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Genitourinary Tract Infections: An Evidence-Based Approach

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Presentation on theme: "Genitourinary Tract Infections: An Evidence-Based Approach"— Presentation transcript:

1 Genitourinary Tract Infections: An Evidence-Based Approach
Ralph Gonzales, MD, MSPH Associate Professor of Medicine; Epidemiology & Biostatistics

2 Self-Assessment Questions -35 yo woman calls with 2-3 days of painful urination, increased urinary frequency and urgency. a) What are the key questions that will help determine if she can be treated by telephone? b) If she fulfills criteria for telephone treatment, what is her probability of having a true UTI? c) If she happened to stop by your office, is there any value to performing a urinalysis? d) What would you treat her with? e) Does she need follow-up appointment or urine culture? f) Patient doesn’t get better, dysuria continues. Other causes?

3 Self-Assessment Questions -35 yo woman calls with 4-5 days of new, foul-smelling vaginal discharge.
a) What are the key questions that will help determine if she can be treated by telephone? b) What is her probability of having a candidal vaginitis (ie, available OTC therapy)? c) How helpful are findings on history and physical examination in establishing an etiology? d) How helpful is microscopy? e) What management options should be considered for recurrent yeast infections?

4 Background: Acute Uncomplicated UTI is Common
Uncomplicated UTI is an extremely common disorder in women Over 7 million office visits annually Affects half of women at least once during their lifetime Direct costs attributed to these infections in the US: $1 billion yearly

5 Background: Microbiology and Pathogenesis of Cystitis
Organisms: E. coli, S. saprophyticus, Proteus, Klebsiella Pathogenesis: Fecal flora Vaginal introitus Urethra Bladder

6 Important Risk Factors for Cystitis in Women
Past history of cystitis, especially if recurrent Recent sexual intercourse Recent diaphragm and/or spermicide use Unmarried Lack of urination after sexual intercourse Presence of asymptomatic bacteruria

7 Clinical Manifestations of UTI
Clinical features of cystitis Dysuria +/- frequency, urgency, suprapubic pain Clinical features of pyelonephritis Fever, flank pain, CVA tenderness, nausea, vomiting Differential Diagnosis For cystitis: urethritis or vaginitis For pyelonephritis: an abdominal process

8 Clinical Features of Complicated UTIs
recent UTI structural abnormalities Genetic/surgical/nephrolithiasis diabetes immunosuppression pregnancy urethral instrumentation Red Flags…

9 How Good is History for the Diagnosis of Cystitis (vs. vaginitis)?

10 Positive Predictive Values for Combinations of Symptoms
Prob UTI, % Summary LR -Dysuria Present -Frequency Present -Vaginal Discharge Absent -Vaginal Irritation Absent Overall % -Dysuria Absent -Vag D/C or Irritation Present Overall % -Dysuria or Frequency Present -Vag D/C or Irritation Absent Overall % Bent et al, JAMA 2002

11 How Good are Lab Tests for the Diagnosis of Cystitis (vs. vaginitis)?

12 How Effective is Treatment of Cystitis? Pooled Results from RCTs

13 Irritable Voiding Symptoms
35 yo woman c/o 2-3 d painful urination, increased frequency, urgency. Denies fever, back pain. Question #1: When should I perform urinalysis?

14 Urinary Tract Infections -Test Characteristics (Bent et al)
Likelihood Ratios positive negative Dysuria ( ) 0.5 ( ) Frequency ( ) 0.6 ( ) Hematuria ( ) 0.9 ( ) Fever ( ) 0.9 ( ) Flank Pain ( ) 0.9 ( ) Vaginal Discharge (Hx) ( ) 3.1 ( ) Vaginal Irritation ( ) 2.7 ( ) Back Pain ( ) 0.8 ( ) Vaginal Discharge (PEx) ( ) 1.1 ( ) CVAT ( ) 0.9 ( ) Urinalysis MAIN FINDINGS from a meta-analysis… thus, aggregated CIs. Multiple voiding symptoms increase probability Notice impact of absence of vaginitis… Let’s see how this plays-out in real life… What do people think is the baseline probability of UTI in a woman who present with voiding symptoms?

