A kidney infection, also called pyelonephritis, is a type of urinary tract infection. The urinary tract includes your:
Kidneys, which make urine
Ureters, which are the tubes that carry urine from the kidneys to the bladder
Bladder, which stores urine
Urethra, which is the tube that drains urine from the bladder
You can have an infection in one or both kidneys. Kidney infections are much more common in women than men.
What is the cause?
Kidney infections are usually caused by bacteria. Normally there should be no bacteria in the urinary tract. Bacteria often spread from the rectum or vagina to the urethra and then up into the bladder. The bacteria travel up to the kidneys from the bladder. In men, the infection might also start as a prostate infection. Bacteria can also spread to the kidneys from an infection somewhere else in the body.
You may also get a kidney infection if urine backs up from your bladder into your kidneys. This may happen if:
You were born with a problem in your urinary system that affects the way urine flows.
You have kidney stones.
You have an enlarged prostate.
What are the symptoms?
The symptoms range from mild to severe. They may include:
Fever and chills or sweating
Pain in your lower belly, low back, or your side
Loss of appetite
Nausea or vomiting
Problems with urination, such as pain when you urinate or a frequent urge to urinate
If you have these symptoms, see your healthcare provider right away.
How is it diagnosed?
Your healthcare provider will ask about your symptoms and medical history and examine you. Tests may include blood and urine tests. If you have bacteria in your urine, you may have:
An intravenous pyelogram (IVP), which is a series of X-rays taken after your healthcare provider injects dye into your blood vessels to look for blockages in your kidneys and urinary tract
An ultrasound, which uses sound waves to show pictures of the kidneys and urinary tract
Women may have a pelvic exam to see if the symptoms may be caused by an infection or other problem of the uterus or ovaries.
How is it treated?
Kidney infection can be serious because:
It can permanently damage your kidneys.
The infection may enter your bloodstream and be life-threatening.
It can cause pregnant women to go into labor too early (premature labor).
Your healthcare provider will likely prescribe an antibiotic. How long it takes to get better depends on how severe your symptoms are when you start treatment. In mild cases, you will start feeling better in the first 1 or 2 days. If your infection has been causing symptoms for several days before treatment or if you have a fever, it may take longer to feel better.
If you are very sick, you may need to spend a day or two in the hospital and get antibiotics by IV.
If you have kidney stones or a problem in your urinary system that affects the way urine flows, you may need surgery to treat the problem and prevent future infections.
How can I take care of myself?
Follow the full course of treatment prescribed by your healthcare provider. If you were prescribed an antibiotic, take all of it as prescribed, even when you no longer have symptoms. Ask your provider:
How and when you will hear your test results
How long it will take to recover
What activities you should avoid and when you can return to your normal activities
How to take care of yourself at home
What symptoms or problems you should watch for and what to do if you have them
Make sure you know when you should come back for a checkup.
How can I help prevent a kidney infection?
The best way to prevent kidney infections is to try to prevent bladder infections. You may help prevent bladder infection if you:
Drink enough liquids to keep your urine light yellow in color.
Drink a glass of cranberry juice each day. The juice should be real cranberry juice, not a cranberry-flavored drink.
Donâ€™t wait to go to the bathroom if you feel the need to urinate.
Urinate soon after sex.
Keep your genital area clean. If you want to have vaginal sex after anal sex, both partners should wash their genitals first.
Empty your bladder completely when you urinate.
Donâ€™t wear a wet bathing suit for long periods of time.
Also, if you are a woman:
If you often have bladder infections, keep a journal to see if they are related to sex. If they do tend to happen after sex, your provider may prescribe medicine for you to take to help prevent infection.
Donâ€™t use irritating cosmetics or chemicals in your genital area. This includes, for example, strong soaps, feminine hygiene sprays, douches, scented tampons, sanitary napkins, or panty liners.
Keep your vaginal area clean. Wiping from front to back after using the toilet may help prevent infections. Use mild, unscented soap to wash your genital area gently each time you bathe or shower.
Wear underwear that is all cotton or has a cotton crotch. Pantyhose should also have a cotton crotch. Cotton keeps your body cooler and drier than nylon. Change underwear and pantyhose every day.
Men should always wash their penis during baths or showers. Men who are not circumcised should gently pull back the foreskin and wash the tip of the penis when they take a bath or shower.
Developed by RelayHealth.
Adult Advisor 2015.1 published by RelayHealth. Last modified: 2014-10-30 Last reviewed: 2014-10-30
This content is reviewed periodically and is subject to change as new health information becomes available. The information is intended to inform and educate and is not a replacement for medical evaluation, advice, diagnosis or treatment by a healthcare professional.
Kidney Infection: References
Kidney (Renal) Infection (Pyelonephritis). (2013). Urology Care Foundation.