Dysmenorrhea subtypes exhibit differential quantitative sensory assessment profiles

Multimodal hypersensitivity and somatic symptoms predict adolescent postmenarchal widespread pain

ABSTRACT

Widespread pain in adolescence is linked with poor mental health, pain, and somatic symptoms in childhood. This prospective study in 207 premenarchal adolescents used quantitative sensory testing (QST) and multimodal hypersensitivity (MMH) measures to assess somatosensory system function and identify predictors for widespread pain (≥3/7 sites). We hypothesized that premenarchal pain, somatic symptoms, psychological factors, and somatosensory system function would predict postmenarchal widespread pain, which would be associated with greater menstrual pain intensity. At premenarchal and postmenarchal study visits, participants completed measures of somatic symptoms, a pain body map, psychosocial questionnaires, QST, and experimental MMH measures including auditory, visual, and visceral stimulation. Electroencephalography (EEG) was collected during auditory and visual tasks to identify neural correlates of MMH. Premenarchal widespread pain was reported by 25% of participants, whereas 29% developed new incident widespread pain postmenarche. Adolescents with postmenarchal widespread pain reported greater menstrual pain intensity (median [interquartile range] 47 [28-61]; 0-100 visual analog scale) than those without (24 [8-50], P = 0.001). Elevated somatic symptoms (P = 0.012), stress (P = 0.015), and sensitivity to visceral (bladder filling) (P = 0.046) and unpleasant visual stimuli (P = 0.043) were significant predictors of postmenarche widespread pain. A multivariable regression model found premenarchal body map score (OR = 1.75, 95% CI [1.20, 2.55]), somatic symptoms (OR = 1.47, 95% CI [1.03, 2.11]), and visual hypersensitivity (OR = 1.62, 95% CI [1.12, 2.33]) predicted postmenarchal widespread pain. No EEG differences in early cortical sensory processing were found. Our results suggest that increased sensitivity to multimodal unpleasant and painful stimuli represents a novel risk factor for postmenarche widespread pain.

Exploring the value of a well-established conditioned pain modulation paradigm in women: a Translational Research in Pelvic Pain (TRiPP) study

Background

Conditioned pain modulation (CPM) is considered a human proxy for descending inhibitory pain pathways. However, there is wide variation in the CPM response described in the literature and ongoing debate about its utility.

Methods

Here we explored CPM in women with (n = 59) and without (n = 26) chronic pelvic pain (CPP), aiming to determine the magnitude of effect and factors influencing variability in the CPM response.

Results

Using a pressure pain threshold test stimulus and ischaemic pressure cuff conditioning stimulus (CS), we found no significant difference in the mean CPM effect between CPP and control participants. Using a robust statistical method (+/-2 standard error of measurement) to further investigate CPM, there was no significant difference in the proportion exhibiting inhibition between controls and CPP participants (X2  = 0.003, p = 0.96). Notably, only 23.1% of our healthy controls demonstrated a "true" CPM effect (n = 4 inhibitory, n = 2 facilitatory). Despite a rich data set, we were unable to identify any single questionnaire, clinical or psychophysical covariate correlating with the CPM effect.

Conclusions

Despite using one of the recommended CPM paradigms we were only able to demonstrate "true" CPM in 23.1% of control participants. Thus, the absence of differences between women with and without chronic pelvic pain must be interpreted with caution. Future studies using different CPM paradigms or larger sample sizes may find different results. Although CPM in chronic pain populations is of major theoretical mechanistic interest, the lack of an established assessment standard led us to question its added value in current clinical research.

Associations between menstrual pain and sexual function: the role of visceral hypersensitivity on developing sexual pain

BACKGROUND

Dyspareunia, defined as pain before, during or after intercourse, is a subset of female sexual dysfunction with overlapping gynecologic, urologic and psychosocial etiologies.

AIM

This study aimed to evaluate the impact of menstrual pain and visceral hypersensitivity on sexual function and to identify risk factors for sexual pain in healthy reproductive-age females.

METHODS

In this prospective cohort study, we evaluated gynecologic and psychologic self-reported histories, validated sexual function questionnaires, and conducted a standardized gynecologic examination enhanced by quantitative sensory testing in reproductive-aged females with menstrual pain versus pain-free controls. Correlation analysis was conducted between the Female Sexual Function Index (FSFI) pain subdomain score and a priori hypothesized risk factors for dyspareunia: menstrual pain severity, experimentally provoked bladder sensitivity, anxiety, depression, pain catastrophizing, and vaginal pressure-pain sensitivity.

OUTCOMES

The primary outcome was severity of sexual pain as measured by the FSFI, comparing participants with moderate-to-severe dysmenorrhea (n = 99), dysmenorrhea with bladder hypersensitivity (n = 49) identified on non-invasive oral water challenge, and pain-free controls (n = 37).

