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HealthInfo Canterbury

Pyelonephritis (kidney infection)

Pyelonephritis (pie-lo-nef-rite-is) is an infection of one or both of your kidneys.

Anyone can get kidney infections, although they're more common in women (especially when they're pregnant) and children. People with diabetes, kidney stones, or who have physical defects in their kidneys are also more likely to get kidney infections.

Acute (suddenly occurring) kidney infection needs urgent medical attention. So, if you have these symptoms, see your GP or after-hours doctor as soon as possible.

Causes of kidney infections

urinary system showing kidneys, ureters, bladder, and urethraKidney infections usually happen because of a germ, or bacteria, that enters your urethra (the tube you pass urine through) from the surrounding skin. It then travels into your bladder and up into your kidneys.

If the infection stops in your bladder, just causing a urine infection, this is called cystitis. It only becomes pyelonephritis if it travels up to your kidneys. It can also happen because of problems with your kidneys, such as kidney stones or defects in your kidneys. But often there is no obvious cause.

Most kidney infections are one-off and come on quite quickly. This is called acute kidney infection.

Repeated episodes of acute kidney infection can lead to chronic (long-lasting) kidney infection. This can lead to long-term kidney problems, or even kidney failure.

Chronic kidney infection is rare. It's usually caused by scarring of your kidneys, repeated urinary infections, or permanent defects in your kidneys at birth.

Symptoms of kidney infections

The symptoms of kidney infection can be vague. But they can include:

You may also notice urinary tract symptoms, which include:

In severe cases, a kidney infection can cause blood poisoning (septicaemia), which is a serious illness.

Diagnosing kidney infections

Your GP will examine you and ask you questions about your general health. They'll diagnose a kidney infection by getting you to have a urine test. Sometimes you might need a blood test to check for signs of infection and to measure your kidney function.

Treating kidney infections

While kidney infections can become serious, they can almost always be cured. But it's best to get them treated quickly to prevent any complications. Although complications are rare, they can cause permanent damage to your kidneys.

Your doctor will usually prescribe antibiotics to get rid of the infection and pain relief to dull the pain and lower your temperature. They'll also tell you to drink plenty of fluids. Make sure you finish all the antibiotics you're prescribed, even if you're feeling better.

If the infection is severe or doesn't clear up quickly with antibiotics, you may need to go to hospital.

Preventing kidney infections

You can do some things to reduce your risk of getting a kidney infection:

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Written by HealthInfo clinical advisers. Endorsed by clinical director, Nephrology Department, Canterbury DHB. Last reviewed November 2019.


See also:

Healthy kidneys

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