Urinary tract infection (UTI) is the name given to an infection of any part of the urinary system.
What is the urinary system?
The urinary system is made up of the kidneys, the ureters (the tubes that carry urine from the kidneys to the bladder), the bladder, and the urethra (the tube that passes from the bladder through the penis, or vulva - which is located between the vaginal opening and the clitoris - through which we urinate).
When we digest food, waste products are left behind in our blood and are removed by either the liver or the kidneys. The most important part of the waste products removed by the kidneys is known as urea. Urea is mixed with water to produce urine. The urine is passed down from the kidneys, through the ureters and into the bladder. Once the bladder is full of urine, the urine is passed from the body, through the urethra, when we urinate.
What is UTI?
A UTI develops when part of the urinary system becomes infected, usually by bacteria. Bacteria can enter the urinary system through the urethra, or more rarely, though the bloodstream. Usually there is no obvious reason why the urinary system gets infected, although some women find that they get UTIs after sexual intercourse.
There are two types of UTI:
- Lower UTI: this is an infection of the lower part of the urinary tract that includes the bladder and the urethra. An infection of the bladder is called cystitis, while an infection of the urethra is known as urethritis.
- Upper UTI: this is an infection of the upper part of the urinary tract that includes the kidneys and the ureters. Upper UTIs are potentially more serious than lower UTIs because there is a possibility of kidney damage.
Who can get a UTI?
UTIs are more common in women than in men. Around 50% of women will need treatment for at least one UTI during their lifetime.
UTIs occur rarely in children. Around 11% of girls and 4% of boys will have a UTI before they reach the age of 16. However, if children do get a UTI, the effects can be serious, so prompt treatment is important. For further information about UTIs in children, see the Useful links.
Treating UTIs in pregnant women is also important. If left untreated, a UTI can cause low birth weight, or premature birth.
UTIs can be treated using antibiotics. If treated properly, UTIs normally cause no further complications and the infection soon passes. However, if left untreated, UTIs can cause serious complications, such as kidney damage and blood poisoning, which can be fatal.
It is impossible to avoid getting a UTI but you can take steps to decrease the risk of developing the condition.