RESULTS

In our young (median age 22 [IQR 19, 29]), nulliparous, predominantly heterosexual cohort (78.3%, 144/185), 64.3% (119/185) engaged in sexual intercourse within the four-week recall period. The median total FSFI score was 27.2 (22.0, 30.2). Across groups, only the dysmenorrhea with bladder hypersensitivity phenotype met the threshold for sexual dysfunction as measured by total FSFI score (24.6 [20.0, 28.1], p = 0.008). Dysfunction was driven by difficulties with lubrication and higher pain levels during and after intercourse. On physical examination, those with and without dyspareunia were largely indistinguishable, with little to no tenderness of the pelvic floor, bladder, uterus and uterosacral ligaments. Amongst the six hypothesized risk factors for sexual pain, only experimentally provoked bladder pain was significantly associated with the severity of dyspareunia (r = 0.41, corrected p < 0.001).

CLINICAL IMPLICATIONS

Young, otherwise healthy individuals with dysmenorrhea and occult visceral hypersensitivity exhibit signs of sexual dysfunction and significantly higher rates of dyspareunia in the absence of reliable clinical examination findings.

STRENGTHS AND LIMITATIONS

Strengths include the use of a nonclinical sample of almost exclusively nulliparous females with no co-morbid pelvic pain diagnoses and prospective diary confirmation of dysmenorrhea severity. The study is limited by the narrow heteronormative, cisnormative sexual experience of penile-vaginal intercourse captured by the FSFI.

CONCLUSION

Sexual pain is more prevalent in those with dysmenorrhea with bladder hypersensitivity than isolated dysmenorrhea, suggesting visceral hypersensitivity may be a non-structural mechanistic driver for dyspareunia.

Evaluation of Central Sensitisation in Bladder Pain Syndrome: A Systematic Review

INTRODUCTION AND HYPOTHESIS

Bladder pain syndrome (BPS) is a debilitating condition characterised by exaggerated bladder sensations and altered bladder function. It is still unknown whether the condition is a peripheral sensory problem or due to abnormal central sensory processing as seen in central sensitisation. This systematic review, which followed a published and Prospective Register of Systematic Reviews-registered protocol (CRD42021229962), is aimed at establishing the scope of central sensitisation in patients with BPS to aid optimal management and treatment.

METHODS

Four databases were searched, and appraisal of the identified studies was conducted by two independent reviewers based on eligibility criteria: patients with BPS being investigated for central sensitisation with or without comparison of controls, English-language articles, full text and publication in a peer-reviewed journal. The Methodological Index for non-Randomised Studies was used to determine study quality. We identified 763 papers in total, with 15 studies included in the final analysis. All studies were observational and had a low risk of bias. Measures included in the evaluation of CS were questionnaires, urodynamics, and quantitative sensory testing methods.

RESULTS

There was evidence of central sensitisation in patients with BPS in all papers evaluated (15 out of 15). In addition, more significant central sensitisation correlated with severe disease presentation (3 out of 3 papers) and concomitant chronic pain conditions (5 out of 5 papers).

CONCLUSIONS

Central sensitisation plays an integral role in BPS patient pathology. Many secondary measures are used to evaluate this condition. Stratification of patients based on their pathology (peripheral, central or a combination of the two) will aid in implementing an individualised management strategy.

A multidimensional appraisal of early menstrual pain experience

BACKGROUND

Symptomatic dysmenorrhea is a global problem, affecting more than 40% of menstruating persons. Cross-sectional studies have implicated psychosocial, biological, and sensory factors in dysmenorrhea but the mechanisms are not fully understood. Only a few prospective longitudinal studies have evaluated such factors in relation to the emergence and course of dysmenorrhea at menarche.

OBJECTIVE

This study aimed to describe the initial menstruation experience and to evaluate the association of premenarchal psychosocial and sensory factors with the intensity of dysmenorrhea during the period in the fourth month.

STUDY DESIGN

This was a prospective cohort study of adolescents who completed premenarchal assessments and postmenarchal daily menstrual diaries for their first (n=149) and fourth month periods (n=114). They were recruited shortly before menarche and completed baseline assessments, including psychosocial questionnaires and experimental pain sensitivity (pressure testing, bladder provocation), and their parents completed related pain questionnaires. The relation between the hypothesized premenarchal factors and month 4 dysmenorrhea intensity was evaluated using Kruskal-Wallis and chi-square tests for low (<3 on a 0-10 scale) vs higher (≥3) menstrual pain groups based on maximal pain ratings recorded in a daily diary.

RESULTS

Low levels of dysmenorrhea characterized the first (median, 1; interquartile range, 0-2) and fourth month periods (1; 0-3). Maximal pain ratings increased from the first to the fourth period (3; 1-5 vs 4; 1-6; P=.007). The distribution of dysmenorrhea was multimodal at month 4 with 31.6% of the participants having low levels of maximal pain (1; 0-1) and 68.4% having higher levels (5; 4-6; Hartigan's dip test P<.001). The baseline demographic, psychosocial, and parental pain characteristics were not associated with the development of worse dysmenorrhea. The baseline experimental pain sensitivity, based on pressure pain thresholds, did not differ between the low (15.7 N; 12.5-22.3) and higher (15.0 N; 10.9-21.4]) level dysmenorrhea groups. Baseline bladder pain at first urge also did not differ (low, 6; 0-20 vs higher, 7; 0-19).

