Cystitis is caused by germs, usually bacteria that enter the urethra and then the bladder. These bacteria can lead to infection, most commonly in the bladder. The infection can spread to the kidneys.
Most of the time, your body can get rid of these bacteria when you urinate. However, sometimes the bacteria can stick to the wall of the urethra or bladder, or grow so fast that some bacteria stay in the bladder.
Women tend to get infections more often than men because their urethra is shorter and closer to the anus. For this reason, women are more likely to get an infection after sexual intercourse or when using a diaphragm for birth control. Menopause also increases the risk for a urinary tract infection.
The following also increase your chances of developing cystitis:
- A tube called a urinary catheter inserted in your bladder
- Blockage of the bladder or urethra
- Enlarged prostate, narrowed urethra, or anything that blocks the flow of urine
- Loss of bowel control (bowel incontinence)
- Older age (especially in people who live in nursing homes)
- Problems fully emptying your bladder (urinary retention)
- Procedures that involve the urinary tract
- Staying still (immobile) for a long period of time (for example, when you are recovering from a hip fracture
Most cases are caused by Escherichia coli (E. coli), a type of bacteria found in the intestines.