Diagnosis of IC
To diagnose IC, diseases that cause similar symptoms must be ruled out.
Urine culture and urinalysis are performed to test for bacteria and signs of infection. In men, prostatic fluid may also be cultured.
A cystoscopy with hydrodistention, performed under general anesthesia, is the standard diagnostic procedure for IC. The bladder is filled to capacity with water (commonly) or gas. This allows a urologist to examine the epithelium with a small, telescopic fiber-optic camera, or scope, that is inserted through the urethra to the bladder. Glomerulations (tiny hemorrhages that are the telltale sign of IC) are revealed only following bladder distention. These petechial hemorrhages (seen below contrasted with a typical bladder) are present in 95 percent of IC cases.
Less frequently, epithelial ulcerations (Hunner's ulcers), lesions, and scars involving the bladder wall are found. Hunner's ulcers are indicative of IC, though hydrodistention is not needed to see them. A biopsy, in which a tissue sample is removed and analyzed, is performed to distinguish between ulcers and cancer and and can evaluate for the presence of mast cells with proper pathological staining, which are sometimes seen in abundance in IC-affected bladders.
Some IC sufferers do not have epithelial glomerulations or ulcers. Cystoscopy may also reveal other bladder pathologies, which can cause symptoms similar to IC.
Cystoscopy and hydrodistension are performed under anesthesia because distending the bladder of an IC sufferer is painful and otherwise causes urgent urination. However, hydrodistension may have therapeutic effects. Some patients repeat the procedure occasionally as treatment for IC because it may temporarily alleviate pain and pressure.
The potassium chloride (KCl) sensitivity test (Parsons test) is a newer procedure used increasingly to test for IC and evaluate a patient's potential response to treatments such as Elmiron that work on the bladder lining. A catheter is used to instill the bladder with a potassium chloride solution. The KCl solution is thought to reveal deficiencies in the GAG layer of the bladder wall. This test can be performed in the physician's office and typically takes less than 5 minutes to complete. Any discomfort experienced during the test is short-lasting and patients usually leave the office after the test feeling comfortable.