urinary tract infection

A urinary tract infection (UTI) is an infection that affects a part of the urinary tract, which includes the bladder, urethra and the kidney. Lower UTIs affect the bladder (cystitis) or urethra while upper UTIs affect the kidney (pyelonephritis). Symptoms from a lower UTI include burning or pain during urination, pain in the lower abdomen and the urge to urinate even when the bladder is empty. Symptoms of a kidney infection are more systemic and include fever or flank pain, usually in addition to the symptoms of a lower UTI. Rarely, the urine may appear bloody. Symptoms may be less clear in very young or old people.

The most common cause of infection is E. coli, though other bacteria or fungi may sometimes be the cause. Risk factors include being female, sexual intercourse, diabetes, using a catheter, and family history. Kidney infections usually occurs when a bladder infection spreads, but may also come from bacteria in the blood. Diagnosis in young healthy women can be based on symptoms alone. In those with vague symptoms, diagnosis can be harder because bacteria may be present even if there is no infection.