Urinary Tract Infection in Women - Complicated

Definition

A complicated urinary tract infection (UTI) in women refers to infection of the urinary tract associated with structural or functional abnormalities, comorbid conditions, or risk factors that increase the likelihood of treatment failure or serious outcomes. It includes infections involving the upper urinary tract, recurrent or resistant infections, and those in pregnant or immunocompromised women.

Epidemiology

• Occurs in women with underlying urinary tract abnormalities or systemic comorbidities
• Accounts for 20–30% of all UTIs in adults
• More common in older women, diabetics, and postmenopausal women
• High recurrence and antibiotic resistance rates
• Hospital-acquired (catheter-associated) UTIs form a major subset

Etiology

• Common pathogens: *Escherichia coli* (50–70%), *Klebsiella*, *Proteus*, *Pseudomonas*, *Enterococcus*, and *Enterobacter* species
• Risk factors: urinary obstruction (stones, strictures), neurogenic bladder, indwelling catheters, diabetes mellitus, pregnancy, immunosuppression
• Recurrent antibiotic use leading to multidrug-resistant organisms
• Ascending infection from lower urinary tract; hematogenous spread in rare cases

Pathophysiology

• Bacterial colonization and ascension in presence of urinary stasis or obstruction
• Compromised host defenses (e.g., diabetes, catheters) allow infection to persist
• Inflammation extends beyond bladder to involve kidneys or peri-renal tissues
• Biofilm formation on catheters or stones leads to chronic or recurrent infections
• Systemic response may cause sepsis or renal damage if untreated