Interstitial cystitis/ bladder pain syndrome (IC/BPS) is defined as as “An unpleasant sensation (pain, pressure, discomfort) perceived to be related to the urinary bladder, associated with lower urinary tract symptoms of more than six weeks duration, in the absence of infection or other identifiable causes.” The AUA recommends an initial basic assessment that documents signs and symptoms of IC/BPS and excludes any other disorders that could be causing the patient’s symptoms. Symptoms are documented with history, physical examination, and laboratory tests which includes the use of voiding diaries, self-report questionnaires and symptom scores, urine analysis and urine cultures, hematuria work up and neurological examination. Cystoscopy and urodynamic studies can also be used on a case-by-case basis because these procedures are invasive and uncomfortable.  
Nevertheless, relying on noninvasive techniques to diagnose IC/BPS may lead to a misdiagnosis of IC/BPS and a delay in true primary diagnoses. Previous studies have reported that patients originally diagnosed with IC/BPS were later found to have their symptoms caused by bladder cancer, cervical cancer, pelvic radiation, and systemic chemotherapy, and at least partially caused by concomitant conditions such as bladder neck obstruction, bladder atony, pelvic floor dysfunction and neuropathically mediated pain syndromes revealed upon further testing. The aim of this retrospective study is to explore how often new patients referred with a diagnosis of interstitial cystitis at their initial visit are later discovered to have an alternate primary diagnosis. Our hypothesis is that after thorough workup, a significant proportion of those carrying the IC/BPS diagnosis will be given a neurological, anatomical, or oncological explanation for their lower urinary tract symptoms.

This is a retrospective chart review of 91 patients in a Urogynecology and Reconstructive Pelvic Surgery (URPS) practice who self-identified via an electronic intake form or who were referred in with a diagnosis of interstitial cystitis from 2022 - 2024. 51 patients had completed their evaluation at the time of data analysis; the 40 who had not completed full recommended evaluation were excluded from analysis. Notes were reviewed for physical examination (pelvic organ prolapse and pelvic floor tension myalgia), urodynamic studies, cystoscopy, neurological evaluation, MRI, EMG, skin biopsy assessing for small fiber neuropathy, and abnormal labs (urinalysis and urine culture, ureaplasma, STIs, lyme, B12, etc). Final diagnosis of interstitial cystitis - or otherwise - was the primary outcome.

Of the 51 fully evaluated patients, 15 (31%) had and 36 (69%) did not have interstitial cystitis as their final diagnosis. Some of the new diagnoses were multiple sclerosis, small fiber neuropathy, Tarlov cyst, high-tone levator dysfunction, pelvic congestion syndrome, recurrent UTI, vesicourethral reflux, cervical or lumbar spinal stenosis, ankylosing spondylitis, lupus, multiple sclerosis, post chemotherapy neuropathy, and MTHFR mutation (table 1) . Using t-test for independent samples, there was no significance in autonomic and neurological review or system tallies. Autonomic scores in reclassified were (M = 8.00, SD = 5.76) and (M = 7.00, SD = 5.76) in IC patients t(7) = 0.31, p = 0.76. Neuro scores in reclassified were (M = 3.15 SD = 2.08) and in IC patients (M = 1.80, SD = 1.10) t(14) = 1.79, p = 0.09. A chi-square test of independence was performed to examine the relation between abnormal neurological examination and reclassification of IC. The relationship was not significant, x^2 (2, n = 40) = 0.03, p = 0.86. 

Of the 36 patients who were reclassified, the urodynamic studies revealed bladder outlet obstruction, including bladder neck obstruction, reduced sensation, detrusor overactivity, detrusor external sphincter dyssynergia, mild obstruction from external urethral sphincter vs voiding dysfunction, small capacity bladder, underactive/ atonic bladder, upper motor neuropathy, dysfunctional voiding, and an obstructing cystocele (table 2).

69% of patients who self-identified or were previously diagnosed with IC/BPS were reclassified with an alternate diagnosis after selective application of physical exam, urodynamic studies, cystoscopy, neurological evaluation, EMG and/or small fiber biopsy.

This study highlights the need for continued exploration of the differential diagnosis in those presenting with a history of interstitial cystitis. When a clinician inherits patients with interstitial cystitis, it is necessary to evaluate previous records to confirm the accuracy of diagnoses and perform further workup as needed. Urologists, gynecologists, and neurologists should work as teams to assess patients with IC/BPS.

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