Ovarian Torsion

Practice Essentials

Ovarian torsion (adnexal torsion) is an infrequent but significant cause of acute lower abdominal pain in women. This condition is usually associated with reduced venous return from the ovary as a result of stromal edema, internal hemorrhage, hyperstimulation, or a mass. The ovary and fallopian tube are typically involved. The clinical presentation is often nonspecific with few distinctive physical findings, commonly resulting in delay in diagnosis and surgical management. A quick and confident diagnosis is required to save the adnexal structures from infarction.^{[1, 2, 3, 4]}

Ovarian torsion involves torsion of the ovarian tissue on its pedicle leading to reduced venous return, stromal edema, internal hemorrhage, and infarction with the subsequent sequelae. Ovarian torsion classically occurs unilaterally in a pathologically enlarged ovary. Torsion of a normal ovary is most common among young children.^{[5, 6]}

Pregnancy is associated with, and may be responsible for, torsion in approximately 20% of adnexal torsion cases.^[7]  Ovarian tumors, both benign and malignant, are implicated in 50-60% of cases of torsion. Approximately 17% of cases have been found to occur in premenarchal or postmenopausal women.^[8]

Classically, patients present with the sudden onset (commonly during exercise or other agitating movement) of severe, unilateral lower abdominal pain that worsens intermittently over many hours. Approximately 25% of patients experience bilateral lower quadrant pain described as sharp and stabbing or, less frequently, crampy. Nausea and vomiting occur in approximately 70% of patients.

Ultrasonography with color Doppler analysis is the method of choice for the evaluation of adnexal torsion because it can show morphologic and physiologic changes in the ovary and can help in determining whether blood flow is impaired.^{[9, 10, 11]}

In a patient with a history and physical examination findings suggestive of ovarian torsion, gynecologic consultation and subsequent laparoscopy are critical.^{[12, 13, 14]}

• References

Pathophysiology

Ovarian torsion involves torsion of the ovarian tissue on its pedicle leading to reduced venous return, stromal edema, internal hemorrhage, and infarction with the subsequent sequelae. Ovarian cysts are 3 times more common in ovarian torsion cohorts than in the general population, and evidence suggests that ovarian cysts are very common in asymptomatic pregnant women but spontaneously resolve as the pregnancy progresses. Pregnancy is a risk factor for torsion (odds ratio: 18:1) but remains an uncommon event (0.167%).^[7]

Ovarian torsion classically occurs unilaterally in a pathologically enlarged ovary. The irregularity of the ovary likely creates a fulcrum around which the oviduct revolves. The process can involve the ovary alone but more commonly affects both the ovary and the oviduct (adnexal torsion). Approximately 60% of cases of torsion occur on the right side.

Although torsion may rarely occur in normal adnexa, it more frequently arises from one of many anatomic changes. Torsion of a normal ovary is most common among young children, in whom developmental abnormalities (eg, excessively long fallopian tubes or absent mesosalpinx) may be responsible. In fact, fewer than half of ovarian torsion cases in pediatric patients involve cysts, teratomas, or other masses.

During early pregnancy, the presence of an enlarged corpus luteum cyst likely predisposes the ovary to torsion. Women undergoing induction of ovulation for infertility carry an even greater risk, in that numerous theca lutein cysts significantly expand the ovarian volume.

• References

Etiology

Anatomic changes affecting the weight and the size of the ovary may alter the position of the fallopian tube and allow twisting to occur.

Pregnancy is associated with, and may be responsible for, torsion in approximately 20% of adnexal torsion cases,^[7] probably secondary to the ovarian enlargement that occurs during ovulation in combination with laxity of the supporting tissues of the ovary.

Congenitally malformed and elongated fallopian tubes may be seen, particularly in young, prepubertal patients.

Ovarian tumors, both benign and malignant, are implicated in 50-60% of cases of torsion. Involved masses are nearly all larger than 4-6 cm, although torsion is still possible with smaller masses. Dermoid tumors are most common. Malignant tumors are much less likely to result in torsion than benign tumors are. This is because of the presence of cancerous adhesions that fix the ovary to surrounding tissues.

Conversely, patients with a history of pelvic surgery (principally tubal ligation) are at increased risk for torsion, probably because of adhesions that provide a site around which the ovarian pedicle may twist.

• References

Epidemiology

Studies reveal that ovarian torsion is the fifth most common gynecologic surgical emergency, accounting for 2.7% of cases of acute gynecologic complaints in 1 series. Ovarian torsion is encountered more often in women who have had ovarian stimulation, which likely accounts for a slightly increased incidence in developed countries.

Ovarian torsion applies strictly to the female sex. It can occur at any age, but most cases occur in the early reproductive years. The median age reported by a large review was 28 years. The percentage of patients younger than 30 years is approximately 70-75%. Two groups of women show a particular tendency to be affected by adnexal torsion (ovarian torsion): (1) women in their mid 20s and (2) women who are postmenopausal.

Approximately 20% of cases of torsion occur during pregnancy.^{[15, 16]} Postmenopausal women with an adnexal mass may also be affected. Adolescents are also at risk; this may be because of changes in the weight of their maturing adnexa.^[16] Approximately 17% of cases have been found to occur in premenarchal or postmenopausal women. Although ovarian torsion in very young children is rare, a case of ovarian cyst torsion was reported in a 2-year-old.^[17]

• References

Prognosis

With early diagnosis and appropriate treatment, the prognosis of ovarian torsion is excellent. However, most patients with ovarian torsion have a delayed diagnosis, often resulting in infarction and necrosis of the ovary. The ovarian salvage rate has been reported below 10% in adults but as high as 27% in a study among pediatric patients.^[12]

Although the loss of a single ovary is unlikely to result in significantly reduced fertility and no cases of death due to ovarian torsion have been reported, early diagnosis allows conservative laparoscopic treatment and reduction in complications. In a retrospective large study comparing pregnant patients with adnexal torsion to nonpregnant patients with adnexal torsion, the recurrence rate of torsion was 19.5% in pregnant women and 9.1% in nonpregnant women.^[13]

• References

History

Classically, patients present with the sudden onset (commonly during exercise or other agitating movement) of severe, unilateral lower abdominal pain that worsens intermittently over many hours. A minority of patients, however, complain of mild pain that follows a more prolonged time course. The pain usually is localized over the involved side, often radiating to the back, pelvis, or thigh. Approximately 25% of patients experience bilateral lower quadrant pain. It may be described as sharp and stabbing or, less frequently, crampy.

