Causes

Your urinary system includes your kidneys, ureters, bladder and urethra. All play a role in removing waste from your body. Your kidneys — a pair of bean-shaped organs located toward the back of your upper abdomen — filter waste from your blood and regulate the concentrations of many substances. Tubes called ureters carry urine from your kidneys to the bladder, where it's stored until it exits your body through the urethra.

Bacterial cystitis

UTIs typically occur when bacteria outside the body enter the urinary tract through the urethra and begin to multiply. Most cases of cystitis are caused by a type of Escherichia coli (E. coli) bacteria.

Bacterial bladder infections may occur in women as a result of sexual intercourse. But even sexually inactive girls and women are susceptible to lower urinary tract infections because the female genital area often harbors bacteria that can cause cystitis.

Noninfectious cystitis

Although bacterial infections are the most common cause of cystitis, a number of noninfectious factors also may cause the bladder to become inflamed. Some examples include:

• Interstitial cystitis. The cause of this chronic bladder inflammation, also called painful bladder syndrome, is unclear. Most cases are diagnosed in women. The condition can be difficult to diagnose and treat.
• Drug-induced cystitis. Certain medications, particularly the chemotherapy drugs cyclophosphamide and ifosfamide, can cause inflammation of your bladder as the broken-down components of the drugs exit your body.
• Radiation cystitis. Radiation treatment of the pelvic area can cause inflammatory changes in bladder tissue.
• Foreign-body cystitis. Long-term use of a catheter can predispose you to bacterial infections and to tissue damage, both of which can cause inflammation.
• Chemical cystitis. Some people may be hypersensitive to chemicals contained in certain products, such as bubble bath, feminine hygiene sprays or spermicidal jellies, and may develop an allergic-type reaction within the bladder, causing inflammation.
• Cystitis associated with other conditions. Cystitis may sometimes occur as a complication of other disorders, such as diabetes, kidney stones, an enlarged prostate or spinal cord injuries.