Urinary tract infections are caused by bacteria entering the urinary tract. Escherichia coli is the most common cause. Women are more likely to get UTIs, with 25% experiencing repeat infections. Risk factors include anatomical abnormalities, functional issues like a neurogenic bladder, diabetes, and immunosuppression. Symptoms depend on whether the infection is in the lower or upper urinary tract. Diagnosis involves microscopic urine examination showing white blood cells, urine culture showing bacterial growth, and imaging tests like intravenous urography in some cases. Treatment involves antibiotics.