At least 50 percent of women will experience a UTI in their lifetime
Editorial note: This article first appeared in the Women’s Integrated Services in Health (WISH) May 2015 newsletter.
At least 50 percent of women experience a urinary tract infection (UTI) during their lifetime, with approximately 5 percent experiencing frequent infections. Urinary tract infections are more prevalent among women than among men (ratio of 20:1), likely due to the relatively short female urethra, which puts the urinary tract closer to the normal bacteria of the vagina and the rectum.
Urinary tract infections account for eight million health care visits per year at the cost of $1.6 billion. Urinary tract infections account for fifteen percent of all patient prescriptions written. Unfortunately, women affected by recurrent urinary tract infections may attempt to cope with symptoms on their own instead of seeking treatment.
Recurrent urinary tract infection is a serious health condition that increases with age and peaks in menopausal women. The rate of urinary tract infections is 1 percent in young children and climbs to approximately 15 percent at age 60, and peaks at 25-50 percent after age 80. Whereas sexual activity and pregnancy are risk factors in younger women, vaginal thinning or vaginal atrophy, illness, and hospitalization are more important risk factors in menopausal women.
Recurrent urinary tract infections can also be blamed on mothers, as there is a genetic predisposition in daughters of women with a history of recurrent urinary tract infections themselves. Many women know that they are more likely to develop urinary tract infections after a course of antibiotics. This is due to the elimination or shifting of the normal bacteria within the vagina that compete with bacteria causing urinary tract infections.
Diagnosis of urinary tract infections
A presumptive diagnosis of UTI can be made with a careful history and physical examination. Typical symptoms are pain with urination (dysuria), although UTI may also present with frequency, urgency, more than two voids at night, and pain midway over the pubic bone. Occasionally, mild incontinence of urine and blood in the urine may occur. In addition to cystitis these symptoms may be caused by yeast infection (candidiasis), Trichomonas vaginitis, and other sexually transmitted infections. A urine sample can be tested for sexually transmitted infections. Vaginal atrophy can also cause urinary tract symptoms that mimic a urinary tract infection. Finally, if a woman has had previous surgery for urinary incontinence or pelvic organ prolapse, the possibility of suture material, mesh, or stones in the bladder or urethra should be investigated.
Urine collected for analysis can be a clean catch or catheterized specimen. In reality, up to one-third of clean catch bacteria on the skin contaminate specimens. Patients are asked to do a clean catch in our University of Colorado office by spreading the labia, wiping around the urethra from front to back with a clean, moistened gauze sponge, and collect a mid-stream urine sample holding the labia apart. In women unable to obtain a clean voided specimen, such as women who are obese or are functionally impaired, urethral catheterization can be performed.
Diagnostic testing for UTI
Diagnostic testing for cystitis includes an office urine dipstick, and urine culture. Whereas a positive urine dipstick in a symptomatic patient are generally considered sufficient evidence to support treatment based on an educated guess of a presumed urinary tract infection, urine cultures should be sent in patient in whom the diagnosis of cystitis is questionable or in whom complicating factors are present. We prefer that a patient arrives at the office with a comfortably full bladder to give a sample, because bacteria will continue to grow if the urine specimen is stored at room temperature. Urine dipstick is a simple urinary tract infection screening for the office or home that detects urine nitrites and leukocyte esterase. Although dipsticks can provide valuable clinical information, ultimately the physician should use clinical judgment and/or additional diagnostic testing to make a final decision regarding treatment.
Urine culture is considered the reference standard for diagnosis of a urinary tract infection. Cultures are submitted if there is a suspected complicated urinary tract infection, a negative dipstick in a symptomatic patient, poor response to initial therapy, and recurrent symptoms less than one month after treatment for a previous urinary tract infection for which no culture was performed.
Management of UTI
General factors that influence the selection of antimicrobial agents (antibiotics) for treatment of urinary tract infections include bacterial sensitivity to medication, cost of the agent, dosing frequency, and severity of adverse effects.
Acute uncomplicated cystitis
Acute uncomplicated cystitis is a superficial infection of the bladder mucosa that rarely results in severe disease. Thus, the primary goal of treatment is to alleviate the patient’s symptoms. Whereas 7- to 10-day therapy has been used to treat cystitis, multiple studies demonstrate the efficacy of a shorter course with certain antibiotics. Shorter treatments offer the advantage of increased compliance and fewer side effects.
