CHAPTER 26 Interstitial Cystitis and Other Inflammatory Conditions of the Lower Urinary Tract
How common is interstitial cystitis (IC) in the United States?
Two large studies have estimated the prevalence of IC. The National Health Interview Study (NHIS) reports the overall prevalence at 500 per 100,000 population and 865 per 100,000 women. The third National Health and Nutrition Examination Survey (NHANES III) reports a prevalence of 470 per 100,000 population and 850 per 100,000 women. This equates to 83,000 men and 1.2 million US women with IC.
What is the term preferred by the International Continence Society (ICS) for IC?
ICS prefers the term Painful Bladder Syndrome (PBS) defined as “the complaint of suprapubic pain related to bladder filling, accompanied by other symptoms such as increased daytime and night-time frequency, in the absence of proven urinary infection or other obvious pathology.”
Are there racial differences in the prevalence of IC?
Yes. 94% of patients are Caucasian.
What percentage of patients with IC are female?
90%.
Is the incidence of childhood bladder problems increased in patients with IC?
Yes. The incidence is 10 times higher in patients with IC than controls.
What is the natural history of IC?
Median presentation is at age 40. Spontaneous remission occurs in up to 50% of patients at a mean of 8 months. Patients may have complete and spontaneous relief from the symptoms, have a waxing and waning course, may be completely asymptomatic with intermittent “flares,” or have a chronically progressive course of increasing symptoms over several years.
What is the etiology of IC?Unknown. The most commonly cited hypotheses include (1) a pathogenic role of mast cells in the detrusor and/or mucosal layers of the bladder as a primary or secondary process, (2) a deficiency in the glycosaminoglycan layer (GAG) on the luminal surface of the bladder resulting in increased permeability of the surface layer and thus exposure of the underlying submucosal tissues to toxic substances in the urine, (3) an infection with a poorly characterized agent such as a slow growing virus or extremely fastidious bacterium which is unable to be cultured, (4) the production of a “toxic” substance in the urine, (5) neurogenic hypersensitivity or neurogenic inflammation mediated locally within the bladder or at the level of the spinal cord, (6) a manifestation of pelvic floor muscle dysfunction or dysfunctional voiding, and (7) autoimmune disorder.
What other diseases or conditions have been associated with IC?
Allergies (41%), irritable bowel (30%), inflammatory bowel disease (7%), Sjögren syndrome, vulvar vestibulitis syndrome, systemic lupus erythematosus, fibromyalgia, and sensitive skin.
What are the characteristic voiding symptoms of patients with IC?
Irritative voiding symptoms including urinary urgency, urinary frequency (>8 times per day by national institute of diabetes & digestive & kidney diseases (NIDDK) criteria) with nocturia, and pain with negative urine cultures. Obstructive symptoms including a sensation of incomplete bladder emptying and double voiding may be present. Absence of nocturnal symptoms suggests an alternative diagnosis.
What are the 2 subgroups of IC?
IC is often divided into 2 distinct subgroups based on intraoperative findings at cystoscopy and bladder overdistension. These categories are the ulcerative (ie, classic) and nonulcerative (ie, Messing–Stamey) types.
Which of the following excludes a diagnosis of IC: endometriosis, pyuria, hematuria, bladder overactivity on urodynamics, or ureteral calculus?
None. All of these conditions may coexist in patients with IC. Each of these may be related to a cause of lower urinary tract symptoms and should be properly investigated and treated prior to making a diagnosis of IC.
What percentage of female patients with IC experience dyspareunia?
Approximately 50% to 75%; such symptoms may be related to IC or associated conditions such as endometriosis or vulvodynia.
What imaging studies are specific for IC?
No known radiographic, ultrasonographic, or other imaging findings are specific for IC. Unless indicated to help exclude alternative diagnoses, radiographic studies have only a limited role in the evaluation of IC. Cross-sectional imaging including MRI, CT scan, and pelvic sonography may be performed when clinically indicated to evaluate for a suggestive pelvic mass that is causing compression of the bladder or for an adjacent inflammatory process (eg, diverticulitis). Cystography and voiding cystourethrography may be used to evaluate the bladder for other causes of irritative lower urinary tract symptoms, including intravesical masses, stones, bladder diverticula, urethral diverticula, urethral stricture, meatal stenosis, or findings suggestive of a neurogenic or nonneurogenic voiding dysfunction.
Which urodynamic findings are common in IC?
There is no urodynamic pattern that is pathognomonic for IC. On filling cystometry, most patients have a hypersensitive bladder with small volume at first sensation to void and at capacity. Filling may be limited by an intense urge to void or pain. Bladder compliance, flow, and postvoid residual are usually normal.
What is the significance of finding detrusor overactivity on urodynamics?
Involuntary bladder contractions may be found in 14% of IC patients. This is not different from the general population. Other than excluding the patient from clinical trials adhering to the NIDDK criteria, there is no other significance.
What are the common findings at cystoscopy in patients with IC?
Prior to hydrodistention—normal appearing bladder and urethral lumen, and rarely a Hunner ulcer (found in <10% of patients).
Following hydrodistention under anesthesia—glomerulations (petechial hemorrhages), submucosal hemorrhages, mucosal cracking, and bloody effluent upon drainage (terminal pinking).
What are the findings during cystoscopy in a patient with “classic” IC as compared to the nonulcerative form of the disease?
Classic IC (10% of IC patients)—reduced capacity under anesthesia (<400 mL during hydrodistention), ulcers, scars.
Nonulcerative disease (90% patients)—capacity >400 mL, no ulcers, scars, or mucosal cracking.
What is the diagnostic utility of a bladder biopsy in IC?
Although a higher proportion of IC patients may have detrusor mastocytosis as compared to normals, there are no-specific histologic findings on bladder biopsy which are pathognomonic of IC. Bladder biopsy is performed in patients being investigated for IC in order to eliminate carcinoma in situ or occult malignancy as a cause for their lower urinary tract symptoms.
What is the significance of the NIDDK criteria for a diagnosis of IC?
These criteria were developed at a national institutes of health (NIH) sponsored consensus conference to ensure a relatively homogenous and uniform population of patients for accrual and inclusion into IC research studies. Fulfillment of these criteria is not necessary for the diagnosis of IC in clinical practice.
What is the potassium chloride (KCl) test?
This is an in-office test used by some physicians in patients suspected of having a diagnosis of IC. After the intravesical instillation of 45 mL KCl (400 mEq/L), 70% of patients with a diagnosis of IC will experience pain versus only 4% of normals. This is felt to be due to a defect in the GAG layer of the bladder in patients with IC. Other conditions such as UTI may give a false-positive result.
What is the role of hydrodistention in patients with IC?
Hydrodistention is utilized both diagnostically and therapeutically in patients being evaluated for IC. A significant number of patients have transient relief of their symptoms following hydrodistention.
Apart from IC, which conditions may manifest glomerulations following hydrodistention?
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