II. Epidemiology
- Accounts for 2-3% of acute surgical emergencies (fifth most common gynecologic emergency)
- More common in young women (peaks at ages 20 to 30 years)
- Torsion occurs outside the reproductive age range and in pregnancy
- Torsion occurs in pediatric patients (15% of cases) and Postmenopause (15% of cases)
- Ovarian Torsion in pregnancy accounts for 20% of cases
III. Pathophysiology
- Partial or complete rotation of ovarian pedicle
- Results in lymphatic and venous engorgement in partial rotation, or in early torsion
- Results in ischemia or infarction in complete rotation, or in late torsion
- Typically unilateral and more commonly right sided
- Typically both the ovary and the fallopian tube are involved in the torsion
- Enlarged ovary or mass is most common predisposing factor (present in a majority of cases)
- However, girls prior to Puberty with Ovarian Torsion typically have normal ovaries
IV. Risk Factors
- No risk factors in 25% of patients
- Prior torsion
- Enlarged Ovary
- Torsion is uncommon in Polycystic Ovary Syndrome (despite the bilateral enlarged ovaries)
- Murakami (2013) Clin Exp Obstet Gynecol 40(4):609-11+PMID: 24597271 [PubMed]
-
Adnexal Mass
- Benign ovarian growths (especially dermoid tumors) have an 11% risk of Ovarian Torsion
- Ovarian Cancer has only a 2% risk of Ovarian Torsion
- Pregnancy
- Related to Adnexal displacement (especially between weeks 6 to 14)
- Ovulation induction (Infertility management)
- Prior pelvic surgery (including Tubal Ligation)
- Adhesions may act at pivot points for torsion
V. Symptoms
- Symptoms are initially non-specific
- Lower Abdominal Pain (often right sided)
- Abrupt onset in only 60% of cases
- Severe, progressive unilateral lower Abdominal Pain or Pelvic Pain
- Pain is sharp and stabbing in >70% of cases, but may be cramping pain in others
- Pain radiates into the thigh, low back or flank
- Pain may be intermittent if partial torsion occurs with spontaneous resolution
- Up to 40% of patients have had episodes of prior similar pain
- Other associated symptoms
VI. Signs
- Abdominal exam
- Frequently benign Abdomen in early cases
- Peritoneal signs suggest a longer standing Ovarian Torsion
- Pelvic exam (bimanual exam)
- Very low sensitivity and Specificity
- Uterus may be shifted toward the affected side
- Palpable, tender Adnexal Mass in 50% of cases
VII. Labs
VIII. Imaging: Pelvic Ultrasound with color doppler
- Findings (combination of factors are most useful in diagnosing or reasonably excluding Ovarian Torsion)
- Ovary is larger than 5 cm in >90% of Ovarian Torsion cases
- Large edema at ovary in partial Ovarian Torsion
- Free pelvic fluid is less common in Ovarian Torsion
- Hyperechogenic foci suggest hemorrhagic changes in the ovary
- Hypoechogenic foci suggest ovarian edema (most common torsion-related Ultrasound finding)
- Cystic, clotted areas suggest infarction
- Whirlpool sign (enlarged ovary has a thick, twisted vascular pedicle)
- Highly suspicious for Ovarian Torsion
- Efficacy
- Early studies suggested 93% for Ultrasound abnormality in Ovarian Torsion
- More recent studies show variable Test Sensitivity 35-85%
- Demonstrates arterial Blood Flow in 50% of Ovarian Torsion cases
- Demonstrates venous Blood Flow in 30% of Ovarian Torsion cases
- Surprisingly Ultrasound is not appreciably better than CT in identifying Ovarian Torsion
- Swenson (2014) Eur J Radiol 83(4): 733-8 +PMID:24480106 [PubMed]
- Precautions
- Vascular Flow on Color Doppler Ultrasound does not exclude partial Ovarian Torsion
- Pelvic Ultrasound need not be done after CT Abdomen specifically to exclude Ovarian Torsion
- Ultrasound does not add significant information not seen on CT Abdomen and Pelvis with IV contrast
- Ultrasound is sufficient in low to moderate suspicion for torsion cases
- Laparoscopy is the only definitive diagnostic tool in high suspicion cases
IX. Differential Diagnosis
X. Precautions
- Consider Ovarian Torsion in any woman with lower Abdominal Pain
- Do not delay surgical Consultation if high level of suspicion
- Ultrasound does not have high enough Test Sensitivity to completely exclude torsion
XI. Evaluation
- High level of suspicion for Ovarian Torsion
- Consult Gynecology early
- Pelvic Ultrasound (normal result does not exclude high suspicion Ovarian Torsion)
- Low to moderate suspicion for Ovarian Torsion
- Pelvic Ultrasound is sufficient to evaluate for Ovarian Torsion
- CT Abdomen (if done to exclude other causes) is also sufficient to evaluate for torsion
- Reflex to pelvic Ultrasound is not needed after CT unless dictated by pathology seen on CT
- Intermittent Torsion
- Pelvic Ultrasound may show normal Blood Flow
- However, intermittent torsion is typically accompanied by Adnexal Mass seen on Ultrasound
XII. Management
- Gynecologic emergency
- Requires prompt diagnosis and treatment for optimal surgical management and ovarian salvage
- However, delayed presentation does not exclude a salvageable ovary
- Diagnostic laparoscopy if Ovarian Torsion suspected
- Often requires conversion to laparotomy if Ovarian Torsion is present
- Untwisting and salvage of ovary is safe if no findings suggestive of a necrotic ovary
- Oophorectomy is recommended for an infarcted ovary due to the risk of Venous Thromboembolism
XIII. References
- Delaney in Herbert (2016) EM:Rap 16(5): 5-6
- Long in Swadron (2023) EM:Rap 23(2): 5-6
- Houry (2001) Ann Emerg Med 38:156-9 [PubMed]
- Martin (2006) CJEM 8(2):126-9 [PubMed]
- Pena (2000) Fertil Steril 73:1047-50 [PubMed]