Dysmenorrhea

Dysmenorrhea, or painful menstruation, is one of the most common complaints of gynecologic patients. Many women experience mild discomfort during menstruation, but the term dysmenorrhea is reserved for women whose pain prevents normal activity and requires medication, whether an over-the-counter or a prescription drug.

There are 3 types of dysmenorrhea: (1) primary (no organic cause), (2) secondary (pathologic cause), and (3) membranous (cast of endometrial cavity shed as a single entity). This discussion focuses mainly on primary dysmenorrhea. Secondary dysmenorrhea is discussed elsewhere in this book in association with specific diseases and disorders (eg, endometriosis, adenomyosis, pelvic inflammatory disease, cervical stenosis, fibroids, and endometrial polyps). Membranous dysmenorrhea is rare; it causes intense cramping pain due to passage of a cast of the endometrium through an undilated cervix. Another cause of dysmenorrhea that should be considered is cramping due to the presence of an intrauterine device (IUD).

Pathogenesis

Pain during menstruation has long been known to be associated with ovulatory cycles. The mechanism of pain has been attributed to prostaglandin activity. Prostaglandins are present in much higher concentrations in women with dysmenorrhea than in those with mild or no pain.

Other studies have confirmed increased leukotriene levels as a contributing factor. Vasopressin was thought to be an aggravating agent, but atosiban, a vasopressin antagonist, has shown no effect on menstrual pain.

Psychologic factors may be involved, including attitudes passed from mother to daughter. Girls should receive accurate information about menstruation before menarche; this can be provided by parents, teachers, physicians, or counselors. Emotional anxiety due to academic or social demands may be a cofactor.

Clinical Findings

Reactions to pain are subjective, and questioning by the physician should not lead the patient to exaggerate or minimize her discomfort. History taking is most important and should include the following questions: When does the pain occur? What does the patient do about the pain? Are there other symptoms? Do oral contraceptives relieve or intensify the pain? Does the pain become more severe over time?

Because dysmenorrhea almost always is associated with ovulatory cycles, it does not usually occur at menarche but rather later in adolescence. As many as 14–26% of adolescents miss school or work as a result of pain. Typically, pain occurs on the first day of the menses, usually about the time the flow begins, but it may not be present until the second day. Nausea and vomiting, diarrhea, and headache may occur. The specific symptoms associated with endometriosis are not present.

The physical examination does not reveal any significant pelvic disease. When the patient is symptomatic, she has generalized pelvic tenderness, perhaps more so in the area of the uterus than in the adnexa. Occasionally, ultrasonography or laparoscopy is necessary to rule out pelvic abnormalities such as endometriosis, pelvic inflammatory disease, or an accident in an ovarian cyst.

Differential Diagnosis

The most common misdiagnosis of primary dysmenorrhea is secondary dysmenorrhea due to endometriosis. With endometriosis, the pain usually begins 1–2 weeks before the menses, reaches a peak 1–2 days before, and is relieved at the onset of flow or shortly thereafter. Severe pain during sexual intercourse or findings of adnexal tenderness or mass or cul-de-sac nodularity, particularly in the premenstrual interval, help to confirm the diagnosis (see Chapter 43). A similar pain pattern occurs with adenomyosis, although in an older age group and in the absence of extrauterine clinical findings.

Treatment

NSAIDs or acetaminophen may relieve mild discomfort. Addition of continuous heat to the abdomen in addition to NSAIDs decreases pain significantly. For severe pain, codeine or other stronger analgesics may be needed, and bed rest may be desirable. Occasionally, emergency treatment with parenteral medication is necessary. Analgesics may cause drowsiness at the dosages required.

Antiprostaglandins

Antiprostaglandins are now used for treatment of dysmenorrhea. The newer, stronger, faster-acting drugs appear to be more useful than aspirin. Ibuprofen, an NSAID that is available over the counter and in prescription strength, has been extremely effective in reducing menstrual prostaglandin and relieving dysmenorrhea. Less frequently dosed naproxen (550 mg/day) also is effective. Cyclooxygenase-2 (COX-2) inhibitors such as valdecoxib (20–40 mg/day) is equally effective and has fewer gastrointestinal side effects, but it is more costly. The drug must be used at the earliest onset of symptoms, usually at the onset of, and sometimes 1–2 days prior to, bleeding or cramping.

Antiprostaglandins work by blocking prostaglandin synthesis and metabolism. Once the pain has been established, antiprostaglandins are not nearly as effective as with early use.

Oral Contraceptives

Cyclic administration of oral contraceptives, usually in the lowest dosage but occasionally with increased estrogen, prevents pain in most patients who do not obtain relief from antiprostaglandins or cannot tolerate them. The mechanism of pain relief may be related to absence of ovulation or to altered endometrium resulting in decreased prostaglandin production. In women who do not require contraception, oral contraceptives are given for 6–12 months. Many women continue to be free of pain after treatment has been discontinued. NSAIDs act synergistically with oral contraceptive pills to improve dysmenorrhea.

Surgical Treatment

In a few women, no medication controls dysmenorrhea. Cervical dilatation is of little use. Laparoscopic uterosacral ligament division and presacral neurectomy are infrequently performed, although some physicians consider these procedures to be important adjuncts to conservative operation for endometriosis.

Adenomyosis, endometriosis, or residual pelvic infection unresponsive to medical therapy or conservative surgical therapy eventually may require hysterectomy with or without ovarian removal in extreme cases. Rarely a patient with no organic source of pain eventually requires hysterectomy to relieve symptoms.

Adjuvant Treatments

Continuous low-level topical heat therapy has been shown to be as effective as ibuprofen in treating dysmenorrhea, although its practicality in daily life may be questionable. Many studies have indicated that exercise decreases the prevalence and/or improves the symptomatology of dysmenorrhea, although solid evidence is lacking.

Diets low in fat and meat products have been shown to decrease serum sex-binding globulin and decrease the duration and intensity of dysmenorrhea.