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Urinary Tract Infection (UTI) in Females

BASICS

Description

  • UTI is the presence of pathogenic microorganisms within the urinary tract with associated symptoms:
  • Dysuria
  • Urinary urgency/frequency
  • Hematuria
  • New/worsening incontinence

Classification

  • Uncomplicated UTI:
  • Normal urinary tract anatomy, no risk factors
  • Complicated UTI:
  • Anatomic/functional abnormality, immunocompromised host, MDR organisms
  • Recurrent UTI:
  • β‰₯2 culture-proven UTIs in 6 months or β‰₯3 in 12 months
  • ~40% of women with prior cystitis may have recurrence
  • Asymptomatic bacteriuria (ASB):
  • Presence of bacteria without symptoms
  • Synonym: Cystitis

EPIDEMIOLOGY

  • Accounts for ~10.5 million outpatient visits/year in the U.S.
  • Annual cost >$2.6 billion
  • Prevalence:
  • 60% of women experience β‰₯1 UTI
  • 11% report β‰₯1/year
  • 25% of uncomplicated UTIs recur within 6 months

ETIOLOGY & PATHOPHYSIOLOGY

  • Mechanism: Ascending infection from urethra to bladder
  • Common Pathogens:
  • Escherichia coli: 80–85%
  • Staphylococcus saprophyticus: 10–15%
  • Klebsiella pneumoniae, Proteus mirabilis: ~4% each
  • Genetic predisposition:
  • HLA-3 and nonsecretor Lewis antigen increase adherence

RISK FACTORS

Biologic

  • Urinary stasis/obstruction: pelvic organ prolapse, neurogenic bladder, bladder diverticula
  • Urinary calculi
  • Immunosuppression: diabetes, HIV, malignancy

Behavioral

  • Sexual intercourse, spermicide use
  • Estrogen depletion (e.g., menopause)
  • Recent antimicrobial use, poor hygiene

GENERAL PREVENTION

  • Hydration β‰₯2 L/day
  • Pre/post-coital voiding
  • Avoid: spermicides, diaphragms, douches, hygiene sprays
  • Wipe front to back
  • Postmenopausal: Consider vaginal estrogen
  • Address urinary obstruction/stasis

ASSOCIATED CONDITIONS

Geriatric Considerations

  • Common: urinary retention, pelvic prolapse, incontinence
  • Altered presentation: mental status change, new incontinence
  • Avoid treating ASB in elderly due to no benefit

Pediatric Considerations

- Risk factors: congenital anomalies (e.g., VUR), bowel-bladder dysfunction

DIAGNOSIS

History

  • Dysuria, urgency, frequency, hematuria, suprapubic pain
  • Nocturia, foul urine odor, new incontinence, dyspareunia
  • Recent sexual activity, prior UTIs

Physical Exam

  • Suprapubic tenderness
  • Vaginal/urethral tenderness
  • CVA tenderness β†’ consider pyelonephritis

Differential Diagnosis

- Vaginitis, urethritis (STIs), stones, tumors, interstitial cystitis

DIAGNOSTIC TESTS

Initial Tests

  • Urinalysis (UA):
  • Pyuria: >10 WBCs/HPF
  • Bacteriuria: any in unspun urine
  • Hematuria: β‰₯3 RBCs/HPF
  • Squamous cells: contamination likely if >15–20/HPF
  • Dipstick:
  • Leukocyte esterase: 75–96% sensitive
  • Nitrite: Specific for gram-negative bacteria
  • Urine culture:
  • Not needed in uncomplicated UTI
  • Required for recurrent/complicated UTI

Special Considerations

  • Imaging (CT/MR urography) only if:
  • Recurrent UTIs
  • Obstruction signs
  • Pediatric VUR (VCUG/ultrasound)

TREATMENT

General Measures

  • Avoid treating ASB in nonpregnant adults
  • Hydration
  • Spontaneous resolution possible in mild cases