CONCLUSION

By their fourth month period, two-thirds of adolescents fell into the higher group for maximal dysmenorrhea, half reported some related impairments in physical activity, and one-seventh reported some related school absence. Premenarchal factors (experimental pain sensitivity, psychosocial profile, parental pain experience) linked to chronic pain emergence in the adult literature did not predict dysmenorrhea intensity, suggesting the dominant factor at menarche may be peripheral afferent activation. Further research is needed to understand the evolution of psychosocial and sensory mechanisms in the development and course of dysmenorrhea.

Comprehensive quantitative sensory testing shows altered sensory function in women with chronic pelvic pain: results from the Translational Research in Pelvic Pain (TRiPP) Study

ABSTRACT

Chronic pelvic pain (CPP), despite its high prevalence, is still relatively poorly understood mechanistically. This study, as part of the Translational Research in Pelvic Pain (TRiPP) project, has used a full quantitative sensory testing (QST) paradigm to profile n = 85 women with and without CPP (endometriosis or bladder pain specifically). We used the foot as a control site and abdomen as the test site. Across 5 diagnostically determined subgroups, we found features which are common across different aetiologies, eg, gain of function in pressure pain threshold (PPT) when assessing responses from the lower abdomen or pelvis (referred pain site). However, disease-specific phenotypes were also identified, eg, greater mechanical allodynia in endometriosis, despite there being large heterogeneities within diagnostic groups. The most common QST sensory phenotype was mechanical hyperalgesia (>50% across all the groups). A "healthy' sensory phenotype was seen in <7% of CPP participants. Specific QST measures correlated with sensory symptoms assessed by the painDETECT questionnaire (pressure-evoked pain [painDETECT] and PPT [QST] [ r = 0.47, P < 0.001]; mechanical hyperalgesia (painDETECT) and mechanical pain sensitivity [MPS from QST] [ r = 0.38, P = 0.009]). The data suggest that participants with CPP are sensitive to both deep tissue and cutaneous inputs, suggesting that central mechanisms may be important in this cohort. We also see phenotypes such as thermal hyperalgesia, which may be the result of peripheral mechanisms, such as irritable nociceptors. This highlights the importance of stratifying patients into clinically meaningful phenotypes, which may have implications for the development of better therapeutic strategies for CPP.

Multimodal hypersensitivity derived from quantitative sensory testing predicts pelvic pain outcome: an observational cohort study

ABSTRACT

Multimodal hypersensitivity (MMH)-greater sensitivity across multiple sensory modalities (eg, light, sound, temperature, pressure)-is associated with the development of chronic pain. However, previous MMH studies are restricted given their reliance on self-reported questionnaires, narrow use of multimodal sensory testing, or limited follow-up. We conducted multimodal sensory testing on an observational cohort of 200 reproductive-aged women, including those at elevated risk for chronic pelvic pain conditions and pain-free controls. Multimodal sensory testing included visual, auditory, and bodily pressure, pelvic pressure, thermal, and bladder pain testing. Self-reported pelvic pain was examined over 4 years. A principal component analysis of sensory testing measures resulted in 3 orthogonal factors that explained 43% of the variance: MMH, pressure pain stimulus response, and bladder hypersensitivity. The MMH and bladder hypersensitivity factors correlated with baseline self-reported menstrual pain, genitourinary symptoms, depression, anxiety, and health. Over time, MMH increasingly predicted pelvic pain and was the only component to predict outcome 4 years later, even when adjusted for baseline pelvic pain. Multimodal hypersensitivity was a better predictor of pelvic pain outcome than a questionnaire-based assessment of generalized sensory sensitivity. These results suggest that MMHs overarching neural mechanisms convey more substantial long-term risk for pelvic pain than variation in individual sensory modalities. Further research on the modifiability of MMH could inform future treatment developments in chronic pain.

Facilitated Central Pain Mechanisms Across the Menstrual Cycle in Dysmenorrhea and Enlarged Pain Distribution in Women With Longer Pain History

Dysmenorrhea (DYS), or recurrent menstrual pain, is a highly prevalent pain condition among otherwise healthy women. However, the progression of DYS over time and the influence of the menstrual cycle phases need to be better understood. While the location and distribution of pain have been used to assess pain mechanisms in other conditions, they are unexplored in DYS. Thirty otherwise healthy women with severe DYS and 30 healthy control women were recruited into 3 subgroups (n = 10) according to the length of their menstrual history (<5, 5-15, or>15 years since menarche). The intensity and distribution of menstrual pain were recorded. Pressure pain thresholds at abdominal, hip, and arm sites, pressure-induced pain distribution, temporal summation of pain, and pain intensity after pressure cessation over the gluteus medius were assessed at 3 menstrual cycle phases. Compared with the healthy control women, those with DYS showed lower pressure pain thresholds in every site and menstrual cycle phase (P < .05), enlarged pressure-induced pain areas during menstruations (P < .01), and increased temporal summation and pain intensity after pressure cessation in the overall menstrual cycle (P < .05). Additionally, these manifestations were enhanced during the menstrual and premenstrual phases compared to ovulation in women with DYS (P < .01). Women with long-term DYS demonstrated enlarged pressure-induced pain distribution, enlarged menstrual pain areas, and more days with severe menstrual pain compared to the short-term DYS subgroup (P < .01). Pressure-induced and menstrual pain distributions were strongly correlated (P < .001). These findings suggest that severe DYS is a progressive condition underscored by facilitated central pain mechanisms associated with pain recurrence and exacerbation. PERSPECTIVE: Enlarged pressure-induced pain areas occur in DYS, associated with the length of the condition and the distribution of menstrual pain. Generalized hyperalgesia is present throughout the entire menstrual cycle and intensifies during premenstrual and menstrual phases.

