by Riley J
(UTI; Lower UTI)


A urinary tract infection (UTI) is an infection in any part of the urinary system including:

  • Upper tract:
    • Kidneys
    • Ureter—tubes from kidneys to bladder
  • Lower tract:
    • Bladder
    • Urethra—tubes from bladder that lets urine pass out of the body

The infection can cause swelling in the tract. This makes it painful to pass urine. The infection may be named for the specific area of the urinary tract that it effects:

The Urinary Tract
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UTIs are caused by bacteria. The bacteria cling to the opening of the urethra. There they begin to grow and spread. The infection can then move up into the bladder. If the infection is not treated it can spread to the kidney. It can then lead to a severe kidney infection.

The bacteria often come from the colon or vagina. They are passed or moved toward the urethra.

Risk Factors

UTIs are more common in women. Other things that may increase your chance of a UTI include:

  • Being sexually active
  • Use of spermicide
  • New sexual partner
  • History of UTIs in sister, mother, or daughter

Some conditions may increase the chance of a UTI:


Some may not have any symptoms. Those that do have symptoms may have:

  • Urgent need to urinate
  • Small amounts of urine during urination
  • Pain in the abdomen or pelvic area
  • Burning sensation during urination
  • Cloudy, bad-smelling urine
  • Increased need to get up at night to urinate
  • Leaking of urine
  • Fever and chills
  • Nausea and low desire to eat

An infection in the kidney can be more serious. Call your doctor right away if you have symptoms of a kidney infection, such as:

  • Bloody urine
  • Low back pain or pain along the side of the ribs
  • High fever and chills


The doctor will ask about symptoms and past health. A physical exam will also be done. Urine will be tested for signs of infection.

Frequent infections may be caused by a blockage or structure issues. Images of the urinary tract may be taken with:


UTIs are treated with antibiotics. They can start to ease symptoms within 1 to 2 days. It is important to take all of the medicine, even if you feel better. A hospital stay may be needed with a severe infection. The antibiotics can then be delivered through an IV.

The infection may cause pain and spasms in the bladder. Medicine can help to ease spasms.


To help decrease the risk of a UTI:

  • Empty your bladder completely after sex. Drink a full glass of water.
  • Drink plenty of fluids throughout the day.


National Kidney Foundation 

Urology Care Foundation 


Canadian Urological Association 

Women's Health Matters 


American College of Obstetricians and Gynecologists. ACOG Practice Bulletin No. 91: Treatment of urinary tract infections in nonpregnant women. Obstet Gynecol. 2008;111(3):785-794. Reaffirmed 2016.

Bladder infection (urinary tract infection—UTI) in adults. National Institute of Diabetes and Digestive and Kidney Diseases website. Available at: Accessed September 7, 2020.

Jepson RG, Craig JC. Cranberries for preventing urinary tract infections. Cochrane Database Syst Rev. 2008;(1):CD001321.

Pohl A. Modes of administration of antibiotics for symptomatic severe urinary tract infections. Cochrane Database of Syst Rev. 2007;(4):CD003237.

Uncomplicated urinary tract infection (UTI) (pyelonephritis and cystitis). DynaMed website. Available at: Accessed September 7, 2020.

Urinary tract infection (UTI) in men. EBSCO DynaMed website. Available at: Accessed September 7, 2020.

What is a urinary tract infection (UTI) in adults? Urology Care Foundation website. Available at: Accessed September 7, 2020.

Revision Information

  • Reviewer: EBSCO Medical Review Board Adrienne Carmack, MD
  • Review Date: 09/2020
  • Update Date: 00/70/2020