Pelvic Pain and Endometriosis

Pelvic Pain

Physiological pelvic pain with menstruation or childbirth is almost universal, but many women have pelvic pain for other reasons. Pelvic pain can be acute (associated with miscarriage, ectopic pregnancy, or appendicitis) or it can be chronic, lasting for many months or years.

With acute pain, there is usually a well-defined pathological cause that either resolves spontaneously or can be effectively treated. It is important to recognise that chronic pelvic pain (CPP) is a symptom, not a diagnosis. CPP is as common as migraine or lower back pain. Aiming for accurate diagnosis and effective management from the first presentation may help to improve the woman’s quality of life, and may avoid a succession of referrals, investigations and operations.

Pelvic pain is considered under the two headings of ‘acute’ and ‘chronic’, and there is often significant overlap. Although there are many gynaecological causes of pelvic pain, the non-gynaecological causes are also important. Therefore, a multidisciplinary approach, particularly for women with CPP, is required.

Pain is a subjective phenomenon, meaning it is a symptom experienced solely by the woman. Many of the factors affecting pain are centrally mediated; hence, pelvic pain is often made worse by psychological, psychiatric, or social distress. The organs within the peritoneal cavity (the viscera) are sensitive to inflammation, chemicals and distortion caused by specific stimuli (e.g., adhesions or gaseous distension). The sensitivity of different organs to stimuli is an important factor influencing the amount of pelvic pain experienced. Compression of the bowel is associated with minimal discomfort, whereas stretching and distension cause severe pain. Unlike painful cutaneous stimuli, it is often very difficult to localize visceral pain.

History

The history is the most important factor in determining how quickly the diagnosis is reached and appropriate treatment is started. Particular attention should be given to the time of onset of the pain; the characteristics, radiation and severity of the pain; exacerbating and relieving factors; cyclicity; and analgesic requirements. Associated symptoms of gastrointestinal, urological or musculoskeletal origin should be ascertained. It is also important to take a detailed menstrual history – in particular, the frequency and character of vaginal bleeding, any intermenstrual bleeding or vaginal discharge, and their relationship to the pain. A sexual history may be of help, particularly superficial or deep dyspareunia, contraception and sexually transmitted infections (STIs). There may be a family history of gynaecological disorders (e.g., endometriosis). A cervical screening history should be recorded.

With chronic pain, there is often value in taking a detailed family and social history, including any relationship problems, pressure at work, financial worries and whether there has been previous sexual abuse. Listening is centrally important to the history taking and may, in itself, be therapeutic for some women. Asking open-ended questions such as ‘What do you think the cause of your pain might be?’ and ‘How is the pain affecting your life?’ gives the woman an opportunity to tell you about aspects of the problem that might not be apparent from a more systematic history.

If the history suggests there is a non-gynaecological component to the pain, referral to the relevant health care professional – such as a gastroenterologist, urologist, genitourinary medicine physician, physiotherapist, psychologist, or psychosexual counsellor – should be considered.

Examination

A detailed account of how to undertake a gynaecological history and examination is described in Chapter 2. Clinical examination is most usefully undertaken when there is time to explore the woman’s fears and anxieties. The examiner should be prepared for new information to be revealed at this point. Observation of the woman’s general demeanour is important when assessing the severity of pain. Collateral accounts from other health professionals and friends or family may also be helpful. The temperature, pulse and blood pressure should be recorded and a urinary pregnancy test (UPT) performed when appropriate.

Abdominal examination should include inspection for distension or masses, palpation for tenderness, rebound, guarding and abdominal auscultation if gastrointestinal obstruction or ileus is suspected. Inspection of the vulva and vagina at speculum examination may reveal abnormal discharge (suggestive of infection) or bleeding. A bimanual examination may reveal uterine or adnexal enlargement suggestive of a pelvic mass, fibroids, or an ovarian cyst. Cervical excitation (pain associated with digital displacement of the cervix) is associated with ectopic pregnancy and pelvic infection. Tenderness or pain elicited by bimanual palpation of the pelvic organs themselves is suggestive of an ongoing inflammatory process, which may be infective (e.g., Chlamydia ) or non-infective (e.g., endometriosis). A fixed, immobile uterus suggests multiple adhesions, and nodules felt on the uterosacral ligaments can be a feature of endometriosis.

Acute Pelvic Pain

There are many causes of acute pelvic pain, but the most important gynaecological conditions are ectopic pregnancy, miscarriage, pelvic inflammatory disease and torsion or rupture of ovarian cysts ( Box 8.1 ). If the UPT is negative, a high vaginal swab, endocervical swab and full blood count should be performed to investigate for infection. All sexually active women below the age of 25 years who are being examined can be offered opportunistic screening for Chlamydia . An ultrasound scan is helpful in identifying ovarian cysts.

The management of miscarriage, pelvic inflammatory disease and ovarian cysts is discussed in the appropriate chapters. Pain experienced mid-cycle with ovulation, the so-called ‘mittelschmerz’, is a self-limiting, physiological cause of pain. This pain is usually sudden in onset, can be quite severe, and, if persistent in each cycle, will respond to ovulation suppression with hormonal contraception.

Chronic Pelvic Pain (CPP)

The definitions of CPP are numerous, but one suitable definition is ‘intermittent or constant pain in the lower abdomen or pelvis of at least 6 months’ duration, not occurring exclusively with menstruation or intercourse and not associated with pregnancy’. A comparison between acute pelvic pain and CPP is shown in Table 8.1 . CPP can lead to loss of employment and relationship difficulties, including divorce. Health care costs associated with CPP are considerable and do not take into consideration the disability and suffering of the woman and loss of earnings to both the individual and wider society. Among high-quality studies, the rate of dysmenorrhoea was 16.8% to 81%, that of dyspareunia was 8% to 21.8%, and that of non-cyclical pain was 2.1% to 24% worldwide.

The care of women with CPP is particularly challenging, as there are many possible causes and contributory factors ( Box 8.2 ). Association with dysmenorrhoea, dyspareunia, irregular menstruation, abnormal vaginal discharge, cyclical pain and subfertility may all be helpful in suggesting an underlying gynaecological problem. Altered bowel habits, excess flatulence, intermittent abdominal bloating, constipation, or diarrhoea, on the other hand, point to a gastrointestinal problem, particularly irritable bowel syndrome (IBS). However, these bowel symptoms can also be associated with the presence of gynaecological pathology, such as endometriosis. Psychiatric, urological and musculoskeletal causes of chronic pain are further possibilities. Physical and sexual abuse can also predispose women to CPP.

Known gynaecological causes of CPP include endometriosis, adhesions and pelvic varices. Adhesions can cause pain if there is associated organ distension, stretching, or tethering. Division of dense adhesions has been shown to relieve pain. Symptoms suggestive of IBS or interstitial cystitis are often present in women with CPP. These conditions may be the primary cause of or a component of CPP.

Up to 40% of women with CPP, despite extensive investigation, do not have an identifiable cause. It is therefore important to consider, in consultation with the woman, which investigations are worthwhile. In gynaecology, investigation can involve a diagnostic laparoscopy, the findings of which guide the approach to care.