Acute cystitis is a bacterial infection of the bladder or lower urinary tract. Acute means sudden or severe.

See also:

• Cystitis - recurrent
• Cystitis - noninfectious
• Interstitial cystitis
• Urinary tract infection

Acute cystitis occurs when the lower urinary tract (urethra and bladder) become infected by bacteria. Most cases are caused by Escherichia coli (E. coli), a bacteria found in the intestines. When you urinate, you help remove bacteria from the bladder. However, sometimes the bacteria grow so fast that some remains in the bladder.

Cystitis is rare in men. Women are more likely to have cystitis. It is much easier for the bacteria to travel into a woman's bladder, because it does not have to travel as far.

The condition is very common, and most often affects sexually active women age 20 to 50. Sexual intercourse may increase the risk of cystitis. However, the infection may also occur in those who are not sexually active.

Older adults also have high risk for developing cystitis. This is due in part to conditions such as benign prostatic hyperplasia (BPH), prostatitis, and urethral strictures.

The following also increase your risk for cystitis:

• Bowel incontinence
• Diabetes
• Blockage of the bladder or urethra
• HIV
• History of analgesic nephropathy or reflux nephropathy
• Immobility or decreased mobility
• Insertion of instruments into the urinary tract (such as a catheter or cystoscope)
• Not drinking enough fluids