Women and visceral pain: Are the reproductive organs the main protagonists? Mini-review at the occasion of the “European Week Against Pain in Women 2007”

Alterations of the White Matter in Patients With Knee Osteoarthritis: A Diffusion Tensor Imaging Study With Tract-Based Spatial Statistics

Background

Functional and structural alterations in the gray matter have been observed in patients with knee osteoarthritis (KOA). However, little is known about white matter changes in KOA. Here, we evaluated fractional anisotropy (FA), mean diffusivity (MD), axial diffusivity (AD), and radial diffusivity (RD) to investigate potential alterations in the white matter of patients with KOA.

Methods

A total of 166 patients with KOA, along with 88 age- and sex-matched healthy controls were recruited and underwent brain magnetic resonance imaging (MRI). Diffusion tensor imaging (DTI) data were collected and analyzed using tract-based spatial statistics (TBSS). Statistical significances were determined at p < 0.05 and were corrected by the threshold-free cluster enhancement (TFCE) method. Then, we evaluated potential correlations between FA, MD, AD, RD values and disease duration, Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) scores, and visual analog scale (VAS) scores.

Results

FA values for the body of corpus callosum, splenium of corpus callosum, bilateral superior longitudinal fasciculus, cingulum, bilateral superior corona radiata, and right posterior corona radiata were significantly higher in patients with KOA than in healthy controls (p < 0.05, TFCE corrected). Compared with healthy controls, patients with KOA also had significantly lower MD, AD, and RD values of the genu of corpus callosum, body of corpus callosum, splenium of corpus callosum, corona radiata, right posterior thalamic radiation, superior longitudinal fasciculus, and middle cerebellar peduncle (p < 0.05, TFCE corrected). Negative correlations were detected between WOMAC scores and AD values for the body of the corpus callosum and the splenium of the corpus callosum (p < 0.05, FDR corrected).

Conclusion

Patients with KOA exhibited extensive white matter alterations in sensorimotor and pain-related regions. Longitudinal observation studies on the causation between abnormalities in the white matter tracts and KOA is needed in the future.

Dysmenorrhea Symptom-Based Phenotypes: A Replication and Extension Study

BACKGROUND

Dysmenorrhea is a prevalent pain condition among women and a risk factor for other chronic pain conditions. Individuals vary in dysmenorrhea pain severity, the number of painful sites, and co-occurring gastrointestinal symptoms. Three dysmenorrhea symptom-based phenotypes were previously identified using latent class analysis; however, there is a need to validate these in an independent sample, so they can be used in mechanistic and interventional research. There is also a need to further characterize dysmenorrhea symptom-based phenotypes in terms of demographic, clinical, and psychobehavioral characteristics so they can be used to inform precision dysmenorrhea treatment.

OBJECTIVES

The study objectives were to (a) determine whether the same dysmenorrhea symptom-based phenotypes would be found in a new sample; (b) determine whether including demographic, clinical, and psychobehavioral covariates in latent class analyses would change individuals' phenotype memberships; and (c) investigate relationships between dysmenorrhea symptom-based phenotypes and demographic, clinical, and psychobehavioral characteristics.

METHODS

This cross-sectional survey study included 678 women (aged 14-42 years) with dysmenorrhea. Participants reported dysmenorrhea symptom severity, demographic, clinical (comorbid chronic pain and gynecological conditions), and psychobehavioral characteristics (perceived stress, anxiety, depression, sleep disturbance, and pain catastrophizing). We used latent class analysis to identify symptom-based phenotypes. We compared analyses with and without covariates (i.e., demographic, clinical, and psychobehavioral characteristics) to determine if individuals' phenotype memberships changed. We then examined associations between phenotypes and demographic, clinical, and psychobehavioral characteristics.

RESULTS

We reproduced three dysmenorrhea symptom-based phenotypes: the "mild localized pain" phenotype (characterized by mild abdominal cramps), the "severe localized pain" phenotype (characterized by severe abdominal cramps), and the "multiple severe symptoms" phenotype (characterized by severe pain at multiple locations and gastrointestinal symptoms). Analyses with and without covariates had little effect on individuals' phenotype membership. Race, comorbid chronic pain condition, endometriosis, and pain catastrophizing were significantly associated with the dysmenorrhea phenotypes.