15 Goal of Diagnostic Testing
Treatment Threshold Diagnostic Threshold 0% 50% 100% Probability of Disease

16 Goal of Diagnostic Testing
Treatment Threshold Diagnostic Threshold 0% 50% 100% Probability of Disease

17 Dysuria Case UTI Prob 1.5dys*1.8freq*3.1d/c-*2.7irr-=23 Step 1: -12/88 = 0.141 Step 2: x 23 = 3.22 Step 3: -3.22 /4.22 = 76%

18 UTI Post-Test Probabilities
Well, it varies quite a bit. I’m using 12% from Komaroff... PreTest Prob Bent et al.


20 Voiding symptoms cont. Question #1: Why perform urinalysis?
Positive test: ppv = 93% Negative test: npv = 49% You diagnose uncomplicated UTI and refrain from performing UA … what are your treatment options?

21 Uncomplicated UTI Rx TMP-sulfa DS bid x 3 days ciprofloxacin, bid x 3 days keflex 250 tid x 7 days macrobid 100 bid x 7 days amoxicillin 500 tid x 7 days Follow-up: No visit or Cx if asymptomatic after 3 days, else return for re-eval. Prevention: avoid spermicides; sexual activity ?Cranberry

22 Suspected UTI Algorithm
Woman > 1 UTI Sx yes Risk Factors? Consider UCx, Empirial Rx yes Fever, Back Pain, N/V? Consider UCx, Empirial Rx yes Vaginitis Sx? About 20% UTI Perform Pelvic Multiple UTI Sx Present yes High Prob UTI, Rx w/o Testing Perform Urinalysis Adapted from Bent et al

23 When should we consider STD Testing?

24 STDs can present with dysuria: -gonorrhea, chlamydia, trichomonas
Shapiro et al. Bronx, NY, ED setting (Acad Emerg Med. 2005) All women had straight cath urine cultures and pelvic exams Used low bacteria count criteria for UTI in symptomatic women (100 cfu) Excluded if new vaginal D/C or other reasons to suspect STD present Mean duration of symptoms: 6.8 days RESULTS Urine culture (+) = 57% Chlamydia (+) = 10%; GC (+) = 1% (n=1); Trich (+) = 8% STD rates equivalent in UCx positive and negative groups **Only predictor of STD was # sexual partners in past year Conclusion: Consider STD testing all women with dysuria seeking ED care, particularly those with >1 sexual partner in the past year.

25 Is Non-Invasive STD Testing Ready for Prime Time?

26 Non-invasive (urine) testing for GC and chlamydia
Systematic review Cook et al. Ann Intern Med 2005;142: Pooled Pooled Sensitivity Specificity Polymerase chain reaction >97% -chlamydia women/men %/84% -GC women % Transcription-mediated amplification >97% -chlamydia women %/88% -GC women % Strand displacement amplication >97% -chlamydia women %/93% -GC women % Conclusion: non-invasive testing equivalent to cervical swab testing Except for GC PCR ?confirmatory test when screening low (<5%) prevalence population If spec=98%, then about 1/3 positives are false-positives If spec>99%, probably not necessary…


28 Vaginitis Symptoms 35 yo woman c/o 4-5 days of foul-smelling, cheesy vaginal discharge and severe itching. Calls by telephone. Question #1: What clinical features can be used to reliably diagnose vulvovaginal candidiasis? When should I perform microscopy?

