Content updated on March 17, 2021 - Medically reviewed by our Medical Advisory Committee

When bacteria get into your kidneys, it can cause an infection. The bacteria that cause kidney infections usually come from another part of your urinary tract, such as your bladder, ureters or urethra. Kidney infections can affect one kidney at a time or both of your kidneys at the same time. It is very important to treat kidney infections as soon as possible. Kidney infections that are not treated soon enough can cause permanent kidney damage or can spread to other parts of your body and cause an even more serious infection.

Who gets kidney infections?

Anyone can get a kidney infection, but some people are more likely than others to get them. You are more likely to get a kidney infection if you:

  • Have a bladder infection. An infection in the bladder can spread to the kidneys.
  • Are a woman. Women get kidney infections more often than men do. This is because of the way the female body is built. In women, the urethra (the part of your urinary tract where your urine exits your body) is shorter than it is in men. Having a shorter urethra makes it easier for bacteria to get into your body and travel up your urinary tract. The urethra is also closer to the vagina and anus in women than it is in men. Bacteria can spread from the vagina and anus to the urethra, and then travel up the urinary tract.
  • Have a problem with the shape of your urinary tract that makes it harder for urine to pass through
  • Have a blockage in your urinary tract, such as a kidney stone or an enlarged prostate (in men)
  • Are pregnant
  • Have diabetes
  • Have a weakened immune system. This could be caused by a disease, such as diabetes or HIV, or by certain medicines called immunosuppressants. People who have had a kidney transplant or other organ transplant take immunosuppressants.
  • Have nerve or spinal cord damage that keeps you from feeling pain in the area of your body where your bladder and urethra are. Not being able to feel pain in this area can keep you from noticing symptoms of a bladder infection. A bladder infection can lead to a kidney infection if left untreated.
  • Use a catheter to drain urine from your bladder
  • Have a health problem called vesicoureteral reflux (VUR). A normal urinary tract only allows urine to flow down the ureters into the bladder. People with VUR have urinary tracts that allow urine to flow backwards, up the ureters, which can lead to kidney infections.

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What are the symptoms of kidney infection?

If you have a kidney infection, you may notice one or more of the following symptoms:

  • Fever
  • Vomiting
  • Pain in your back, side(s) or groin
  • Chills
  • Nausea
  • Urinating (peeing) often
  • Feeling like you have to urinate (pee) often, even if you just went
  • Pain or burning when urinating
  • Pus (thick, white/yellow liquid) or blood in your urine
  • Cloudy or bad-smelling urine

If you notice any of these symptoms, contact your health care provider as soon as possible. If you are currently taking medicine to treat a urinary tract infection (UTI), but you are still having any of these symptoms, contact your health care provider.

If your health care provider thinks you might have a kidney infection, he or she might ask you for a urine sample to look or bacteria or other signs of infection. You might also need to have a blood test or imaging tests, such as an X-ray, ultrasound or CT scan.

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What is the treatment for a kidney infection?

Kidney infections are treated with antibiotics. Your health care provider may tell you to take an antibiotic medicine that treats the most common types of infections, until your urine can be looked at to figure out the exact type of infection you have. Once your urine test results are available, your health care provider might tell you to take a different type of antibiotic, depending on the type of infection you have.

If you have a very serious infection, you may need to stay in the hospital to receive treatment.

If your kidney infection was caused by a problem with the shape of your urinary tract, you may need to have surgery to correct the problem and prevent future kidney infections.

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How can I prevent kidney infections?

You may be able to lower your chances of getting a kidney infection by:

  • Drinking plenty of water
  • Urinating as soon as you feel the need to do so
  • Urinating after having sex
  • Wiping from front to back after going to the bathroom, if you are a woman. This helps to keep bacteria from your vagina or anus from getting into your urethra.
  • Avoiding the use of deodorant sprays or douches in your genital area.

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