Scientific Knowledge Graph of Dysmenorrhea: A Bibliometric Analysis from 2001 to 2021

Purpose

This study aims to help researchers master the most active hotspots and trends quickly through bibliometric analysis in the field of dysmenorrhea.

Methods

We retrieved literature on Web of Science from 2001 to 2021, and bibliometric analysis software CiteSpace was used in combination with VOSviewer.

Results

We finally acquired 944 papers and an upward trend in articles continued in this field overall. Through the map, China contributed the most, followed by the USA and Turkey. For institutions, Beijing University of Chinese Medicine in China contributed the most, followed by National Yang-Ming University in Taiwan, China. Hsieh JC and Hellman KM were both the most prolific authors with 14 articles. Five major research groups, respectively, with Hsieh JC, Hellman KM, Zhu J, Liang F and Dun W were the key group. Dawood MY was the most dominant author and most frequently cited author. The Cochrane Database of Systematic Reviews Journal was the most productive, and the Fertility and Sterility Journal was the most cited. Advances in pathogenesis and management for primary dysmenorrhea written by Dawood MY was most cited and influential. Pathophysiology, the potential central mechanism, syndrome, evaluation index, diagnosis of adenomyosis-associated dysmenorrhea, treatment, etc., were the main trends and hotspots.

Conclusion

Dysmenorrhea research has received a lot of attention from scholars. Strengthening international cooperation may promote the development of this field. The pathophysiology of dysmenorrhea, its impact on public health and its treatment are current research hotspots and are likely to be the focus of future study.

Bladder Pain Sensitivity Is a Potential Risk Factor for Irritable Bowel Syndrome

BACKGROUND

Although dysmenorrhea is a highly prevalent risk factor for irritable bowel syndrome (IBS), the factors underlying this risk are not fully understood. Prior studies support a hypothesis that repeated distressing menstrual pain promotes cross-organ pelvic sensitization with heightened visceral sensitivity.

AIMS

To further explore cross-organ pelvic sensitization we examined the association of dysmenorrhea, provoked bladder pain, and other putative factors with self-reported IBS-domain pain frequency and new onset after 1-year follow up.

METHODS

We measured visceral pain sensitivity with a noninvasive provoked bladder pain test in a cohort of reproductive-aged women, enriched for those reporting moderate-to-severe menstrual pain intensity but without any prior IBS diagnosis (n = 190). We analyzed the relationship between menstrual pain, provoked bladder pain, pain catastrophizing, anxiety, and depression with primary outcomes: (1) frequency of self-reported IBS-domain pain and (2) new onset of IBS-domain pain after 1-year follow up.

RESULTS

All hypothesized factors correlated with the frequency of IBS-domain pain (p's ≤ 0.038). In a cross-sectional model, only menstrual pain (standardized adjusted odds ratio 2.07), provoked bladder pain (1.49), and anxiety (1.90) were independently associated with IBS-domain pain ≥ 2 days/month (C statistic = 0.79). One year later, provoked bladder pain (3.12) was the only significant predictor of new onset IBS-domain pain (C statistic = 0.87).

CONCLUSION

Increased visceral sensitivity among women with dysmenorrhea could lead to IBS. Because provoked bladder pain predicted subsequent IBS, prospective studies should be performed to see if the early treatment of visceral hypersensitivity mitigates IBS.

The role of catastrophizing in chronic cyclical pelvic pain: A systematic review and meta-analysis

BACKGROUND

Dysmenorrhea (painful menstrual cramps) is one of the most common gynecological complaints in women and girls. Dysmenorrhea may be a condition itself or a result of another medical condition, including endometriosis and chronic pelvic pain. Research examining the relationship between menstrual pain ratings and catastrophizing has produced mixed results.

OBJECTIVE

To review and meta-analyze the relationship between catastrophizing and pain ratings of chronic cyclical pelvic pain.

DESIGN

Cross-sectional, longitudinal, and intervention studies that reported the relationship between menstrual/pelvic pain and catastrophizing were included. Study populations had to include healthy menstruating persons or persons with a condition associated with cyclical pelvic pain including primary dysmenorrhea, endometriosis, and/or chronic pelvic pain.

DATA SOURCES AND METHODS

A systematic search of articles published since 2012 on PubMed, PsychInfo, CINHAL, and Medline was conducted in January and rerun in November of 2022. Search terms included cyclical pelvic pain, dysmenorrhea, endometriosis, pelvic pain, and catastrophizing. Data extraction was completed independently by two extractors and cross-checked for errors. A random-effects meta-regression was used to synthesize the data using restricted maximum likelihood.

