Interstitial Cystitis (cont.)

Because the symptoms of PBS/IC are similar to those of other disorders of the urinary system and because there is no definitive test to identify PBS/IC, doctors must exclude other conditions before making a diagnosis of PBS/IC. Among the disorders to be excluded are urinary tract or vaginal infections, bladder cancer, bladder inflammation or infection caused by radiation to the abdomen, eosinophilic and tuberculous cystitis, kidney stones, endometriosis, neurological disorders, sexually transmitted diseases, urinary tract infection with small numbers of bacteria, and, in men, chronic bacterial and nonbacterial prostatitis.

Medical tests that help identify other conditions include a urinalysis, urine culture, cystoscopy, biopsy of the bladder wall and, in men, laboratory examination of prostatic secretions.

Physical examination

Physical examination of an individual with PBS/IC may reveal tenderness of the bladder either when pushing on the abdomen over the bladder (just above the pubic bone) or during the pelvic examination in women. No specific physical findings are associated with PBS/IC.

Laboratory tests

Urinalysis and urine culture. These tests can detect and identify the most common bacteria in the urine that may be causing PBS/IC-like symptoms. A urine sample is obtained either by catheterization or by the "clean catch" method. For a clean catch, the patient washes the genital area before collecting a sample of urine "midstream" in a sterile container. White and red blood cells and bacteria in the urine suggest an infection of the urinary tract that can be treated with antibiotics. If urine is sterile for weeks or months while symptoms persist, a doctor may consider a diagnosis of PBS/IC.

Culture of prostatic secretions. In men, the doctor can obtain a sample of prostatic fluid. This fluid is examined under the microscope for signs of an infection such as red and white blood cells and also can be cultured for bacteria. Prostatic infections can be treated with antibiotics.

Potassium sensitivity test. A test known as the intravesical potassium sensitivity test (PST) has been developed to evaluate the leakiness of the protective lining of the bladder. Many people with PBS/IC have an abnormal PST suggesting an overly leaky urothelium (bladder lining). In the PST test, two different solutions (sterile water and a solution of potassium) are instilled separately into the bladder. The patient rates the severity of pain and/or urgency that occur when each solution is instilled. Using a scale of 0 to 5, the test is considered abnormal (positive) if the potassium solution induces at least a pain level of "2" and causes more pain than the sterile water.

Studies using the PST have shown that 78% of people suffering from PBS/IC have an abnormal test, while only 2% of women without PBS/IC have an abnormal test. An abnormal test can be considered as proof that a person has PBS/IC if there are no other identifiable conditions that may be causing the symptoms; however, a normal test does not exclude the possibility that PBS/IC is present.

Cystoscopy under anesthesia with bladder distension. During cystoscopy, the doctor uses a cystoscope -- an instrument made of a hollow tube about the diameter of a drinking straw with several lenses and a source of light -- to look inside the bladder and urethra. The doctor will also distend or stretch the bladder to its capacity by filling it with a liquid or gas. Because bladder distension is painful in PBS/IC patients, before the doctor inserts the cystoscope through the urethra into the bladder, the patient must be given either regional or general anesthesia. Cystoscopy with distension of the bladder with fluid can detect inflammation, a thick and stiff bladder wall, and Hunner's ulcers. After the fluid has been drained from the bladder, small red spots, called glomerulations, that represent enlarged blood vessels and pinpoint areas of bleeding can be seen in the bladder's lining.

The doctor may also determine a patient's bladder capacity -- the maximum amount of liquid or gas the bladder can hold under anesthesia. (Without anesthesia, capacity is limited by either pain or a severe urge to urinate.) Most people without PBS/IC have normal or large maximum bladder capacities under anesthesia. A small bladder capacity (due to scarring) under anesthesia helps to support the diagnosis of PBS/IC.

Before the relatively recent development of the PST, cystoscopy was the best diagnostic test available for PBS/IC. However, cystoscopy has its limitations. Ulcers are generally not observed in mild or early cases of PBS/IC, and glomerulations have been observed in normal individuals without symptoms of PBS/IC. Studies also have shown that cystoscopy has a 60% rate of underdiagnosing PBS/IC. Because of these limitations, cystoscopy is recommended only to exclude other possible causes of symptoms and not as the definitive diagnostic measure in PBS/IC.

One important note is that the distension often performed with cystoscopy leads to relief of symptoms in 20%-30% of people with PBS/IC, which generally lasts for three to six months following the procedure.

Biopsy. A biopsy is a microscopic examination of a small sample of tissue. Samples of the bladder and urethra may be removed during cystoscopy and examined with a microscope later. A biopsy helps to exclude bladder cancer. It also may confirm the presence of mast cells or inflammation of the bladder wall that are consistent with a diagnosis of PBS/IC. Nevertheless, there is nothing on the biopsy that can make an absolute diagnosis of PBS/IC.

Source: MedicineNet.com
http://www.medicinenet.com/interstitial_cystitis/article.htm