From the Guidelines
Recurrent urinary tract infections (UTIs) are diagnosed when a patient experiences at least three episodes of infection within the preceding 12 months, with complete resolution of symptoms between episodes. This definition is based on the most recent and highest quality study available, which emphasizes the importance of distinguishing between recurrent UTIs and other conditions with similar symptoms 1. The diagnostic criteria for recurrent UTIs include a thorough history to document previous UTI episodes with dates and causative organisms, as well as a physical examination to assess for pelvic organ prolapse, atrophic vaginitis, or other anatomical abnormalities.
Key Diagnostic Criteria
- A clean-catch or catheterized specimen for culture typically reveals >100,000 organisms per milliliter of urine 1
- Escherichia coli is the most common organism in all patient groups, causing approximately 75% of recurrent UTIs 1
- Symptoms typically include dysuria, frequency, urgency, suprapubic pain, and sometimes hematuria
- Urine analysis and culture during symptomatic episodes are essential
Additional Testing
Additional testing may include post-void residual measurement, renal ultrasound, or cystoscopy for patients with risk factors for complicated UTIs, such as immunosuppression, urological abnormalities, or recalcitrant infections 1. However, imaging is usually not appropriate for recurrent uncomplicated lower UTIs in a female with no known underlying risk factors 1.
Management Strategies
These diagnostic criteria help distinguish true recurrent UTIs from other conditions with similar symptoms, allowing for appropriate management strategies, including prophylactic antibiotics, behavioral modifications, or further urological evaluation 1. Women who have three or more symptomatic infections over a 12-month period may benefit from prophylaxis 1.
From the Research
Diagnostic Criteria for Recurrent UTI
The diagnostic criteria for recurrent UTI are typically defined as:
- Three or more UTIs within 12 months, or
- Two or more occurrences within six months 2 Episodes of recurrent UTI are typically characterized by dysuria and urinary frequency or hesitancy.
Risk Factors
Established risk factors for recurrent UTI in premenopausal women include:
- Sexual intercourse three or more times per week
- Spermicide use
- New or multiple sex partners
- Having a UTI before 15 years of age 2 In postmenopausal women, risk is primarily increased by sequelae of lower estrogen levels.
Diagnosis and Treatment
At least one symptomatic episode should be verified by urine culture to confirm the diagnosis and guide treatment 2 Findings from the history or physical examination that suggest complicated infection or another disease process warrant additional evaluation. Short courses of antibiotics are as effective as longer courses, and patient-initiated treatment can lower the cost of diagnosis, number of physician visits, and number of symptomatic days compared with physician-initiated treatment 2
Predicting Antibiotic Susceptibility
A prior culture can be used to predict antibiotic susceptibility in patients with recurrent UTI, with good predictive value for detecting future susceptibility to first-line agents such as nitrofurantoin and trimethoprim-sulfamethoxazole 3 The use of a prior culture as a guide can enhance the probability of selecting an effective empirical agent.
Diagnostic Tests
The performance characteristics of diagnostic tests such as the nitrite test and leucocyte-esterase (LE) test can be used to confirm UTI, with a positive nitrite test or a negative nitrite test with a positive LE test confirming UTI 4 A negative nitrite test with a negative LE test does not rule out infection.
Management and Referral Patterns
The evaluation and treatment patterns for recurrent UTI before specialist referral can vary widely, with a large proportion of patients referred for recurrent UTI to a specialty practice having no prior culture, physical examination, or symptom-specific evaluation before referral 5 Current guidelines for the management of uncomplicated and recurrent UTIs recommend the use of fosfomycin, nitrofurantoin, or Cotrimoxazole for uncomplicated UTIs, and urine culture and imaging for complicated UTIs 6