Approach to dysmenorrhea: Clinical sciences

Dysmenorrhea is pain with menstruation. It can be primary in nature, meaning pain without pelvic pathology; or secondary indicating pain from pelvic pathology or a recognized medical condition. Causes of secondary dysmenorrhea include endometriosis, adenomyosis, uterine leiomyomas, adnexal masses, pelvic inflammatory disease, vaginal obstructive anomalies, and cervical stenosis. Dysmenorrhea is one of the most common gynecologic conditions and can have a significant impact on your patients’ physical and mental well-being.

Let’s begin with primary dysmenorrhea. When evaluating a patient your first step is to obtain a focused history. Pain typically begins with the onset of ovulatory cycles, which usually occurs within 6-12 months following menarche. The pain is typically located in the lower back, pelvis, and/or the upper thighs. It can be associated with other symptoms, like nausea, vomiting, diarrhea, headaches, muscle cramps, and poor sleep. If your patient’s history meets these criteria, you can diagnose primary dysmenorrhea, which is more common in adolescence.

Here’s a clinical pearl! Keep secondary dysmenorrhea in mind for patients whose symptoms do not improve within 3 to 6 months of treatment; whose symptoms are progressively worsening; or if pelvic pathology is suspected.

Okay, let's move on to secondary dysmenorrhea. On history, common symptoms might include severe dysmenorrhea, which may have begun immediately after menarche or may have developed some time after menarche; progressively worsening dysmenorrhea; abnormal uterine bleeding; mid-cycle or acyclic pain; infertility; lack of response to empiric medical treatment…

Other symptoms can be dyspareunia or pain with intercourse, pelvic pain associated with vaginal discharge, and family history of pelvic pathology, such as endometriosis or congenital anomalies. Any of these symptoms should raise your suspicion for underlying pelvic pathology and secondary dysmenorrhea. Now let’s assess for causes of secondary dysmenorrhea.

Let’s start with the most common one, endometriosis. This is characterized by endometrial stroma or glandular tissue outside of the endometrial cavity. A focused history may reveal the 4 “Ds” of endometriosis: dysmenorrhea, dyspareunia, dyschezia or painful defecation, and in some patients, non-bacterial dysuria. These symptoms, as well as generalized pelvic pain, are often exacerbated by menses and can be cyclic in nature.

On a physical exam, you might find lower abdominal or pelvic tenderness, a pelvic mass, reduced uterine mobility, a tender posterior vaginal fornix, and rectovaginal nodularity. If this is the case, consider endometriosis. The next step is to obtain a pelvic ultrasound and consider performing a diagnostic laparoscopy to confirm your diagnosis.

Characteristic findings include a pelvic or adnexal mass, such as an ovarian endometrioma or deep infiltrating endometriosis. Endometriomas appear as cysts that contain low-level, homogeneous internal echoes consistent with old blood. If you see an endometrioma on ultrasound; or if the laparoscopy reveals an endometrioma or endometriotic implants and scarring, you can diagnose endometriosis.

Here’s a clinical pearl! The definitive diagnosis of endometriosis can only be made by pathologic confirmation of lesions removed via laparoscopic surgery. However, given surgical risks and costs, many clinicians make a presumptive diagnosis of endometriosis based on clinical history, physical exam, and ultrasound.

And now a high-yield fact! An endometrioma can also be referred to as a "chocolate cyst" because it contains old blood that, when expressed, looks like chocolate syrup!

Next up is adenomyosis. Here, the glandular endometrial tissue extends into the uterine myometrium. The patient might report heavy vaginal bleeding and intermenstrual spotting. Physical exam findings may include lower abdominal or pelvic tenderness and an enlarged globular uterus. In this case, consider adenomyosis and obtain a pelvic ultrasound. Signs of adenomyosis on ultrasound include a heterogeneous myometrium, myometrial cysts, and asymmetric endometrial thickness. If you see these findings, diagnose adenomyosis.

Moving on to leiomyomas, or uterine fibroids. These are common, benign, solid neoplasms made up of smooth muscle cells and fibroblasts. History might reveal heavy vaginal bleeding, as well as the symptoms of uterine enlargement, such as pelvic pressure or low back pain, urinary frequency, and constipation.

On physical exam, you may note abdominal or pelvic tenderness and an enlarged uterus or an irregular uterine contour. With these findings, consider a uterine leiomyoma and obtain a pelvic ultrasound. If the ultrasound reveals an enlarged uterus with at least one myometrial mass, the diagnosis is leiomyoma.

Here’s another high-yield fact! Uterine leiomyomas are the most common gynecologic pelvic neoplasm. Without surgical removal and histologic analysis, they’re difficult to distinguish from the rare but aggressive leiomyosarcoma.

Okay, let’s move on to adnexal pathology. Your patient may describe intermittent unilateral pain that’s indolent or progressive in nature. They may also report abdominal distention or bloating along with pelvic pressure. A physical exam might reveal abdominal or pelvic tenderness and a pelvic mass. In these patients, consider an adnexal mass and obtain a pelvic ultrasound. If the ultrasound demonstrates a cystic… or solid adnexal mass, your diagnosis is either a benign or malignant adnexal mass.