Background

Adnexal torsion, commonly referred to as ovarian torsion, occurs when the vascular pedicle twists and may involve the Fallopian tubes and ovaries. The most common initial symptom is sudden onset intermittent unilateral lower quadrant abdominal pain. Thirty percent of cases occur in females under the age of 20 and younger individuals often present with a longer delay since pain began (24 versus 8 hours).¹ The majority of patients with ovarian torsion present for initial evaluation to the emergency department (ED) (75%) rather than the primary care or gynecology clinic – and usually within 12 hours of symptom onset.² Ovarian torsion is commonly misdiagnosed and only considered in the differential diagnosis in 47% of cases.² Up to 80% of ovarian torsion cases are associated with usually benign ovarian tumors or cysts, but only 25% of patients with ovarian torsion report a history of a known ovarian cyst or mass.² Additional risk factors for ovarian torsion include both first‐trimester pregnancy and chemical induction of ovulation.^2,3 Although ovarian torsion is the fifth most common reason for emergent surgery in women presenting with abdominal pain (Figure 43.1), the diagnosis is still quite rare, with an annual prevalence of about 3%.⁴ Consequently, diagnostic research is limited to retrospective case series.

The ovaries have a dual blood supply from the uterine and ovarian arteries, so complete arterial obstruction is rare. Attempts at surgical salvage via detorsion are therefore warranted even if the diagnosis is made at 72 hours (or later) in the disease course because ovarian function is preserved in 93% of laparoscopically detorsed cases.^5–7 If detorsion is unsuccessful, one ovary is sufficient to maintain fertility.⁸ In pediatric (and probably adult) patients, optimal ovarian salvage rates are obtained in those who are taken to the operating room within 8 hours of diagnosis. In cases where operative detorsion has been delayed for over 24 hours, salvage rates approach zero.⁹

The differential diagnosis of atraumatic abdominal pain in women includes appendicitis, ovarian cysts, ectopic pregnancy, renal colic, urinary tract infection, pelvic inflammatory disease, malignancy, and diverticulitis.¹⁰ In the evaluation of acute female abdominal pain, the choice of which initial imaging modality to obtain should be based upon the most likely etiology after a careful history and physical exam, including a pelvic exam. Ultrasound is generally considered the imaging technique of choice for ovarian torsion. Computed tomography (CT) is only 34% sensitive for the diagnosis of ovarian torsion (specificity unknown) and agrees with ultrasound results only 50% of the time.^11,12Magnetic resonance imaging (MRI) may be considered in pregnant patients or as an alternative imaging strategy if ultrasound is unavailable or indeterminant.¹³

Clinical question

What is the diagnostic accuracy of physical exam findings for ovarian torsion in women with abdominal pain?

Right‐sided ovarian torsion is more common (55.8%) than left‐sided ovarian torsion, possibly due to a stabilizing effect of the sigmoid colon on the left.¹⁴ Other common symptoms of ovarian torsion include nausea (57–77%) and lower quadrant abdominal pain (90%), which can be characterized as sharp or stabbing in 70% and of moderate to severe intensity in 82% of patients with ovarian torsion.¹⁵ However, only half of patients present with the classical pain and up to 30% will not have tenderness on exam.¹⁶ Other clinical findings are not sufficiently sensitive to be useful in the ED (Table 43.1). Suspected ovarian torsion is confirmed operatively in only half of the cases.¹⁷