Causes of Kidney Infection

A kidney infection is a painful and unpleasant illness that usually happens when bacteria travel up from your bladder into one or both of your kidneys.

The medical name for a kidney infection is pyelonephritis. It's more serious and different from cystitis, which is a common infection of the bladder that makes urinating painful.

If treated promptly, a kidney infection doesn't cause serious harm but it will make you feel very unwell. If a kidney infection isn't treated, it can get worse and cause permanent kidney damage.

Often the symptoms of a kidney infection come on quickly within a few hours. You can feel feverish, shivery, sick and have a pain in your back or side

A kidney infection happens when bacteria enters and infects one or both of your kidneys. The bacteria are usually a type called E. coli, which live in your bowel.

The bacteria get in through the opening of the urethra and move upwards through your urinary tract, first infecting your bladder and then your kidneys.

It's thought that one way the bacteria get into your urinary tract is by accidentally spreading from your anus to your urethra. This can happen if you wipe your bottom after going to the toilet and the soiled toilet paper comes into contact with your genitals. It can also happen during sex.

In rare cases, a kidney infection can develop if bacteria or fungi infect the skin and the infection spreads through your bloodstream and into your kidney. However, this type of infection usually only occurs in people with weakened immune systems.

Who's most likely to get a kidney infection?

Women and children are most at risk of developing a kidney infection, as well as other urinary tract infections (UTIs) such as cystitis.

In women, the urethra is closer to the anus than it is in men, making it easier for bacteria from the anus to enter the urethra accidentally. The female urethra is also much shorter than the male urethra (which runs through the penis). This makes it easier for bacteria to reach the bladder and move into the kidneys.

Can kidney infections be prevented?

You can reduce your chances of developing a kidney infection by keeping your bladder and urethra free from bacteria. This can be achieved with simple measures such as drinking plenty of fluids and practicing good genital hygiene.