Managing Urinary Tract Infections in Women

Managing UTIs in Women
Managing UTIs in Women

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

Evaluation


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

Pregnancy Diabetes
Older age Multiple sclerosis
Spinal-cord injury
AIDS
Indwelling catheters
Urological abnormalities
Incomplete bladder emptying
Decreased functional ability

Physical examination follows the patient history and includes checking vital signs to assess for fever, tachycardia, and tachypnea. Suprapubic and costovertebral angle tenderness is checked with palpation and percussion of the abdomen and back. Observe skin turgor and urine output to assess for dehydration.

When UTI is suspected, an in-office urine dipstick is appropriate. If the dipstick reads positive (leukocytes and/or nitrites), the likelihood of infection is 25%, and treatment with antibiotics can be initiated.2

A negative dipstick does not rule out an infection. In a case of suspected UTI, a culture is definitely indicated, and treatment decisions should be made on an individual basis. Such other testing as clean-catch urine specimen for urinalysis (UA) and culture and sensitivity (C&S) is indicated in women with recurrent infections.

A catheterized urine specimen may be indicated in women who have repeated contaminated urine specimens, microscopic hematuria, and those that are elderly and functionally impaired or obese).3

A pelvic examination is performed based on symptoms, sexual history, and in cases of recurrent or complicated infection. Check for vaginal pH and the integrity of the urethra and vaginal mucosa. Presence of vaginal discharge and any urethral and/or cervical tenderness should be noted. Because symptoms of dysuria, frequency, and urgency are also present in individuals with urethritis and vaginitis, a vaginal exam, cultures, wet mount, and laboratory testing for sexually transmitted infection (STI) is appropriate.3

Additional and invasive testing may be considered in women who have persistent or complicated infections and in those that present with physiologic or functional abnormalities. Because women with pelvic organ prolapse frequently have incomplete bladder emptying, a catheterized specimen can be sent for UA and C&S as well as to provide documentation of post-void residual urine.

Renal and pelvic ultrasound is used to evaluate the urinary system and to identify stones and obstructions. CT scan with and without contrast can further evaluate for stones, masses, and hematuria. Cystoscopy is a valuable tool in the differential diagnosis of complicated and recurrent infections, especially in women with suspected fistulas or hematuria and in those with previous bladder or pelvic surgery (Table 2).3

Table 2. Differential Diagnosis of UTI

Vaginitis/Urehritis Overactive bladder/urge incontinence
Trauma/Previous bladder surgery Pelvic organ prolapse
Interstitial cytitis
Bladder cancer
Irritant urethritis


Treatment Strategies


Uncomplicated or first-time UTIs may be treated empirically with antibiotics based on symptoms with or without a positive urine dipstick in the office. Management strategies include rest and fluids. Such bladder-irritating substances as coffee, tea, carbonated beverages, dietary sweeteners, and tomato-based foods can exacerbate symptoms and should be avoided.2

When prescribing antibiotics to treat UTI, consider the following general guidelines: (1) the likelihood that the medication will be effective according to geographical resistance patterns; (2) the ability of the medication to concentrate in the urine; (3) limited toxicity for the patient; (4) reasonable cost; and (5) a low alteration of vaginal or bladder flora.2,3 Short-term antibiotic treatment (i.e., three days) is adequate to treat uncomplicated infections and has been shown to be as effective as seven days of medication.5

Nitrofurantoin (Furadantin, Macrobid) and trimethoprim/sulfamethoxazole (TMP/SMX) (Bactrim, Septra) are well tolerated and inexpensive and good first-line choices for the treatment of uncomplicated UTI.

Nitrofurantoin is effective against most genitourinary pathogens and has developed little resistance in most areas. However, nitrofurantoin is not effective against Pseudomonas infection and can result in pulmonary toxicity, especially in the elderly. The sulfa-based medication TMP/SMX is very effective. Resistance is typically low but has increased in certain areas. Side effects and allergies are the major disadvantages to this medication.6

Fosfomycin (Monurol) is a broad-spectrum antibiotic that can be effective in the treatment of uncomplicated UTI. Fosfomycin has an affinity for the bladder with good tissue penetration (it is excreted unchanged in the urine). Bacterial resistance remains low, and this medication has a 90% efficacy against genitourinary bacteria, including methicillin-resistant Staphylococcus aureus, E. coli, Enterococcus faecalis, and Klebsiella.

Fosfomycin is a single-dose medication with a long half-life and low allergic profile. The downside to this medication is its cost and the fact that it is not readily available and might need to be ordered, thereby delaying treatment.6

Quinolones are strong broad-spectrum antibiotics and should be set aside for complicated infections, infections with Pseudomonas, or the treatment of resistant bacteria. Cephalosporins and macrolides should also be reserved for complicated or resistant infections. These three classes of medications are most effective for sensitive bacteria following positive urine cultures in women with complicated or recurrent infections.6,7

A number of prophylactic treatment options are recommended for recurrent and/or complicated UTIs: (1) daily low-dose antibiotic therapy, such as nitrofurantoin (50 or 100 mg) or TMP-SMX (half-strength tablet) for three to six months; (2) a self-treatment option with a pre-prescribed three-day course of antibiotics to be taken when symptoms start; (3) postcoidal antibiotics (nitrofurantoin 100 mg) to be taken one hour before or after sexual relations.

If symptoms worsen or are not controlled, the patient should be re-evaluated.5 For a list of medications commonly prescribed for treatment of UTI, see Table 3.

