Ovarian torsion
Updates to Article Attributes
The terms Ovarianovarian torsion and tubo-ovarian torsion refer;are synonymous and refer to torsion of an ovary with a small part of athe adjacent fallopian tube. Adnexal torsion includes the less common torsion of a paraovarian cyst or isolated torsion of a fallopian tube. Twisting of the infundibulopelvic and utero-ovarian ligaments compromises blood supply and can cause infarction.
Torsion can be sustained or intermittent and recurrent and causes lymphatic, venous and arterial obstruction of varying degrees. Urgent surgical intervention may prevent ovarian necrosis however delayed diagnosis is all too common.
The term adnexal torsion includes the rare entities of paraovarian cyst torsion and isolated torsion of a fallopian tube. The presence of normal ovaries makes these conditions even harder to diagnose.
Epidemiology
Ovarian torsion accounts for < 3% of gynaecological surgical emergencies and most commonly affectsinvolves the ovary with a small portion of the adjacent fallopian tube (67%) 12.
Premenopausal women are most commonly affected and there is commonly no visible precipitating lesion. Known risk factors include 2, 20:
hypermobility of the ovary
: <50(up to 50%)pregnancy 1, especially during the first trimester
-
adnexal mass:
most lesions arecommonly dermoid cysts or paraovarian cysts between 5-10 cm 13ovarian hyperstimulation with large cystic ovaries
masses between 5-10 cm are at most risk13
prior pelvic surgery
Clinical presentation
Most patientsPatients typically present with sudden severe acute non-specific lower abdominal and pelvic pain, either intermittent or sustained. Often patients report a similar episode during the previous month. Nausea and vomiting are a helpful clue to the diagnosis, occurring in 85% of patients and particularly common in the paediatric age-group. Leucocytosis and fever are common and the affected ovary or adnexal tissue is tender.
Pathology
Twisting of the infundibulopelvic and utero-ovarian ligaments compromises lymphatic, venous and arterial flow. Ovarian oedema and swelling are almost universal and can progress to haemorrhagic infarction within hours if untreated.
Torsion of a normal but hypermobile ovary is common in young children with excessively long fallopian tubes or an absent mesosalpinx.
In adulthood, causes include both benign and malignant ovarian tumours, polycystic ovaries and adhesions. In early pregnancy, a torsion can occur secondary to a corpus luteal cyst or laxity of the adjacent tissues.
Radiographic features
The key feature of torsion is ovarian oedema and swelling due to venous and lymphatic engorgement. This exacerbates arterial compromise and can cause haemorrhage and infarction. The twisted vascular pedicle may be apparent as a layered vascular “whirlpool” with small quantities of fat. The oedema fluid fills peripheral follicles and leaks into the adjacent peritoneal cavity.
The presence of vascularity indicates viability.
There may be an underlying ovarian lesion, reduced or absent vascularity and a twisted dilated tubular structure corresponding to the vascular pedicle. Adnexal torsion is commonly unilateral, with a slight (3:2) right-sided predilection (presumably due to the protective effects of the sigmoid colon on the left) 6,8.
Ultrasound
Ultrasound is the initial imaging modality of choice. Sonographic features include:
enlarged ovary (>4 cm in longest dimension or > 20cc in volume), if the ovaries are normal in size and symmetric, torsion is unlikely.
ovarian oedema 17
-
variable echogenicity (hypo- or hyperechoic)
a long-standing infarcted ovary may have a more complex appearance with cystic or haemorrhagic degeneration
-
peripherally displaced follicles with hyperechoic central stroma
midline ovary position
-
Doppler findings in torsion are widely variable 3
little or no ovarian venous flow (common; sensitivity of 100% and specificity of 97%) 14
absent arterial flow (a less common, sign of poor prognosis)
absent or reversed diastolic flow
-
normal vascularity does not rule out intermittent torsion
normal Doppler flow can also occasionally be found due to dual supply from both the ovarian and uterine arteries
whirlpool sign of twisted vascular pedicle 3
an underlying ovarian lesion may be seen (possible lead point for torsion)
ovary tenderness to transducer pressure 13
free pelvic fluid may be seen in >80% of cases
CT
CT is useful for ruling out ovarian torsion if a normal ovary/adnexa is seen on ultrasound.
