Increased Pressure Pain Sensitivity in Women With Chronic Pelvic Pain

Abstract

OBJECTIVE To determine if women with chronic pelvic pain and variable degrees of endometriosis demonstrate altered pain sensitivity relative to pain-free healthy controls, and whether such differences are related to the presence or severity of endometriosis or comorbid pain syndromes. METHODS Four patient subgroups (endometriosis with chronic pelvic pain (n=42), endometriosis with dysmenorrhea (n=15), pain-free endometriosis (n=35), and chronic pelvic pain without endometriosis (n=22)) were each compared to 30 healthy controls in this cross-sectional study. All patients completed validated questionnaires regarding pain symptoms and underwent screening for comorbid pain disorders. Pain sensitivity was assessed by applying discrete pressure stimuli to the thumbnail using a previously validated protocol. RESULTS While adjusting for age and education, pain thresholds were lower in all subgroups of women with pelvic pain, relative to healthy controls (all p-values <0.01). There was no difference in pain thresholds when comparing endometriosis patients without pelvic pain to healthy controls (mean difference 0.02 kg/m2, 95% confidence interval -0.43, 0.47). The presence and severity of endometriosis and number of comorbid pain syndromes were not associated with a difference in pain thresholds. CONCLUSION Women with chronic pelvic pain demonstrate increased pain sensitivity at a nonpelvic site compared to healthy controls, which is independent of the presence or severity of endometriosis or comorbid pain syndromes. These findings support the notion that central pain amplification may play a role in the development of pelvic pain, and may explain why some women with pelvic pain do not respond to therapies aimed at eliminating endometriosis lesions.

Toll-like Receptor 4 and comorbid pain in Interstitial Cystitis/Bladder Pain Syndrome: A Multidisciplinary Approach to the Study of Chronic Pelvic Pain research network study

“…Pressure pain sensitivity was evaluated at the thumbnail (As-Sanie et al, 2013; Giesecke et al, 2004; Petzke et al, 2001) using the Multimodal Automated Sensory Testing (MAST) system (Harte et al, 2013). The MAST system consists of a control computer that executes testing algorithms and stores testing data, and a touch-screen interface for participant feedback.…”

Inflammation and nerve fiber interaction in endometriotic pain

“…Furthermore, chronic pelvic pain in endometriosis patients was associated with generalized hyperexcitability in the central nervous system [79], as well as a centrally mediated sensitization to pain in other peripheral areas [80]. It is therefore possible that a continued peripheral stimulation, coupled with the involvement of the central nervous system, will induce chronic pain that becomes independent of the lesion itself.…”

Association of Chronic Pelvic Pain and Endometriosis With Signs of Sensitization and Myofascial Pain

“…Clinical manifestations of sensitization include regional allodynia and regional hyperalgesia (11–13). Central and peripheral sensitization are reported in regional pain syndromes including endometriosis (14,15), migraine (16), fibromyalgia (17), painful bladder syndrome (18), irritable bowel syndrome (19), and overlapping pain conditions (20). …”