Kidney Infection (Pyelonephritis)

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Definition & Facts

Kidney infection is a type of urinary tract infection (UTI) that commonly begins in your bladder and moves upstream to one or both of your kidneys. In rare cases, kidney infections can lead to serious health problems, but quick treatment prevents most complications.

ill woman taking her temperature in bed wile feeling sick

Symptoms & Causes

Symptoms of kidney infection can vary depending on your age and may include chills, fever, and painful urination. A kidney infection is caused by bacteria or viruses that infect your bladder and move upstream to infect one or both of your kidneys.


Health care professionals use your medical history, a physical exam, and tests to diagnose kidney infection. Depending on your age, sex, and response to treatment, they will use certain tests to diagnose kidney infection.


Doctors may treat your kidney infection by prescribing antibiotics. Make sure to take all of your medicine, even if you start to feel better.

Eating, Diet, & Nutrition

If you have a kidney infection, drink lots of liquids to help flush bacteria from your urinary tract. If you have kidney failure, you should not drink this much liquid. Talk with your health care professional about how much liquid is right for you.

Clinical Trials

The National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK) and other components of the National Institutes of Health (NIH) conduct and support research into many diseases and conditions.

Related Diagnostic Tests

The Urinary Tract & How it Works

The urinary tract is the body’s drainage system for removing urine, which is composed of wastes and extra fluid. In order for normal urination to occur, all body parts in the urinary tract need to work together in the correct order.

Your Kidneys & How They Work

Your kidneys keep the makeup of your blood stable, which lets your body work well. Each day, the two kidneys filter blood to remove waste and extra fluid, which leaves the body as urine.

Last Reviewed April 2017

This content is provided as a service of the National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK), part of the National Institutes of Health. NIDDK translates and disseminates research findings to increase knowledge and understanding about health and disease among patients, health professionals, and the public. Content produced by NIDDK is carefully reviewed by NIDDK scientists and other experts.

The NIDDK would like to thank:
Ann E. Stapleton, MD, FIDSA, FACP, University of Washington School of Medicine