Differential Diagnoses for Pelvic Pain and Abnormal Uterine Bleeding

Clinical Presentation and Diagnosis

The American College of Radiology recommends transvaginal ultrasound as the first-line imaging modality for detecting secondary causes of dysmenorrhea, with 82.5% sensitivity and 84.6% specificity 1
The depth of endometriosis lesions correlates with pain severity, not the type of lesions, according to the American Family Physician 2
Left-sided pain could indicate endometriotic implants on the left ovary, uterosacral ligament, or bowel, as reported in the Journal of the American College of Radiology 3
Small endometrial implants are not well detected on imaging, and a normal prior transvaginal ultrasound does not exclude endometriosis, as noted in the Journal of the American College of Radiology 4
The Journal of the American College of Radiology recommends using a combined transabdominal and transvaginal approach to assess for fibroids, adenomyosis, ovarian masses, and signs of endometriosis 1
MRI without IV contrast is recommended as the next step if ultrasound is inconclusive or shows complex findings, according to the Journal of the American College of Radiology 5
MRI excels at differentiating adenomyosis from fibroids and can detect deep infiltrating endometriosis, as reported in the Journal of the American College of Radiology 3, 5
Associated fertility issues are common in endometriosis patients, with approximately 50% of patients experiencing infertility, as noted in the American Family Physician 2

Pain is confined to the menstrual period, typically 1-3 days, and does not progressively worsen over years, affecting women with no underlying pelvic pathology 6

Characterized by progressive worsening of menstrual pain over time and pain extending beyond the menstrual period, often associated with underlying pelvic pathology such as endometriosis, adenomyosis, or uterine fibroids 6
Endometriosis is a common cause, affecting 2-10% of reproductive-aged women, and presenting with secondary dysmenorrhea, deep dyspareunia, and sacral backache with menses 7
Approximately 50% of endometriosis patients present with associated infertility 6
Uterine fibroids can cause pain through torsion, prolapse, or acute degeneration, and are the second most common cause of acute pelvic pain in perimenopausal/postmenopausal women 8, 9, 10

The American College of Radiology recommends transvaginal ultrasound as the first-line imaging method when secondary causes of dysmenorrhea need to be excluded, with a sensitivity of 82.5% and specificity of 84.6% 6, 11
Red flags suggesting secondary dysmenorrhea include progressive worsening of pain severity over months to years, pain timing extending beyond menstruation, associated infertility, and failure to respond to NSAIDs and hormonal contraceptives after 3-6 months 6, 11

For reproductive‑age women presenting with cyclic pelvic pain, the American College of Radiology recommends using transvaginal ultrasound as the first‑line imaging study and avoiding CT scans, because ultrasound offers superior diagnostic capability for gynecologic pathology while eliminating radiation exposure. (Evidence: expert consensus; strength not explicitly graded) 12