Urinary tract infections (UTIs) account for about eight million visits to physicians each year in the United States. These infections are much more common in adults, particularly in women. Children account for one to two percent of all UTIs, but their infections are often more serious. About 40 percent of women and 12 percent of men have a UTI at some time in their lives.
The urinary system or “tract” is composed of the kidneys, ureters, bladder and urethra. The kidneys filter waste products from the blood and produce urine that passes down the ureters to the bladder, where it is stored, before passing out the urethra. An infection can involve one or more parts of the urinary tract.
Bacteria that normally inhabit the bowel and live around the anus are the cause of most UTIs. The gut bacterium Escherichia coli (E. coli) is far and away the most common offender. Bacteria cause UTIs by making their way to the opening of the urethra where they can enter and start to multiply.
The two most common ways bacteria enter the urinary tract in women is through improper hygiene (reaching between the legs and wiping from back to front after a bowel movement), and sexual intercourse. Older men are also more prone to UTIs because their bladders may not empty completely due to obstruction from enlargement of the prostate (not prostrate) gland.
If the urethra is the only part of the urinary tract involved, the infection is called urethritis. This can be caused by colon bacteria but may also be caused by sexually transmitted organisms. The infection can progress up the urinary tract causing infection of the bladder (cystitis) or one or both kidneys (pyelonephritis).
Urinary tract infections can be simple or complicated. Most are simple, responding rapidly to antibiotics. Complicated UTIs are caused by bacteria that are resistant to antibiotics, or that have become too numerous to easily respond to treatment. Children may develop complicated infections because of anatomic abnormalities in their urinary tracts. As a general rule the farther up the urinary tract an infection is found, the more severe it is.
UTI symptoms vary based on the location of the infection. Urethritis usually results in burning with urination (dysuria). This is usually described as external burning (i.e. not deep in the pelvis). Cystitis irritates the wall of the bladder and results in frequent urination, urgency and sometimes pelvic pain and cramping. It may also cause blood in the urine (hematuria). Children may present with frequent urination, fever, abdominal pain, vomiting, foul-smelling urine or loss of bladder control. Infants can be difficult to diagnose and may present with non-specific symptoms such as irritability, decreased feeding or fever.
If the infection progresses up the ureters to the kidneys (pyelonephritis), the resulting inflammation can cause back or flank pain. This usually results in high fever, as well as nausea and vomiting. Pyelonephritis, particularly in children, can lead to scarring of the kidneys and put the children at increased risk of developing high blood pressure later in life.
Most UTIs can be treated effectively with oral antibiotics. Simple UTIs usually respond to a three to five-day course of antibiotics. Many bacteria are becoming resistant to antibiotics like sulfa and ciprofloxacin (often due to inappropriate overprescribing of antibiotics), so a different antibiotic may be required.
For women who develop UTIs following sexual intercourse, it is helpful to urinate immediately after sex. Treatment with a single dose of a “post-coital” antibiotic is also a common way to combat this problem.
People who have UTIs that are either recurrent or unresponsive to treatment should have their urine sent to the microbiology lab to identify the causative organism, and to have an antibiotic sensitivity panel performed to determine what antibiotics will kill the bacteria. Since UTIs are relatively uncommon in non-elderly men, it is usually recommended that they have cultures done routinely.
Children under age five who develop UTIs should be evaluated carefully with possible imaging of their urinary systems to look for anatomic abnormalities. If they have had pyelonephritis, they should also have their blood pressure checked on a regular basis.
And here’s the answer to the burning question: is cranberry juice helpful in prevention and treatment of UTIs? Unfortunately, the evidence says no.