Table 3. Medication Regimens for UTI

Medication Dose Efficacy Cautions Side effects
Nitrofurantoin
(Furadantin, Macrobid)
100 mg b.i.d. for seven days
Escherichia coli,g ram-
postitive pathogens, most gram-
negative pathogens
  • Take with food
  • Renal clearance
GI upset, headache, dizziness, pulmonary disorders
Trimethoprim/
sulfamethoxazole (TMP/SMX) (Bactrim, Septra)
One double-strength or two regular-strength tablet every 12 hours for three to five days
E. coli (resistance up to 39% in some areas)
  • Take with plenty of fluids
  • Hepatic/renal dysfunction
GI upset, blood dyscrasia, fever, rash, ataxia
Quinolones
250 mg every 12 hours for three to five days
Gram-negative coverage
(expanded to include specific gram-positive organisms)
  • Tendonitis or tendon ­rupture, hyperglycemia
GI upset, CNS effects, arrhythmias
Tetracyclines
250 mg-500 mg four times a day for seven to 10 days
Test for sensitive infections
  • Take with fluids one hour before meals or two hours after meals
GI upset, esophagitis,
headache, rash
Cephalosporins
250 mg-500 mg b.i.d. for seven to 10 days
Test for sensitive infections
  • Renal impairment
GI upset, abdominal pain, liver dysfunction, headache
Macrolides
500 mg b.i.d.
Test for sensitive infections
  • Hepatic dysfunction
GI upset, abdominal pain, ­superinfection
Fosfomycin (Monurol)
One 3-g sachet
of granules
Uncomplicated UTIs  in women
  • Decreased serum levels with GI medications
GI upset, back pain, dizziness
Source: Adapted from Monthly Prescribing Reference. Oral therapy for UTIs in adults.


Prevention


Prevention strategies can be initiated for women with recurrent infections and for those with medical comorbidities after complete evaluation of the genitourinary system. Acute infections should always be treated prior to initiating prevention measures.

Cranberry juice or capsules are the most well known preventive agent for UTIs. Cranberry is believed to deter infections by preventing the adherence of fimbrae, thereby assisting in the flushing out of bacteria through voiding. A review of the literature determined that cranberry products significantly reduced the incidence of UTIs over a 12-month period compared with placebo/control.7

Methenamine hippurate has been studied for its preventive benefits, especially if taken with vitamin C. This combination ensures the acidity of the urine and is believed to form formaldehyde in the urine that can initiate the breakdown of the bacterium protein.

Methenamine with vitamin C is a good option for women with uncomplicated recurring infections and has also been used in women having recurrent UTIs related to incomplete bladder emptying (this use has not been supported in the literature, however).8

In postmenopausal women with recurrent UTIs, treatment with vaginal estrogen is thought to change the vaginal pH, creating a less conducive environment for colonization and ascending infection.4 Vaginal and oral probiotics are thought to have the same benefit through change in the vaginal pH, but the evidence and efficacy are still under investigation.

A number of herbal formulations are available in various forms, but their efficacy and safety has not been studied. Caution patients that herbal products are known to interact with other medications or foods and can have serious side effects.

Summary


UTIs in women are prevalent and often prompt an office visit. Uncomplicated UTIs are easily managed, and treatment is tailored to alleviating symptoms. Urine testing and C&S, although not necessary with first infections, can eventually be important for documentation and treatment strategies if symptoms become recurrent or persistent.

Antibiotic treatment with nitrofurantoin or TMP/SMX will most likely resolve uncomplicated or first-time UTIs. A urine C&S is imperative in cases of recurrent UTI, with treatment of the active infection first followed by the additional initiation of prevention techniques.

The tree acceptable prophylactic treatment options for recurrent UTIs are low dose antibiotics daily for three to six months, self-start antibiotics, and postcoital antibiotics. Follow-up and documentation of recurrent infections combined with ongoing communication and individualized testing and treatment strategies is the best approach to this common medical problem.

Joan E. Zaccardi, DrNP, APRN-BC, is the administrative practice manager of Urogynecology Arts of New Jersey, in East Brunswick.


References


  1. Foxman B. Epidemiology of urinary tract infections: incidence, morbidity, and  economic costs. Am J Med. 2002;113 Suppl 1A:5S-13S.
  2. Hanno MP. Lower urinary tract infections in women and pyelonephritis. In: Hanno PM, Malkowicz SB, Wein AJ, Penn Clinical Manual of Urology. Philadelphia, Pa.: Saunders Elsevier; 2007:155-176.
  3. Grimes CL, Lukacz ES. Urinary tract infections. Female Pelvic Med Reconstr Surg. 2011;17:272-278.
  4. Litza JA, Brill JR. Urinary tract infections. Prim Care. 2010;37:491-507.
  5. American College of Obstetricians and Gynecologists. ACOG Practice Bulletin No. 91: Treatment of urinary tract infections in nonpregnant women. Obstet Gynecol. 2008;111:785-794. 
  6. Gupta K, Hooton TM, Naber KG, et al. International clinical practice guidelines for the treatment of acute uncomplicated cystitis and pyelonephritis in women: A 2010 update by the Infectious Diseases Society of America and the European Society for Microbiology and Infectious Diseases. Clin Infect Dis. 2011;52:e103-e120.
  7. Sivick KE, Mobley HL. Waging war against uropathogenic Escherichia coli: winning back the urinary tract. Infect Immun. 2010;78:568-585.
  8. Jepson RG, Craig JC. Cranberries for preventing urinary tract infections. Cochrane Database Syst Rev. 2008;1:CD001321.
  9. Lee BS, Bhuta T, Simpson JM, Craig JC. Methenamine hippurate for preventing urinary tract infections. Cochrane Database Syst Rev. 2012;10:CD003265.
All electronic documents accessed January 15, 2013.


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