First-line Medications

  • Phenazopyridine: 100–200 mg TID short-term symptom relief
  • Alters dipstick results (not culture)
  • Uncomplicated UTI:
  • TMP/SMX (Bactrim): 160/800 mg BID x 3 days
  • Nitrofurantoin: 100 mg BID x 5 days
    • Avoid if CrCl <30 or suspected pyelonephritis
  • Fosfomycin: 3 g single dose (alternative)

Pregnancy

  • Nitrofurantoin: 100 mg BID x 7 days (not after 35 weeks)
  • Cephalexin: safe
  • Avoid TMP/SMX (1st & 3rd trimesters), fluoroquinolones

Postcoital UTI

  • Single-dose TMP/SMX or cephalexin

Complicated UTI

  • 7–10 days, start with cephalosporin
  • Avoid nitrofurantoin (poor tissue penetration)

Second-line

  • Ξ²-lactams: amoxicillin/clavulanate, cefpodoxime (3–7 days)
  • Avoid fluoroquinolones in uncomplicated cases (FDA warnings)

RECURRENT UTI MANAGEMENT

  • Confirm with urine culture
  • Options:
  • Continuous suppression: TMP/SMX 80/400 mg or nitrofurantoin 50–100 mg
  • Postcoital prophylaxis
  • Patient-initiated therapy
  • Intermittent prophylaxis (e.g., MWF schedule)

REFERRAL INDICATIONS

  • Recurrent or complicated UTI β†’ Urologist
  • Pediatric UTI <1 year old β†’ Pediatric Urologist

SURGICAL / PROCEDURAL INTERVENTIONS

  • Sepsis + obstruction β†’ urgent drainage (stent or nephrostomy)
  • Pediatric: Febrile UTI + VUR β†’ consider ureteral reimplantation

COMPLEMENTARY & ALTERNATIVE THERAPIES

  • Cranberry extract (not juice cocktail): reduces bacterial adherence
  • Probiotics, Methenamine (Hiprex): recurrent UTI prevention
  • Vaginal estrogen: beneficial in postmenopausal women

ADMISSION & NURSING CONSIDERATIONS

  • Inpatient care only for complicated UTI
  • Most uncomplicated UTIs are treated outpatient

ONGOING CARE

Follow-up

  • No follow-up needed if first UTI resolves with 3-day therapy
  • If symptoms persist >2–3 days β†’ obtain urine culture

Pregnancy

  • Always perform culture
  • Treat 7–14 days
  • Culture each trimester
  • May need prophylaxis during pregnancy

Monitoring

  • Avoid repeat cultures if asymptomatic
  • Persistent symptoms β†’ repeat culture before changing antibiotics

DIET

- Reduce glycosuria (optimize glycemic control)

PATIENT EDUCATION

- Urology Care Foundation

PROGNOSIS

- Most symptoms resolve within 2–3 days with treatment

COMPLICATIONS

  • Pyelonephritis
  • Sepsis
  • Renal abscess
  • Urinary obstruction

PREGNANCY CONSIDERATIONS

- Pregnant women, infants, young children with cystitis are at higher risk of pyelonephritis

CLINICAL PEARLS

  • Do NOT treat asymptomatic bacteriuria in nonpregnant women
  • Uncomplicated UTI:
  • TMP/SMX x 3 days
  • Nitrofurantoin x 5 days
  • Always treat bacteriuria in pregnancy
  • Avoid fluoroquinolones for uncomplicated UTI

REFERENCES

  1. Gupta K, Trautner BW. Diagnosis and management of recurrent urinary tract infections in nonpregnant women. BMJ. 2013;346:f3140.
  2. Anger J, Lee U, Ackerman AL, et al. Recurrent uncomplicated urinary tract infections in women: AUA/CUA/SUFU guideline. J Urol. 2019;202(2):282–289.

SEE ALSO

- Algorithm: Dysuria

CODES

  • ICD-10:
  • N39.0 – Urinary tract infection, site not specified
  • N30.90 – Cystitis, unspecified