Definition | Causes | Risk Factors | Symptoms | Diagnosis | Treatment | Prevention


Kidney infections may occur in one or both kidneys.

The kidneys remove waste from the body through urine. They also balance the water and mineral content in the blood. An infection may prevent them from working properly.

Anatomy of the Kidney

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Kidney infections are caused by a bacteria. The specific type of bacteria can vary. The bacteria most often comes from an untreated bladder infection.

Risk Factors

Bacteria may be introduced to the urinary tract and ultimately the kidneys by:

  • Sexual activity
  • Conditions that block or slow the flow of urine such as:
    • Tumors
    • Enlarged prostate gland
    • Kidney stones
    • Birth defect of the urinary tract, including vesicoureteral reflux
  • Having a test to examine the bladder— cystoscopy
  • Having a catheter or stent placed in the urinary tract
  • Conditions that impair bladder emptying like multiple sclerosis and spina bifida

Other medical conditions that increase your risk of infection include:


Symptoms of kidney infection may include:

  • Pain in the abdomen, lower back, side, or groin
  • Frequent urination
  • Urgent urination that produces only a small amount of urine
  • Sensation of a full bladder—even after urination
  • Burning pain with urination
  • Fever and chills
  • Nausea and vomiting
  • Pus and blood in the urine
  • Loss of appetite


You will be asked about your symptoms and medical history. A physical exam will be done.

Your bodily fluids will be tested. This can be done with:

  • Blood tests
  • Urine tests

Images may be taken of your bodily structures. This can be done with:


Complications from untreated or poorly treated kidney infection can lead to:

  • A serious infection that spreads throughout the body— sepsis
  • Chronic infection
  • Severe kidney disease, which may result in scarring of tissue or permanent damage

You will be treated with antibiotics. Be sure to take all of the medication. Antibiotics may need to be delivered through an IV. This may require a stay in the hospital.


Surgical correction of vesicoureteral reflux in children may reduce risk for pyelonephritis.

Kidney infection is often a complication of a bladder infection. You can prevent bladder infections if you:

  • Drink plenty of fluids throughout the day. Cranberry juice is a good choice to prevent bladder infection.
  • Practice good hygiene.
  • Urinate as soon as you feel the urge.
  • Take showers rather than baths.
  • For women:
    • Wipe from the front to the back after using the toilet.
    • Urinate before and after sex. Drink water to help flush bacteria.
    • Avoid genital deodorant sprays and douches.