Small Fiber Polyneuropathy in Hunner Lesion and Non-Hunner Lesion Interstitial Cystitis/Bladder Pain Syndrome.

OBJECTIVE

This study aimed to determine whether small fiber polyneuropathy (SFPN) diagnosis differs between Hunner lesion interstitial cystitis/bladder pain syndrome (HL IC/BPS) and non-Hunner lesion IC/BPS (NHL IC/BPS).

METHODS

This was a pilot study of 20 women with IC/BPS. Results from baseline questionnaires, such as Genitourinary Pain Index, Interstitial Cystitis Symptom Index/Interstitial Cystitis Problem Index (ICSI/ICPI), Patient Health Questionnaire-2, were collected.Two punch biopsies were performed on each patient: distal leg and thigh. The samples were evaluated for intraepidermal nerve fiber density. One intraepidermal nerve fiber density less than the fifth percentile, regardless of site, indicated a positive SPFN diagnosis.

RESULTS

Twenty patients were enrolled; 10 HL IC/BPS and 10 NHL IC/BPS. The HL IC/BPS group was found to be significantly older than the NHL IC/BPS group (63 vs 48 years, P = 0.007). No significant differences were found in employment or relationship statuses, or in levels of education or comorbidities between the 2 groups.Sixty percent (6/10) of patients had SFPN in the NHL IC/BPS group compared with 40% (4/10) in the HL IC/BPS group. No significant differences were seen in SFPN positivity (P = 0.3) or Genitourinary Pain Index, Patient Health Questionnaire-2, or Interstitial Cystitis Symptom Index/Interstitial Cystitis Problem Index scores between the NHL and HL IC/BPS groups.

CONCLUSIONS

Similar to previously published studies, 60% of NHL IC/BPS patients in this cohort were positive for SFPN compared with only 40% of the HL IC/BPS patients. Larger studies may be needed to realize the full impact of SFPN in IC/BPS.