Interstitial Cystitis (cont.)
Melissa Conrad Stöppler, MD
Melissa Conrad Stöppler, MD
Melissa Conrad Stöppler, MD, is a U.S. board-certified Anatomic Pathologist with subspecialty training in the fields of Experimental and Molecular Pathology. Dr. Stöppler's educational background includes a BA with Highest Distinction from the University of Virginia and an MD from the University of North Carolina. She completed residency training in Anatomic Pathology at Georgetown University followed by subspecialty fellowship training in molecular diagnostics and experimental pathology.
In this Article
How is interstitial cystitis diagnosed?
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 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.
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
The doctor may also determine a patient's bladder
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.
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