Reclassification of Interstitial Cystitis

Objectives: The AUA defines interstitial cystitis/ bladder pain syndrome (IC/BPS) as a diagnosis of exclusion requiring proper evaluation of any possible lower urinary tract symptoms (LUTS) disorders. Previous studies have reported patients originally diagnosed with IC/BPS who 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. The aim of this study is to explore how often new patients referred with a diagnosis of IC 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 LUTS.

Methods: This is a retrospective chart review of 91 patients who self-identified or were diagnosed with or treated for interstitial cystitis from an electronic intake form and with billing or ICD-10 codes from 2022 - 2024. 51 patients had completed their evaluation at the time of data analysis; 40 had not completed full recommended evaluation. Notes were reviewed for physical examination, UDS, cystoscopy, neurological evaluation, MRI, EMG, skin biopsy assessing for small fiber neuropathy, and abnormal labs. Final diagnosis of IC or otherwise was the primary outcome.

Results: Of the 51 fully evaluated patients, 16 (31%) had and 35 (69%) did not have interstitial cystitis as their final diagnosis. Some 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. 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, x2 (2, n = 40) = 0.03, p = 0.86.
Of the 35 patients who were reclassified, UDS revealed bladder outlet obstruction, including bladder neck obstruction, reduced sensation, detrusor overactivity, detrusor external sphincter dyssynergia, obstruction from external urethral sphincter, voiding dysfunction, small capacity bladder, underactive/ atonic bladder, upper motor neuropathy, dysfunctional voiding, and an obstructing cystocele.

Conclusions: 69% of patients who self-identified or were previously diagnosed with IC/BPS were reclassified with an alternate diagnosis after evaluation.