Autonomic Testing in Women with Chronic Pelvic Pain

Abstract

Purpose Determine if abnormal autonomic nervous system (ANS) innervation of the bladder underlies interstitial cystitis/bladder pain syndrome (IC/BPS) differently than other chronic pelvic pain (CPP). Material and Methods IRB approved protocol, 134 subjects enrolled, 3 excluded, 39 healthy controls (HC), 36 IC/BPS, 14 myofascial pelvic pain (MPP), 42 IC/BPS plus MPP. ANS evaluations: deep breathing, Valsalva maneuver, tilt table test (TTT), and sudomotor test (evaluates for autonomic neuropathy (AN)). A modified validated composite autonomic laboratory score was applied. Results IC/BPS group 47.5 (21, 78) yrs was older than HC 34 (20, 75)yrs (p=0.006), MPP group 33 (22, 56)yrs (p=0.004), and IC/BPS plus MPP 38 (18, 64)yrs (p= 0.03). BMI was not significantly different among groups, but the MPP and IC/BPS plus MPP groups had a higher BMI than HC (p=0.03 and p= 0.05 respectively). Cardiovascular and adrenergic indexes did not differ among groups. TTT showed more orthostatic intolerance (OI) in all CPP groups. TTT diagnoses (orthostatic hypotension, postural tachycardia syndrome -POTS, reflex syncope) occurred rarely. Baseline heart rate (HR) was higher in all CPP groups (p=0.004). All MPP groups showed significantly more clearcut AN (defined as sweat score ≥ 3) compare to HC (HC vs IC/BPS plus MPP p= 0.007; HC vs MPP p = 0.03). Conclusions Some CPP types show an autonomic neuropathy, and some show vagal withdrawal. In all types, orthostatic intolerance likely reflects cenral sensitization and perhaps catastrophization. Some of these findings suggest novel therapeutic targets.

Autonomic neurophysiologic implications of disorders comorbid with bladder pain syndrome vs myofascial pelvic pain

“…Probabilistic pairwise comparisons (Table 1) show that the earliest disorders, migraine and PTSD, always preceded other disorders, whereas intermediate disorders, TMJD and dysmenorrhea, preceded or followed, while most other disorders occurred later. As previously described, 5 small fiber neuropathy develops late, after MPP (P = 0.01).…”

“…Loss of parasympathetic (vagal) modulation occurred in subjects with BPS, but not in those with MPP . In contrast, a sympathetic autonomic neuropathy was found in MPP but not in BPS . Current findings amplify this theme.…”

“…4 In contrast, a sympathetic autonomic neuropathy was found in MPP but not in BPS. 19 Current findings amplify this theme. The comorbidities seen in BPS could well reflect vagal dysfunction, while those seen in MPP may suggest sympathetic dysfunction.…”

“…Major autonomic neurophysiologic differences emerged between the two pelvic pain disorders. Vagal withdrawal characterized BPS, while sympathetic dysfunction typified MPP . Since the vagus nerve also modulates visceral afferent sensitivity; reduced vagal modulation might, therefore, contribute to visceral pain syndromes like BPS, and we might expect BPS to segregate preferentially with disorders involving loss of visceral modulation.…”

“…Vagal withdrawal characterized BPS, 4 while sympathetic dysfunction typified MPP. 5 Since the vagus nerve also modulates visceral afferent sensitivity 6 ; reduced vagal modulation might, therefore, contribute to visceral pain syndromes like BPS, and we might expect BPS to segregate preferentially with disorders involving loss of visceral modulation. In contrast, sympathetic dysfunction would primarily impact vasomotor function, and we might expect MPP to segregate with disorders with known impairment of vascular control.…”