Dysmenorrhea

Dysmenorrhea is defined as cramping pain in the lower abdomen occurring at the onset of menses. Dysmenorrhea is commonly divided into two main categories:

Primary dysmenorrhea, when there is no discernible pelvic pathology

Secondary dysmenorrhea, which is due to pelvic pathology such as endometriosis.

Primary dysmenorrhea is a diagnosis of exclusion. A thorough history and physical will help determine if there is any pelvic pathology.
Table 103.5 will help to differentiate primary from secondary dysmenorrhea.

Primary Dysmenorrhea

Primary dysmenorrhea is the most common menstrual disorder in women. Women with dysmenorrhea often experience sharp, intermittent spasms of pain, usually centered in the suprapubic area. Pain may radiate to the back of the legs or the low back. Systemic symptoms of nausea, vomiting, diarrhea, fatigue, fever, headache, or light-headedness are fairly common. Pain usually starts within hours of onset of menses and peaks within the first 1 to 2 days.

There are some theories that smoking, obesity, and alcohol consumption are related to more dysmenorrhea, but these remain controversial. The etiology of primary dysmenorrhea is not precisely understood, but most symptoms can be explained by the action of uterine prostaglandins, particularly PGF₂. This prostaglandin is released as the endometrium sloughs, causing uterine contractions.

Treatment of Primary Dysmenorrhea

NSAIDs are the first choice for treatment. NSAIDs work through prostaglandin synthetase inhibition. Prostaglandins are felt to be responsible for the uterine contractions and the systemic symptoms mentioned such as nausea and diarrhea. If one particular NSAID is not effective, try one from another class.

Oral contraceptives are second-line therapy unless a woman is also seeking contraception, then they would become first-line therapy. Oral contraceptives are 90% effective in improving primary dysmenorrhea and work by reducing menstrual blood volume and suppressing ovulation. It may take up to 3 months for the oral contraceptives to become effective. Norplant and Depo-provera are also effective since these methods often induce amenorrhea.

For the 10% of patients who do not respond to NSAIDs and/or oral contraceptives, a wide range of alternative therapies have been proven effective, including transcutaneous electrical nerve stimulation (TENS), acupuncture, omega-3 fatty acids, transdermal nitroglycerin, thiamine, and magnesium supplements.

Secondary Dysmenorrhea

The onset of secondary dysmenorrhea generally occurs after age 25. The pelvic pathology can be divided into uterine causes and extrauterine causes. The uterine causes are adenomyosis, pelvic inflammatory disease, cervical stenosis, polyps, fibroids, and IUDs. The extrauterine causes are endometriosis; inflammation and scarring (adhesions); functional ovarian cysts; benign or malignant tumors of the ovary, bowel, or bladder; and inflammatory bowel disease. Some of these disorders can be determined by a careful pelvic exam. The two most important diagnostic steps are a pelvic ultrasound, including an intravaginal probe component, and laparoscopy.