Cystitis is an infection of the urinary bladder that usually occurs in women, with less than 10% occurring in men because of the longer length of their urethra (the tube leading from the bladder to the outside).
A bacterial infection can enter the bladder by coming up the urethra from outside the body, or through the bloodstream to the kidneys and then the bladder.
Entry from the outside is far more common, and often due to irritation of the urethra with sex. Slackness of the muscle ring that controls the release of urine from the bladder can also allow bacteria to enter the bladder. This damage may be caused by childbirth or prolapse of the uterus (womb), and may eventually cause incontinence with a cough or laugh.
The symptoms include burning pain on passing urine, pain in the pelvis, the desire to pass urine very frequently and blood may be seen in the urine. The infection may spread up the ureters to the kidneys to cause acute pyelonephritis.
The urine can be cultured to identify the responsible bacteria and correct antibiotic. Further investigations such as X-rays and ultrasound scans of the bladder and kidneys may be performed, to exclude more serious causes of recurrent cystitis.
Appropriate antibiotic tablets for a week or two, and urinary alkalinisers (in the form of a powder that makes a fizzy drink) result in a rapid cure in most patients. Drinking extra fluid will help wash the infection out of the bladder.
Commercial urinary alkalinisers or cranberry juice may be used regularly to prevent cystitis in women who have this problem regularly.
If a woman passes urine and takes a urinary alkaliniser immediately after sex she will reduce the risk of developing a bladder infection.