Originally published on: May 14th, 2021. Last modified on September 1st, 2021

What is Pyelonephritis?

Pyelonephritis is a type of urinary tract infection in the form of a painful kidney infection. It is an unpleasant illness that usually happens when bacteria travels up from your bladder into one or both of your kidneys. The kidneys and ureters are often both infected at the same time.
Often the symptoms come on quickly, within a few hours, and they can make you feel feverish, shivery, sick and with a strong ache or pain in your back or side.

Symptoms of Pyelonephritis

The symptoms may include those of a lower UTI (see Cystitis) as well as:

  • High temperature (over 38˚C or 101˚F)
  • Nausea or vomiting
  • Shivering or chills (Rigours)
  • Pain in lower back (may only be one side)

If you have any of these symptoms you should seek medical advice as soon as possible.

What causes Pyelonephritis?

A kidney infection usually happens when bacteria, often E. coli, gets into the urethra from the anus and then travels up through the bladder into one of the kidneys.

Most people can be treated at home by taking a course of antibiotics and painkillers too. It’s also important to drink plenty of fluids because this will help to flush out the bacteria from your kidneys. If you’re frequently passing pale coloured urine then that is a good sign that you’re drinking enough fluids.

Further Information 

If you think you may have pyelonephritis or other UTI it is most important to make an appointment to see your doctor straight away. You may also wish to seek advice from your local continence clinic. The continence clinics are run by the NHS and you don’t always need to be referred to a clinic by your GP, as some clinics will allow you to book an appointment yourself.

For more information about UTIs and treatments available, see Urinary Tract Infections

To find your nearest continence clinic use our Healthcare Professional Finder.