Urinary Tract Infection

Approximately 8 to 10 million people in the United States develop a urinary tract infection (UTI) each year. Women develop the condition much more often than men.

Urinary tract infection (UTI) is a common infection that usually occurs when bacteria enter the opening of the urethra and multiply in the urinary tract. The urinary tract includes the kidneys, ureters (tubes that carry urine from the kidneys to the bladder), bladder, and urethra (tube that carries urine from the bladder). The special connection of the ureters at the bladder help to prevent urine from backing up into the kidneys, and the flow of urine through the urethra helps to eliminate bacteria. Men, women, and children can develop UTIs.

Bladder infection (cystitis) is by far the most common type of UTI. Infection of the urethra is called urethritis. Kidney infection (pyelonephritis) will often cause fever and flank pain and requires urgent treatment.

Approximately 8 to 10 million people in the United States develop a UTI each year. Women develop the condition much more often than men, for reasons that are not fully known, although the much shorter female urethra is suspected. The condition is rare in boys and young men.

Twenty percent of women in the United States develop a UTI and 20% of those have a recurrence. Urinary tract infections in children are more common in those under the age of 2.

Risk Factors

Escherichia coli (E. coli) causes about 80% of UTIs in adults. These bacteria are normally present in the colon and may enter the urethral opening from the skin around the anus and genitals. Other bacteria that cause urinary tract infections include Staphylococcus saprophyticus (5 to 15% of cases), Chlamydia trachomatis, and Mycoplasma hominis. Men and women infected with chlamydia trachomatis or mycoplasma hominis can transmit the bacteria to their partner during sexual intercourse, causing UTI.

Urinary catheterization (small tube inserted into the bladder through the urethra to drain urine) can also cause UTI by introducing bacteria into the urinary tract. The risk for developing a UTI increases when long-term catheterization is required.

Other risk factors include:

  • Bladder outlet obstructions (e.g., kidney stones, BPH)
  • Conditions that cause incomplete bladder emptying (e.g., spinal cord injury)
  • Congenital abnormalities of the urinary tract (e.g., vasicoureteral reflux)
  • Suppressed immune system
  • Additionally patients may have certain blood types that enable bacteria to attach more easily to cells that line the urinary tract greatly increasing the risk for recurrent UTIs

Your physician will review your symptoms and conduct a physical exam. He or she will also check for tenderness of the bladder or kidney area of your back. A urinalysis may be performed to detect bacteria and pus. Additionally a urine culture and susceptibility is helpful to identify the bacteria causing the infection and determine the specific antibiotics that will work in treatment. 

For repeated infections or symptoms that continue after treatment, your physician may suggest:

  • An intravenous pyelogram (IVP). An IVP is a special type of x-ray of the kidneys, ureters, and bladder;
  • An ultrasound scan to look at the urinary tract;
  • A cystoscopy, which is a small telescope used to examine the inside of the bladder.

Treatment for simple cystitis will often involve a short course of antibiotics. Pyelonephritis is treated for a longer course and may require hospitalization for intravenous antibiotics. In patient with recurrent infections or complicated infections additional diagnostic and therapeutic measures are often required to treat underlying abnormalities that are leading to infections. Urine culture is crucial with more complicated or recurrent infections to determine the specific bacterial pathogen and look for patterns of antibiotic resistance.

Many patients benefit from simple preventative strategies such as daily cranberry supplementation, voiding after intercourse, and timed voiding to assure the bladder is emptying. Additionally, some select patients may benefit from antibiotic prophylaxis either daily or after intercourse.