Small fiber neuropathy (SFN) affects the unmyelinated Aδ and C fibers, which are responsible for pain transmission and autonomic function. Since, due to the expertise of our collaborating neurologist/pain specialist, our pelvic health center sees a high volume of patients with known SFN, the current study assesses differences in systemic and pelvic symptoms at presentation in patients with a known history of small fiber neuropathy at presentation.

All patients presenting to our institution’s subspecialty Urogynecology and Reconstructive Pelvic Surgery (URPS) and Multidisciplinary Pelvic Pain Clinics were requested to complete an electronic multidisciplinary intake questionnaire, consisting of history, validated measures, and review of systems (ROS) including neurological and autonomic ROS. Patients reporting a history of SFN had undergone a comprehensive neurological workup with a neurologist subspecialized in pain management, leading to a positive skin biopsy to confirm the diagnosis. Comparisons were made among  those with without SFN in 1) the general subspecialized presenting population 2) those reporting presence of pelvic (bladder, bowel, sexual, pain) symptoms and 3) those reporting pelvic pain.

Statistical analysis included t-tests for continuous variable comparison and chi-squared tests and Fisher's exact tests for categorical variable comparison.

The results are viewable in Table 1, Table 2 and Table 3

22 of 600 patients (3.7%) reported a known diagnosis of SFN at presentation. The average age with and without SFN were 46 ± 15 year vs. 54 ± 18 years, respectively.

Patients with SFN had significantly higher POPDI-6 (40.5 ± 12.5 vs. 31.1 ± 19.1, p = 0.014) and GUPIQOL q9 scores (4.82 ± 1.18 vs. 4.25 ± 1.53, p = 0.038) compared to those without. Additionally, patients with SFN reported significantly more neurological symptoms (5.73 ± 3.22 vs. 2.04 ± 2.44, p < 0.001), localized pelvic pain sites (12.41 ± 6.14 vs. 5.59 ± 5.85, p < 0.001), extra-pelvic pain sites (6.91 ± 3.24 vs. 2.25 ± 2.45, p < 0.001), and autonomic symptoms (12.09 ± 5.95 vs. 4.21 ± 4.52, p < 0.001).

Among patients with pelvic symptoms, concurrent presence of SFN was associated with higher POPDI-6  (40.5 ± 12.5 vs. 31.2 ± 19.1, p = 0.014), more autonomic symptoms (12.2 ± 6.1 vs. 4.7 ± 4.8, p = 0.001), and increased neurological symptoms (5.8 ± 3.3 vs. 2.3 ± 2.5, p < 0.001). These patients also had a higher number of localized pelvic pain sites (13.0 ± 5.7 vs. 7.1 ± 5.8, p < 0.001) and extra-pelvic pain sites (6.9 ± 3.3 vs. 2.5 ± 2.6, p < 0.001). Concurrent SFN in patients with pelvic symptoms was associated with lower orgasm intensity (2.0 ± 0.5 vs. 2.5 ± 1.0, p = 0.009).

Among patients with pain, those with SFN exhibited more autonomic (12.5 ± 6.3 vs. 5.9 ± 5.4, p < 0.001) and neurological symptoms (6.1 ± 3.2 vs. 3.1 ± 2.7, p < 0.001) compared to those without. These patients also had a higher number of localized pelvic pain sites (13.7 ± 5.5 vs. 10.9 ± 5.1, p = 0.043) and extra-pelvic pain sites (7.1 ± 3.3 vs. 3.0 ± 2.9, p = 0.001). SFN was associated with lower orgasm intensity (2.0 ± 0.5 vs. 2.4 ± 1.0, p = 0.036).

Small fiber neuropathy is an emerging condition relevant to pelvic health specialists. Symptomatology in those with SFN is more severe, even than those presenting with pelvic symptomatology for subspecialized URPS and Pain Management. SFN also increases symptom burden in patients with existing pelvic symptoms and pelvic pain.