, UTIs can be life threatening.
Risk Factors and Causes for UTIs
Anything that reduces bladder emptying or irritates the urinary tract can cause UTIs. Many factors can put someone at risk.
Blockages that make it difficult to empty the bladder can cause a UTI. Obstructions can be caused by an enlarged prostate, kidney stones, and certain forms of cancer.
Women are more likely to get UTIs. This is because their urethras are shorter. UTIs in men are less common and 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 pathogens within 24 hours. Bowel bacteria may have properties that allow them to stick to the bladder.
Wiping from back to 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 into the bladder.
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 seen a higher UTI risk in women who use diaphragms.
Diabetes may make patients more susceptible to 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 Bladder Catheters
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 upon what part of the urinary tract is infected.
Lower UTIs are infections of the urethra and bladder. Their symptoms include:
- burning with urination
- increased frequency of urination with scant amounts of urine being passed
- bloody urine
- cloudy urine
- urine that looks like cola or tea
- strong odor to urine
- pelvic pain (women)
- rectal pain (men)
Upper UTIs are infections of the kidneys. These are potentially life threatening, if bacteria move from the infected kidney into the blood. This condition is called sepsis. Sepsis can cause dangerously low blood pressures, shock, and death. Symptoms of upper 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 premature delivery and high blood pressure. UTIs during pregnancy are also more likely to spread to the kidneys.
Diagnosis of UTI
History and physical exam may suggest you have a lower or upper UTI.
Definitive diagnosis requires a “clean catch” urine specimen. This is urine collected from the middle of the urinary stream. Your doctor will instruct you how to do a clean catch. The goal is to avoid picking up bacteria from your skin.
Doctors will look for a large number of white blood cells in your urine. This can signal an infection. Your urine will also be cultured for bacteria. This can identify the cause of infection. It can also help your doctor choose appropriate treatment.
If an upper 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.
People with recurrent UTIs may need to be checked for obstructions. Some tests for this include:
- intravenous pyelogram (IVP) – this injected dye allows doctors to see your entire urinary tract
- cystoscopy, which uses 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 bladder cancer
Treatment of UTI
Antibiotics are used to treat UTIs. Lower UTIs can be treated with oral antibiotics. Upper UTIs require intravenous antibiotics.
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 recurrent UTIs.
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 comfortable underwear, tight fabric traps moisture
- wearing underpants with a cotton crotch
While these steps are useful, they don’t guarantee that you won’t get a UTI. Contact your medical provider whenever you have any symptoms of UTI. If you have recurrent UTIs and use spermicides or a diaphragm, your doctor may recommend alternative birth control.