"I woke up one morning and every time Ihad to urinate it became more and more painful," says Amy, a 28-year-oldpublicist. The pain worsened throughout the day until she noticed she was"peeing pink."

"I thought it was because I was drinking so muchcranberry juice," she says. It turned out the discoloration was due toblood in her urine, caused by a bladder infection (cystitis).

Such infections occur when bacteria (usually E. coli,normally found in the colon) enter the bladder.

Cystitis is the most common type of urinary tract infection(UTI), a prevalent disorder that leads to about 9.6 million doctor visitsannually, according to the National Institute of Diabetes and Digestive andKidney Diseases. Women are especially at risk, with one in five developing aUTI during her lifetime.

It's important to seek treatment for a bladder infectionbecause it can lead to a kidney infection -- a more serious and potentiallylife-threatening disorder -- if not treated.

Women's Risk

While researchers still aren't clear why bladder infectionsare so common in women, it's thought to be because a woman's urethra (the tubethat carries urine from the bladder out of the body) is short, and its openingis close to the anus, making it easy for bacteria to travel from the colon tothe bladder.

Certain risk factors increase likelihood of a bladderinfection. They include:

• sexual activity, which can introduce bacteria into the urinary tract;
• use of diaphragms and spermicides, which alter the bacteria in a woman'surethra;
• pregnancy, because of changes in anatomy and physiology (a UTI can put theunborn child at risk and a doctor should be consulted immediately);
• increased age;
• poor hygiene;
• diabetes;
• medical conditions that suppress the immune system or make emptying thebladder difficult. Once a woman has a UTI, her chances of developing anotherone increase substantially.

Diagnosis and Treatment

If you have signs of a bladder infection, consult a doctoras soon as possible, before the problem becomes more serious. Other conditionswith similar symptoms include urethritis (inflammation of the urethra),interstitial cystitis (a bladder infection with unknown cause), urinary stonesand bladder tumors. Your doctor will ask questions about your medical andsexual history and take a urine sample to see whether it contains bacteria and,if so, what type.

Bladder infections are treated with a wide variety ofantibiotics. Symptoms usually clear up within a few days in uncomplicatedcases, though the medication needs to be taken for the entire prescribed courseto cure the infection. Other medications may be given to treat symptoms untilthe antibiotics kick in.

Dr. James Lewis, chief of obstetrics and gynecology atKaiser Permanente Golden Gate Hospital in San Francisco, recommends aurological evaluation for anyone who gets recurrent infections (more than twoor three a year), to see whether another medical problem or a congenitalmalformation is causing them.