Interstitial Cystitis: Enhancing Early Identification in Primary Care Settings

Brittany N. Heck, FNP, MSN

Disclosures

Journal for Nurse Practitioners. 2007;3(8):509-519. 

In This Article

Diagnostic Workup

Several diagnostic tools are available to assist clinicians in reaching a diagnosis of IC and PBS. Although none of these tests is considered exclusively diagnostic, their use in conjunction with history and findings on physical examination can help rule out other similar conditions and enhance early diagnosis of IC and PBS in the clinical setting.

Cystoscopy with Hydrodistention

Until recently, cystoscopy with hydrodistention of the bladder was considered the "gold standard" for the diagnosis of IC and PBS. The practice of cystoscopy with hydrodistention was widely adopted in response to the clinical and cystoscopic criteria presented by the National Institutes of Health, National Institute of Diabetes and Digestive and Kidney Diseases. The presence of glomerulations (pinpoint hemorrhages) or classic Hunner ulcer (reddened mucosa with a central scar) were thought necessary to confirm diagnosis.[34] As the criteria were being implemented in clinical practice, it became clear that the criteria were too strict, and, when applied, they frequently missed the diagnosis in patients who actually did have IC and PBS. More recently, Nickel et al[33] found that Hunner ulcers occur in less than 10% of patients with IC and PBS and only 50% of patients may have glomerulations. As a result, cystoscopy with hydrodistention is no longer used to diagnose cases of IC and PBS. However, cystoscopy with hydrodistention is indicated in patients who present with hematuria, abnormal cytology results, or both, because these findings may indicate the presence of a malignancy.[27]

Urodynamic Studies

Urodynamic testing in the diagnostic workup for IC and PBS is not recommended. In the past urodynamic studies were helpful in identifying patients who displayed reduced bladder capacities in relation to the disease process; however, evidence supports that early cases of IC and PBS rarely present with a reduction in bladder capacity.[35] However, urodynamic studies may distinguish difficult cases of painful voiding disturbances or OAB from IC and PBS.[36]

Potassium Sensitivity Test

The PST is based on the theory that patients with IC and PBS have a dysfunctional bladder epithelium, leading to increased potassium diffusion into the underlying tissues. One investigation found that 80% of patients with IC and PBS test positive on the PST.[24] The PST begins with instilling sterile water into the bladder and having patients rate the degree of pain or urgency on a scale from 0 to 5, to obtain a baseline score. After the water is drained, potassium chloride is then instilled into the bladder; patients who test positive report an increase in the baseline score by two or more points. Clinicians should be aware that patients with UTIs and radiation cystitis are expected to have a 100% false-positive rate on the PST.[36] Findings from the history and physical examination can assist clinicians in differentiating between IC and PBS and UTI and radiation cystitis. Findings suggest that a positive PST is strongly correlated with higher patient PUF scores,[24] which supports the use of the questionnaire as an effective screening tool within the clinical setting.

Intravesical Anesthetic Challenge Test

The anesthetic challenge test is a relatively new diagnostic procedure to identify patients with IC or PBS. The pain experienced in patients with IC or PBS stems from the bladder; however, in light of the variable symptom presentation, this may not always be clear. The anesthetic challenge test consists of instilling an anesthetic lidocaine-bicarbonate solution into the bladder of suspected patients with IC and PBS and waiting to determine whether there is a resulting reduction in pain.[37] Preliminary studies show this solution quickly improves pain symptoms in patients with IC and PBS, with pain scores decreasing from 6 before treatment to 1.8 after treatment.[38] A positive test in patients with IC and PBS, namely a reduction of pain sensation, may help clinicians identify the bladder as the source of pain and assist in differentiating IC and PBS from other diagnoses. However, further research is needed to assess the efficacy of the anesthetic challenge test, because it is not currently validated as a diagnostic test for IC.

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