One of the common symptoms of a urinary tract infection—a bacterial infection in the kidneys, the bladder, or the urethra—is none whatsoever. Fortunately, there often is some indication, such as frequent urination and a persistent urge to urinate despite a burning sensation when urinating. UTIs can also make themselves known through the appearance of the urine. Cloudiness is one sign, and another is red or pink blood in the urine; blood may also give urine a dark color. UTIs also can cause urine to have an unusually strong odor. Bladder infections can cause pain in the lower abdomen.
Perhaps unsurprisingly, UTIs can present differently in men and women. Women with UTIs often experience pelvic pain, while for men the equivalent pain will be felt in the rectum. A broader difference is that, while women suffer UTIs more frequently, men are more likely to be hospitalized as a result. Part of the reason for this may be social—because UTIs are more unusual among men, men are more likely to seek hospital care rather than treat it on their own, as women for whom UTIs are more or less routine might do. Differences in male and female anatomy may also be a factor in which patients can be treated on an outpatient basis and which patients must be hospitalized.
There are several ways the urinary tract might become infected, and sometimes the cause is simply unknown. Sometimes gut bacteria normally expelled as waste get into the urethra and infect the urinary tract that way. Sexual activity can be a causative factor, particularly in women. Sometimes, certain STDs can lead to UTIs, or increase vulnerability to such infections. UTIs can be treated by a course of antibiotics—though this can make further infections more likely. Cranberry juice is often suggested as a treatment, and it demonstrably effective as a preventative measure.
Another preventative measure, especially for relapses, has been tested in laboratory animals and is expected to be effective in humans as well. A compound called chitosan was found to help eliminate what are called reservoir populations of bacteria. Antibiotics are effective against bacteria causing the infection, but leave behind their dormant brethren nestled in the inner layers of the bladder; in tests, chitosan appeared to eliminate even these.