An in-depth report on the causes, diagnosis, treatment, and prevention of urinary tract infections.
Antibiotics are the main treatment for all UTIs. A variety of antibiotics are available, and choices depend on many factors, including whether the infection is complicated or uncomplicated or primary or recurrent. Treatment decisions are also based on the type of patient (man or woman, a pregnant or nonpregnant woman, child, hospitalized or nonhospitalized patient, person with diabetes). Treatment should not necessarily be based on the actual bacteria count. For example, if a woman has symptoms, even if bacterial count is low or normal, infection is probably present, and the doctor should consider antibiotic treatment.
UTIs in low-risk women can often be successfully treated over the phone. In such cases, a health professional provides the patients with 3-day antibiotic regimens without requiring an office urine test. This course is recommended only for women at low risk for recurrent infection, who do not have symptoms (such as vaginitis) suggesting other problems.
Antibiotic Regimen. Oral antibiotic treatment cures 94% of uncomplicated urinary tract infections, although the rate of recurrence remains high. The following antibiotics are commonly used for uncomplicated UTIs:
After a week of antibiotic treatment, most patients are free of infection. If the symptoms do not clear up within the first few days of therapy, doctors generally suggest that women discontinue their antibiotic and provide a urine sample for culturing in order to identify the specific organism causing the condition.
Treatment for Relapsing Infection. A relapsing infection (caused by treatment failure) occurs within 3 weeks in about 10% of women. Relapse is treated similarly to a first infection, but the antibiotics are usually continued for 7 - 14 days. (Relapsing infections may be due to structural abnormalities, abscesses, or other problems that may require surgery, and such conditions should be ruled out.)
Women who have two or more symptomatic UTIs within 6 months or three or more over the course of a year may need preventive antibiotics. A woman's own perception of discomfort can generally guide her decisions on whether or not to use preventive antibiotics. All women should use lifestyle measures to prevent recurrences.
Intermittent Self Treatment. Many, if not most, women with recurrent UTIs can effectively self-treat recurrent UTIs without going to a doctor. In general, this requires the following steps:
A woman should consult a doctor under the following circumstances:
Women who are not good candidates for self-treatment are those with impaired immune systems, previous kidney infections, structural abnormalities of the urinary tract, or a history of infection with antibiotic-resistant bacteria.
Postcoital Antibiotics. If recurrent infections are clearly related to sexual activity and episodes recur more than two times within a 6-month period, a single preventive dose taken immediately after intercourse is effective. Antibiotics for such cases include TMP-SMX, nitrofurantoin, cephalexin, or a fluoroquinolone (such as ciprofloxacin). (Fluoroquinolones are not appropriate during pregnancy.)
Continuous Preventive Antibiotics (Prophylaxis). Continuous preventive (prophylactic) antibiotics are an option for some women who do not respond to other measures. With this approach, low-dose antibiotics are taken continuously for 6 months or longer.
Patients with uncomplicated kidney infections (pyelonephritis) may be treated at home with oral antibiotics. Patients with moderate-to-severe acute kidney infection and those with severe symptoms or other complications may need to be hospitalized. In such cases, antibiotics are usually given intravenously for several days. Chronic pyelonephritis may require longterm antibiotic treatment.
Treating Pregnant Women. Pregnant women should be screened for UTIs, since they are at high risk for UTIs and their complications. The antibiotics used during pregnancy include amoxicillin, ampicillin, nitrofurantoin, and cephalosporin. Fosfomycin (Monurol) is not as effective as others but may be used during pregnancy. Pregnant women should not take fluoroquinolones.
Pregnant women with asymptomatic bacteriuria (evidence of infection but no symptoms) have a 30% risk for acute pyelonephritis in their second or third trimester. They need screening and treatment for this condition. In such cases, they should be treated with a short course of antibiotics (3 - 5 days). For an uncomplicated UTI, pregnant women may need longer-term antibiotics (7 - 10 days).
Treating Children with UTIs. Children with UTIs are generally treated with TMP-SMX, cephalexin (Keflex) and other cephalosporins, amoxicillin,or amoxicillin/clavulanic acid (Augmentin). These drugs are usually taken by mouth in either liquid or pill form. Doctors sometimes give them as a shot or IV. Children usually respond to treatment within a few days.
Vesicoureteral reflux (VUR) is a concern for children with UTIs. (See "Risk Factors" section.) VUR can lead to kidney infection (pyelonephritis), which can cause kidney damage. The two treatment options for children with VUR are long-term antibiotics to prevent infections or surgery to correct the condition. However, there is debate as to the benefit of these approaches. Recent studies indicate that preventive treatment with antibiotics may not be much help for preventing recurrent urinary tract infections in children, and that VUR itself may not substantially increase the risk for recurrent UTIs.
Children with acute kidney infection are treated with oral cefixime (Suprax) or a short course (2 - 4 days) of an intravenous (IV) antibiotic (typically gentamicin, given in one daily dose). An oral antibiotic then follows the IV.
Catheter-induced urinary tract infections are very common, and preventive measures are extremely important. Catheters should not be used unless absolutely necessary, and they should be removed as soon as possible. Reducing the risk for infections during long-term catheter use, however, remains problematic.
Intermittent Use of Catheters. If a catheter is required for long periods, it is best to use it intermittently if possible (as opposed to an indwelling catheter). Some doctors recommend replacing it every 2 weeks to reduce the risk of infection and irrigating the bladder with antibiotics between replacements.
Daily Hygiene. A typical catheter is one that has been preconnected and sealed and uses a drainage bag system. To prevent infection, some of the following tips may be helpful:
Antibiotics for Catheter-Induced Infections. Patients using catheters who develop UTIs with symptoms should be treated for each episode with antibiotics and the catheter should be removed, if possible, or changed. A major problem in treating catheter-related UTIs is that the organisms involved are constantly changing. Because there are likely to be multiple species of bacteria, doctors generally recommend an antibiotic that is effective against a wide variety of microorganisms.
Although high bacteria counts in the urine (bacteriuria) occur in most catheterized patients, administering antibiotics to prevent a UTI is rarely recommended. Many catheterized patients do not develop symptomatic urinary tract infections even with high bacteria counts. If bacteriuria occurs without symptoms, antibiotic therapy has little benefit if the catheter is to remain in place for a long period.
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