Small Fiber Polyneuropathy May Be a Nexus Between Autonomic Nervous System Dysregulation and Pain in Interstitial Cystitis/Bladder Pain Syndrome.

Dylan T Wolff,Stephen J Walker

doi:10.3389/fpain.2021.810809

Abstract

Interstitial cystitis/bladder pain syndrome (IC/BPS) is a highly heterogeneous chronic and debilitating condition which effects millions of women and men in the United States. While primarily defined by urinary symptoms and pain perceived to be emanating from the bladder, IC/BPS patients frequently have co-occurring conditions and symptoms, many of which affect diverse body systems related to autonomic nervous system function. The impact on the autonomic system appears to stem from increased sympathetic innervation of the urinary tract, along with increased systemic sympathetic tone and decreased parasympathetic tone. Concurrent with these findings is evidence for destruction of peripheral sympathetic innervation to the sweat glands which may relate to small fiber polyneuropathy. It is unknown to what degree the wider alterations in autonomic function are also related to destruction/alterations in the small fibers carrying autonomic innervation. This potential nexus is an important point of investigation to better understand the unclarified pathophysiology of interstitial cystitis/bladder pain syndrome, the numerous co-occurring symptoms and syndromes, and for the identification of novel targeted therapeutic strategies.

Highlights

Interstitial cystitis/bladder pain syndrome (IC/BPS) is a debilitating chronic affliction characterized by bladder pain of unspecified origin
Bladder pain is the defining characteristic, IC/BPS frequently co-occurs with numerous nonurological symptoms and syndromes including psychiatric disorders such as depression, vague
Many of the symptomatic and functional changes described in patients with IC/BPS are related to the autonomic nervous system, i.e., the system responsible for the regulation of a wide variety of bodily systems and functions (Figure 1)

Summary

Introduction

Interstitial cystitis/bladder pain syndrome (IC/BPS) is a debilitating chronic affliction characterized by bladder pain of unspecified origin. Dysautonomia in Interstitial Cystitis symptoms such as chronic fatigue and sleep disturbances, as well as other poorly understood chronic functional pain disorders such as irritable bowel syndrome (IBS), fibromyalgia syndrome (FMS), and migraines [5]. The clustering of these comorbidities, along with evidence stemming from physiologic and anatomic studies, including the high frequency of small fiber polyneuropathy (SFPN) [6], point to widespread neurologic abnormalities in this patient population. The objective of this review is to highlight and discuss the evidence for autonomic system dysregulation in IC/BPS patients and to explore the potential link between dysautonomia and SFPN

Objectives

Findings

Conclusion