Cystitis is usually caused when bacteria enter the urethra and bladder and cause inflammation and infection. It is a very common condition. After infancy, urinary tract infections occur more often in females because their urethra is shorter and closer to the anus. During childhood, about 1% of boys and up to 5% of girls will develop urinary tract infections. In boys the peak age is before the first birthday. Urinary tract infections are much more common among uncircumcised boys. In girls, the peak age for first infections is 3 years, overlapping with the toilet training period. Because cystitis in children can be promoted by abnormalities in the urinary tract, children with cystitis (especially those under age 5) deserve special follow-up to prevent later kidney damage. Older adults are at high risk for developing cystitis, with the incidence in the elderly being as high as 33 out of 100 people.
Over 90% of cases of cystitis are caused by E. coli, a bacterium normally found in the intestine. Normally, the urethra and bladder have no bacteria. Bacteria that manage to enter the bladder are usually removed during urination. But if bacteria remain in the bladder, they grow easily and quickly and result in infection.
The risk of cystitis is higher when the bladder or urethra becomes blocked, and the flow of urine stops. It can also occur when instruments are inserted into the urinary tract (such as during catheterization or cystoscopy). Other risks include pregnancy, diabetes, and a history of analgesic nephropathy or reflux nephropathy. Sexual intercourse can increase the risk of urinary tract infections in women because bacteria can be introduced into the bladder through the urethra.
The elderly population are at increased risk for developing urinary tract infections due to incomplete emptying of the bladder associated with such conditions as benign prostatic hyperplasia (BPH), prostatitis, and urethral strictures. Also, lack of adequate fluids, bowel incontinence, immobility or decreased mobility, indwelling urinary catheters and placement in a nursing home, all place the person at increased risk for developing cystitis.
Related disorders include:
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