DISCUSSION

Findings provide a foundation to further study mechanisms of dysmenorrhea symptom heterogeneity and develop dysmenorrhea precision treatments. The three dysmenorrhea symptom-based phenotypes were validated in a second sample. Demographic, clinical, and psychobehavioral factors were associated with dysmenorrhea symptom-based phenotypes.

Viscero-visceral hyperalgesia in dysmenorrhoea plus previous urinary calculosis: Role of myofascial trigger points and their injection treatment in the referred area

BACKGROUND

Women with dysmenorrhoea plus symptomatic urinary calculosis experience enhanced pain and referred muscle hyperalgesia from both conditions than women with one condition only (viscero-visceral hyperalgesia). The study aimed at verifying if enhanced dysmenorrhoea persists after urinary stone elimination in comorbid women and if local anaesthetic inactivation of myofascial trigger points (TrPs) in the lumbar area (of urinary pain referral) also relieves dysmenorrhoea.

METHODS

Thirty-one women with dysmenorrhoea plus previous urinary calculosis (Dys+PrCal) and lumbar TrPs, and 33 women with dysmenorrhoea without calculosis (Dys) underwent a 1-year assessment of menstrual pain and muscle hyperalgesia in the uterus-referred area (electrical pain threshold measurement in rectus abdominis, compared with thresholds of 33 healthy controls). At the end of the year, 16 comorbid patients underwent inactivation of TrPs through anaesthetic injections, whereas the remaining 12 received no TrP treatment. Both groups were monitored for another year at the end of which thresholds were re-measured.

RESULTS

In year1, Dys+PrCal presented significantly more painful menstrual cycles and lower abdominal thresholds than Dys, thresholds of both groups being significantly lower than normal (p < .001). Anaesthetic treatment versus no treatment of the lumbar TrP significantly reduced the number of painful cycles during year2 and significantly increased the abdominal thresholds (p < .0001).

CONCLUSION

Viscero-visceral hyperalgesia between uterus and urinary tract may persist after stone elimination due to nociceptive inputs from TrPs in the referred urinary area, since TrPs treatment effectively reverses the enhanced menstrual symptoms. The procedure could represent an integral part of the management protocol in these conditions.

SIGNIFICANCE

A past pain process from an internal organ can continue enhancing pain expression from a painful disease in another neuromerically connected organ (viscero-visceral hyperalgesia) if secondary myofascial trigger points (TrPs) developed in the referred area at the time of the previous visceral disease. Inactivation of these TrPs reverts the enhancement. Assessment and treatment of TrPs in referred areas from past visceral pain conditions should be systematically carried out to better control pain from current diseases in other viscera.

What women say about their dysmenorrhea: a qualitative thematic analysis

Background

Dysmenorrhea is highly prevalent and is the leading cause of absence from school and work among women of reproductive age. Evidence suggests that dysmenorrhea may also be a risk factor for other chronic pain conditions. Limited research has examined women’s experience with dysmenorrhea using qualitative data. Research is warranted to address issues and needs that are important from women’s own perspectives. Therefore, the purpose of this study was to describe women’s salient thoughts about their experiences of dysmenorrhea.

Methods

We analyzed data collected from an open-ended question within a cross-sectional survey study conducted in the United States. Using qualitative thematic analysis, free text responses to a question asking women to share their experience with dysmenorrhea were analyzed.

Results

The sample consisted of 225 women who provided valid responses to the open-ended question. Six themes were identified: (1) The dysmenorrhea symptom experience varied among women; (2) The dysmenorrhea symptom experience varied across time, (3) A variety of factors influenced the dysmenorrhea symptom experience, (4) Dysmenorrhea symptoms could have a negative impact on the women’s daily lives, (5) Dysmenorrhea was not seen as a legitimate health issue by the women, health care providers, or society, and (6) Treatment for women with dysmenorrhea varied in acceptability and effectiveness.

Conclusions

The findings of this study have important implications for dysmenorrhea symptom assessment and the development of personalized interventions to support dysmenorrhea management.

Reasons women do not seek health care for dysmenorrhea

AIMS AND OBJECTIVES

To identify and describe reasons women do not seek health care for dysmenorrhea symptoms.

