A kidney infection is a type of urinary tract infection (UTI) that usually starts in your urethra or bladder and travels to one or both of your kidneys. If not treated immediately and properly, a kidney infection can become life-threatening. Learn what to look out for—including how to prevent and treat kidney infections—and who is most at risk.*

What are the symptoms of a kidney infection?

Signs and symptoms of a kidney infection can vary depending on your age and sex. Children under the age of two may only develop a high fever. People over 65 may appear confused and jumble their speech. 

For most people, the signs of a kidney infection include:

• Fever
• Chills
• Pain in the abdomen, back, side, or groin
• Frequent urination or urge to urinate
• Burning sensation or pain during urination
• Nausea and vomiting
• Pus or blood in your urine
• Urine that is cloudy or has an unusually strong odor

If you have any of the above symptoms, make an appointment with your doctor. Seek immediate medical attention if pain, fever, or chills are combined with bloody urine or vomiting. 

Who is at the greatest risk for kidney infections?

You run a greater risk of developing a kidney infection if you:

• Are female. Since a woman’s urethra is shorter than a man’s, it’s easier for outside bacteria to reach the bladder—and thus, the kidneys. The urethra’s nearness to the vagina and anus also increases bacteria’s access to inner organs. Pregnant women are at even higher risk.
• Have a urinary tract blockage. Anything, including kidney stones, an enlarged prostate gland, or a structural abnormality, that slows the flow of urine or reduces your ability to empty your bladder when urinating can cause a bacterial infection. 
• Have a compromised immune system. Medical conditions, such as diabetes and HIV, and immunosuppressant drugs, such as those taken following an organ transplant, can leave you especially vulnerable to infections. 
• Have nerve damage around your bladder. Nerve or spinal cord damage can block the sensations of a bladder infection so that you’re unaware when it reaches your kidneys.
• Use a urinary catheter long-term. Urinary catheters are tubes that drain urine from the bladder. They are used after certain diagnostic and surgical procedures or if you are bedridden. 
• Have a medical condition that causes urine to flow backward. Both children and adults with vesicoureteral reflux (VUR) or similar conditions are at higher risk for infection. 

How are kidney infections treated?

Kidney infections are treated with antibiotics. They will usually go away quickly when addressed early and if antibiotics are taken as directed. Serious infections may require a hospital stay. Infections caused by structural abnormalities in the urinary tract may require surgery for correction. 

What happens if a kidney infection goes untreated?

Untreated kidney infections can result in potentially serious complications, such as:

• Kidney scarring: The buildup of scar tissue in the kidneys can lead to high blood pressure and eventual kidney failure.
• Blood poisoning (septicemia): Kidney infections can spread bacteria through your bloodstream, turning your body toxic.
• Pregnancy complications: Women who develop a kidney infection during pregnancy have a higher risk of delivering low-birth-weight babies.

Are kidney infections preventable?

Reduce your risk of kidney infection by taking steps to prevent urinary tract infections. Women, in particular, may reduce their risk of urinary tract infections if they:

• Drink fluids, especially water and other clear liquids. Adequate hydration helps remove bacteria from your body when you urinate. If you have chronic kidney disease or kidney failure, consult your doctor concerning what a safe fluid intake is for you.
• Urinate when you feel the urge. Don’t “hold it in” if you don’t have to. 
• Empty your bladder right after intercourse to clear bacteria from the urethra.
• Wipe thoroughly—and from front to back—after urination and bowel movements. 
• Avoid using feminine sprays or similar products in your genital area, as they can cause irritation. 

Additional information on kidney infections can be found on the American Kidney Fund and National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK) websites.

*Mayo Clinic. (2020, Aug. 26). What is a Kidney Infection? https://www.mayoclinic.org/diseases-conditions/kidney-infection/symptoms-causes/syc-20353387