Acute cystitis is a bacterial infection of the bladder. It is a urinary tract infection (UTI) that causes urinary irregularities and other symptoms. Up to 1.3 percent of pregnant women develop acute cystitis.

Approximately 75 to 80 percent of infections are caused by a single bacterium, E. coli. Other common disease-causing agents, pathogens, include Klebsiella pneumoniae, Proteus species, group B streptococci, enterococci, and staphylococci. These organisms normally reside in the vagina, on the perineum (the area between the vagina and anus), and in the colon. Problems arise when these infections are introduced into the urethra. This can occur during sexual intercourse (honeymoon cystitis) or when wiping after a bowel movement. From there, the bacteria can ascend into the bladder.

Risk Factors

Several factors can make you more susceptible to cystitis:

  • sexual intercourse;
  • use of instruments in the urinary tract (catheterization during delivery of a baby);
  • sickle cell disease or sickle cell traits;
  • insulin-dependent diabetes; or
  • immunodeficiency disorders.

Patients with acute cystitis typically have the following urinary symptoms:

  • frequency (the need to urinate often);
  • urgency (the need to urinate immediately);
  • hesitancy (delay in starting the stream of urine);
  • dribbling; or
  • painful urination, also known as dysuria.

You may also experience hematuria (blood in your urine), a low-grade fever (99 to 101? F), or pain in the pubic area. Another condition that causes symptoms similar to those of cystitis is acute urethritis.


If not diagnosed and treated in time, acute cystitis can evolve into a kidney infection, which can dramatically increase your risk of preterm delivery-the most common cause of complications and death in newborn babies.

In non-pregnant women, acute cystitis is usually a mild infection that clears up on its own and rarely causes complications. However, in pregnancy, due to pregnant women's added susceptibility, acute cystitis may evolve rapidly into a kidney infection (pyelonephritis). Pyelonephritis, in turn, may cause preterm labor, bacterial invasion of the bloodstream (sepsis), or adult respiratory distress syndrome.

Your doctor can definitively diagnose acute cystitis by culturing (growing in a lab) a sample of your urine. However, the final result of a urine culture is not usually available for 24 to 48 hours, and you must be treated before the test result is known. Therefore, your doctor is likely to make a preliminary diagnosis of acute cystitis based on your symptoms and on the results of a simple urinalysis. Urine is best collected by catheterization (inserting a slender, hollow tube into the urethra to collect urine) and then tested with a dipstick for nitrites and leukocyte esterase-chemicals that indicate the presence of bacteria in the urine.

The first episode of acute cystitis can usually be treated with a three-day course of oral antibiotics. If you have recurrent episodes, you will be treated with 7- to 10-day courses of oral antibiotics. The following table lists the antibiotics most often used to treat acute cystitis.

Antibiotics to Treat Acute Cystitis

DrugOral Dose*Relative CostRemarks
Sulfisoxazole (Gantrisin)2 grams initially, then 1 gram 4 times dailyLowestshould not be used near the time of delivery; may aggravate neonatal jaundice
Trimethoprim-sulfamethoxazole double strength (Bactrim-DS, Septra-DS)One twice dailyLowshould not be used near the time of delivery; may aggravate neonatal jaundice
Nitrofurantoin monohy-drate macrocrystals (Macrobid)100 mg twice dailyIntermediateshould not be used in patients with glucose-6-phosphate dehy-drogenase (G6PD) deficiency; may cause hemolysis
Cephalexin (Keflex)500 mg twice dailyIntermediate to Highuse with caution if allergic to penicillin
Ampicillin or amoxicillin250-500 mg four times dailyLowmay cause diarrhea, monilia vulvovaginitis, and allergic reaction; many strains of uropathogens are now resistant; should only be used if entero coccus is the cause of infection
Amoxicillin-clavulanate (Augmentin)875 mg twice dailyHighshould be used for recurrent infections caused by resistant organisms
Quinolone antibiotics (ciprofloxacin, Cipro)500 mg twice dailyHighshould be used for recurrent infections caused by resistant organisms; should not be used in pregnancy

*Drug dosages may vary; your doctor will prescribe what is right for you.

Some women experience recurrent episodes of acute cystitis, especially after sexual intercourse. If this happens to you, you can take steps to reduce the frequency of recurrent infection. One way is to urinate as soon as possible after intercourse. This reduces the concentration of bacteria introduced into the urethra. In addition, talk to your doctor about using antibiotics as a preventive measure. Preventive antibiotics may be taken in one of two ways:

  • in a single dose taken immediately after coitus; or
  • in a three-day course taken at the first onset of symptoms. Sulfisoxazole (Gantrisin), trimethoprim-sulfamethoxazole-double strength (Bactrim-DS, Septra-DS), and nitrofurantoin monohydrate macrocrystals (Macrobid) are all excellent choices for prophylaxis (see table).