There are many features seen on CT which favour ovarian torsion
enlarged ovary
involved ovary shifted to the midline and most often anterior to the uterus
lead mass may be identified
twisted pedicle in the adnexa
uterus displaced to the involved side
minimal free fluid
fat stranding in the adnexa
The appearance of a twisted ovarian pedicle on CT is pathognomonic for ovarian torsion 11.
HU >50 on non-contrast CT suggests haemorrhagic necrosis 2. A lack of contrast enhancement may be seen. Haemorrhagic necrosis is a sign of nonviability.
An underlying ovarian lesion may be present (lead point for torsion).
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MRI
MRI is not the imaging modality of choice if torsion is suspected, as urgent imaging is required.
If haemorrhagic infarction is present, signal changes include 4:
-
T1
thin rim of high signal (methaemoglobin) without contrast enhancement
endometriomas and haemorrhagic corpus luteal cysts are less likely to have a high T1 rim and do not usually involve the entire ovary
T2: can have low signal due to interstitial haemorrhage
Treatment and prognosis
Urgent surgery is required to prevent ovarian necrosis. Most ovaries are not salvageable, in which case a salpingo-oophorectomy is required. If not removed, the necrotic ovary can become infected and cause an abscess or peritonitis. In the case of a non-infarcted adnexa, surgical untwisting can be performed. Mortality resulting from ovarian torsion is rare. Spontaneous detorsion has also been reported.
Differential diagnosis
For an enlarged oedematous ovary +/- fallopian tube, consider:
pelvic inflammatory disease (PID): has a very different clinical presentation
Practical points
the ovary should be tender to transducer pressure
absence of ovarian Doppler flow is highly specific for torsion, but normal Doppler flow does not completely rule out torsion
an ovarian mass causing the torsion must always be sought
-<p><strong>Ovarian torsion</strong> and <strong>tubo-ovarian torsion</strong> refer to torsion of an ovary with a small part of a fallopian tube. <strong>Adnexal torsion</strong> includes the less common torsion of a paraovarian cyst or isolated torsion of a fallopian tube. Twisting of the infundibulopelvic and utero-ovarian ligaments compromises blood supply and can cause infarction.</p><p>Torsion can be sustained or intermittent and recurrent and causes lymphatic, venous and arterial obstruction of varying degrees. Urgent surgical intervention may prevent ovarian necrosis however delayed diagnosis is all too common.</p><h4>Epidemiology</h4><p>Ovarian torsion accounts for < 3% of gynaecological surgical emergencies and most commonly affects the ovary with a small portion of the adjacent fallopian tube (67%) <sup>12</sup>.</p><p>Premenopausal women are most commonly affected and there is commonly no visible precipitating lesion. Known risk factors include <sup>2, 20</sup>: </p><ul>-<li><p>hypermobility of the ovary: <50%</p></li>- +<p>The terms <strong>ovarian torsion</strong> and <strong>tubo-ovarian torsion</strong> are synonymous and refer to torsion of an ovary with a small part of the adjacent fallopian tube. Urgent surgical intervention may prevent ovarian necrosis.</p><p>The term <strong>adnexal torsion</strong> includes the rare entities of paraovarian cyst torsion and isolated torsion of a fallopian tube. The presence of normal ovaries makes these conditions even harder to diagnose.</p><h4>Epidemiology</h4><p>Ovarian torsion accounts for < 3% of gynaecological surgical emergencies and most commonly involves the ovary with a small portion of the adjacent fallopian tube <sup>12</sup>.</p><p>Premenopausal women are most affected and there is commonly no visible precipitating lesion. Known risk factors include <sup>2, 20</sup>: </p><ul>
- +<li><p>hypermobility of the ovary (up to 50%)</p></li>
-<li><p>most lesions are <a href="/articles/mature-cystic-ovarian-teratoma-1">dermoid cysts</a> or <a href="/articles/paraovarian-cyst">paraovarian cysts</a></p></li>- +<li><p>commonly <a href="/articles/mature-cystic-ovarian-teratoma-1">dermoid cysts</a> or <a href="/articles/paraovarian-cyst">paraovarian cysts</a> between 5-10 cm <sup>13</sup></p></li>