RESULTS

Twenty-five studies examining 4,540 participants were included. A random effects model found a meta-correlation between catastrophizing and pain of r = .31 (95% confidence interval: .23-.40) p < .001. Heterogeneity was large and significant (I2 = 84.5%, Q(24) = 155.16, p < .001). Studies that measured general pelvic pain rather than cyclical pelvic pain specifically and those that used multi-item rather than single-item measures of pain had significantly higher correlations. Age and depression did not moderate the relationship between catastrophizing and pain.

CONCLUSION

A systematic review and meta-analysis found that catastrophizing had a small but significant positive association with pain ratings. Patients experiencing cyclical pelvic pain may benefit from interventions targeting the psychological management of pain.

REGISTRATION

This meta-analysis was registered in PROSPERO on 14 January 2022. Registration number: CRD42022295328.

Generalized sensory sensitivity is associated with comorbid pain symptoms: a replication study in women with dysmenorrhea

ABSTRACT

Dysmenorrhea is characterized by high rates of transition to chronic pain. In a previous study using structural equation modeling, we demonstrated that several symptom domains associated with the emerging concept of nociplastic pain can be described using 2 symptom groups: generalized sensory sensitivity (GSS; composed of widespread pain, interceptive sensitivity, and environmental sensitivity) and SPACE (composed of unrefreshing sleep, pain, affective disturbances, cognitive issues, and reduced energy). Here, we perform a secondary cross-sectional analysis examining the same symptoms groups in a cohort of patients with dysmenorrhea without a diagnosis of chronic pain. Our purpose is to determine if the same symptom patterns are apparent and if they are associated with the presence and severity of comorbid pain. Participants were 201 women with dysmenorrhea. We replicated the hypothesized 2-factor structure in this cohort (comparative fit index = 0.971 and root mean square error of approximation =0.055; 90% CI: 0.000-0.097). Generalized sensory sensitivity was associated with the severity of bladder, bowel, and overall pain in multivariable models including SPACE, patient age, and BMI (all β > 0.32, all P < 0.05). Sleep, pain, affective disturbances, cognitive issues, and reduced energy were associated with menstrual pain during nonsteroidal anti-inflammatory drug use, whereas GSS was associated with the same in the absence of nonsteroidal anti-inflammatory drug use (both P < 0.05). This 2-factor model of symptoms seems to be replicable and valid in a cohort of women at risk for developing chronic pain conditions. These symptom groups are promising potential markers of future pain chronification and may point to patients in need of earlier or more aggressive intervention.

The progestin-only pills drospirenone 4 mg and desogestrel 0.075 mg as an option for the management of dysmenorrhea and mastodynia

INTRODUCTION

Dysmenorrhea and mastodynia are the most common gynecologic pain causes in women of all ages and races during their reproductive life. The following study aimed to show the influence of two POP´s in the development of dysmenorrhea and mastodynia after nine months of use.

MATERIAL AND METHODS

A total of 858 women with 6691 drospirenone (DRSP) cycles and 332 women with 2487 desogestrel (DSG) cycles were analyzed. Women included in this study were all child-bearing potentials, at risk of pregnancy, agreeing to use only the study medication for contraception for the duration of the study medication treatment, aged 18 to 45.

RESULTS

At screening, 168 (19.6%) of the 858 patients using DRSP and 64 (19,3%) of the DSG patients reported that they had suffered from dysmenorrhea within six cycles prior to the first visit before starting with the medication. 20,2% of the DRSP and 10,9% of the DSG group had a sever dysmenorrhea. After 9 cycles this was reduced to 0,6% and 3,1% respectively. In total, 96 women (11.2%) in the DRSP and 49 (14,8%) experienced mastodynia within six cycles before the screening. Of these 91.6% in the DRSP group and 91,8% in the DSG group had no or mild mastodynoa at follow-up.

DISCUSSION

The progestins 4 mg and desogestrel 0,075 mg showed a marked effect in the non-contraceptive aspects of dysmenorrhea and mastodynia so that new possibilities are opened for these two benign gynecological diseases. Future studies must reaffirm these first data.

Prevalence of chronic pelvic pain and primary dysmenorrhea in women of reproductive age in Ecuador

Background

Chronic pelvic pain (CPP) and primary dysmenorrhoea are debilitating conditions that can impair the quality of life of affected women. These conditions are frequently neglected, delaying proper diagnosis and healthcare provision. This study aimed to estimate the prevalence of CPP and primary dysmenorrhoea in Ecuador and identify potential variables associated with their occurrence.

Methods

We conducted a cross-sectional survey in an urban neighbourhood of Quito, the capital of Ecuador. A total of 2397 participants of 14–49 years of age were included. The data were collected through questionnaires administered by trained interviewers.The crude and adjusted prevalence ratios were calculated using a log-binomial regression model. The correlation between pain intensity catastrophising of symptoms were statistically analysed.

