It is generally caused by bacteria that may normally be present only at the opening of the urethra. These bacteria are also usually present in the vagina and the rectum. Normally, urine flows out of the bladder, through the urethra, and out of the body. However, sometimes bacteria may make their way up the urethra and into the bladder, leading to infection, and discomfort.
Sexual intercourse seems to predispose some women to cystitis.
Symptoms Common symptoms of cystitis include a sensation that one needs to urinate frequently and in small amounts. Some women note blood in their urine. Fever and back pain are unusual for bladder infections, and indicate the need for immediate medical evaluation for a possible kidney infection. Diagnosis Cystitis is detected by performing a laboratory analysis of a urine specimen. Repeated bouts of cystitis may indicate the need for further investigation.