Dr. med. Dirk Manski

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Bladder infection (bacterial cystitis)

Review literature: (Fihn, 2003) (Krieger, 2003).


Bacterial cystitis is a common infection of the urinary bladder. Bladder infection is considered uncomplicated in the absence of anatomical abnormalities, bladder catheters or other urological implants or urological procedures have not been performed. The diagnostic work-up and treatment differs between uncomplicated and complicated bladder infection.

Epidemiology of Bladder Infection

20–30% of adult women have one or more times per year an episode of dysuria, bacterial bladder infection accounts for half of the cases. The prevalence rate of asymptomatic bacteriuria in sexually active women (20–45 years) lies around 5%, of which 8% develop a symptomatic urinary tract infection (compared to 1% without preexisting asymptomatic bacteriuria).

Etiology (Causes) of Bladder Infection

Principles, pathogenesis and causes of UTI see section urinary tract infection.

Gram-negative pathogens

E. coli, Klebsiella, Enterobacter, Serratia, Pseudomonas, Proteus mirabilis and other gram-negative coliform bacteria in 80%.

Gram-positive pathogens

Staphylococcus aureus, Staph. saprophyticus, Enterococci.



Pathology of Bacterial Cystitis

In the early stages of acute cystitis the bladder wall shows hyperemia, edema and infiltration by neutrophil granulocytes. In later stages, the mucosa is replaced by easily vulnerable granulation tissue. Small ulcers may develop. The lamina muscularis is usually not involved by the inflammation. Without treatment, hemorrhage and necrosis are possible.

Signs and Symptoms

Diagnosis of Bladder Infection

Diagnostic Work-up of Uncomplicated Cystitis in Healthy Women

Healthy women with typical symptoms for bacterial cystitis (dysuria and urinary frequency without vaginal discharge) may be treated with antibiotics with no further diagnostic work-up. Urinalysis, urine culture or imaging are not absolutely necessary, since the probability for bacterial cystitis is over 70%, and the diagnostic accuracy will not improve with further work-up [DGU (2009) S3-guideline for UTI].

Diagnostic Work-up of Bladder Infections


Urinalysis is performed with a dip stick and/or microscopic examination of the urine. Signs of a bladder infection are pyuria, bacteriuria, hematuria or a positive nitrite test.

Urine culture:

A urine culture is recommended in complicated UTI, for cystitis in men, pregnant women or postmenopausal women after unsuccessful treatment or with diabetes mellitus. 105 colony-forming units CFU/ml in a cleanly collected midstream urine indicate a UTI (Kass, 2002). A colony count from 103–104 CFU/ml may be significant in patients with typical symptoms and if typical uropathogens in pure culture (no mixed bacterial growth) are found. Forced diuresis or pollakiuria lead to a shorter retention time of the urine in the urinary bladder and can thus result in false-low bacterial counts despite UTI. Bacterial growth in a urine sample collected by catheterization or urinary bladder puncture is always pathological.

Ultrasound imaging of bladder and kidneys:

Renal ultrasound: Obstructive uropathy? Anatomical variants? Bladder ultrasound: Postvoid residual volume? Diverticula of the bladder? Bladder stones?

Vaginal examination:

Vaginal discharge should initiate a vaginal examination to diagnose vaginitis or pelvic inflammatory disease, and swabs for microbiological diagnosis are collected.

Intravenous urography:

IVU is an option in recurrent cystitis to diagnose e.g. infection stones, obstructive uropathy, diverticula or ureterocele of the bladder.


Cystoscopy should be considered in recurrent cystitis and for differential diagnosis of hematuria (after treated acute bladder infection).

Voiding cystourethrogram:

VCUG for patients with recurrent cystitis or pyelonephritis to exclude vesicoureteral reflux.

Differential Diagnosis of Bladder Infection

Index: 1–9 A B C D E F G H I J K L M N O P Q R S T U V W X Y Z


Fihn 2003 FIHN, S. D.:
Clinical practice. Acute uncomplicated urinary tract infection in women.
In: N Engl J Med
349 (2003), Nr. 3, S. 259–66

Krieger 2003 KRIEGER, J. N.:
Urinary tract infections: what’s new?
In: J Urol
168 (2003), S. 2351–58.