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Infection of the lower urinary tract is a common health issue encountered by primary-care providers, gynecologists, urologists, and other health-care professionals.
Urinary tract infections (UTIs) are more prevalent in women than in men, with greater than 50% of women having at least one infection in their lifetime. Approximately 25% of these women will have another UTI in 6 months, while 50% will have another within one year.1 UTIs result in close to 7 million office visits per year and run up a health-care tab of nearly $1.6 billion dollars.1
Although the diagnosis and treatment of an acute uncomplicated infection is basic and straightforward, treatment of recurrent and/or complicated infections can be difficult and quite frustrating for patients and providers. Clinicians must be aware of the signs, symptoms, and pathophysiology of the disease; know how to clinically evaluate and test for diagnosis; and stay up to speed on the latest treatment strategies for simple and complicated infections.
Classification and pathophysiology
Classification of UTI as uncomplicated or complicated is based on the type of infecting organisms, the functioning of the urinary system, and general health of the patient. Uncomplicated UTIs generally occur in a healthy person with a normal urinary tract and are easily treated with limited testing and without adverse consequences.
Complicated infections, on the other hand, occur in a person with a compromised immune system or with a functionally or structurally abnormal urinary tract. These infections can be caused by pathogens with increased virulence and antibiotic resistance, making them more difficult to treat and cure.2
Escherichia coli is the pathogen most often responsible for UTI.2 E. coli is normally found in the digestive tract and has the potential to ascend into the bladder following colonization at the vaginal introitus. Although the female urethra is short and located close to the vagina and anus, it contains antimicrobial defenses that help prevent bacteria from entering and adhering to the urethra and bladder. Interference with any of the host’s defense mechanisms, such as vaginal atrophy, high pH, trauma or genitourinary surgery, can open the door to ascending infection.
Uropathogenic E. coli is a virulent gram-negative bacterium with an affinity for the genitourinary tract. This pathogen has fingerlike projections called fimbriae that allow it to adhere to the urethra and bladder wall rather than being flushed from the urinary system by voiding. Sometimes, E. coli can “seed” the bladder by creating podlike structures that house the bacteria and lead to resistant or recurrent infections.2
Approximately 85% of community acquired infections and 50% of nosocomial infections are caused by E. coli.2 Other pathogens commonly responsible for UTIs in premenopausal women include Staphylococcus saprophyticus, Klebsiella pneumonia, and Proteus mirabilis.
Pathogens most often encountered in postmenopausal women include E. coli, P. mirabilis, and K. pneumonia. Women with diabetes are most often infected with Klebsiella, while Pseudomonas bacteria are predominant in those with indwelling catheters.3
The evaluation of the genitourinary tract begins with a focused history of presenting symptoms. The diagnosis of UTI can often be made on history alone, as the symptoms of dysuria, frequency and urgency, pressure, and hematuria raise the probability of a UTI to greater than 50%.4
History consistent with past UTIs; abnormalities of the urinary system; previous surgery involving the urinary tract; frequent sexual activity; and such medical conditions as diabetes, neurologic disorders, sickle cell disease, and pelvic organ prolapse increases the likelihood of an infection. Other risk factors for UTI are listed in Table 1.
Any pain in the suprapubic area, flank, or lower back should be noted, along with associated symptoms of nausea, vomiting, malaise, fever, or chills.
Table 1. Risk factors for UTI
|Older age||Multiple sclerosis|
|Indwelling catheters||Urological abnormalities|
|Incomplete bladder emptying||Decreased functional ability|