BACKGROUND

Although dysmenorrhea is highly prevalent among women, can cause significant disruptions in their daily lives, and may increase their risk for future chronic pain conditions, few women seek health care for dysmenorrhea. A better understanding of why women do not seek health care is necessary to develop strategies that facilitate care seeking and optimal symptom management.

DESIGN

A qualitative descriptive design was used to guide the study and summarise text responses to an open-ended survey question.

METHODS

Participants in an online survey study who had not sought health care for dysmenorrhea (N = 509) were asked to write about their reasons for not seeking care. Data were collected in January and February 2015. Participants' text responses were analysed using qualitative content analysis.

RESULTS

Nine categories of reasons were identified as follows: assuming symptoms are normal, preferring to self-manage symptoms, having limited resources, thinking providers would not offer help, being unaware of treatment options, considering symptoms to be tolerable, being wary of available treatments, feeling embarrassed or afraid to seek care and not seeking health care generally.

CONCLUSIONS

Findings can guide the development of strategies to promote care seeking and inform policy and clinical practice to improve dysmenorrhea management.

RELEVANCE TO CLINICAL PRACTICE

Findings underscore the need to provide routine screening for dysmenorrhea, avoid dismissing dysmenorrhea symptoms, initiate discussions and provide education about dysmenorrhea, provide treatments options based on evidence and women's preferences and raise public awareness of dysmenorrhea and its impact.

Altered white matter microarchitecture in the cingulum bundle in women with primary dysmenorrhea: A tract-based analysis study

Primary dysmenorrhea (PD), as characterized by painful menstrual cramps without organic causes, is associated with central sensitization and brain function changes. Previous studies showed the integrated role of the default mode network (DMN) in the pain connectome and its key contribution on how an individual perceives and copes with pain disorders. Here, we aimed to investigate whether the cingulum bundle connecting hub regions of the DMN was disrupted in young women with PD. Diffusion tensor imaging was obtained in 41 PD patients and 41 matched healthy controls (HC) during their periovulatory phase. The production of prostaglandins (PGs) was obtained in PD patients during their pain-free and pain phases. As compared with HC, PD patients had similar scores of pain intensity, anxiety, and depression in their pain-free phase. However, altered white matter properties mainly located in the posterior section of the cingulum bundle were observed in PD. Besides PGs being related to menstrual pain, a close relationship was found between the white matter properties of the cingulum bundle during the pain-free phase and the severity of the menstrual pain in PD patients. Our study suggested that PD had trait changes of white matter integrities in the cingulum bundle that persisted beyond the time of menstruation. We inferred that altered anatomical connections may lead to less-flexible communication within the DMN, and/or between the DMN and other pain-related brain networks, which may result in the central susceptibility to develop chronic pain conditions in PD's later life. Hum Brain Mapp 38:4430-4443, 2017. © 2017 Wiley Periodicals, Inc.

Evolutionary considerations in the development of chronic pelvic pain

Chronic pelvic pain is common among women of reproductive age and is associated with significant morbidity and comorbidities. In this Viewpoint, we explore the evolutionary cause of pelvic pain and summarize evidence that supports a menstruation-related evolutionary cause of chronic visceral pelvic pain: (1) lifetime menstruation has increased; (2) severe dysmenorrhea is common in the chronic pelvic pain population, particularly among those with pain sensitization; and (3) a potential biological mechanism can be identified. Thus, chronic pelvic pain may arise from the mismatch between the slow pace of biological evolution in our bodies and the relatively rapid pace of cultural changes that have resulted in increased menstrual frequency due to earlier menarche, later mortality, and lower fecundity. One possible mechanism that explains the development of persistent pain from repeated episodes of intermittent pain is hyperalgesic priming, a physiological process defined as a long-lasting latent hyperresponsiveness of nociceptors to inflammatory mediators after an inflammatory or neuropathic insult. The repetitive severely painful menstrual episodes may play such a role. From an evolutionary perspective the relatively rapid increase in lifetime menstruation experience in contemporary society may contribute to a mismatch between lifetime menstruation and the physiological pain processes, leading to a maladaptive state of chronic visceral pelvic pain. Our current physiology does not conform to current human needs.