Results

The prevalence of CPP and primary dysmenorrhoea was 9.8% and 8.9%, respectively. Irritative urinary symptoms, primary dysmenorrhoea, and underlying mental disorders were associated with CPP, while smoking, irritable bowel syndrome, sleep disturbance, dyspareunia, and mental disorders were associated with primary dysmenorrhoea.

Conclusions

The prevalence of CPP and primary dysmenorrhoea in Ecuador was similar to that in other Latin American countries. Primary dysmenorrhoea is a risk factor of CPP, and less than a quarter of women are undergoing treatment for the condition. Our findings reinforce the importance of healthcare interventions in anticipating the diagnosis of these conditions in women of reproductive age.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12905-022-01948-y.

Cortical mechanisms of visual hypersensitivity in women at risk for chronic pelvic pain

ABSTRACT

Increased sensory sensitivity across non-nociceptive modalities is a common symptom of chronic pain conditions and is associated with chronic pain development. Providing a better understanding of the brain-behavior relationships that underlie multimodal hypersensitivity (MMH) may clarify the role of MMH in the development of chronic pain. We studied sensory hypersensitivity in a cohort of women (n = 147) who had diary confirmation of menstrual status and were enriched with risk factors for chronic pelvic pain, such as dysmenorrhea and increased bladder sensitivity. We administered 2 experimental tasks to evaluate the cross-modal relationship between visual and visceral sensitivity. Visual sensitivity was probed by presenting participants with a periodic pattern-reversal checkerboard stimulus presented across 5 brightness intensities during electroencephalography recording. Self-reported visual unpleasantness ratings for each brightness intensity were simultaneously assessed. Visceral sensitivity was evaluated with an experimental bladder-filling task associated with early clinical symptoms of chronic pelvic pain. Visually evoked cortical activity increased with brightness intensity across the entire scalp, especially at occipital electrode sites. Visual stimulation-induced unpleasantness was associated with provoked bladder pain and evoked primary visual cortex activity. However, the relationship between unpleasantness and cortical activity was moderated by provoked bladder pain. These results demonstrate that activity in the primary visual cortex is not greater in individuals with greater visceral sensitivity. We hypothesize that downstream interpretation or integration of this signal is amplified in individuals with visceral hypersensitivity. Future studies aimed at reducing MMH in chronic pain conditions should prioritize targeting of cortical mechanisms responsible for aberrant downstream sensory integration.

Central sensitization inventory in endometriosis

ABSTRACT

A key clinical problem is identifying the patient with endometriosis whose pain is complicated by central nervous system sensitization, where conventional gynecologic treatment (eg, hormonal therapy or surgery) may not completely alleviate the pain. The Central Sensitization Inventory (CSI) is a questionnaire previously validated in the chronic pain population. The objective of this study was an exploratory proof-of-concept to identify a CSI cutoff in the endometriosis population to discriminate between individuals with significant central contributors (identified by central sensitivity syndromes [CSS]) to their pain compared to those without. We analyzed a prospective data registry at a tertiary referral center for endometriosis, and included subjects aged 18 to 50 years with endometriosis who were newly or re-referred to the center in 2018. The study sample consisted of 335 subjects with a mean age of 36.0 ± 7.0 years. An increasing number of CSS was significantly correlated with dysmenorrhea, deep dyspareunia, dyschezia, and chronic pelvic pain scores (P < 0.001), and with the CSI score (0-100) (r = 0.731, P < 0.001). Receiver operating characteristic analysis indicated that a CSI cutoff of 40 had a sensitivity of 78% (95% CI: 72.7%-84.6%) and a specificity of 80% (95% CI: 70.3%-84.5%) for identifying a patient with endometriosis with ≥3 CSS. In the group with CSI ≥ 40, 18% retrospectively self-reported pain nonresponsive to hormonal therapy and 40% self-reported daily pain, compared with 6% and 20% in the CSI < 40 group (P = 0.003 and 0.002, respectively). In conclusion, a CSI ≥ 40 may be a practical tool to help identify patients with endometriosis with pain contributors related to central nervous system sensitization.

Noninvasive bladder testing of adolescent females to assess visceral hypersensitivity

ABSTRACT

Excess pain after visceral provocation has been suggested as a marker for chronic pelvic pain risk in women. However, few noninvasive tests have been validated that could be performed readily on youth in early risk windows. Therefore, we evaluated the validity and reliability of a noninvasive bladder pain test in 124 healthy premenarchal females (median age 11, [interquartile range 11-12]), as previously studied in adult women. We explored whether psychosocial, sensory factors, and quantitative sensory test results were associated with provoked bladder pain and assessed the relation of bladder pain with abdominal pain history. Compared with findings in young adult females (age 21 [20-28]), results were similar except that adolescents had more pain at first sensation to void (P = 0.005) and lower maximum tolerance volume (P < 0.001). Anxiety, depression, somatic symptoms, and pain catastrophizing predicted provoked bladder pain (P's < 0.05). Bladder pain inversely correlated with pressure pain thresholds (r = -0.25, P < 0.05), but not with cold pressor pain or conditioned pain modulation effectiveness. Bladder pain was also associated with frequency of abdominal pain symptoms (r = 0.25, P = 0.039). We found strong retest reliability for bladder pain at standard levels of sensory urgency in 21 adolescents who attended repeat visits at 6 to 12 months (intraclass correlations = 0.88-0.90). Noninvasive bladder pain testing seems reproducible in adolescent females and may predict abdominal pain symptomatology. Confirmation of our findings and further investigation of the bladder test across menarche will help establish how visceral sensitivity contributes to the early trajectory of pelvic pain risk.

