Diagnosing and treating urinary tract infections

  • UTI symptoms vary by age, gender and whether a catheter is present, but the infections are eight times more common in women than men. Initial symptoms typically include a frequent and intense urge to urinate and a painful, burning feeling in the bladder or urethra during urination. Urine may look cloudy, dark or bloody, or have a foul smell.

  • Escherichia coli, shown in this color enhanced scanning electron micrograph (SEM), is responsible for 75% to 90% cases of acute uncomplicated cystitis. Clinicians should also rule out sexually transmitted Chlamydia and Mycoplasma infections, which can infect the urethra but not the bladder. Other differential diagnoses include pelvic inflammatory disease, radiation cystitis, hemorrhagic cystitis caused by medications and urine contamination with normal flora.

  • Clinicians can make a presumptive UTI diagnosis in symptomatic women if there is either dysuria and frequency without vaginal symptoms; or dipstick urinalysis showing positive nitrite or positive leukocyte esterase. IDSA guidelines state that definitive diagnosis is based on urine culture with ≥1,000 colony forming units (CFU)/mL; use of traditional standard (100,000 CFU/mL) results in frequent missed diagnoses.

  • Typically, uncomplicated cystitis does not cause fever. If a patient has a fever the UTI may have spread to the kidneys. Pyelonephritis symptoms include pain in the back or side below the ribs, nausea and vomiting. This illustration shows urine reflux, a common cause of pyelonephritis, in which a malfunctioning valve causes a patient’s ureter to open into the kidney. Persistent urine reflux may cause repeated bacterial kidney infections.

  • Urinary tract infections in men are often the result of an obstruction — for example, a urinary stone or enlarged prostate — or from a catheter used during a medical procedure. This CT scan of the abdomen of an elderly man shows a calculus in the kidney, which has caused swelling of the renal cavities and has blocked the ureter that links the kidney to the bladder.

  • Optimal empiric therapy for nonpregnant women with uncomplicated UTI is with trimethoprim-sulfamethoxazole (TMP-SMZ, Bactrim, Septra) 160 mg/800 mg orally b.i.d. for three days. In areas with >15%-20% E. coli resistance to TMP-SMZ, options include fluoroquinolones; ciprofloxacin, levofloxacin, nitrofurantoin and fosfomycin.

  • A cocktail for uncomplicated UTI

    A cocktail for uncomplicated UTI

    Cranberry juice and supplements are thought to be a good alternative preventive treatment for recurrent UTIs. Rich in vitamins C and E, antioxidants and anthocyanins, cranberry may help prevent E. coli from attaching to the bladder wall as well as bladder stone formation, and provide symptom relief for cystitis.

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A urinary tract infection (UTI) is one of the most common diagnoses in family medicine — accounting for approximately 8.1 million primary care visits annually. View the slideshow to learn about UTI treatment.

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