urinary tract infection
Summary
Urinary tract infection (UTI) is a bacterial infection of any part of the urinary system, most commonly the bladder (cystitis) or kidneys (pyelonephritis). E. coli is the most common causative organism, accounting for 80-85% of uncomplicated UTIs. Women are at higher risk due to shorter urethra and anatomical factors.
Detail
UTIs result from bacterial ascension through the urethra, with E. coli being the predominant pathogen due to its uropathogenic virulence factors and ability to adhere to uroepithelial cells. Risk factors include female gender, sexual activity, pregnancy, urinary stasis, catheterization, and anatomical abnormalities. Lower UTIs (cystitis) present with dysuria, frequency, urgency, and suprapubic pain, while upper UTIs (pyelonephritis) additionally cause fever, flank pain, and systemic symptoms. Diagnosis is confirmed by urinalysis showing pyuria, bacteriuria, and positive nitrites/leukocyte esterase, with urine culture for organism identification and antibiotic sensitivity. Complications include recurrent infections, pyelonephritis, sepsis, and in pregnancy, preterm labor. Treatment typically involves fluoroquinolones, trimethoprim-sulfamethoxazole, or nitrofurantoin for uncomplicated cases, with duration varying by infection type and patient factors.
Sources
- Harrison's Principles of Internal Medicine
- First Aid for the USMLE Step 1
- UpToDate: Urinary tract infections in adults
- Campbell-Walsh Urology
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