Bladder infection (bacterial cystitis)

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

Definitions

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.

Fungi

Candida.

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

• Irritable bladder symptoms: dysuria, urinary frequency, urinary urgency, sometimes urge incontinence.
• Suprapubic pain
• Cloudy urine or hematuria
• Complication: Ascension of the pathogens with pyelonephritis, risk factors are vesicoureteral reflux and pregnancy.

Diagnosis of Bladder Infection

Diagnostic Work-up of Uncomplicated Cystitis in Premenopausal Women

Premenopausal 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:

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.

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 obtained.

Intravenous urography:

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

Cystoscopy:

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

Micturition cystourethrogram:

In recurrent cystitis or pyelonephritis MCUG should exclude vesicoureteral reflux.

Differential Diagnosis of Bladder Infection

• Vulvovaginitis
• Genital herpes
• Urethritis, gonorrhea
• Acute urethral syndrome: symptoms suggestive of bladder infection, but in the absence of significant bacteriuria
• Urinary tract infections like pyelonephritis or acute prostatitis.
• Pelvic irradiation
• Trauma: urethral irritation after sexual intercourse, after urethral manipulations, foreign body in the urinary bladder.
• Chemotherapy with cyclophosphamide
• Interstitial cystitis
• Neurogenic bladder dysfunction
• Bladder cancer
• Psychosomatic disorder

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References

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.