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The planning of effective services for patients with particular conditions demands an understanding of epidemiology, pathophysiology and therapy. In the case of chronic pain in general, and chronic pelvic pain in particular, elements of the pathophysiology are beginning to be elucidated, and certain treatments that were formerly deployed only in pain clinics are now entering use in gynaecological settings. These developments have been reviewed elsewhere1. Here we assess the scale of the health problem posed by chronic pelvic pain (CPP) and the kind of clinical services that would optimize outcomes.
Thanks to population based studies in the USA and in the UK, robust estimates of the incidence and prevalence of CPP are now available. The first of these was an opinion-poll-style telephone survey2 in which American women aged 18-50 were interviewed about pelvic pain related symptoms. 17 927 households were contacted and 5325 women agreed to participate. Of these, 925 reported pelvic pain of at least six months' duration, including pain within the past three months. After exclusion of those who were pregnant or postmenopausal or having only cycle-related pain, 773/5263 (14.7%) were identified as suffering from chronic pelvic pain. Direct costs of healthcare, estimated from Medicare tariffs and hence very conservative, were $881.5 million; patients' out-of-pocket expenses were $1.9 billion; and indirect costs due to time off work were $555.3 million.
A British postal survey included 2016 women randomly selected from the Oxfordshire Health Authority register of 141 000 women aged 18-493. In this study chronic pelvic pain was defined as recurrent pain of at least six months' duration, unrelated to menstruation, intercourse or pregnancy. For the survey, a ‘case’ was defined as a woman with chronic pelvic pain in the previous three months, and on this basis the prevalence was 483/2016 (24.0%). Among those with pelvic pain, dysmenorrhoea was reported by 81% of those who had periods and dyspareunia was reported by 41% of those who were sexually active. Among women who did not have chronic pelvic pain as defined above, dysmenorrhoea was reported by 58% of those who had periods and dyspareunia by 14% of those who were sexually active.
Not all women who experience CPP consult their general practitioner about it, and of those who do, not all are referred for hospital investigation. Among the 483 Oxfordshire women with chronic pelvic pain, 195 (40%) had not sought a medical consultation, 127 (26%) reported a past consultation and 139 (29%) reported a recent consultation for pain3. Another study by the Oxford group analysed contacts with general practitioners by means of data from a national database: of women identified as cases of pelvic pain, 28% were not given a specific diagnosis and 60% were not referred to hospital4. It is noteworthy that these national data have shown consulting rates to be just as high among older women, whose experiences have so far not been studied at the population level.
The US population-based study likewise drew attention to the large numbers of women who have troublesome symptoms but do not seek medical attention: 75% of this sample had not seen a healthcare provider in the previous three months. It is possible that not seeking care would indicate milder symptoms, and indeed in the US study those who did seek medical attention had higher pain and lower general health scores than those who did not. However, among those not seeking help, scores for pain and functional impairment were still substantial.
The impact of chronic pelvic pain on health-related quality of life has been assessed by use of the SF-36 questionnaire in the Oxfordshire study and also among women referred by general practitioners to a gynaecology outpatient clinic in Southampton (i.e. not a specialized pain service). The SF-36 has eight subscales which can be concatenated into two summary scales, the ‘mental component’ and the ‘physical component’6. Figure 1, based on data from the Oxfordshire and Southampton studies, uses these scales to illustrate the trend in mental and physical quality-of-life impact among women with CPP—on a spectrum ranging from those who seek medical advice, through to those investigated in hospital.
In the general hospital series described above, a spectrum of chronicity and severity of pain was reported. At six-month follow-up most women reported improvement of their pain: just under one-quarter reported complete resolution and the median visual analogue score for ‘usual level of pain’ fell from 67 to 20 on a 100 mm scale. In a multivariate analysis improvement was associated with a range of illness and consultation related variables; for example, the presence of endometriosis was associated with a higher level of continuing pain, while a good initial consultation had a favourable influence on outcome, especially in those without exercise impairment7. Thus far, however, good or bad outcome cannot be predicted with accuracy. In the context of general gynaecological practice, what steps can be taken to optimize the outcome of referrals and consultations for chronic pelvic pain?
The typical woman who reaches the gynaecologist has experienced symptoms for months or years before consulting even her general practitioner. She has high expectations of her consultation with the specialist. By contrast, the gynaecologist may see the purpose of the visit as to rule out organic abnormality (which will seldom be present). A risk of a mismatch of expectations exists, and this is doubtless part of the reason for women's reported frustration and dissatisfaction with such contacts8,9. These negative elements of the consultation can be counteracted by efforts on the part of the clinician to establish the patient's goals and expectations, and to meet them as far as possible. For many women, explanation of the cause of symptoms is as important as the pursuit of symptomatic relief; for others, the objective is symptom control.
In view of the high prevalence of irritable-bowel syndrome (IBS) in the female population and the considerable overlap of this form of visceral pain with CPP, the history must include detailed enquiry about bowel function. IBS is a clinical diagnosis based on a constellation of suggestive symptoms including diarrhoea, constipation and abdominal distension in association with acute episodes of pain. Distension is a common symptom in the premenstrual phase of the cycle and this needs to be distinguished from distension associated with pain. Dyspareunia should not be ascribed to IBS unless the pain is described as building up after rather than during intercourse. Abdominal and pelvic examination can be helpful in identifying a loaded large bowel in those who have an apparently normal bowel habit but are in fact chronically constipated. Stimulant laxatives such as sodium picosulphate elixir are more appropriate than bulking agents or lactulose, which can exacerbate bloating and colonic spasm10.