Circulating sex steroids and bladder pain sensitivity in dysmenorrhea

Although elevated estradiol levels facilitate chronic pelvic pain in animal models, it remains to be determined whether sex steroid levels are altered in a cross-section of women with chronic pelvic pain (CPP) and those at-risk for developing CPP. We sought to determine if sex steroid levels are increased in women with menstrual pain and whether those changes were more extreme in two groups of women with worsened pelvic pain profiles: a) dysmenorrhea plus evidence of bladder pain sensitivity and b) bladder pain syndrome. Serum samples were collected during the mid-luteal phase to measure estradiol, progesterone, testosterone, and sex hormone-binding globulin. We also compared quantitative sensory testing profiles to evaluate how sex steroid differences influence proposed pain sensitivity mechanisms. Women with combined dysmenorrhea and bladder sensitivity had higher estradiol concentrations than controls (487 [IQR 390 - 641] vs 404 [336 - 467] pmol/L, p = 0.042). Bladder pain syndrome participants had greater sex hormone-binding globulin than controls (83 [71 - 108] vs 55 [42 - 76 nmol/L; p = 0.027). Levels of pain sensitivity and mood were different across the groups, but the only significant relationship to sex steroids was that sex hormone-binding globulin was correlated to somatic symptoms (r = 0.26, p = 0.03). These findings show women potentially at-risk for CPP and women with diagnosed CPP exhibit altered circulating levels of sex steroids. Because these hormonal differences appear to be independent of mood or pain sensitivity, the role of sex steroids in the emergence of CPP may be via sensitization of visceral afferents.

Menstrual Pain and Elasticity of Uterine Cervix

Menstrual pain is consequent to intense uterine contraction aimed to expel menstrual flow through downstream uterine cervix. Herein it was evaluated whether characteristics of uterine cervix are associated with intensity of menstrual pain. Ultrasound elastography was used to analyze cervix elasticity of 75 consecutive outpatient women. Elasticity was related to intensity of menstrual pain defined by a Visual Analogue Scale (VAS). Four regions of interest (ROI) were considered: internal uterine orifice (IUO), anterior (ACC) and posterior cervical (PCC) compartment and middle cervical canal (MCC). Tissue elasticity, evaluated by color score (from 0.5 = blue/violet (low elasticity) to 3.0 = red (high elasticity), and percent tissue deformation was analyzed. Elasticity of IUO was lower (p = 0.0001) than that of MCC or ACC, and it was negatively related (R2 = 0.428; p = 0.0001) to menstrual VAS (CR −2.17; 95%CI −3.80, −0.54; p = 0.01). Presence of adenomyosis (CR 3.24; 95% CI 1.94, 4.54; p = 0.0001) and cervix tenderness at clinical examination (CR 2.74; 95% CI 1.29, 4.20; p = 0.0004), were also independently related to menstrual VAS. At post hoc analysis, women with vs. without menstrual pain had lower IUO elasticity, expressed as color score (0.72 ± 0.40 vs. 0.92 ± 0.42; p = 0.059), lower percent tissue deformation at IUO (0.09 ± 0.05 vs. 0.13 ± 0.08; p = 0.025), a higher prevalence of cervical tenderness at bimanual examination (36.2% vs. 9.5%; p = 0.022) and a higher prevalence of adenomyosis (46.5% vs. 19.9%; p = 0.04). These preliminary data indicate that IUO elasticity is associated with the presence and the intensity of menstrual pain. Mechanisms determining IUO elasticity are useful to be explored.

Cortical Mechanisms of Visual Hypersensitivity in Women at Risk for Chronic Pelvic Pain

Multisensory hypersensitivity (MSH), which refers to persistent discomfort across sensory modalities, is a risk factor for chronic pain. Developing a better understanding of the neural contributions of disparate sensory systems to MSH may clarify its role in the development of chronic pain. We recruited a cohort of women (n=147) enriched with participants with menstrual pain at risk for developing chronic pain. Visual sensitivity was measured using a periodic pattern-reversal stimulus during EEG. Self-reported visual unpleasantness ratings were also recorded. Bladder pain sensitivity was evaluated with an experimental bladder-filling task associated with early clinical symptoms of chronic pelvic pain. Visual stimulation induced unpleasantness was associated with bladder pain and evoked primary visual cortex excitation; however, the relationship between unpleasantness and cortical excitation was moderated by bladder pain. Thus, future studies aimed at reversing the progression of MSH into chronic pain should prioritize targeting of cortical mechanisms responsible for maladaptive sensory input integration.

