History/review of systems/physical examination
It is important to understand the characteristics of the patient’s pain including location, duration, character, intensity, and radiation, as well as aggravating and relieving factors. Suprapubic, midline, or generalized pelvic pain is suggestive of IC. Localized or unilateral pain symptoms may indicate focal musculoskeletal or nerve dysfunction. The practitioner should inquire about a history of recurrent bladder infections. Sometimes, these symptoms have occurred in the distant past.12 Recurrent “yeast” infection symptoms without significant discharge or vulvodynia may also represent flares of bladder pain referred to the vulva.13
The review of systems of the pelvic organs is especially important. Clinical diagnosis of other pelvic pain conditions is common in patients with IC.11 Patients should be screened for symptoms of endometriosis (cyclic symptoms, dyspareunia), IBS (constipation, diarrhea), and fibromyalgia (headache, migraine, other chronic pain).
Finally, a history of sinus allergy symptoms, asthma, and autoimmune conditions are common in patients with IC and can help direct therapy. This focused review of systems can be completed quickly, and higher numbers of positive responses increase the likelihood that a particular patient has IC.
The pelvic exam can also provide clues to the diagnosis of IC. The clinician should start with a single-handed rather than a bimanual exam to exclude the muscles of the lower abdominal wall in the evaluation. Bladder base tenderness and/or bilateral levator tenderness (ie, pelvic floor dysfunction) is common in patients with IC. If the abdominal or pelvic exam reveals focal muscle tenderness, ilioinguinal or pudendal nerve blocks may be helpful. Anesthetic blocks, although not actually a direct treatment for IC, can be very helpful for patients with focal muscle findings. Improvement in symptoms from nerve blocks would suggest an alternative diagnosis, as IC is often a diagnosis of exclusion.
Laboratory and ancillary testing
Urinalysis with microscopy should be performed in all patients with suspected IC to exclude infection and hematuria. A urine culture should be performed if the urinalysis suggests UTI.10 For patients with persistent microscopic hematuria and negative urine cultures, consider work-up using AUA guidelines, which include serum creatinine, computed tomographic urogram, and cystoscopy (see Resources).
The potassium sensitivity test (PST) was developed to aid in the diagnosis of IC. It is based on the hypothesis that an abnormally permeable urothelium allows diffusion of potassium into the bladder wall, where it causes characteristic symptoms. Although the PST can be useful, false-positive and false-negative results are possible, and the test can be uncomfortable and irritating for the patient. Thus, it is no longer recommended for routine diagnosis of IC.11,14 An easier test, the anesthetic bladder challenge (ABC) or bladder instillation, is now used by many experts.15 This test/treatment can be administered quickly and easily during a patient’s first visit, and it avoids the discomfort associated with the PST.
For patients with a PUF questionnaire score greater than 10 to 15, and a history, review of symptoms, and exam suggestive of IC, administering the ABC as a confirmatory test should be considered. Typical supplies, medications, and administration are detailed in Table 2. This mixture can be prepared and administered in just a few minutes. As it can precipitate, the mixture should be used within 24 to 48 hours.
Patients should be told to schedule a follow-up visit to confirm the diagnosis. They should also be encouraged to monitor their response to the ABC and learn about IC through online or printed resources. In the absence of infection, temporary improvement in symptoms for several hours or days after administration of the ABC can be used to support the diagnosis and justify the initiation of therapy.10 Once IC is diagnosed, multimodal therapy can be initiated as outlined in the following section. For patients with more subtle symptoms or response to the ABC, administering 3 to 4 ABCs over several weeks can be considered to establish a diagnosis prior to initiating therapy. Separate visits for diagnosis and initiation of treatment can be helpful for patients and practitioners alike.