What are the typical symptoms of endometriosis and the recommended diagnostic work‑up?

Endometriosis: Symptoms and Diagnostic Approach

Typical Clinical Presentation

Endometriosis presents with three characteristic pain patterns: secondary dysmenorrhea that begins before menstrual onset, deep dyspareunia that worsens during menses, and sacral backache coinciding with menstruation. 1

The hallmark features that distinguish endometriosis from other causes of pelvic pain include:

• Progressive worsening of menstrual pain over time (not static pain that remains the same year after year) 2
• Pain timing that extends beyond the menstrual period itself (unlike primary dysmenorrhea where pain is confined to menstruation) 2
• Associated infertility in approximately 50% of patients, affecting at least one-third of women presenting with infertility 2
• Chronic non-menstrual pelvic pain lasting at least six months that occurs outside the menstrual cycle 3
• Cycle-dependent urinary symptoms (dysuria) or bowel symptoms (dyschezia, pain with defecation) in young premenopausal women 4

Additional symptoms include dyspareunia, bleeding disturbances, and nonspecific cycle-associated gastrointestinal or urogenital symptoms. 4 The depth of endometriotic infiltration correlates with pain severity, though the specific type of lesion shows little relationship to pain intensity. 1

Recommended Diagnostic Work-Up

Clinical Diagnosis is Sufficient to Begin Treatment

The American College of Radiology confirms that endometriosis diagnosis is fundamentally clinical and does not require surgical confirmation before initiating empiric treatment—laparoscopy with histologic confirmation is no longer required before starting therapy. 2

This represents a critical shift in practice: you can and should begin treatment based on clinical suspicion alone, reserving invasive procedures for specific indications.

First-Line Imaging

Transvaginal ultrasound with expanded protocol is the recommended first-line imaging modality, with sensitivity of 82.5% and specificity of 84.6% for detecting endometriosis. 2

• Transvaginal ultrasound is particularly helpful for detecting endometriotic cysts (endometriomas) 5
• MRI pelvis should be considered if ultrasound is inconclusive or for surgical planning 2
• Transrectal ultrasound and MRI are valuable for detecting deep infiltrating lesions, especially in the rectovaginal septum 5

Laboratory Testing Has Limited Value

Serum CA-125 has limited diagnostic utility, particularly in cases of mild or minimal endometriosis, as it is usually elevated only in advanced stages and therefore not suitable for routine screening. 1, 5

Currently available laboratory markers are of limited value, and no consistent biomarkers for disease diagnosis exist. 5, 6

When Surgical Diagnosis is Indicated

While not required before starting treatment, laparoscopy with histologic examination remains the gold standard for definitive diagnosis in specific circumstances:

• When empiric medical therapy is ineffective 3
• When immediate definitive diagnosis is necessary 3
• When the patient desires pregnancy (as surgical excision may enhance fertility) 3
• When peritoneal lesions have uncertain appearance, peritoneal biopsy should be performed to establish definitive diagnosis 1

Experienced surgeons may rely on visual inspection alone for classical-appearing lesions, but histologic examination is recommended for non-classical lesions. 1 However, be aware that the correlation of laparoscopic observations with histological findings is often low. 5

Critical Pitfalls to Avoid

• Do not delay treatment waiting for surgical confirmation—begin empiric hormonal therapy based on clinical presentation alone 2
• Do not dismiss progressively worsening dysmenorrhea as "normal period pain"—this pattern suggests secondary dysmenorrhea from endometriosis rather than primary dysmenorrhea 2
• Do not overlook the infertility connection—always ask about fertility concerns in patients with suspected endometriosis 2
• In postmenopausal women, do not perform routine imaging for suspected endometriosis, as the disease is estrogen-dependent and typically regresses after menopause; persistent symptoms are more likely due to scarring or reactivation from hormonal therapy 2

Differential Diagnosis Considerations

Primary dysmenorrhea is excluded because it does not progressively worsen over years, is not associated with infertility, and pain is confined to the menstrual period. 2 Chronic pelvic inflammatory disease typically presents with acute or subacute symptoms rather than progressive worsening over years. 2 Adenomyosis is possible but typically affects older, multiparous women. 2