Kidney infection

A kidney infection (pyelonephritis) is a painful and unpleasant illness caused by bacteria travelling from your bladder into one or both of your kidneys.

It’s more serious than cystitis, a common infection of the bladder that makes urinating painful.

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

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

Read more about the symptoms of a kidney infection

Symptoms

The symptoms of a kidney infection usually develop quite quickly over a few hours or days.

Common symptoms include:

pain and discomfort in your side, lower back or around your genitals high temperature (it may reach 39.5C or 103.1F) shivering or chills feeling very weak or tired loss of appetite feeling sick or being sick  diarrhoea

You may have other symptoms if you also have cystitis or urethritis (an infection of the urethra). These additional symptoms may include:

pain or a burning sensation during urination need to urinate frequently or urgently feeling that you’re unable to urinate fully blood in your urine cloudy or foul smelling urine pain in your lower abdomen