Dysmenorrhea is painful menstrual cramps. Primary dysmenorrhea is the pain, often incapacitating, that accompanies periods only when secondary dysmenorrhea, due to underlying pathology, is excluded.

Pathophysiology: Primary dysmenorrhea is the direct result of the peak levels of prostaglandins at menses in an ovulatory cycle. This results in increased rhythmic uterine contractions from vasoconstriction of the small vessels in the uterine wall. Increased prostaglandins synthesis also may be responsible for the distressing gastrointestinal symptoms occasionally present.

Secondary dysmenorrhea may include the effects of excess prostaglandins, as well as excessive uterine contractions secondary to an underlying pathology such as endometriosis, adenomyosis, infection, or another underlying disease.

Frequency:
 

• In the US: Approximately 40% of adult females have menstrual pain, and 10% are incapacitated for 1-3 days each month.

Mortality/Morbidity: While primary dysmenorrhea is not life threatening, it is the most common reason women miss work. Dysmenorrhea is a leading cause of absenteeism for women younger than 30 years. Diagnose dysmenorrhea only after serious causes of pelvic pain are excluded.

Age:

• Primary dysmenorrhea most commonly begins within a few years of onset of ovulatory cycles at menarche.

• Secondary dysmenorrhea can occur with an anovulatory cycle years after the onset of menarche.

History:

• Pain with primary dysmenorrhea usually starts within 24 hours of menses and may last for 48-72 hours.

• In secondary dysmenorrhea, the patient may have onset of pain a week or more prior to the onset of menses, and pain may continue for a few days after cessation of flow.

• History should include a review of systems with particular attention to gynecologic and gastrointestinal systems. Pay particular attention to the description of pain.

• Gynecologic history should include menarche, abnormal vaginal bleeding, discharge, dyspareunia, and infertility.

• The type and severity of pain is important. Inquire about the radiation of the pain and associated symptoms, including the following:

• Headache

• Suprapubic cramping

• Backache

• Pain radiating down to anterior thigh

• Nausea and vomiting

• Diarrhea

• Syncope

Physical: In the initial physical examination, include complete evaluation of the patient in pain and the exclusion of serious underlying pathology.

• Primary dysmenorrhea

• Vital signs are normal.

• Pelvic examination may disclose a tender uterus but no cervical motion tenderness or adnexal abnormalities.

• Secondary dysmenorrhea

• Vital signs may vary depending on the underlying etiology.

• Perform pelvic examination to determine uterine size and mobility. Adnexal tenderness and enlargement may be noted. Evaluate uterosacral ligaments and rectovaginal septum for palpable abnormalities or nodularities.

• The absence of physical findings does not completely exclude secondary dysmenorrhea. In endometriosis, the ectopic endometrial tissue may be observed only on direct visual examination. Since exact diagnosis is beyond the scope of the emergency department (ED), refer the patient for gynecologic evaluation and possible diagnostic laparoscopy and laparotomy.

Causes:

• Primary dysmenorrhea is caused by elevated production of prostaglandins and other mediators in the uterus, which produce uterine ischemia through the following:

• Platelet aggregation

• Causes of secondary dysmenorrhea include the following:

• Endometriosis (ectopic endometrial tissue)

• Adenomyosis (endometrial tissue within uterine wall)

• Pelvic infection (acute, subacute salpingitis)

• Intrauterine device

• Risk factors for primary dysmenorrhea include the following:
  • Nulliparity
  • Obesity
  • Cigarette smoking
  • Positive family history

• Risk factors for secondary dysmenorrhea include the following:
  • Pelvic infection
  • Sexually transmitted diseases
  • Endometritis