Diagnosis of exclusion: symptoms should guide interstitial cystitis Tx.(Gynecology)

NEW ORLEANS -- Interstitial cystitis is a commonly missed diagnosis, Dr. Joslyn Fisher said at the annual meeting of the American College of Physicians.

As a cause of chronic pelvic pain in women, interstitial cystitis (IC) presents a major clinical conundrum. Because the disease lacks a specific marker, the diagnosis is made when all else--including recurrent urinary tract infections, endometriosis, overactive bladder, fibromyalgia, and prior or current sexual abuse--is ruled out, said Dr. Fisher of Baylor College of Medicine and Ben Taub General Hospital, Houston.

Interstitial cystitis affects about 700,000 people in the United States, but that number may be a vast underestimate, depending on how the condition is defined. In 1988, the National Institute of Diabetes, Digestive, and Kidney Diseases established research criteria for IC: There must be pain, urgency, and frequency, as well as glomerulations (pinpoint bleeding from bladder distension,) or Hunner's ulcer on cystoscopy; in addition, 13 more conditions, including other types of cystitis, must be excluded (J. Urol. 140[1]:203-06, 1988).

The clinical usefulness of the NIDDK criteria is debated. Even urologists are avoiding cystoscopy, which is invasive and not specific or sensitive. Recent data suggest that glomerulations are seen in as many as half of women without IC, whereas Hunner's ulcer occurs in fewer than 10% of women with IC.

Other invasive diagnostic tests are advised only if there is a specific concern. For example, biopsy is recommended to rule out bladder cancer, urodynamics for suspected detrusor instability, and pelvic/vaginal ultrasound to look for fibroids.

A new tool called the Pelvic Pain and Urgency/Frequency (PUF) scale has been shown to predict the likelihood that a woman would test positive on a potassium sensitivity test (PST) performed via cystoscopy, in which instillation of potassium chloride during hydrodistension causes pain in those with IC.

The PUF ...