Beliefs About Dysmenorrhea and Their Relationship to Self-Management

Dysmenorrhea is highly prevalent and is the leading cause of work and school absences among women of reproductive age. However, self-management of dysmenorrhea is not well understood in the US, and little evidence is available on factors that influence dysmenorrhea self-management. Guided by the Common Sense Model, we examined women's representations of dysmenorrhea (beliefs about causes, symptoms, consequences, timeline, controllability, coherence, and emotional responses), described their dysmenorrhea self-management behaviors, and investigated the relationship between representations and self-management behaviors. We conducted a cross-sectional, web-based survey of 762 adult women who had dysmenorrhea symptoms in the last six months. Participants had varied beliefs about the causes of their dysmenorrhea symptoms, which were perceived as a normal part of life. Dysmenorrhea symptoms were reported as moderately severe, with consequences that moderately affected daily life. Women believed they understood their symptoms moderately well and perceived them as moderately controllable but them to continue through menopause. Most women did not seek professional care but rather used a variety of pharmacologic and complementary health approaches. Care-seeking and use of self-management strategies were associated with common sense beliefs about dysmenorrhea cause, consequences, timeline, and controllability. The findings may inform development and testing of self-management interventions that address dysmenorrhea representations and facilitate evidence-based management. © 2016 Wiley Periodicals, Inc.

Pelvic floor muscle dysfunctions are prevalent in female chronic pelvic pain: a cross-sectional population-based study

BACKGROUND

No current standardized set of pelvic floor muscle (PFM) outcome measures have been specifically tested for their applicability in a general female chronic pelvic pain (CPP) population. We aimed to compare PFM function between a randomly selected population-based sample of women with CPP and age-matched pain-free controls using multiple standardized intravaginal examination measures recommended by the International Continence Society.

METHODS

This was a cross-sectional, population-based and controlled study with randomly selected participants among women in Denmark. We reported blinded findings from a set of standardized vaginal PFM examination manoeuvres in 50 female participants (24 with CPP, 26 pain free). A preliminary pilot study ensured the intra- and intertester reliability of the test procedure. PFM outcomes were resting tone, relaxation capacity, strength, surface electromyographic activity and mechanosensitivity. Statistical analyses included unpaired t-tests, Fisher's exact tests and Mann-Whitney tests.

RESULTS

The examination protocol was a reliable and predictable clinical measurement of associated PFM dysfunction in female CPP. Women with CPP had higher PFM resting tone and decreased maximal PFM strength and relaxation capacity compared with pain-free controls. Enhanced PFM pressure-pain sensitivity measured by palpometry during examination was also associated to CPP.

CONCLUSION

This controlled, single-blinded study with randomly selected participants provides new population-based information regarding associated PFM dysfunction in women with CPP using multiple intravaginal examination methods. However, to identify women with CPP who will benefit from a physiotherapeutic specialized intervention, future prospective randomized controlled trials using these reliable and predictive outcomes are needed.

Female reproductive tract pain: targets, challenges, and outcomes

Pain from the female reproductive tract (FRT) is a significant clinical problem for which there are few effective therapies. The complex neuroanatomy of pelvic organs not only makes diagnosis of pelvic pain disorders difficult but represents a challenge to development of targeted therapies. A number of potential therapeutic targets have been identified on sensory neurons supplying the FRT but our knowledge on the basic neurophysiology of these neurons is limited compared with other viscera. Until this is addressed we can only guess if the new experimental therapies proposed for somatic, gastrointestinal, or bladder pain will translate to the FRT. Once suitable therapeutic targets become clear, the next challenge is drug delivery. The FRT represents a promising system for topical drug delivery that could be tailored to act locally or systemically depending on formulation. Development of these therapies and their delivery systems will need to be done in concert with more robust in vivo and in vitro models of FRT pain.

Cotton-tipped applicator test: validity and reliability in chronic pelvic pain

OBJECTIVE

We sought to assess the concurrent validity and interrater reliability of the cotton-tipped applicator (CTA) test as a screening tool for diagnosis of cutaneous allodynia in patients with viscerally related chronic pelvic pain (CPP).