Impact of Endometriosis on Life-Course Potential: A Narrative Review

Endometriosis may exert a profound negative influence on the lives of individuals with the disorder, adversely affecting quality of life, participation in daily and social activities, physical and sexual functioning, relationships, educational and work productivity, mental health, and well-being. Over the course of a lifetime, these daily challenges may translate into limitations in achieving life goals such as pursuing or completing educational opportunities; making career choices or advancing in a chosen career; forming stable, fulfilling relationships; or starting a family, all of which ultimately alter one's life trajectory. The potential for endometriosis to impact the life course is considerable, as symptom onset generally occurs at a time of life (menarche through menopause, adolescence through middle age) when multiple life-changing and trajectory-defining decisions are made. Using a life-course approach, we examine how the known effects of endometriosis on life-domain satisfaction may impact health and well-being across the life course of affected individuals. We provide a quasi-systematic, narrative review of the literature as well as expert opinion on recommendations for clinical management and future research directions.

Ecological Momentary Assessment of Non-Menstrual Pelvic Pain: Potential Pathways of Central Sensitization in Adolescents and Young Adults with and without Primary Dysmenorrhea

Purpose

Primary dysmenorrhea (PD; menstrual pain without an identified organic cause) has been proposed as a possible risk factor for the development of chronic pelvic pain, but the mechanism through which this process occurs is unknown. One possible mechanism is central sensitization – alterations in the central nervous system that increase responsiveness to pain leading to hypersensitivity. Repeated episodes of pain, such as those experienced over time with PD, may alter how the brain processes pain. Ecological momentary assessment (EMA; collection of data in real time in participants’ natural environments) is a novel data collection method that may help elucidate pain occurring during non-menstrual cycle phases.

Patients and Methods

The current observational study assessed the feasibility and acceptability of using EMA via text messages to collect pelvic pain data during menstrual and non-menstrual cycle phases in a community sample of adolescents and young adults (AYA) aged 16–24 years with and without PD and explored occurrence rates and intensity of non-menstrual pelvic pain (NMPP) in each of these groups.

Results

Thirty-nine AYA with PD and 53 healthy controls reported pelvic pain level via nightly text message. Global response rate was 98.5%, and all participants reported that the EMA protocol was acceptable. AYA with PD reported higher intensity (2.0 vs 1.6 on 0–10 numeric rating scale; p=0.003) and frequency (8.7% vs 3.1% of days; p=0.004) of NMPP compared to healthy controls.

Conclusion

The EMA protocol was feasible and acceptable. Though both the intensity and frequency of NMPP were low and at levels that would not typically warrant clinical assessment or intervention, these repeated nociceptive events may represent a potential mechanism contributing to the transition from cyclical to chronic pelvic pain in some individuals.

Commentary: Novel Use of Offset Analgesia to Assess Adolescents and Adults with Treatment Resistant Endometriosis-Associated Pain

Background and Objective

Endometriosis, affecting approximately 176 million adults and adolescents worldwide, is a debilitating condition in which uterine tissue grows outside the uterus. The condition costs the US economy approximately $78 billion annually in pain-related disability. By understanding the neural underpinnings of endometriosis-associated pain (EAP) and risk factors for chronification, translational research methods could lessen diagnostic delays and maximize successful pain remediation. This can be accomplished by the novel use of a known method, offset analgesia (OA), to better elucidate the neural mechanisms that may contribute to and maintain EAP. This commentary will provide justification and rationale for the use of OA in the study of EAP.

Conclusion

Utilizing an OA paradigm in patients with endometriosis, especially adolescents, may (1) provide insight into neural mechanisms contributing to pain maintenance, which could capture those at-risk for the transition to chronic pelvic pain, (2) provide a metric for the development of future centrally mediated treatment options for this population, and (3) elucidate the brain changes that result in resistance to treatment and pain chronification.

Abnormal white matter microstructure along the thalamus fiber pathways in women with primary dysmenorrhea

Primary dysmenorrhea (PDM) is a cyclic menstrual pain in the absence of pelvic anomalies, and women with PDM have an increased sensitivity to pain than the internal and external areas associated with menstrual pain. However, the brain abnormality in the ascending pain pathways in dysmenorrhea remains largely unclear. As the thalamus plays a significant role in transmission of nociceptive input, we examined whether white matter microstructure of the thalamus-related fiber tracts obtained by DTI in women with PDM (n = 47) differs from healthy controls. A novel tractography atlas-based analysis method that detects tract integrity and altered microstructural properties along selected fibers was employed. The fiber bundles of interest contained the thalamus- primary somatosensory cortex (SI), thalamus- dorsal anterior cingulate cortex (dACC)/supplementary motor area (SMA), thalamus-insula, and thalamus-ACC. As compared with controls, abnormal white matter microstructures were found along the thalamus-related white matter fiber tracts. Additionally, the intensity of menstrual pain was significantly associated with diffusion measures of thalamus-SI fiber connections. Our study suggested that the thalamus-related pain processing pathways had altered white matter integrity that persisted beyond the time of menstruation, and the white matter microstructure of the thalamus-SI pathways was closely related to menstrual pain in the intensity by women with PDM.