29 Etiology of Vaginitis in PC
40% Bacterial Vaginosis 30% Unknown 20% Candida 10% Trichomonas Other Causes GC/chlamydia?… investigate when fever/lower abd pain HSV allergic reaction (chemical, latex, semen) atrophic vaginitis

30 Challenges in History Women buying OTC yeast preps
candida=33%; BV=19%; mixed=21%; normal exam=12%; trichomonas=2% Patients and physicians disagree on key findings patient physician clear d/c 21% % yellow d/c 15% % white/gray d/c 42% % Poor agreement between call center nurse diagnosis and physician If a woman presents with suspected yeast… ppv goes from 20% to 33% All of these problems have led toward recommendations for accurate diagnosis to be based on physical examination

31 Vaginitis -Likelihood Ratios for Hx/PEx (Anderson et al)
positive negative YEAST Cheesy Discharge ( ) 0.5 ( ) Watery Discharge ( ) 1.5 ( ) Itching ( ) 0.3 ( ) Chief Complaint ( ) 0.8 ( ) Malodor ( ) ( ) Curdy D/C or Vulvar Inflamm (8.8-32) ( ) Curdy D/C + Itching (20-100) ( ) Fishy Odor (PEx) (0-0.5) ( ) BACTERIAL VAGINOSIS Malodor (Hx) ( ) 0.07* ( ) “High Cheese” Odor (PEx) ( ) ( ) MAIN FINDINGS ** tricky, since unlike PNA and UTI… we are trying to diagnose specific etiologies… So each cause get’s its own set of LRs WARNING… many of these studies are single or multiple small trials… hence the wide confidence intervals. Watery does not equate with Yeast Malodor does no equate with Yeast vulvar/vaginal inflammation (erythema, edema, excoriations) are all strong predictors of Yeast

32 Candida Vaginitis Post-Test Probabilities
. So, you might perform microscopy to confirm that vulvar inflammation is due to yeast… when positive it yields a 70% prob… but when negative, it’s still almost 50%!! PreTest Prob Anderson et al.

33 Vaginitis Case: Yeast Prob
2.4chs*1.5wtry-*3.3itch *0.5odor =5.9 Step 1: -20/80 = 0.251 Step 2: x 5.9 = 1.492 Step 3: /2.492 = 60%

34 Vaginitis symptoms cont.
Question #2: Why perform microscopy? Agreement between clinician-read microscopy & culture is poor. Rapid commercial tests are here/around the corner You diagnose candidal vaginitis… you treat with fluconazole 150 mg x 1, but patient returns 1 week later with recurrence. What now?

35 Complicated Candidiasis CDC MMWR 2002;51:RR-6
Recurrent vulvovaginal candidiasis obtain vaginal culture to assess for non-albicans species treatment: topical therapy x 7-14 d; or fluconazole 150 mg, po, repeated in 3 d maintenance (x 6 mo): clotrimazole 500 mg vag supp q week; fluconazole mg q week; itraconazole 400 mg q month or 100 mg q d. Severe vulvovaginitis Non-albicans vulvovaginitis treatment: d non-fluconazole azole drug; if recurs, 600 mg boric acid in gelatin capsule qd x 2 wks

36 Bacterial Vaginosis CDC MMWR 2002;51:RR-6
Criteria 3 of 4 present: vaginal discharge clue cells vaginal pH > 4.5 whiff test (fishy odor after 10% KOH Management of Sex Partners response to Rx and relapse are not affected by Rx of sex partner Clinical Criteria Treatment Recommended Regimen* metronidazole 500 mg bid x 7 d, OR metronidazole gel 0.75%, one full applicator (5 g) iv, qd x 5 d, OR clindamycin cream 2%, one full applicator (5 g) iv qhs x 7d Alternative Regimens metronidazole 2 g po x 1, OR clindamycin 300 mg po bid x 7 d, OR clindamycin ovules 100 g iv qhs x 3 d

37 Trichomoniasis CDC MMWR 2002;51:RR-6
Counseling Management of Sex Partners treat sex partners Microscopy or Cx Treatment Recommended Regimen* metronidazole 2 g po x 1 Alternative Regimens metronidazole 500 mg bid x 7 d

38 SUMMARY UTI Typical Voiding Sx and no vaginitis... Empiric Rx
Know local E.coli antibiotic-resistance rates Threshold 20-30% sulfa-resistance to switch to FQ first-line… Consider STD testing, particularly in young, sexually active women (prevalence >=10%)… particularly for Chlamydia Non-invasive testing is a reliable option Vaginitis Curdy discharge + vulvar inflamm/itching = Yeast Malodor = non-yeast Absence of malodor history may rule-out BV.

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