Urinary Tract Infection (UTI) | Symptoms & Causes | MedStar Health

A urinary tract infection (UTI) is an infection in any part of your urinary system, including your kidneys, ureters, bladder, and urethra (the structure through which urine passes before being expelled from the body). Most infections involve the lower urinary tract (the bladder and the urethra). The further up the urinary tract an infection occurs, the more serious the infection is.

UTIs usually occur when bacteria enter the urinary bladder through the urethra and begin to multiply. When that happens, bacteria may take hold and grow into a full-blown infection in the urinary tract.

UTIs are classified as uncomplicated (or simple) when infections occur in the normal urinary tract, and complicated when infections occur in an abnormal urinary tract or when the bacteria causing the infection is highly resistant to many antibiotics.

Urinary Tract Infection

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Bacteria can enter the urinary system through the urethra causing cystitis or urinary tract infection - or UTI, as it is commonly called.

Urinary tract infection symptoms

Urinary tract infections don’t always produce symptoms, but when they do, they may include:

  • A strong, continual urge to urinate

  • A burning sensation during urination

  • Passing frequent, small amounts of urine

  • Urine that appears cloudy

  • Urine that appears red, pink, or rust-colored (signaling the presence of blood in the urine). This may indicate a more serious infection and you should contact your doctor.

  • Fever or flank pain may indicate an infection of the kidney (pyelonephritis) a more serious infection and should be treated as an emergency.

What causes urinary tract infections?

Bacteria live in the rectum, vagina, and on your skin. Bacteria can migrate from these areas through the urethra and into the bladder. Women are more prone to UTI because they have shorter urethras than men and bacteria can more easily travel into the bladder.

Risk factors

  • Sexual activity

  • Use of a diaphragm or condoms with spermicidal foam

  • Urinary tract instrumentation (foley catheter)

  • Obstruction, with blockage of urine flow (stricture of urethra, bladder neck, or enlarged prostate)

  • Diabetes with decreased immune function reduces our ability to resist bacterial infections

  • Anatomic abnormalities (diverticulum of bladder or urethra)

  • Nerve communication abnormalities occurring secondarily to stroke, spinal cord injury, multiple sclerosis, or Parkinson’s disease can cause failure of the bladder to store or empty properly (neurogenic bladder)

  • Post-menopausal women have reduced estrogen levels that may lead to changes in the vagina that can increase the risk for UTI

  • Genetic predisposition. The urinary tract in these patients allows bacteria to adhere more easily and increases the risk for UTI

Diagnosing urinary tract infections

  • Urinalysis

  • Urine culture

Treatments for urinary tract infections

  • Most uncomplicated UTIs can be treated with a short course of oral antibiotics (three days in most cases). Complicated UTIs (pyelonephritis) may require a longer course.

  • In addition to antibiotics, increased hydration to increase frequency of urination to help clear bacteria, and reduce bladder inflammation. Be sure to complete the full course of antibiotics and call your doctor if symptoms do not improve after the antibiotic course.

  • For complicated UTIs and frequently recurrent UTIs, additional evaluation of the urinary tract may be necessary. Studies such as a sonogram or CT scan may be ordered by your doctor.

  • Some women who have frequent UTIs, especially after sexual activity, may benefit from antibiotic prophylaxis and should discuss this option with their doctor.  Urination after sexual activity may decrease the risk of UTI by flushing out bacteria. A single dose of an antibiotic after intercourse can help prevent UTI.

  • Alternative birth control may be needed (diaphragm and spermicidal foam are known risk factors).

Our providers

Ryan Cleary is a urology and robotic surgery specialist with MedStar Health in Baltimore Maryland.

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