-<li><p>masses between 5-10 cm are at most risk <sup>13</sup></p></li>-</ul><h4>Clinical presentation</h4><p>Most patients present with severe acute non-specific lower abdominal and pelvic pain, either intermittent or sustained. Nausea and vomiting are a helpful clue to the diagnosis, occurring in 85% of patients and particularly common in the paediatric age-group. Leucocytosis and fever are common and the affected ovary or adnexal tissue is tender. </p><h4>Pathology</h4><p>Ovarian oedema and swelling are almost universal and can progress to haemorrhagic infarction within hours if untreated. </p><p>Torsion of a normal but hypermobile ovary is common in young children with excessively long <a href="/articles/fallopian-tube-1">fallopian tubes</a> or an absent <a href="/articles/mesosalpinx">mesosalpinx</a>.</p><p>In adulthood, causes include both benign and malignant <a href="/articles/ovarian-tumours">ovarian tumours</a>, <a href="/articles/polycystic-ovaries">polycystic ovaries</a> and <a href="/articles/abdominal-adhesions">adhesions</a>. In early pregnancy, a torsion can occur secondary to a <a href="/articles/corpus-luteal-cyst">corpus luteal cyst</a> or laxity of the adjacent tissues.</p><h4>Radiographic features</h4><p>The key feature of torsion is ovarian oedema and swelling due to venous and lymphatic engorgement. This exacerbates arterial compromise and can cause haemorrhage and infarction. The twisted vascular pedicle may be apparent as a layered vascular “whirlpool” with small quantities of fat. The oedema fluid fills peripheral follicles and leaks into the adjacent peritoneal cavity. </p><p>The presence of vascularity indicates viability.</p><p>There may be an underlying ovarian lesion, reduced or absent vascularity and a twisted dilated tubular structure corresponding to the vascular pedicle. Adnexal torsion is commonly unilateral, with a slight (3:2) right-sided predilection (presumably due to the protective effects of the sigmoid colon on the left) <sup>6,8</sup>.</p><h5>Ultrasound</h5><p>Ultrasound is the initial imaging modality of choice. Sonographic features include:</p><ul>- +</ul><h4>Clinical presentation</h4><p>Patients typically present with sudden severe pelvic pain, either intermittent or sustained. Often patients report a similar episode during the previous month. Nausea and vomiting are a helpful clue to the diagnosis, occurring in 85% of patients and particularly common in the paediatric age-group. Leucocytosis and fever are common and the affected ovary or adnexal tissue is tender.</p><h4>Pathology</h4><p>Twisting of the infundibulopelvic and utero-ovarian ligaments compromises lymphatic, venous and arterial flow. Ovarian oedema and swelling are almost universal and can progress to haemorrhagic infarction within hours if untreated.</p><p>Torsion of a normal but hypermobile ovary is common in young children with excessively long <a href="/articles/fallopian-tube-1">fallopian tubes</a> or an absent <a href="/articles/mesosalpinx">mesosalpinx</a>.</p><p>In adulthood, causes include both benign and malignant <a href="/articles/ovarian-tumours">ovarian tumours</a>, <a href="/articles/polycystic-ovaries">polycystic ovaries</a> and <a href="/articles/abdominal-adhesions">adhesions</a>. In early pregnancy, a torsion can occur secondary to a <a href="/articles/corpus-luteal-cyst">corpus luteal cyst</a> or laxity of the adjacent tissues.</p><h4>Radiographic features</h4><p>The key feature of torsion is ovarian oedema and swelling due to venous and lymphatic engorgement. This exacerbates arterial compromise and can cause haemorrhage and infarction. The twisted vascular pedicle may be apparent as a layered vascular “whirlpool” with small quantities of fat. The oedema fluid fills peripheral follicles and leaks into the adjacent peritoneal cavity.</p><p>The presence of vascularity indicates viability.</p><p>There may be an underlying ovarian lesion, reduced or absent vascularity and a twisted dilated tubular structure corresponding to the vascular pedicle. Adnexal torsion is commonly unilateral, with a slight (3:2) right-sided predilection (presumably due to the protective effects of the sigmoid colon on the left) <sup>6,8</sup>.</p><h5>Ultrasound</h5><p>Ultrasound is the initial imaging modality of choice. Sonographic features include:</p><ul>
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