STUDY DESIGN

We performed a prospective cohort comparative observational study of referred patients to a gynecology clinic with CPP. A total of 22 females with CPP were compared to 23 pain-free controls and 12 cyclic pain patients. Participants were evaluated by 2 clinicians. The CTA test was performed to detect the appearance of pain in dermatomes of T10-L1.

RESULTS

Interrater reliability resulted in 98% agreement for the 3 study groups. CTA test showed 73% sensitivity and 100% specificity for differentiating patients with CPP from pain-free patients.

CONCLUSION

The CTA test had excellent interrater reliability and concurrent validity for diagnosis of cutaneous allodynia in CPP patients with visceral diseases versus controls.

Endometriosis and abdominal myofascial pain in adults and adolescents

Endometriosis and myofascial pain are common disorders with significant impact on quality of life. Increasingly, these conditions are being recognized as highly interconnected through processes that have been described for more than a century. This review is directed to this interconnection through a description of the relationships of endometriosis to proposed mechanisms of pain and chronic pain physiology; the clinical assessment of myofascial representations of this pain; and an approach to the management of these interconnected disorders.

Bedside testing for chronic pelvic pain: discriminating visceral from somatic pain

Objectives. This study was done to evaluate three bedside tests in discriminating visceral pain from somatic pain among women with chronic pelvic pain. Study Design. The study was an exploratory cross-sectional evaluation of 81 women with chronic pelvic pain of 6 or more months' duration. Tests included abdominal cutaneous allodynia (aCA), perineal cutaneous allodynia (pCA), abdominal and perineal myofascial trigger points (aMFTP) and (pMFTP), and reduced pain thresholds (RPTs). Results. Eighty-one women were recruited, and all women provided informed consent. There were 62 women with apparent visceral pain and 19 with apparent somatic sources of pain. The positive predictive values for pelvic visceral disease were aCA-93%, pCA-91%, aMFTP-93%, pMFTP-81%, and RPT-79%. The likelihood ratio (+) and 95% C.I. for the detection of visceral sources of pain were aCA-4.19 (1.46, 12.0), pCA-2.91 (1.19, 7.11), aMTRP-4.19 (1.46, 12.0), pMFTP-1.35 (0.86, 2.13), and RPT-1.14 (0.85, 1.52), respectively. Conclusions. Tests of cutaneous allodynia, myofascial trigger points, and reduced pain thresholds are easily applied and well tolerated. The tests for cutaneous allodynia appear to have the greatest likelihood of identifying a visceral source of pain compared to somatic sources of pain.

Exposure to static magnetic field delays induced preterm birth occurrence in mice

OBJECTIVE

The purpose of this study was to demonstrate that daily 40-minute whole body exposure to an inhomogeneous static magnetic field (SMF) prolongs induced preterm birth (PTB) in mice.

STUDY DESIGN

The murine model for PTB induction was performed by the administration of 25 μg/animal lipopolysaccharide (LPS) intraperitoneally. The applied SMF was an inhomogeneous gradient field with 2.8-476.7 millitesla peak-to-peak magnetic induction range by 10 mm lateral periodicity. During SMF exposure, mice were free to move in their cage.

RESULTS

The fetal development and the delivery were normal in animals that were exposed to SMF but not treated with LPS. SMF in these cases did not influence the term of delivery. In LPS-challenged animals, SMF exposure prolonged the time of PTB occurrence from 17.43 h (n = 7) to 21.93 h (n = 15) after the challenge (P < .05).

CONCLUSION

Exposure to inhomogeneous SMF may have a valuable effect in the prevention of PTB and may have clinical relevance to humans.

Myofascial pain in the adolescent

PURPOSE OF REVIEW

Whereas in the recent past pain in the child and adolescent was directed to cancer management, there is increasing interest in pain in children and adolescents in relation to nonmalignant conditions. Additionally, there is an emerging literature related to disorders of myofascial function as a cause of pain.

