The condition occurs when the normally clean lower
urinary tract is infected by bacteria and becomes inflamed.
Urinary tract infections are very common. Most of the time, symptoms of a urinary tract infection disappear within 24 - 48 hours after treatment begins. However, if the condition occurs more than twice in 6 months, lasts longer than 2 weeks, or does not respond to usual treatment, it is considered chronic. The elderly are at increased risk for such infections.