Six months of lower abdominal pain in a 13-year-old female around menses; most likely diagnosis?

• A. Ovarian cyst
• B. Endometriosis
• C. Primary dysmenorrhea
• D. Premenstrual syndrome

Answer: (C)

Painful menstrual cramps in an adolescent who has just begun menstruating and experiences cyclical pelvic pain with each period is most consistent with primary dysmenorrhea. This occurs when prostaglandins released by the endometrium cause strong uterine contractions and temporary reduced blood flow, leading to cramping that starts with the onset of menses and lasts a day or two. Pelvic exams are typically normal, and there isn’t an underlying pathology driving the pain in early adolescence.

Ovarian cysts usually present with localized, sometimes unilateral pain and may not align precisely with the cycle. Endometriosis can cause painful menses as well, but it often appears a bit later in adolescence or young adulthood and may include additional symptoms like pain between periods, dyspareunia, or infertility concerns. Premenstrual syndrome features mood and physical symptoms that occur in the luteal phase and resolve with menses, rather than being limited to cramping around the start of the period.

So the cyclical cramping in a young teen around menses, without other pelvic findings, points to primary dysmenorrhea. Treatments typically involve NSAIDs started at the onset of menses and heat or analgesics; hormonal therapy can be considered if symptoms are persistent or severe.