Lower Urinary Tract Infection: Pathogenesis and Clinical Findings



- Predisposing Factors:  Immunocompromised state, diabetes, elderly, female (short urethra), stagnant urine (anatomical variant, obstruction, neurogenic bladder, urinary reflux) -> Impairment of body's natural defense systems, or stagnant urine, allow for bacterial accumulation

 - Bacterial entry (Less Common): Indwelling catheter, surgical inoculation, hematogenous spread, trauma (Staphylococcus, Enterococcus, Candida) -> Portal of entry bypasses body's physical defenses (gravity and repetitive outward urine flow)

 - Fecal bacteria access urethra (E. coli, Proteus, Klebsiella) -> Bacterial fimbriae and pili allow them to ascend urethra and adhere to epithelium



-> Lower Urinary Tract Infection ("Cystitis"): Infection of bladder or distal tract by capable bacteria colonizing epithelium and causing symptoms



Signs/Symptoms: 

 - Urgency: Sensation of need to urinate quickly or impending incontinence

 - Frequency: Repetitive need to urinate

 - Dysuria

 - Fever,  Malaise, Incr WBC (Rare in LUTI)

 - Suprapubic Tenderness

 - Urine Findings:

    Incr Colony Count (>107 CFU/L)

    Incr WBC (>10 WBC/gL)

    (+) Bacterial culture

    (+) Nitrites, Leukocyte Esterase

    (+) Foul, turbid urine +/- Hematuria (rare)



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