Pyelonephritis

Background

• Also known as acute cystitis; abbreviation = UTI

Definitions

• UTI = significant bacteriuria in presence of symptoms
  • Described by location: urethritis, cystitis, or pyelonephritis
• Relapse
  • Recurrence of symptoms w/in month despite tx
    • Caused by same organism and represents treatment failure
• Reinfection
  • Development of symptoms 1-6mo after tx
  • Usually due to a different organism
  • If pt has >3 recurrences in 1 yr consider tumor, calculi, diabetes
• Men <50 yr: symptoms of dysuria or urinary frequency usually due to STI
• Men >50 yr: incidence of UTI rises dramatically d/t prostatic obstruction
• Uncomplicated UTI:
  • No structural or functional abnormalities w/in urinary tract or kidney
  • No relevant comorbidities that place pt at risk for more serious adverse outcome
  • Not associated with GU tract instrumentation

Risk factors for complicated UTI

1. Male sex
   1. In young males dysuria is more commonly d/t STI
   2. Suspect underlying anatomic abnormality in men with culture-proven UTI
2. Anatomic abnormality of urinary tract or external drainage system
   1. Indwelling urinary catheter, stent
   2. Nephrolithiasis, neurogenic bladder, polycystic renal disease, recent instrumentation
3. Recurrent UTI (three or more per year)
4. Advanced age in men (BPH, recent instrumentation, recent prostatic biopsy)
5. Nursing home residency (w/ or w/o indwelling bladder catheter)
6. Neonatal state
7. Comorbidities (DM, sickle cell disease)
8. Pregnancy
9. Immunosuppression (AIDS, immunosuppressive drugs)
10. Advanced neurologic disease (CVA w/ disability, Spinal Cord Injuries)
11. Known or suspected atypical pathogens (Non–E. coli infection)
12. Known or suspected abx resistance (resistance to Cipro predicts multidrug resistance)

Microbiology

• Most common pathogen is E. coli
• Anaerobic organisms are rarely pathogenic (do not grow well in urine)
• Complicated UTIs more likely to be caused by pseudomonas or enterococcus