Genes
Some genetic subtypes, in some people, have been linked to the disorder. An antiproliferative factor is secreted by the bladders of people with IC/BPS which inhibits bladder cell proliferation, thus possibly causing the missing bladder lining. PAND, at gene map locus 13q22–q32, is associated with a constellation of disorders (a "pleiotropic syndrome") including IC/BPS and other bladder and kidney problems, thyroid diseases, serious headaches/migraines, panic disorder, and mitral valve prolapse. Diagnosis
A diagnosis of IC/BPS is one of exclusion, as well as a review of clinical symptoms. The American Urological Association Guidelines recommend starting with a careful history of the person, physical examination and laboratory tests to assess and document symptoms of interstitial cytitis, as well as other potential disorders. The KCl test, also known as the potassium sensitivity test, is no longer recommended. The test uses a mild potassium solution to evaluate the integrity of the bladder wall. Though the latter is not specific for IC/BPS, it has been determined to be helpful in predicting the use of compounds, such as pentosan polysulphate, which are designed to help repair the GAG layer.For complicated cases, the use of hydrodistention with cystoscopy may be helpful. Researchers, however, determined that this visual examination of the bladder wall after stretching the bladder was not specific for IC/BPS and that the test, itself, can contribute to the development of small glomerulations (petechial hemorrhages) often found in IC/BPS. Thus, a diagnosis of IC/BPS is one of exclusion, as well as a review of clinical symptoms.
There is also some evidence of an association between urologic pain syndromes, such as IC/BPS and CP/CPPS, with non-celiac gluten sensitivity in some people.In addition, men with IC/PBS are frequently diagnosed as having chronic nonbacterial prostatitis, and there is an extensive overlap of symptoms and treatment between the two conditions, leading researchers to posit that the conditions may share the same cause and pathology. Causes
The cause of IC/BPS is not known. However, several explanations have been proposed and include the following: autoimmune theory, nerve theory, mast cell theory, leaky lining theory, infection theory, and a theory of production of a toxic substance in the urine. Other suggested etiological causes are neurologic, allergic, genetic, and stress-psychological. In addition, recent research shows that those with IC may have a substance in the urine that inhibits the growth of cells in the bladder epithelium. An infection may then predispose those people to develop IC. Evidence from clinical and laboratory studies confirms that mast cells play a central role in IC/BPS possibly due to their ability to release histamine and cause pain, swelling, scarring, and interfere with healing. Research has shown a proliferation of nerve fibers is present in the bladders of people with IC which is absent in the bladders of people who have not been diagnosed with IC.Regardless of the origin, most people with IC/BPS struggle with a damaged urothelium, or bladder lining. When the surface glycosaminoglycan (GAG) layer is damaged (via a urinary tract infection (UTI), excessive consumption of coffee or sodas, traumatic injury, etc.