Recurrent Urinary Tract Infections: Comprehensive Notes

Introduction

  • Recurrent Urinary Tract Infections (RUTI):
    • Definition: RUTI is defined as three or more symptomatic urinary tract infections (UTIs) over a 12-month period.
    • RUTIs can be classified as re-infections or relapses.

Definition of Terms

  • Urinary Tract Infection (UTI):
    • Common bacterial infection, especially among women.
    • Bacteriuria: Presence of bacteria in urine.
    • Symptomatic: 100 CFU/mL.
    • Asymptomatic: 100,000 CFU/mL.

Epidemiology

  • Prevalence:
    • Affects 20% of women aged 20-56 annually.
    • 40-50% experience at least one UTI in their lifetime.
    • One in four women will have recurrences, predominantly within 6-12 months.
  • Recurrence Rates:
    • Shorter intervals (<60 days) for catheterized individuals.

Risk Factors for RUTI

1. Healthy Young/Premenopausal Women:
  • Sexual Intercourse:
    • Strong association with RUTI. Postulated to introduce uropathogens.
  • Contraceptive Use:
    • Use of spermicides, diaphragms, and oral contraceptives increases risk.
  • Antimicrobial Use:
    • Disruption of normal vaginal flora promotes E. coli colonization.
  • Oestrogen Impact:
    • Role is mixed; may facilitate uropathogen adherence, or deficiency could increase risk.
  • Genetics:
    • Increased incidence in immediate female relatives of those with RUTI.
  • Urethra-Anus Distance:
    • Shorter distances associated with increased risk.
2. Postmenopausal Women:
  • Common factors:
    • Oestrogen deficiency, urogenital surgery, previous UTIs, and incontinence.
  • Divided into healthy and institutionalized groups; higher risk in the latter.

Complicated UTIs:

  • More likely to involve multi-resistant pathogens.
  • Risk factors include urinary stasis due to anatomical issues (e.g., kidney stones, neurogenic bladder, etc.).

Bacteriology

  • Common Pathogens:
    • E. coli: Most prevalent (70-95%).
    • Other pathogens: Staphylococcus saprophyticus (5-20%), Klebsiella, Proteus.
    • Polymicrobic infections are common in complicated cases.

Mechanism of Infection

  • Most UTIs arise from the gastrointestinal flora, particularly E. coli.
  • Colonization begins at the vaginal flora, leading to periurethral colonization and bladder infection.
  • Uropathogenic E. coli (UPEC):
    • Uses pili for adhesion to urinary tract epithelial cells, forming biofilms that protect against immune response and antibiotics.

Clinical Presentation

  • Symptoms: Dysuria, frequency, urgency, and suprapubic discomfort.
  • Upper tract infection may present as fever or flank pain.

Investigations

  • Urine Examination:
    • Clean-catch sample for microscopy and culture; culture is gold standard.
  • Urine Cytology and Blood Tests:
    • Used to detect underlying conditions (e.g., malignancy or diabetes).
  • Imaging:
    • Imaging funded for persistent infections to check for complications.

Management Approaches

  • Treatment of underlying causes is crucial.
  • Antibiotic Prophylaxis:
    • Options: Long-term (e.g., TMP-SMX, nitrofurantoin) or post-coital prophylaxis for women whose infections are linked to sexual activity.
  • Patient-Initiated Therapy:
    • Women manage their symptoms and initiate therapy when they recognize UTI onset.

Non-Antibiotic Prophylactic Options

  • Oestrogen Therapy:
    • Can help restore normal flora in postmenopausal women, though results are mixed.
  • Cranberry Juice:
    • Shown to reduce bacteriuria by preventing bacterial adhesion to the uroepithelium.

Summary of Prevention Strategies

  • Long-term prophylaxis: 6-12 months; can reduce recurrences.
  • Post-coital therapy: Effective for women with infections related to sexual activity.
  • Further studies are needed on the role of oestrogen and vaccines in future management.