Urinary tract infection (UTI)

Urinary tract infection is the term given to any infection of part of the urinary system. The urinary system consists of the kidneys, the bladder, the ureters (tubes that connect the kidneys to the bladder) and the urethra (tube connecting the bladder to the outside world), and is responsible for excreting some soluble wastes from the body.

The kidneys act as filtration units to remove some of the body’s wastes from the blood, such as urea and ammonia, which are then passed from the kidney as urine. The urine passes through the ureters into the bladder and then leaves the body through the urethra.

What causes urinary tract infection?

Urinary tract infection (UTI) occurs when part of the urinary tract becomes infected, usually with bacteria, and is common in women who are sexually active. The most common type of UTI is known as cystitis (inflammation of the bladder). It has been estimated that one third of women experience the symptoms of cystitis at some point in their life.

Urine is normally free from germs and bacteria, however, the normal human body is covered with bacteria and the normal intestine contains enormous numbers of harmless bacteria. Urinary tract infections are usually upward-travelling infections that occur when some of the harmless bacteria from the intestine manage to get into the urethra and then travel up into the bladder.

This happens more commonly in women than in men, because women have a shorter urethra. Women who are sexually active are at higher risk of UTIs. Bacteria from the area around the anus are normally found all over the perineum (the area of tissue between the vulva and the anus), including the opening to the vagina and around the entrance to the urethra. In predisposed women, sexual intercourse helps the passage of these bacteria via the urethra into the bladder by a process of urethral massage.

If not treated, the infection may travel further from the bladder up the ureters to the kidneys.

What are the symptoms of a UTI?

When you have a UTI, the bladder and the lining of the urethra become red and inflamed. Common symptoms related to UTIs may include:

  • a burning sensation or lower abdominal discomfort when you pass urine;
  • needing to urinate urgently;
  • passing urine much more frequently than usual;
  • 'leaking' urine;
  • feeling an urge to urinate, but being unable to or only passing a few drops;
  • foul smelling urine;
  • urine that is cloudy, bloody or dark; and
  • having a temperature.

What are the risk factors for developing a UTI?

Some factors that may increase your likelihood of developing a UTI may include the following.

  • Being female. UTIs are more common in women than in men because a women’s urethra is located closer to their rectum than a man’s. Also, the female urethra is shorter, so it is easier for bacteria to reach the bladder.
  • Being pregnant.
  • Having tumours or stones in the urinary tract.
  • Having diabetes.
  • Using a diaphragm as contraception.
  • Having a medical condition involving the bladder or kidneys.
  • Having a urinary catheter.
  • Anything that obstructs the flow of urine out of the bladder — such as an enlarged prostate. For this reason UTIs are increasingly common in men as they age.

How are UTIs treated?

UTIs are usually treated with antibiotics. If your doctor suspects a UTI, they may test a sample of your urine to confirm the diagnosis, but often they will know you have a UTI from the symptoms you have.

If you have a UTI, your doctor will prescribe a course of antibiotics that should alleviate symptoms in a few days.

As with any course of antibiotics, it is important to complete the entire course prescribed by your doctor, even if you are no longer experiencing symptoms of a UTI.

How can I help prevent a UTI?

Here are some tips for preventing UTIs.

  • Drink lots of water.
  • Urinate as soon as you feel the need.
  • Wipe your bottom from front to back to prevent bacteria from around the anus entering the urethra.
  • Make sure you have adequate lubrication during sex, and urinate after having sex — this flushes out any germs that may have entered the urethra during intercourse.
  • Avoid using feminine hygiene products such as sprays or douches.
  • If you use a diaphragm, ask your doctor about other forms of contraception you might use.
  • Take vitamin C or cranberry juice — they are said to be urinary antiseptics.
Last Reviewed: 18 April 2009
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