Managing UTIs in women

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.

From the January 01, 2013 Issue of Clinical Advisor