What is the workup for suspected ovarian torsion?

Workup for Ovarian Torsion

The optimal workup for suspected ovarian torsion should begin with transvaginal and transabdominal ultrasound with Doppler imaging as the first-line diagnostic modality due to its high sensitivity (79-80%) and specificity (76-88%) for detecting this surgical emergency. 1, 2

Clinical Presentation

• Acute onset of unilateral lower abdominal/pelvic pain (typically severe and sharp)
• Associated symptoms:
  • Nausea and vomiting (common)
  • Anorexia
  • Tenderness with palpable laterouterine pelvic mass
• Risk factors:
  • Presence of ovarian mass or cyst (primary risk factor)
  • Fertility treatment (controlled ovarian stimulation)
  • Pregnancy

Diagnostic Algorithm

1. Imaging Studies

First-Line: Ultrasound with Doppler

• Combined transvaginal and transabdominal approach is recommended 1
• Key ultrasound findings suggestive of torsion:
  • Unilaterally enlarged ovary
  • Central afollicular stroma with peripheral follicles
  • Abnormal Doppler flow patterns (absent or decreased flow)
  • Whirlpool sign (highly specific finding - 90% of patients with this sign had confirmed torsion on laparoscopy) 1, 3
  • Free fluid in pelvis

Important caveat: Normal blood flow on Doppler does NOT exclude torsion, as demonstrated in a prospective study where 62% of patients with only abnormal venous flow but normal arterial flow had confirmed torsion 1, 2

Second-Line: CT with IV Contrast

• Consider when ultrasound is inconclusive or unavailable
• CT findings of ovarian torsion include:
  • Enlarged, featureless, and hypoenhancing ovary
  • Swirling of vascular pedicle
  • Abnormal craniocaudal orientation of ovary
  • Uterine deviation to the affected side 1

Third-Line: MRI

• Reserved for problem-solving when ultrasound or CT are inconclusive
• MRI findings of torsion (80-85% sensitive) 1:
  • Enlarged ovary with stromal edema and surrounding fluid
  • Absent or diminished ovarian enhancement
  • Tubal knot or whirlpool sign
  • Mural thickening of the fallopian tube
  • Peripheralized and/or hemorrhagic follicles
  • Anatomic deviation of adnexa and uterus

2. Laboratory Tests

• Pregnancy test (to rule out ectopic pregnancy)
• Complete blood count (may show leukocytosis)
• No specific laboratory test can confirm or exclude ovarian torsion

Management Considerations

• Surgical intervention is the mainstay of treatment and should be performed promptly when ovarian torsion is suspected 2
• Laparoscopic approach is preferred when feasible
• Options include:
  • Detorsion (preferred to preserve ovarian function)
  • Oophorectomy (if ovary appears necrotic or in postmenopausal women)

Common Pitfalls to Avoid

1. Delayed diagnosis due to nonspecific symptoms or misdiagnosis as other conditions (e.g., renal colic, appendicitis) 4
2. Ruling out torsion based on presence of arterial flow on Doppler (torsion can still be present with normal arterial flow) 1, 2
3. Waiting for "classic" symptoms before imaging (symptoms can be variable)
4. Delaying surgical intervention when clinical suspicion is high, even with equivocal imaging findings

Early recognition and prompt surgical intervention are crucial to preserve ovarian function and minimize morbidity in cases of ovarian torsion 5, 6.