What is the diagnostic approach for a patient presenting with symptoms suggestive of interstitial cystitis, such as pelvic pain, urinary frequency, and urgency?

Diagnostic Approach for Interstitial Cystitis/Bladder Pain Syndrome

Interstitial cystitis (IC/BPS) is diagnosed clinically based on bladder/pelvic pain with urinary frequency and urgency lasting at least 6 weeks, with negative urine cultures and exclusion of other identifiable causes—cystoscopy is reserved only for suspected Hunner lesions or when diagnosis is uncertain. 1, 2

Essential Clinical Criteria

The diagnosis requires three core elements present for at least 6 weeks: 1, 2

• Bladder or pelvic pain, pressure, or discomfort perceived to be related to the urinary bladder 2, 3
• Lower urinary tract symptoms including urinary frequency, nocturia, and urgent desire to void 2, 3
• Documented negative urine cultures with absence of infection or other identifiable causes 1, 2

Pain typically worsens with bladder filling and improves with urination, and patients often describe "pressure" rather than pain, so use broad descriptors when evaluating symptoms. 3

Step-by-Step Diagnostic Algorithm

1. History Documentation

Document the following specific symptom characteristics: 1

• Number of voids per day and sensation of constant urge to void 1
• Location, character, and severity of pain, pressure, or discomfort 1
• Dyspareunia in women and ejaculatory pain in men 1
• Relationship of pain to menstruation in women 1
• Exacerbating factors such as specific foods or drinks 3

2. Physical Examination

Perform a focused examination including: 1, 2

• Brief neurological exam to rule out occult neurologic problems 1, 2
• Evaluation for incomplete bladder emptying to rule out occult retention 1, 2
• Pelvic examination to exclude other causes of pelvic pain 1

3. Mandatory Laboratory Testing

Order the following tests for all patients: 2

• Urinalysis and urine culture (even if urinalysis is negative, culture may detect lower bacterial levels not identifiable on dipstick) 1, 2
• Urine cytology if the patient has a smoking history or unevaluated microhematuria 1, 2

4. Baseline Symptom Measurement

Use validated tools to establish baseline values for treatment monitoring: 1, 2

• One-day voiding log (at minimum) to establish low-volume frequency voiding pattern characteristic of IC/BPS 1, 2
• Pain assessment using Genitourinary Pain Index (GUPI), Interstitial Cystitis Symptom Index (ICSI), or Visual Analog Scale (VAS) 1, 2

Very low voiding frequencies or high voided volumes should prompt a diligent search for an alternate diagnosis. 1

When to Perform Cystoscopy

Cystoscopy is NOT routinely necessary for uncomplicated presentations, as the benefits/risks ratio is unfavorable for younger patients who have much lower prevalence of Hunner lesions. 1, 4

Perform cystoscopy only in these specific situations: 1, 2, 4

• Suspected Hunner lesions (the only consistent cystoscopic finding diagnostic for IC/BPS and the only reliable way to diagnose them) 1, 2, 4
• Diagnosis is in doubt or unclear abnormal findings from previous cystoscopy 1, 2
• To exclude bladder cancer, bladder stones, or intravesical foreign bodies 1, 2
• Proper hematuria workup in patients with unevaluated hematuria or tobacco exposure 1

When Hunner lesions are suspected, perform cystoscopy early without requiring patients to fail other treatments first, as most patients with Hunner lesions will respond to treatment. 1, 4

When to Perform Urodynamics

Urodynamics are NOT recommended for routine diagnosis, as there are no agreed-upon urodynamic criteria diagnostic for IC/BPS. 1, 2

Consider urodynamics only when: 1, 2

• Suspicion of outlet obstruction in either sex 1, 2
• Possibility of poor detrusor contractility 1, 2
• Other conditions that could explain why patients are refractory to behavioral or medical therapies 1, 2

Tests to Avoid

Do not perform the potassium sensitivity test, as it lacks specificity and sensitivity to change clinical decision-making. 2

Critical Differential Diagnoses to Exclude

Rule out these conditions that can mimic IC/BPS: 1, 2, 3

• Urinary tract infections (documented negative cultures required) 1, 2
• Bladder cancer (especially in smokers or those with hematuria) 1, 2
• Bladder stones and intravesical foreign bodies 1, 2
• Endometriosis 2
• Chronic pelvic pain from other causes 2
• Overactive bladder without pain (IC/BPS patients void to avoid/relieve pain, not to avoid incontinence) 2, 3
• Chronic prostatitis/chronic pelvic pain syndrome in men (shares similar characteristics; some men may meet criteria for both) 3

Common Diagnostic Pitfalls

Avoid these errors that delay diagnosis or lead to inappropriate treatment: 3, 4

• Using research or clinical trial definitions in clinical practice rather than the clinical diagnostic criteria 3
• Treating with antibiotics when no infection is present, which leads to antibiotic resistance and disruption of protective flora 3
• Confusing glomerulations with Hunner lesions—glomerulations are non-specific findings that can occur in asymptomatic patients 4
• Performing cystoscopy on every IC/BPS patient, which has an unfavorable benefit/risk ratio in younger patients 1, 4
• Requiring patients to fail multiple treatments before performing cystoscopy when Hunner lesions are suspected, which delays definitive diagnosis and effective treatment 4