RECENT FINDINGS

Pain associated with myofascial dysfunction is common in the adolescent female. Pain in this group of women has been shown to extend into adulthood. Although there has been attention directed to the management of endometriosis through laparoscopic surgical approaches, these are seen as limiting. Myofascial dysfunction is now regarded as an important factor in the evaluation of adolescent pain. One of the most important approaches to the reduction of severe pain in the adolescent is the complete menstrual suppression through use of continuous oral contraceptives or contraceptive rings. Operative laparoscopy has been heavily utilized but there are increasing concerns about the overutilization of this procedure

SUMMARY

Alternative approaches to myofascial pain include multidisciplinary care with a rehabilitative perspective.

Biopsychosocial assessment criteria for functional chronic visceral pain: a pilot review of concept and practice

Functional chronic visceral pain (FCVP) is one of the most common causes of morbidity in the general population. Pain perceived within the abdomen may occur due to a range of different mechanisms according to the organ and their afferent pathways. Advances in our understanding of the complexities of FCVP could lead to the exploitation of contemporary research in order to develop and utilize our understanding of neurobiological and psychobiological visceral mechanisms in a clinical setting. This progression, together with increasing amounts of epidemiological and gender based information concerning specific abdominal pain syndromes can allow us to develop assessment tools that go beyond disease only analysis and move toward a more comprehensive assessment model so that patients may have access to expert or multidisciplinary management sooner, rather than later. Based on current evidence, one must consider the main contributors to pain, whether it is nociceptive, neuropathic or psychosocial or as is common with FCVP, a combination of all three.

AIM

This comprehensive assessment model should encompass not only systematic evaluation for reliable communication, but should also progress toward idiographic diagnosis relating to the uniqueness of the patient. This model should be practical in a multidisciplinary setting, taking into account the multi-faceted nature of this presentation.

Viscero-visceral hyperalgesia: characterization in different clinical models

Co-existing algogenic conditions in two internal organs in the same patient may mutually enhance pain symptoms (viscero-visceral hyperalgesia). The present study assessed this phenomenon in different models of visceral interaction. In a prospective evaluation, patients with: (a) coronary artery disease (CAD)+gallstone (Gs) (common sensory projection: T5); (b) irritable bowel syndrome (IBS)+dysmenorrhea (Dys) (T10-L1); (c) dysmenorrhea/endometriosis+urinary calculosis (Cal)(T10-L1); and (d) gallstone+left urinary calculosis (Gs+LCal) (unknown common projection) were compared with patients with CAD, Gs, IBS, Dys or Cal only, for spontaneous symptoms (number/intensity of pain episodes) over comparable time periods and for referred symptoms (muscle hyperalgesia; pressure/electrical pain thresholds) from each visceral location. In patients' subgroups, symptoms were also re-assessed after treatment of each condition or after no treatment. (a) CAD+Gs presented more numerous/intense angina/biliary episodes and more referred muscle chest/abdominal hyperalgesia than CAD or Gs; cardiac revascularization or cholecystectomy also reduced biliary or cardiac symptoms, respectively (0.001<p<0.05). (b) IBS+Dys had more intestinal/menstrual pain and abdomino/pelvic muscle hyperalgesia than IBS or Dys; hormonal dysmenorrhea treatment also reduced IBS symptoms; IBS dietary treatment also improved dysmenorrhea (0.001<p<0.05) while no treatment of either conditions resulted in no improvement in time of symptoms from both. (c) Cal+Dys had more urinary/menstrual pain and referred lumbar/abdominal hyperalgesia than Cal or Dys; hormonal dysmenorrhea treatment/laser treatment for endometriosis also improved urinary symptoms; lithotripsy for urinary stone also reduced menstrual symptoms (0.001<p<0.05). (d) In Gs+LCal, cholecystectomy or urinary lithotripsy did not improve urinary or biliary symptoms, respectively. Mechanisms of viscero-visceral hyperalgesia between organs with documented partially common sensory projection probably involve sensitization of viscero-viscero-somatic convergent neurons.

