Urinary Tract Infections (UTIs)

Take the UTI Quiz Urinary Tract Infection (UTI) Slideshow Pictures Urinary Incontinence in Women Slideshow Pictures

Medical Author:

Jerry R. Balentine, DO, FACEP

Jerry R. Balentine, DO, FACEP

Dr. Balentine received his undergraduate degree from McDaniel College in Westminster, Maryland. He attended medical school at the Philadelphia College of Osteopathic Medicine graduating in1983. He completed his internship at St. Joseph's Hospital in Philadelphia and his Emergency Medicine residency at Lincoln Medical and Mental Health Center in the Bronx, where he served as chief resident.

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Medical Editor:

Melissa Conrad Stöppler, MD, Chief Medical Editor

Melissa Conrad Stöppler, MD, Chief Medical Editor

Melissa Conrad Stöppler, MD, is a U.S. board-certified Anatomic Pathologist with subspecialty training in the fields of Experimental and Molecular Pathology. Dr. Stöppler's educational background includes a BA with Highest Distinction from the University of Virginia and an MD from the University of North Carolina. She completed residency training in Anatomic Pathology at Georgetown University followed by subspecialty fellowship training in molecular diagnostics and experimental pathology.

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• Urinary Tract Infections (UTIs) Overview
• Urinary Tract Infection Causes
• UTI Symptoms and Signs
• When to Seek Medical Care
• Urinary Tract Infection Diagnosis
• Urinary Tract Infections Treatment
• UTI Home Remedy
• Medical Treatment
• Follow-up
• UTI Prevention
• Urinary Tract Infection Prognosis
• For More Information
• Synonyms and Keywords
• Authors and Editors
• Take the UTI Quiz
• Urinary Tract Infection (UTI) - Slideshow
• Urinary Incontinence in Women - Slideshow
• Read more on Urinary Tract Infections from Healthwise
• Viewer Comments: Urinary Tract Infections - Symptoms
• Viewer Comments: Urinary Tract Infections - Effective Treatments

Urinary Tract Infections Overview

A urinary tract infection (UTI) is an infection involving the kidneys, ureters, bladder, or urethra. These are the structures that urine passes through before being eliminated from the body.

• The kidneys are a pair of small organs that lie on either side of the spine at about waist level. They have several important functions in the body, including removing waste and excess water from the blood and eliminating them as urine. These functions make them important in the regulation of blood pressure. Kidneys are also very sensitive to changes in blood sugar levels and blood pressure. Both diabetes and hypertension can cause damage to these organs.



• Two ureters, narrow tubes about 10 inches long, drain urine from each kidney into the bladder.



• The bladder is a small saclike organ that collects and stores urine. When the urine reaches a certain level in the bladder, you experience the sensation that you have to void, then the muscle lining the bladder can be voluntarily contracted to expel the urine.



• The urethra is a small tube connecting the bladder with the outside of the body. A muscle called the urinary sphincter, located at the junction of the bladder and the urethra, must relax at the same time the bladder contracts to expel urine.

Any part of this system can become infected. As a rule, the farther up in the urinary tract the infection is located, the more serious it is.

• The upper urinary tract is composed of the kidneys and ureters. Infection in the upper urinary tract generally affects the kidneys (pyelonephritis), which can cause fever, chills, nausea, vomiting, and other severe symptoms.



• The lower urinary tract consists of the bladder and the urethra. Infection in the lower urinary tract can affect the urethra (urethritis) or the bladder (cystitis).

Urinary tract infections are usually referred to as simple or complicated.

• Simple infections occur in healthy urinary tracts and do not spread to other parts of the body. They usually go away readily with treatment.



• Complicated infections are caused by anatomic abnormalities, spread to other parts of the body, are worsened by underlying medical conditions, or are resistant to many antibiotics. They are more difficult to cure.

In the United States, urinary tract infections account for more than 7 million visits to medical offices and hospitals each year.

• Urinary tract infections are much more common in adults than in children, but about 1%-2% of children do get urinary tract infections. Urinary tract infections in children are more likely to be serious than those in adults and should not be ignored (especially in younger children).



• Urinary tract infection is the most common urinary tract problem in children besides bedwetting.



• Urinary tract infection is second only to respiratory infection as the most common type of infection.



• These infections are much more common in girls and women than in boys and men younger than 50 years of age. The reason for this is not well understood, but anatomic differences between the genders (a shorter urethra in women) might be partially responsible.



• About 40% of women and 12% of men have a urinary tract infection at some time in their life.