Whether a woman with CPP proves to have endometriosis or no evident disease, her likelihood of a concomitant mood disorder is the same11. Clearly, mood disorder is easily missed in a general gynaecology clinic; however, simple enquiry about mood and sleep should be routine. There is no evidence that antidepressant treatment per se will ameliorate the symptoms of CPP12, but treatment of depression or anxiety will improve the patient's general quality of life. It is important to identify individuals with multiple unexplained physical symptoms, who may be at risk of inappropriate surgical or medical treatment; in such cases, psychiatric liaison referral is called for13.
For women who have not responded to initial investigation and treatment, further management demands strategies beyond the capacity of a typical gynaecology clinic. In a pain clinic the aim is to ameliorate symptoms while avoiding the adverse effects of long-term therapy. Pain clinics tend to focus on functional capacity, and key elements of this approach are a halt to further investigations, provision of continuity of care and the offer of follow-up on a time-contingent rather than pain-contingent basis. Services include direct pain-relieving interventions including the use of tricyclic antidepressants, anticonvulsants or nerve blockade. The multi-disciplinary ‘package’ may include cognitive behavioural psychotherapy, physiotherapy, nursing support (especially for problems with medications between clinic visits) and the use of complementary treatments such as acupuncture. Some elements of the programme can be offered to groups rather than individuals, and this not only saves money but also yields peer support.
Information about women referred to British pain clinics for chronic pelvic pain is available from the Pain Society's PACS database, to which many units contribute anonymous data in a standard format. During 1998-2001, of 284 women identified as having chronic pelvic pain, 200 reported that the symptom had been present for more than two years. Scores on the various dimensions of the Brief Pain Inventory were very similar to those in the general pain clinic population (Figure 2). However, the range of treatments offered was rather different, with medication preferred over injections (Figure 3). Psychotherapy and physiotherapy were little used, doubtless because most UK clinics have very limited access to those treatments.
The results of CPP referral to pain clinics have not been notably encouraging. Why should women with CPP fare less well than, say, those with longstanding musculoskeletal pain? One reason is that many will still be in search of a cure—perhaps even appropriately, since treatable conditions such as endometriosis, ovarian entrapment post-hysterectomy or abdominal wall nerve related pain sometimes go unrecognized. Moreover, group activities can be difficult when participation requires a woman to speak of intimate and embarrassing symptoms. There is therefore a strong case for a targeted multidisciplinary service configuration where women are seen in a specific clinic including a gynaecologist as well as the pain management team. The role of the gynaecologist is to identify treatable disease or functional conditions that can be influenced to reduce the level of pain. For example, hormonal manipulations are helpful in pain related to pelvic congestion and endometriosis, and access to laparoscopic surgery is essential for those with continuing active endometriosis. Specific advice may be required when the adjunctive therapy interacts with existing medication—for example carbamazepine and the combined oral contraceptive pill. For women who have undergone several unsuccessful interventions and who are now experiencing neuropathic or post-surgical pain the gynaecologist's continued interest can ease the patient's reorientation towards a pain-managment mode of thinking, and enable her to give up the fruitless quest for a specific cure. Strategies such as cognitive behavioural therapy require a high level of motivation which is absent in those who still believe that the doctor can get rid of the pain.
The main evidence to support a multidisciplinary approach to CPP comes from a randomized trial conducted in Leiden14. This study showed a benefit for the multidisciplinary approach versus conventional management in self-assessment and quality-of-life outcomes, but not in McGill pain score—a result consistent with the typical objectives of a pain management programme. There are questions to be addressed about the configuration of a multidisciplinary clinic: which elements are essential and which peripheral to success? There is strong (grade A) evidence for the effectiveness of cognitive behavioural therapy in other chronic pain conditions15. We cannot ask for randomized trials of every component in comparison with all the others, so future clinical practice will need to be guided by observational studies and audits of clinical outcomes. At present, cost—utility analysis is required to assess the effectiveness of multidisciplinary care for CPP patients in relation to the high costs of provision, set against the benefits to the patient in terms of functional improvement and the avoidance of subsequent multiple referral, investigative procedures and surgery.
In the UK, access to multidisciplinary pelvic pain clinics is at present very limited, and a much greater provision is desirable16. Meanwhile some form of triage will continue to be required—based on severity of pain and functional impairment and an incomplete response to conventional gynaecological treatment—to identify those most in need of those extra resources. But longitudinal research might well show that this sort of triage is entirely the wrong approach: a better strategy might be to intervene rapidly when a woman has a new episode of pain, so preventing progression into functional impairment and the chronic pain state.
Clinicians can do much to improve the experience of care for women with chronic pelvic pain, and to bring into the gynaecological setting some of the insights that have influenced current pain management approaches. As the burden of illness and functional impairment resulting from CPP becomes ever clearer there will be growing demand for health services that offer a full range of treatments.