Health Illustrated Encyclopedia

Cystitis - acute


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

See also:

Alternative Names

Uncomplicated urinary tract infection; UTI - acute; Acute bladder infection; Acute bacterial cystitis;


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:


Additional symptoms that may be associated with this disease:

* Often in an elderly person, mental changes or confusion are the only signs of a possible urinary tract infection.

Exams and Tests

Urinalysis commonly shows white blood cells (WBCs) or red blood cells (RBCs). There may be blood in the urine.

Urine culture (clean catch) or catheterized urine specimen may be done to find out what kind of bacteria is causing the infection and to determine the appropriate antibiotic for treatment.


Cystitis should be promptly treated. Antibiotics are used to fight the bacterial infection. You should finish the entire course of antibiotics. Commonly used antibiotics include:

  • Amoxicillin
  • Cephalosporins
  • Ciprofloxacin or levofloxacin
  • Doxycycline
  • Nitrofurantoin
  • Sulfa drugs (sulfonamides) such as trimethoprim-sulfamethoxazole (Bactrim)

A medicine called phenazopyridine (Pyridium) may be used to reduce the burning and urgency associated with cystitis.

Over-the-counter products that increase acid in the urine, such as ascorbic acid or cranberry juice, may be recommended to decrease the concentration of bacteria in the urine.

Follow-up may include urine cultures to make sure that bacterial infection is gone.

Outlook (Prognosis)

Most cases of cystitis are uncomfortable but disappear without complication after treatment.

Possible Complications

When to Contact a Medical Professional

Call your health care provider if you have symptoms of cystitis, or if you have already been diagnosed and symptoms get worse. You should also call if new symptoms develop, particularly fever, back pain, stomach pain, or vomiting.


Keeping the genital area clean and wiping from front to back may reduce the chance of introducing bacteria from the rectal area to the urethra.

Drink plenty of fluids to allow for frequent urination to flush the bacteria from the bladder.

Urinating immediately after sexual intercourse may help eliminate any bacteria that may have been introduced during intercourse. If you do not urinate for a long period of time, the bacteria has time to multiply. Frequent urinating may reduce risk of cystitis in those who are prone to urinary tract infections.

Drinking cranberry juice prevents certain types of bacteria from attaching to the wall of the bladder and may reduce your risk of infection.


Norrby SR. Approach to the patient with urinary tract infection. In: Goldman L, Ausiello D, eds. Cecil Medicine. 23rd ed. Philadelphia, Pa: Saunders Elsevier; 2007:chap.306

Foster RT Sr. Uncomplicated urinary tract infections in women. Obstet Gynecol Clin North Am. 2008 Jun;35(2):235-48, viii.

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Review Date: 9/18/2008
Reviewed By: Linda Vorvick, MD, Seattle Site Coordinator, Lecturer, Pathophysiology, MEDEX Northwest Division of Physician Assistant Studies, University of Washington School of Medicine. Also reviewed by David Zieve, MD, MHA, Medical Director, A.D.A.M., Inc.
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