Interstitial cystitis is noninfectious bladder inflammation that causes pain (suprapubic, pelvic, and abdominal), urinary frequency, and urgency with incontinence. Diagnosis is by history and exclusion of other disorders clinically and by cystoscopy and biopsy. With treatment, most patients improve, but cure is rare. Treatment varies but includes dietary changes, bladder training, pentosan, analgesics, and intravesical therapies.
Incidence of interstitial cystitis is unknown, but the disorder appears to be more common than once thought and may underlie other clinical syndromes (eg, chronic pelvic pain). Whites are more susceptible, and 90% of cases occur in women.
Cause is unknown, but pathophysiology may involve loss of protective urothelial mucin, with penetration of urinary K and other substances into the bladder wall, activation of sensory nerves, and smooth muscle damage. Mast cells may mediate the process, but their role is unclear.
Symptoms and Signs
Interstitial cystitis is initially asymptomatic, but symptoms appear and worsen over years as the bladder wall is damaged. Suprapubic and pelvic pressure or pain occurs, usually with urinary frequency (up to 60 times/day) or urgency. These symptoms worsen as the bladder fills and diminish when patients void; in some people, symptoms worsen during ovulation, menstruation, seasonal allergies, physical or emotional stress, or sexual intercourse. Foods with high K content (eg, citrus fruits, chocolate, caffeinated drinks, tomatoes) may cause exacerbations. Tobacco, alcohol, and spicy foods may worsen symptoms. If the bladder wall becomes scarred, bladder compliance and capacity decrease, causing or worsening urinary urgency and frequency.
Diagnosis is suggested by symptoms after testing has excluded more common disorders that cause similar symptoms (eg, UTIs, pelvic inflammatory disease, chronic prostatitis or prostatodynia, diverticulitis). Cystoscopy is necessary and sometimes reveals benign bladder (Hunner) ulcers; biopsy is required to exclude bladder cancer. Assessment of symptoms with a standardized symptom scale or during intravesical KCl infusion (K sensitivity testing) may improve diagnostic accuracy but is not yet routine practice.
Up to 90% of patients improve with treatment, but cure is rare. Treatment should involve avoidance of tobacco, alcohol, foods with high K content, and spicy foods as well as bladder training, drugs, intravesical therapies, and surgery as needed. Stress reduction and biofeedback (to strenghten pelvic floor muscles, eg, with Kegel exercises) may help. No treatment has been proved effective, but a combination of ≥ 2 nonsurgical treatments is recommended before surgery is considered.
The most commonly used drug is pentosan polysulfate sodium, a heparin-like molecule similar to urothelial glycosaminoglycan; doses of 100 mg po tid may help restore the bladder's protective surface lining. Improvement may not be noticed for 2 to 4 mo. Intravesical instillation of 15 mL of a solution containing 100 mg of pentosan or 40,000 units of heparin plus 80 mg of lidocaine and 3 mL of Na bicarbonate may benefit patients unresponsive to oral drugs. Tricyclic antidepressants (eg, imipramine 25 to 50 mg po once/day) and NSAIDs in standard doses may relieve pain. Antihistamines (eg, hydroxyzine 10 to 50 mg once before bedtime) may help by directly inhibiting mast cells or by blocking allergic triggers.
Dimethyl sulfoxide instilled into the bladder through a catheter and retained for 15 min may deplete substance P and trigger mast cell granulation; 50 mL q 1 to 2 wk for 6 to 8 wk, repeated as needed, relieves symptoms in up to one half of patients. Intravesical instillation of BCG and hyaluronic acid are under study.
Bladder hydrodistention, cystoscopic resection of a Hunner's ulcer, and sacral nerve root (S3) stimulation help some patients.
Surgery (eg, partial cystectomy, bladder augmentation, neobladder, and urinary diversion) is a last resort for patients with intolerable pain refractory to all other treatments. Outcome is unpredictable; in some patients, symptoms persist.
Last full review/revision November 2012 by Patrick J. Shenot, MD