Interstitial Cystitis, also known as painful bladder syndrome, is a disease of the urinary bladder without a known cause that generally results in severe pelvic and bladder pain, urinary urgency and frequency, and possibly painful urination. Women aged 30-60 are most commonly affected, up to 85% of reported cases involve women between the ages of 40 and 45, and in a 2006 epidemiological report of interstitial cystitis there are early signs of disease in up to 12% of women. The diagnostic criteria that must be met in order to establish this diagnosis of interstitial cystitis are very controversial but most often include a triad of clinical findings: (1) pain or burning on urination, (2) absence of identifiable signs that indicate a different urinary tract disease or disorder, and (3) presence of a characteristic appearance on of the lining of the bladder on cystoscopy.
There are several theories on what causes interstitial cystitis. There is generally a damaged bladder lining, which is made up of a protective coat of mucin or glycosaminoglycans (GAGs). These GAGs are relatively complex polymers composed of carbohydrates (called polysaccharides) that "are friendly with water" (hydrophilic) and form micelles (roughly spherical aggregates of molecules with the hydrophilic portions that are in contact with aqueous fluids (like urine) on the outside of the spheres) that act as a barrier between the tissues lining the cavity of the bladder and urine.
A popular theory on what causes interstitial cystitis is that the GAG layer is somehow damaged which results in a leaky or permeable urinary bladder lining which then allows the underlying bladder tissues to be directly exposed to irritants within urine. The damage to the GAG layer may be the result of various conditions, such as frequent urinary tract infections, excessive consumption of caffeine in sodas or coffee, trauma, or an autoimmune disorder.
The characteristic findings on cystoscopy include petechiae, or tiny red or purple spots caused by small hemorrhages (broken capillary blood vessels), under the inner lining of the bladder wall (mucosa) that are called "glomerulations." However, researchers have found that the distention of the bladder that normally occurs during cystoscopy can also cause these glomerulations, making them a nonspecific finding (it is not diagnostic of interstitial cystitis by itself). In the most severe 5-10% of cases of interstitial cystitis there may be Hunner's ulcers, which are larger and visible wounds in the bladder lining that may need to be removed by fulgaration (burning) or cutting around the ulcer to remove it and the surrounding inflamed tissues (excision). When they are found, Hunner's ulcers are diagnostic of interstitial cystitis.
On cystometric analysis, patients with interstitial cystitis almost always have decreased bladder capacity and decreased bladder compliance. A potassium challenge test is sometimes useful, in which the patient ranks her severity of pain after her bladder is filled with 40 mL of sterile water and then with 40 mL of potassium chloride solution (at a concentration of 400 mEq/L of KCl) and the results suggest interstitial cystitis when there is no pain with sterile water but significantly more pain with the potassium solution.
Treatment of interstitial cystitis may include:
- a change in diet. Avoiding foods that may further irritate the bladder, such as coffee, tea, sodas, concentrated fruit juices, monosodium glutamate, chocolate, and bananas (since they are rich in potassium).
- bladder coatings. Instillation of astringent solutions further strip off the bladder lining and is no longer used for interstitial cystitis. Oral Elmiron is FDA approved for the treatment of interstitial cystitis since it is thought to provide a protective coating for the bladder lining, but in 2005 research unfortunately found that about 85% of Elmiron is excreted intact in feces and another approximately 5% is excreted in the urine. Bladder instillation of DMSO is FDA approved but is not very popular in urology practices since the approved concentration of 50% may cause irreversible muscle contractions and the method of action for DMSO is not fully understood. Research on other compounds for bladder instillation is active.
- pelvic floor treatments. Chronic pelvic floor tension can result from the chronic irritation of interstitial cystitis and physical therapists are actively developing protocols to treat this problem
- pain control. The pain of interstitial cystitis can be intense and may require a variety of pain medications, including narcotics. Alternative treatments such as acupuncture, biofeedback and meditation may also sometimes be valuable.