Give Online: Help shape patient care for generations to come.
Cleveland Clinic Logo



Request an Appointment



Contact us with Questions

Expand Content

Kidney Infection

Kidney Infections

Kidney infection (the medical term is pyelonephritis) is a bacterial infection of one or both kidneys. The disease occurs in roughly 3 to 7 of every 10,000 people in the U.S. it is readily treatable if diagnosed early. Most kidney infections are readily diagnosed and easily resolved with antibiotic treatment. Skilled specialists at the Glickman Urological and Kidney Institute are experienced in treating kidney infections and resolving the primary problems such as kidney stones, and others that can lead to infections.

What is kidney infection (pyelonephritis)?

Kidney infection (pyelonephritis) is a bacterial infection. A bacteria called Escherichia Coli (E Coli) causes about 90% of the infections. The bacteria migrate from the genitals through the urethra into the bladder and up the tubes (ureters) that connect the bladder to the kidneys. Normally such bacteria are flushed out by the flow of urine. However, if the urine flow is obstructed by structural abnormalities, kidney, an enlarged prostate gland (benign prostatic hyperplasia) compressing the urethra, or backflow (reflux) of urine from the bladder to the kidneys, the bacteria can gain a foothold. Some bacteria such as staphylococcus infections can enter the kidneys from the bloodstream.

Symptoms of a kidney infection include a sudden onset of chills, fever, pain in the lower back or side, nausea and vomiting. In some instances, the abdominal muscles may contract. General symptoms include flushed or reddened skin, painful urination, increased urination, unproductive attempts to urinate despite feelings of urgency, general ill feelings, cloudy urine, abnormally colored urine, blood in the urine, and a foul smelling urine. These are symptoms of acute uncomplicated pyelonephritis.

People with urinary tract abnormalities, kidney stones, benign prostatic hyperplasia, or reflux are at risk of developing kidney infections. Those with diabetes and immune systems weakened by disease or therapeutic interventions for disease are also at risk. Pregnant women are at risk because the enlarging uterus can squeeze the ureters and reduce the flow of urine allowing the bacteria to migrate to the kidneys.

Two common laboratory tests are performed. A urine sample is examined under a microscope to determine if white and/or red blood cells are present. The urine may also be cultured to see if bacteria grow. The strain of bacteria that are cultured often determines the type of therapy that will be applied. In some cases, an intravenous pyelogram (IVP) or computed tomography (CT) scan will be conducted to determine if the kidneys are enlarged.

CT scans produce images of structures and organs similar to x-rays but without the radiation. During an IVP, a colored fluid is injected into a vein and allowed to flow through the body. As it flows, x-rays are taken to chart its course, particularly as it moves through the urinary tract. This allows the examiner to determine not only the size of the kidneys but how well they are functioning.

A physician will treat the disease based on his or her examination. He or she may start the patient on the standard treatment of a course of antibiotics before the lab tests results are available. The medication may change once the exact strain of bacteria is revealed by the lab tests.

Most antibiotic treatments last for 14 days and it is essential that patients take the pills as recommended for the full 14 days even though symptoms may disappear after a few days. The disappearance of symptoms does not mean all bacteria are killed. Some may remain and the infection may reappear.

There is also a concern that those bacteria that remain may develop resistance to the medication. For some reason the disease is more difficult to treat in men and they may have to take medication for up to six weeks. Patients with severe illness, those that have significant nausea and vomiting, high fevers, significant pain and signs of dehydration may be hospitalized for a few days while the antibiotics are administered intravenously. Urine samples are taken after about six weeks of treatment and examined to insure the bacterial infection is eradicated.

Call us for an Appointment

Urology Appointments: 800.223.2273 ext. 4-5600
Nephrology Appointments: 800.223.2273 ext. 4-6771

Schedule an Appointment Online

Talk to a Nurse

Do you have a question about our services? Ask the nurse in the Glickman Urological & Kidney Institute.

This information is provided by Cleveland Clinic and is not intended to replace the medical advice of your doctor or health care provider. Please consult your health care provider for advice about a specific medical condition.

© Copyright 2016 Cleveland Clinic. All rights reserved.