Definition & Classification

Definition of UTI in Women

  • Criteria for the presumptive diagnosis of urinary tract infection
    • Symptoms of bladder irritation (dysuria, urgency or frequency of urination) or of infection of the kidney (flank pain, fever, costovertebral angle tenderness).
    • Urine sediment containing 8 to 10 or more white blood cells per high-powered field
    • Quantitative urine culture revealing at least 100,000 microorganisms per milliliter of urine in a clean-voided specimen
      • It is possible to have a bacterial urinary tract infection with a negative urinalysis and/or bacterial counts in the urine of less than 105
      • The presence of 100,000 microorganisms per milliliter of urine in a patient without symptoms is termed "asymptomatic bacteriuria."
    • Consistent sterile cultures can be used to rule out bacterial infection of the urinary tract as a cause of symptoms, and make one look to other diagnoses


Classification of UTI in Women

  • Site of origin
    • Cystitis
      • Refers to the nonspecific clinical syndrome of dysuria, urinary frequency, urgency, and suprapubic fullness
    • Pyelonephritis
      • Fever, chills, and flank pain caused by bacterial infection of the renal parenchyma
        • Based on symptoms, it is remarkably difficult to differentiate infection involving the upper tracts from bacteriuria confined to the bladder.
        • Localizing the site of infection in clinically uncomplicated infections is unnecessary.
  • Complexity
    • Uncomplicated: occurring in a normal urinary tract
    • Complicated: structural or anatomic impairments that decrease antibiotic efficacy
  • Stamey Classification
    • First infections: isolated or remotely occurring bacterial cystitis
    • Unresolved bacteriuria occurs when the urine cannot be sterilized despite antibiotic treatment
      • Common causes include preexisting or acquired bacterial resistance, inadequate coverage of a second organism, rapid reinfection with a new organism during therapy, azotemia preventing access of the antibiotic to the urinary tract, and noncompliance with treatment
    • Recurrent infection is an infection diagnosed after successful treatment of an antecedent infection (95% of UTI in women)
    • Bacterial persistence: sterilization of the urine is short-lived, and within weeks, a relapse with the identical organism occurs
      • Indicates a site of persistent infection within the urinary tract that could represent a stone, enterovesical fistula, or infected anatomic anomaly


Etiology of UTI in Men

  • Neurogenic bladder
    • Can be secondary to prolonged outlet obstruction, neurologic disorder, diabetes
    • Diabetes can cause a sensory neuropathy and resultant bladder decompensation with chronic residual urine. Glyocsuria can impair bacterial phagocytosis.
  • Urethral stricture disease
  • Infected bladder calculi
  • Urethral catheterization
    • Incidence of bacteriuria 5 percent per single catheterization and 5 percent increase per day of catheterization
  • External collecting devices
  • Unprotected anal intercourse
  • Poor preputial care in uncircumcized males
  • Enterovesical fistula secondary to tumor or diverticulitis


Signs & Symptoms of Bacterial Cystitis

  • Signs and symptoms
    • Dysuria, urgency, frequency, nocturia
    • Suprapubic or low back pain may be present
    • Hematuria
    • Fever and chills may indicate systemic infection, pyelonephritis, acute bacterial prostatitis
    • Asymptomatic bladder colonization is not infrequent in elderly populations


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