Acute cystitis

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Genitourinary infection

(1) Human urinary system: (2) kidney; (3) renal pelvis; (4) ureter; (5) urinary bladder (6) urethra.
Additional structures: (7) adrenal gland; (8) renal artery and vein; (9) inferior vena cava; (10) abdominal aorta; (11) common iliac artery and vein; (12) liver; (13) large intestine; (14) pelvis.

"UTI" frequently refers specifically to acute cystitis, but may also be used as a general term for all urinary infections; use location-specific diagnosis.


  • Uncomplicated
    • 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
  • Relapse
    • Recurrence of symptoms within month despite treatment
      • Caused by same organism and represents treatment failure
  • Reinfection
    • Development of symptoms 1-6mo after treatment
    • Usually due to a different organism
    • If pt has >3 recurrences in 1 yr consider tumor, calculi, diabetes

Risk factors for complicated acute cystits

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



Clinical Features



WBC count
  • WBC >5 in pt w/ appropriate symptoms is diagnostic
    • Lower degrees of pyuria may still be clinically significant in presence of UTI sx
      • False negative may be due to: dilute urine, systemic leukopenia, obstruction
    • WBC 1-2 w/ bacteriuria can be significant in men
  • Very high specificity (>90%) in confirming diagnosis of UTI
  • Low sensitivity (enterococcus, pseudomonas, acinetobacter are not detected)

Urine Culture

  • Indicated for:
    • Complicated acute cystitis
    • Pyelonephritis
    • Pregnant women
    • Children
    • Adult males
    • Relapse/reinfection

Blood Culture

  • Not indicated
    • Organisms in blood cx matched those in urine cx 97% of time

Differential Diagnosis


Pelvic Pain

Pelvic origin

Abdominal origin



  • Consider local resistance patterns (if >10-20% use a different agent)
  • Avoid use of fluoroquinolones for uncomplicated cystitis if possible
Consider longer course of complicated cystitis if
  • Symptoms >7d
  • DM
  • UTI in previous 4wk
  • Men
  • Age 65 yr
  • Women who use spermicides or diaphragm
  • Relapse
  • Pregnancy


Women, Uncomplicated

  • Nitrofurantoin ER 100mg BID x 5d, OR
  • TMP/SMX DS (160/800mg) 1 tab BID x 3d, OR
  • Cephalexin 250mg QID x 5d, OR
  • Ciprofloxacin 250mg BID x3d
    • Avoid using fluoroquinolone for the first-line treatment of uncomplicated urinary tract infections (UTIs) in women.[3]
  • Fosfomycin 3 g PO once
    • Lower clinical and microbiologic success compared to nitrofurantoin TID for 5 days [4]

Women, Complicated

Women, Concern for Urethritis


Inpatient Options


Uncomplicated UTI

  • Admit
    • Unable to tolerate PO
  • Discharge
    • Consider phenazopyridine 100-200mg TID after meals x2d only (bladder analgesic)


Suspect in pts who have inadequate or atypical response to tx for presumed pyelonephritis
  • Acute bacterial nephritis
    • CT shows ill-defined focal areas of decreased density
  • Renal/Perinephric Abscesses
    • Sign/symptoms similar to pyelo (fever, CVAT, dysuria)
    • Occurs in setting of ascending infection w/ obstructed pyelo
    • Associated w/ DM and Renal Stones
    • Also occurs due to bacteremia w/ hematogenous seeding (Staph)
  • Emphysematous pyelonephritis
    • Rare gas-forming infection nearly always occurring in pts w/ DM and obstruction
      • Pts appear toxic and septic; nephrectomy may be required

Special Populations


  • TMP-SMX resistance is increased due to its use in PCP PNA prophylaxis
  • Most acute cystitis is caused by typical pathogens or common STI organisms

Pregnant Women

  • Treat all cases of asymptomatic bacteriuria

See Also


  • Norris DL, Young JD. UTI. EM Clin N Am. 2008; 26:413-30.
  • Norris DL, Young JD. UTI. EM Clin N Am. 2008; 26:413-30.
  • Choosing Wisely. American Urogynecologic Society.
  • Huttner, A., Kowalczyk, A., Turjeman, A., Babich, T., Brossier, C., Eliakim-Raz, N., … Harbarth, S. (2018). Effect of 5-Day Nitrofurantoin vs Single-Dose Fosfomycin on Clinical Resolution of Uncomplicated Lower Urinary Tract Infection in Women: A Randomized Clinical Trial. JAMA: The Journal of the American Medical Association, 319(17), 1781–1789.