Urinary Tract Infection (UTI) is an infection in any part of the urinary system, most commonly the bladder (cystitis) or urethra (urethritis), and less often the kidneys (pyelonephritis) or ureters. It is primarily caused by bacteria (usually Escherichia coli from the gastrointestinal tract) entering the urethra and multiplying in the urinary tract, with risk factors including female anatomy (shorter urethra), sexual activity, urinary retention, catheters, menopause (reduced estrogen), diabetes, kidney stones, or anatomical abnormalities. Symptoms typically include a strong, persistent urge to urinate, burning or pain during urination (dysuria), frequent urination of small amounts, cloudy or strong-smelling urine, pelvic pressure or lower abdominal discomfort in women, and sometimes blood in the urine (hematuria); upper UTI (kidney involvement) adds fever, chills, flank/back pain, nausea, or vomiting. In older adults, it may present atypically with confusion or agitation rather than classic urinary symptoms. UTIs are far more common in women than men but can affect anyone.
