What is the best course of action for a patient with suspected endometriosis who develops left lower abdominal pain after 4 days?

Acute Management of Left Lower Abdominal Pain in Suspected Endometriosis

This patient requires urgent evaluation to rule out acute complications, particularly ovarian torsion or ruptured endometrioma, before attributing symptoms to endometriosis alone. 1

Immediate Diagnostic Approach

First-Line Imaging

• Obtain transvaginal ultrasound (TVUS) immediately as the initial imaging modality to evaluate for acute adnexal pathology, with sensitivity of 82.5% and specificity of 84.6% for endometriosis-related findings. 2
• TVUS can identify ovarian torsion (asymmetrically enlarged ovary, twisted pedicle, abnormal or absent ovarian enhancement) and ruptured endometriomas that require urgent intervention. 1
• If TVUS is inconclusive or technically limited, proceed to MRI pelvis without IV contrast, which demonstrates 90.3% sensitivity and 91% specificity for deep pelvic endometriosis. 2

Critical Acute Complications to Exclude

• Ovarian torsion: Look for asymmetrically enlarged ovary with twisted pedicle, subacute ovarian hematoma, abnormal or absent ovarian enhancement, ascites, and deviation of the uterus to the side of the twist. 1
• Ruptured endometrioma: Assess for free fluid beyond physiologic amounts (small to moderate fluid in pouch of Douglas is normal depending on menstrual cycle phase), acute hemorrhage, and peritoneal signs. 1, 2
• Tubo-ovarian abscess: Evaluate for thick-walled fluid density in adnexal location, septations, indistinct borders between uterus and bowel, and gas bubbles within mass. 1

Management Algorithm Based on Imaging Findings

If Acute Surgical Emergency Identified

• Immediate surgical consultation for ovarian torsion, ruptured endometrioma with hemodynamic instability, or tubo-ovarian abscess requiring drainage. 1
• Laparoscopic approach is preferred unless conversion to laparotomy is necessary for safe management of involved organs. 2

If No Acute Emergency but Endometriosis Confirmed

• Initiate first-line hormonal therapy immediately without waiting for surgical confirmation, as clinical diagnosis is sufficient to begin empiric treatment. 3, 2, 4
• Combined oral contraceptives (continuous dosing) or progestin-only options (norethindrone 0.35 mg daily or depot medroxyprogesterone acetate) are equally effective first-line choices, with mean pain reduction of 13.15-17.6 points on 0-100 visual analog scale. 5, 4
• Add NSAIDs at appropriate doses and schedules for immediate pain relief while hormonal therapy takes effect. 3

If Deep Infiltrating Endometriosis Suspected

• Obtain expanded protocol TVUS or MRI pelvis to map disease extent, particularly for uterosacral ligaments (92.4% sensitivity, 94.6% specificity), intestinal involvement (88% sensitivity, 83.3% specificity), and bladder wall (50% sensitivity, 97.3% specificity). 1, 2
• Preoperative imaging reduces morbidity by decreasing incomplete surgeries requiring reoperation and enables better surgical planning. 3, 2

Treatment Escalation Strategy

Second-Line Options (If First-Line Fails After 3-6 Months)

• GnRH agonists for at least 3 months provide significant pain relief even without surgical confirmation of endometriosis. 3, 5
• Mandatory add-back therapy must be implemented to reduce bone mineral loss without reducing pain relief efficacy. 3, 5

Surgical Referral Indications

• Consider surgery if: medical treatment is ineffective after 6-12 months, contraindicated, patient desires pregnancy, or severe deep infiltrating disease is identified on imaging. 3, 5, 4
• Surgical excision by a specialist is the definitive treatment, though 25-44% of women experience symptom recurrence within one year. 3, 5, 4
• For completed childbearing with refractory symptoms, hysterectomy with bilateral salpingo-oophorectomy remains definitive, though 25% experience recurrent pain and 10% require additional surgery. 3, 4

Critical Pitfalls to Avoid

• Do not delay imaging in acute presentation—new unilateral adnexal pain requires urgent evaluation to exclude torsion or rupture. 1
• Do not assume physiologic fluid in pouch of Douglas is pathologic—small to moderate amounts are normal depending on menstrual cycle phase. 2
• Do not use CT pelvis as initial imaging—it has no role in standard endometriosis diagnosis and exposes patient to unnecessary radiation. 1, 2
• Do not wait for surgical confirmation before initiating hormonal therapy—clinical diagnosis based on symptoms and imaging is sufficient. 2, 4
• Do not use medical therapy if patient is actively seeking pregnancy, as hormonal suppression does not improve future fertility outcomes. 3

Long-Term Monitoring Considerations

• Up to 44% of patients experience symptom recurrence within one year after any treatment modality, requiring ongoing management. 3, 5, 4
• Women with endometriosis have 16-34% increased risk of stroke and should undergo vascular risk factor evaluation and modification. 5
• Pain severity correlates poorly with laparoscopic appearance but correlates with lesion depth, so imaging findings guide treatment intensity. 3, 2