Cystitis, Acute (Urinary Tract Infection)

For further information, see CMDT Part 23-03: Genitourinary Tract Infections

Essentials of Diagnosis

• Irritative voiding symptoms

• Patient usually afebrile

• Positive urine culture; blood cultures may also be positive

General Considerations

• Most commonly due to the coliform bacteria (especially Escherichia coli) and occasionally gram-positive bacteria (enterococci)

• The route of infection is typically ascending from the urethra

• Uncomplicated cystitis in men is rare and implies a pathologic process such as infected stones, prostatitis, or chronic urinary retention requiring further investigation

Symptoms and Signs

• Frequency, urgency, dysuria, suprapubic discomfort, gross hematuria

• Suprapubic tenderness, no systemic toxicity

Differential Diagnosis

• In women

  • Vulvovaginitis

  • Pelvic inflammatory disease

• In men

  • Urethritis

  • Prostatitis

• In both

  • Pelvic irradiation

  • Chemotherapy (cyclophosphamide)

  • Bladder carcinoma

  • Interstitial cystitis

  • Voiding dysfunction disorders

  • Psychosomatic disorders

Laboratory Tests

• Urinalysis: pyuria, hematuria, bacteriuria

• Urine culture: positive, though colony counts > 10⁵/mL not required

• Urine culture and sensitivity

Imaging Studies

• Abdominal ultrasonography, postvoid residual testing, and cystoscopy help identify any underlying problem

• Obtain CT scan if pyelonephritis, recurrent infections, or anatomic abnormalities are suspected

Medications

• Uncomplicated cystitis: fosfomycin, nitrofurantoin, and trimethoprim-sulfamethoxazole are the medications of choice

  • Fosfomycin trometamol (3 g single dose)

  • Nitrofurantoin (100 mg twice daily for 5–7 days)

  • Trimethoprim-sulfamethoxazole (160/800 mg twice daily for 3 days)

Therapeutic Procedures

• Symptomatic relief: hot sitz baths or urinary analgesics (phenazopyridine, 200 mg three times daily orally)

• Uncomplicated cystitis in men warrants elucidation of underlying problem

Prognosis

• Infections typically respond rapidly to treatment

• Failure to respond suggests resistance to the selected drug or anatomic abnormalities requiring further investigation

Prevention

• Drinking plenty of fluid and emptying the bladder frequently and completely can reduce risk of developing infection

• Women in whom urinary tract infections tend to develop after intercourse should be advised to void before, and especially after intercourse, and may benefit from a postcoital single dose of antibiotic

• Postmenopausal women with recurrent urinary tract infections (3 or more episodes per year) may benefit from a topical estrogen cream

• Women with recurrent episodes of cystitis (3 or more episodes per year) may also benefit, after treatment of the urinary tract infection, from prophylactic antibiotic therapy to prevent recurrences

• Before starting antibiotic prophylaxis, a thorough urologic evaluation is warranted to exclude any anatomic abnormality (eg, stones, reflux, fistula)

• An initial course of 6 to 12 months of prophylactic antibiotics can be offered

• The benefits of prophylactic antibiotics should be weighed against the risks of developing bacterial resistance

When to Refer

• Suspicion or radiographic evidence of anatomic abnormality

• Evidence of urolithiasis

• Recurrent cystitis due to bacterial persistence