Chronic Pelvic Pain: It isn't all in her head

By Steven D. McCarus, MD

Chronic pelvic pain poses a significant problem in women's health care in the United States for patients and clinicians, and in overall costs to the health care system. An estimated 9 million American women, or nearly 15% of women in their reproductive years, have chronic pelvic pain (CPP), defined as pelvic pain that lasts longer than 6 months.¹

Three of 4 women who experience CPP do not recognize the serious implications and do not seek consistent medical management. More than half never receive any diagnosis.¹ Instead, they rely on over-the-counter pain medications, jumping from physician to physician or visiting urgent care centers whenever symptoms worsen. Only about 10% of women with CPP are under the care of a physician for this condition.

A diagnostic challenge
Accurately diagnosing CPP can be a painstaking process of elimination requiring patience, diligence, and compassion. There can be numerous explanations for pelvic pain. Once anatomic, GI, and genitourinary causes are ruled out, there is an 80% chance that the patient has pelvic endometriosis.²

Approximately 5.5 million women in North America have endometriosis, one of the top 3 causes of infertility, which affects 30% to 40% of women with endometriosis.³ The resultant pain can destroy sexual relations in a marriage and lead to depression as women lose hope for finding a solution. It is also the leading reason for hysterectomy and the third most likely reason for hospitalization of women during their childbearing years.⁴

Historically, the disease has been dubbed "husbanditis" because the complaint of pelvic pain during intercourse was deemed an excuse to avoid sexual encounters. This bias may still linger today. Because of the difficulty of diagnosing the disorder, in some cases it may be tempting to consider that the pain is "all in the patient's head." However, current research shows that with rare exceptions, such as in cases of sexual abuse, trauma, or mental illness, endometriosis is a real disorder in need of medical intervention.

It is challenging for busy primary care clinicians to commit the time to properly take a thorough patient history in order to rule out the many disorders that can present in the same way as endometriosis. On average, it takes a woman 9 years to receive a diagnosis of endometriosis.

While symptoms of endometriosis are varied, many patients complain of dysmenorrhea, dyspareunia, heavy or irregular bleeding, and infertility. A questionnaire distributed by the Endometriosis Association revealed that 100% of respondents experienced pain 1 to 2 days prior to menstruation, and 71% reported pain midcycle.

Less common are reports of bowel or bladder symptoms, including painful defecation or urination, lower back pain, or pain that radiates down one or both legs, particularly during menstrual periods. Endometriotic pain can be either cyclic or noncyclic. It is essential to note that some women with even advanced endometriosis have no symptoms, and that the size or number of growths is not directly correlated to pain.

Although some primary care clinicians may choose to refer these patients directly to a gynecologist, many diagnostic eliminations can be completed by the general practitioner. First, the clinician should complete a thorough review to rule out conditions such as ruptured ovarian cyst, ectopic pregnancy, appendicitis, GI disorders, urologic or neurologic conditions, musculoskeletal disorders, psychological issues, and domestic violence.

Knowing when to refer
If the patient has suffered CPP of at least 3 to 6 months' duration, and has been unresponsive to a trial of nonsteroidal anti-inflammatory drugs (NSAIDs) and/or oral contraceptives, a diagnosis of endometriosis should be suspected and referral to a gynecologist would be appropriate.

Thorough rectal examination and pelvic examination of the uterus, ovaries, fallopian tubes, and cervix are essential. If possible, the examination should be performed during early menses when endometrial lesions are likely to be at their largest and most tender (FIGURE). An axis deviation of the uterus is an anatomic sign that endometriosis may be retracting a ligament, causing the uterus to tilt.

During the rectal examination, the physician will test for focal tenderness at the uterosacral ligaments, cardinal ligaments, and rectovaginal septum. Focal tenderness is associated with a 97% chance that a lesion exists in the area that will be visible during laparoscopy and a 66% chance that the lesion is related to endometriosis.⁵
The physician should test for adnexal and uterine tenderness, looking for retroflection of the uterus, limited uterine mobility, pelvic masses, and uterosacral ligaments that may be indurated or nodular. The rectovaginal examination should focus on uterosacral, cul-de-sac, and septal nodules.

Imaging studies can be extremely helpful during the workup for CPP. Pelvic ultrasound can detect ovarian endometriomas with a high level of sensitivity and specificity and, when performed transrectally, has been used with some success to diagnose rectovaginal endometriosis.^6,7 Magnetic resonance imaging (MRI) also shows a high level of sensitivity. However, neither MRI nor ultrasonography can detect peritoneal endometrial implants.⁸ If the ultrasound shows any abnormality, a laparoscopy should be recommended.

While some patients may insist on laparoscopic confirmation, the procedure provides a relatively definitive diagnosis rate of 43% to 45%.^9,10 The patient should be informed that established practice today is to treat the condition empirically without surgical diagnostic confirmation due to its limitations.¹¹ In addition, successful diagnosis is closely linked to surgical expertise. In one study endometriosis was detected in only 28% of patients, whereas experienced laparoscopists found the condition in 70% of their cases.^12,13

A finding of no focal tenderness in a patient with CPP suggests that the disease is in its early stages and infertility is not yet an issue. In this case, it is appropriate to inform the patient that it is safe and effective to empirically treat her for endometriosis even in the absence of surgical confirmation.

Weighing the options for treatment
Hysterectomy is considered the only cure for endometriosis; however, it is clearly a last resort. Treatment generally progresses from simple pain relievers, to oral contraceptives, to medications that mimic pregnancy or menopause for women who don't wish to become pregnant. Many women experience relief with a low dose of the testosterone derivative danazol (roughly 100 to 200 mg per day). The androgenic progesterone-related side affects with this therapy can include weight gain, acne, muscle cramps, unwanted hair growth, voice deepening, water retention, and, occasionally, liver problems, as the liver has to metabolize this drug.

The gonadotropin-releasing hormone agonist, GnRHa, temporarily lowers the levels of estrogen, reducing endometriotic growths and relieving symptoms. Drugs such as leuprolide acetate for depot suspension can be administered once every 3 months (11.25 mg) or once each month (3.75 mg) for a 6-month treatment period. Side effects may be those associated with menopause, including hot flashes and loss of bone density. Add-back therapy (norethindrone acetate 5 mg daily) can reduce the hypoestrogenic side effects of GnRH agonists. These treatments may also be used to inhibit recurrence following laparoscopic surgery to remove growths and lesions. Finally, since endometriosis includes a high rate of infertility, patients who wish to have children may be counseled regarding the risks of waiting.

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