According to the American Congress of Obstetricians and Gynecologists guidelines, first-line therapy for acute uncomplicated cystitis should be:
• nitrofurantoin monohydrate microcrystals (Macrobid) (100 mg twice daily for five days),
• trimethoprim-sulfamethoxazole (160/180 mg twice daily for three days), or
• fosfomycin (3-gram sachet in a single dose).
One of these agents is selected based on the patient’s allergy profile and compliance history, cost, and culture results when available. Fluoroquinolones such as ciprofloxacin (250 mg twice daily for three days) and levofloxacin (250-500 mg once daily for three days) have a higher risk of systemic side effects (vaginal yeast infection, thrush, etc) and should not be considered first-line treatment.
A urinary pain controlling medication such as phenazopyridine (Azo® or Pyridium®) can be used up to three times a day to alleviate bladder discomfort, although it should be not used long-term because it may mask symptoms that require evaluation. Repeat urine cultures are not indicated in patients with infrequent cystitis whose symptoms have resolved. Persistent symptoms may results from an incorrect diagnosis of cystitis, an infection with a resistant organism, or patient noncompliance with treatment.
Recurrent urinary tract infection
A recurrent urinary tract infection is defined as two or more infections during a 6-month period or three or more infections in a year. The infections MUST be culture proven, and separated by at least two weeks.
Most recurrent infections are caused by ascent of rectal and vaginal flora into the bladder. Intercourse is one of the strongest risk factors for recurrent urinary tract infections. Isolation of Proteus on urine culture is suggestive of bladder stones and should prompt appropriate imaging studies and referral to a urologist.
Antibiotic prophylaxis or pre-treatment should be considered in women with particularly bothersome recurrent urinary tract infections, although it is used with caution in women with a history of a multi-drug resistant infection. Continuous prophylaxis can decrease the risk of recurrent infection by 95 percent, but it puts the patient at risk of antibiotic-related side effects and colonization with antibiotic-resistant organisms. Regimens include one tablet of nitrofurantoin or trimethoprim-sulfamethoxazole nightly, or fosfomycin every 10 days. There is no definitive evident indicating the proper duration of treatment, but most authorities advocate treatment for six months or longer. A single dose after intercourse (post-coital prophylaxis) should be considered in women whose symptoms seem related in time to intercourse. Self-treatment of symptomatic urinary tract infections is an alternative to prophylaxis, because studies show women are over 80 percent accurate in self-diagnosis.
Topical estrogen is considered for urinary tract infection prevention in postmenopausal women with recurrent urinary tract infections. Topical or local estrogen normalizes the vaginal flora/bacteria. In a double-blind, placebo-controlled trial of 93 postmenopausal women, vaginal estrogen decreased the risk of recurrent urinary tract infection by 90 percent. Data regarding probiotics for prevention of recurrent urinary tract infections are inconclusive, but they suggest that probiotics may be beneficial.
There has been great interest in the use of cranberry juice and cranberry extract for the use of urinary tract infection prevention. Although cranberry juice has been shown to decrease the adherence (e.g. stickiness) of bacteria to the urothelium in a laboratory, clinical studies with humans do not demonstrate efficacy in urinary tract infection prevention. Other measures like voiding after sex, increasing fluid intake, and wiping from front to back have not been well studied though they are low risk.
Imaging with cystoscopy where a lighted telescope is placed into the urethra should be considered in women with recurrent urinary tract infections in who there is concern regarding possible structural or functional abnormalities in the urinary tract. The correction urinary tract abnormalities causing recurrent urinary tract infections include: urethral diverticulum, infected stone, significant cystocele, papillary necrosis, foreign body like mesh in the bladder, duplicated ureter, and medullary sponge kidney.
In conclusion, given the growing number of urinary tract infection cases treated annually it is encouraging to see shorter courses of antibiotics and topical medications have been proven effective to treat menopausal patients.
University of Colorado Urogynecology is a specialty women’s health practice focused on female pelvic health and surgery. Our physicians are also professors & researchers for the CU School of Medicine, one of the top-ranked medical schools in the nation.