Q. I'm a 45-year-old woman. Now and then, I suddenly feel pain every time I urinate. It lasts for a week or so and then goes away. My doctor said I don't have a urinary infection and didn't prescribe any treatment. What else might be causing my symptoms?
A. Several different conditions can cause such symptoms:
• A bladder infection (cystitis) often starts when bacteria enter the urethra during sexual intercourse. The urethra is the tube that connects the bladder to the outside world. Bacteria live around the opening of the urethra; sometimes they can get into the tube and travel to the bladder. This tends to happen more often following sex, because sex tends to push the bacteria back up into the bladder.
There is a widely held belief that women and girls who wipe with toilet tissue from back to front following a bowel movement can also push bacteria up into the bladder. However, I once did a study that did not confirm this belief.
• Kidney infection. A kidney sometimes can become infected when bacteria cause a bladder infection. Long tubes called ureters connect the kidneys to the bladder; bacteria can sometimes make the long trip up the ureters to the kidneys. The symptoms of a kidney infection, in contrast to a bladder infection, include fevers, pain in the side of the back, nausea, shaking chills and sometimes low blood pressure. Kidney infections always need urgent medical attention.
• Urethritis is an inflammation of the urethra. It is usually caused by organisms that cause several sexually transmitted diseases, such as chlamydia. It also can be caused by contact with an irritating chemical (such as bubble bath or spermicides). Or it may result from irritation from an object, such as a tube inserted to drain urine.
• Vaginitis is an inflammation of the vagina. It can be caused by an allergic reaction to an irritating chemical such as a spermicide, douche or bath soap. Low levels of estrogen after menopause can cause vaginitis. So can an object such as a tampon. Infections including bacterial vaginosis, candidiasis and trichomoniasis can also cause vaginitis. Usually vaginitis causes discharge from the vagina, but sometimes it just causes pain with urination.
The doctor who said you don't have a urinary infection may have checked only for bacterial infections of the bladder and urethra. You might ask your doctor about urethritis and vaginitis.
If you continue to have pain when you urinate, check with your doctor again. To confirm a diagnosis, you may need to have a urine test, blood test, a swab of the infected area, or other tests to check for sexually transmitted diseases.
To help prevent urinary and vaginal infections in the future:
• Drink several glasses of water each day.
• Urinate soon after sexual intercourse.
• Keep your genital area clean and dry.
• Change tampons and sanitary napkins frequently.
• Avoid using irritating soaps, vaginal sprays and douches.
• Practice safe sex.
• Dr. Komaroff is a physician and professor at Harvard Medical School. To send questions, go to AskDoctorK.com.