Reproductive · Gynecology
The facts most likely to be tested
Primary dysmenorrhea is caused by an excess of prostaglandin F2-alpha leading to myometrial contractions and uterine ischemia.
Primary dysmenorrhea typically presents in adolescents shortly after menarche with normal pelvic anatomy.
First-line pharmacotherapy for primary dysmenorrhea is nonsteroidal anti-inflammatory drugs (NSAIDs) to inhibit cyclooxygenase (COX) enzymes.
Secondary dysmenorrhea is suspected when symptoms begin in patients older than 25 years or when pain is non-cyclical and progressive.
Endometriosis is the most common cause of secondary dysmenorrhea, classically presenting with dyspareunia and a fixed, retroverted uterus or uterosacral ligament nodularity.
Adenomyosis presents with secondary dysmenorrhea and a uniformly enlarged, globular, tender uterus on bimanual examination.
Pelvic ultrasound is the initial imaging modality of choice to rule out structural pathology in patients with suspected secondary dysmenorrhea.
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A 28-year-old woman presents with a 6-month history of worsening pelvic pain that begins 2 days before her menses and persists throughout her period. She reports deep dyspareunia and difficulty conceiving for the past year. On physical examination, she has tenderness with movement of the cervix and palpable nodularity along the uterosacral ligaments. Her uterus is fixed and retroverted.
What is the most likely diagnosis?
Endometriosis
The patient's age, progressive secondary dysmenorrhea, and classic physical exam findings of uterosacral nodularity and a fixed uterus are highly suggestive of endometriosis, which is the most common cause of secondary dysmenorrhea.
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High yield triage
Etiology / Epidemiology
Primary dysmenorrhea is caused by excess prostaglandins; secondary is due to pelvic pathology (e.g., endometriosis).
Clinical Manifestations
Pain with menses; chocolate cysts in secondary cases. Cyclic pelvic pain is the hallmark.
Diagnosis
Laparoscopy is the gold standard for secondary causes; primary is a clinical diagnosis.
Treatment
NSAIDs are first-line; do not use in active peptic ulcer disease.
Prognosis
Most primary cases resolve with age; secondary cases require long-term management of underlying pathology.
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Epidemiology & Etiology
Primary dysmenorrhea is most common in adolescents due to ovulatory cycles. Secondary dysmenorrhea typically presents in women >25 years old with new-onset pain. Risk factors include nulliparity, early menarche, and heavy menstrual flow.
Pertinent Anatomy
The uterus and surrounding pelvic structures are the primary sites of pain. In secondary dysmenorrhea, adhesions or implants may involve the uterosacral ligaments or the rectovaginal septum.
Pathophysiology
Primary dysmenorrhea results from prostaglandin F2-alpha release in the endometrium, causing intense myometrial contractions and ischemia. Secondary dysmenorrhea involves structural abnormalities like adenomyosis or endometriosis. These conditions trigger chronic inflammation and localized tissue destruction.
Clinical Manifestations
Patients report cramping pelvic pain radiating to the lower back or thighs. Red flags include pain that does not respond to NSAIDs, dyspareunia, or pain occurring outside of menses. Endometriosis often presents with the classic triad of dysmenorrhea, dyspareunia, and infertility.
Diagnosis
Primary dysmenorrhea is a clinical diagnosis after excluding secondary causes. For suspected secondary disease, pelvic ultrasound is the initial imaging modality. Laparoscopy remains the gold standard for definitive diagnosis of endometriosis.
Treatment
NSAIDs (e.g., ibuprofen, naproxen) are the first-line treatment to inhibit prostaglandin synthesis. Combined oral contraceptives are the next step if NSAIDs fail. Contraindications for OCPs include history of DVT/PE, smoking in women >35, and uncontrolled hypertension.
Prognosis
Primary dysmenorrhea often improves after first pregnancy or with advancing age. Secondary dysmenorrhea requires monitoring for infertility and chronic pelvic pain syndrome. Surgical intervention may be required for severe structural disease.
Differential Diagnosis
Endometriosis: chronic pelvic pain and dyspareunia
Adenomyosis: symmetrically enlarged, tender uterus
Pelvic Inflammatory Disease: cervical motion tenderness
Leiomyoma: irregularly enlarged, firm uterus
Ovarian Cyst: acute, unilateral pelvic pain