Urinary Tract Infections, Adult

Basics

Description

  • Colonization of urine with uropathogens and invasion of genitourinary (GU) tract
  • Defined as urinary symptoms with ≥102 to 105 CFU/mL of uropathogen and ≥10 WBC/mm3
  • Lifetime risk of UTI in women is >50%
  • Uncomplicated cystitis:
    • Females aged 13–50
    • Symptoms <2–3 d
    • Not pregnant
    • Afebrile (temperature <38°C)
    • No flank pain
    • No costovertebral angle tenderness (CVAT)
    • Fewer than 4 UTIs in past year
    • No recent instrumentation or previous GU surgery
    • No functional/structural GU abnormality
    • Not immunocompromised
    • Neurologically intact
  • Complicated cystitis:
    • Do not meet above criteria
    • Male gender
    • Patients with anatomic, functional, or metabolic abnormalities of GU tract
    • Postvoid residual urine
    • Catheters
    • Resistant pathogens
    • Recent antimicrobial use
  • Uncomplicated pyelonephritis:
    • Renal parenchymal infection
    • Dysuria, frequency, urgency
    • Fever, chills, myalgias, nausea, vomiting
    • Flank, back, or abdominal pain
    • CVA tenderness
    • Leukocytosis (common)
  • Complicated pyelonephritis:
    • Renal parenchymal infection
    • Temperature >40°C
    • Urosepsis with septic shock
    • Intractable nausea, vomiting
    • Diabetes, other immunosuppression
    • Pregnancy (especially latter half)
    • Concomitant obstruction or stone
    • Asymptomatic (occult)

Etiology

  • Mechanism:
    • Organisms colonize periurethral area and subsequently infect the GU tract
  • Risk factors:
    • Population:
      • Newborn, prepubertal girls, young boys
      • Sexually active young woman
      • Postmenopausal woman, elderly males
    • Behavior:
      • Sexual intercourse, spermicides, diaphragms
  • Elderly females/postmenopausal state
  • Less efficient bladder emptying, bladder prolapse, alteration of bladder defenses
  • Increased vaginal pH
  • Contamination due to urinary or fecal incontinence (Enterobacteriaceae)
  • Instrumentation:
    • Elderly males due to prostatic hypertrophy and instrumentation
  • Organisms:
    • Escherichia coli (80–85%)
    • Staphylococcus saprophyticus (10%)
    • Other (10%): Klebsiella, Proteus mirabilis, Enterobacter spp., Pseudomonas aeruginosa, group D streptococci

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