Unity vs. diversity of neuropathic pain mechanisms: Allodynia and hyperalgesia in rats selected for heritable predisposition to spontaneous pain

Do contrasting neuropathic pain diagnoses share common pathophysiological mechanisms? Selective breeding was used to derive rat lines with a common genetic background but a striking difference in the degree of spontaneous pain behavior expressed in the neuroma model of neuropathic pain (HA rats (high autotomy) and LA rats (low autotomy)). The contrasting pain phenotype in these lines is attributable to allelic differences at a small number of genetic loci. Here we show that HA and LA rats also differ in their nocifensive response to applied stimuli in the Chung (spinal nerve ligation, SNL) model of neuropathic pain. This includes tactile allodynia and hyperalgesia, and heat allodynia. The degree of hypersensibility varied with sex, age at the time of nerve injury, and the extent of the nerve lesion. F1 crosses of HA and LA rats and inbred Lewis rats showed low levels of autotomy but variable levels of hypersensibility to applied stimuli. Results indicate that alleles which predispose to spontaneous neuropathic pain also predispose to stimulus-evoked pain (allodynia and hyperalgesia). This, in turn, suggests that despite contrasting etiology and behavioral endpoints, pain phenotype in the neuroma and the SNL models shares common pathophysiological mechanisms.

Demonstration of cutaneous allodynia in association with chronic pelvic pain

Pelvic pain is a common condition that is associated with dysmenorrhea and endometriosis. In some women the severe episodes of cyclic pain change and the resultant pain becomes continuous and this condition becomes known as Chronic Pelvic Pain. This state can be present even after the appropriate medical or surgical therapy has been instituted. It can be associated with pain and tenderness in the muscles of the abdomen wall and intra-pelvic muscles leading to severe dyspareunia. Additional symptoms of irritable bowel and interstitial cystitis are common. A common sign of the development of this state is the emergence of cutaneous allodynia which emerges from the so-called viscero-somatic reflex. A simple bedside test for the presence of cutaneous allodynia is presented that does not require excessive time or special equipment. This test builds on previous work associated with changes in sensation related to gall bladder function and the viscera-somatic reflex(1;2). The test is undertaken with the subject s permission after an explanation of how the test will be performed. Allodynia refers to a condition in which a stimulus that is not normally painful is interpreted by the subject as painful. In this instance the light touch associated with a cotton-tipped applicator would not be expected to be painful. A positive test is however noted by the woman as suddenly painful or suddenly sharp. The patterns of this sensation are usually in a discrete pattern of a dermatome of the nerves that innervate the pelvis. The underlying pathology is now interpreted as evidence of neuroplasticity as a consequence of severe and repeating pain with changes in the functions of the dorsal horns of the spinal cord that results in altered function of visceral tissues and resultant somatic symptoms(3). The importance of recognizing the condition lies in an awareness that this process may present coincidentally with the initiating condition or after it has been treated. It also permits the clinician to evaluate the situation from the perspective that alternative explanations for the pain may be present that may not require additional surgery.

Is There a Role for Acupuncture in Endometriosis Pain, Or ‘endometrialgia’?

Endometriosis is a common cause of pelvic pain in women, many of whom suffer a progression of symptoms over their menstrual life. Symptoms may include combinations of abnormal visceral sensations and emotional distress. Endometriosis pain, or ‘endometrialgia’ often has a negative influence on the ability to work, on family relationships and sense of worth.

Endometrialgia is often considered to be a homogeneous sensory entity, mediated by a specialised high threshold sensory system, which extends from the periphery through the spinal cord, brain stem and thalamus to the cerebral cortex. However, multiple mechanisms have been detected in the nervous system responsible for the pain including peripheral sensitisation, phenotypic switches, central sensitisation, ectopic excitability, structural reorganisation, decreased inhibition and increased facilitation, all of which may contribute to the pain.

Although the causes of endometrialgia can differ (eg inflammatory, neuropathic and functional), they share some characteristics. Endometrialgia may be evoked by a low intensity, normally innocuous stimulus (allodynia), or it may be an exaggerated and prolonged response to a noxious stimulus (hyperalgesia). The pain may also be spontaneous in the absence of any apparent peripheral stimulus.

Oestrogens and prostaglandins probably play key modulatory roles in endometriosis and endometrialgia. Consequently many of the current medical treatments for the condition include oral drugs, like non-steroid anti-inflammatory drugs, contraceptives, progestogens, androgenic agents, gonadotrophin releasing hormone analogues, as well as laparoscopic surgical excision of the endometriosis lesions. However, management of pain in women with endometriosis is currently inadequate for many. Possibly acupuncture and cognitive therapy may be used as an adjunct.