Nausea and vomiting occur in approximately 70% of patients, mimicking a gastrointestinal source of pain and further obscuring the diagnosis.

A history of previous episodes may be elicited, possibly attributable to partial, spontaneously resolving torsion. Fever may occur as a late finding as the ovary becomes necrotic.

Ovarian torsion in premenarchal girls is associated with a longer interval from onset of symptoms and an increased rate of fever and pelvic mass at presentation compared with postmenarchal patients, according to one study. Median duration of symptoms before presentation was 24 hours for premenarchal patients, versus 8 hours for postmenarchal patients.^[1]  In another study, of 32 premenarchal patients with ovarian torsion, the main presenting symptoms were abdominal pain (92.3%) and nausea and vomiting (84.6%). Abdominal tenderness was present in 64.1%.On abdominal ultrasound, an enlarged ovary was identified in 28.9%.^[2]

In a retrospective study of ovarian torsion in premenarchal and postmenarchal patients in Israel, there was a higher frequency of nausea and vomiting in the premenarchal patients. Ovarian cysts were more commonly demonstrated in postmenarchal patients, and a normal adnexal appearance on ultrasound was more common in premenarchal patients.  Because of a normal adnexa in 69% of cases in premenarchal patients, a high index of suspicion is necessary in any premenarchal patient with acute-onset abdominal pain.^[3]

Ovarian torsion in the third trimester of pregnancy is likely to present as nonspecific symptoms of lower abdominal pain, nausea, and vomiting and can often be misdiagnosed as appendicitis or preterm labor. Although conservative treatment has been proposed during pregnancy, surgical intervention may be necessary if ovarian torsion is highly suspected. Ultrasonography in early pregnancy should address the cervix and the adnexa for early diagnosis and management of ovarian masses, thus avoiding later emergency situations and the possibility of preterm deliveries.^[4]

• References

Physical Examination

The physical examination, like the history, is typically nonspecific and is highly variable. A unilateral, tender adnexal mass has been reported in between 50 and 90% of patients. However, the absence of such a finding does not exclude the diagnosis. Tenderness to palpation is common; however, it is mild in approximately 30% and absent in another 30% of patients. Therefore, the absence of tenderness cannot be used to rule out torsion.

Peritoneal findings are infrequent and indicate advanced disease if present.

• References

Complications

Complications of ovarian torsion include the following:

• Infection
• Peritonitis
• Sepsis
• Adhesions
• Chronic pain
• Infertility (rare)

• References

Approach Considerations

Diagnostic ultrasonography should be the first examination performed; typically, the affected ovary is enlarged, with multiple immature or small follicles along its periphery.

Ultrasonography with color Doppler analysis is the method of choice for the evaluation of adnexal torsion because it can show morphologic and physiologic changes in the ovary and can help in determining whether blood flow is impaired.^{[21, 10, 22, 23, 24, 11]} . Gray-scale and spectral findings are correlated with the age of the torsion (ie, acute torsion or chronic torsion) and the degree of the twist or torsion. Normal Doppler imaging must not, however, be used as a basis for excluding the diagnosis.

Rarely, computed tomography (CT) or magnetic resonance imaging (MRI) is needed to make a definitive diagnosis. CT or MRI can serve as a secondary modality when ultrasonographic findings are nondiagnostic.^{[25, 26, 27]}

Culdocentesis is a nonspecific test that is unlikely to confirm or exclude torsion and therefore is not recommended in the diagnostic workup.

• References

Ultrasonography

Findings indicative of torsion

Ovarian enlargement secondary to impaired venous and lymphatic drainage is the most common sonographic finding in ovarian torsion. A coexistent mass is often seen. The ovary usually contains several cysts along its periphery; these are follicles that have likely been displaced peripherally because of ovarian edema and venous congestion. In addition, there may be irregular echogenic areas within the ovary corresponding to stromal edema and/or hemorrhage.

Color Doppler sonography may be helpful in predicting viability of adnexal structures by depicting blood flow within the twisted vascular pedicle and presence of central venous flow.^[14] On color Doppler sonograms, little or no intraovarian venous flow is present; this finding is followed by a lack of intraovarian arterial flow. Flow within the adnexal vessels may be preserved (see the video below).^[22]

View Video

Video depicts 2 findings: (1) enlarged hypovascular left ovary and (2) flow in healthy right ovary. Small amount of intraperitoneal fluid surrounds left ovary.

Occasionally, the twisted pedicle of the affected ovary can be recognized. A twisted pedicle is a relatively specific sign for ovarian torsion. With isolated tubal torsion, the tube is usually distended and lacks flow or has reversed flow during diastole. Because venous flow is under low pressure, it is the first flow to be affected by the increased interstitial pressure of a twisted ovary. In chronic torsion, arterial waveforms can mimic venous waveforms. When torsion is complete, no arterial waveforms can be detected within the ovary.

Intraperitoneal fluid may surround the twisted ovary. This usually is the result of interstitial fluid that weeps off an affected ovary rather than a true rupture of the capsule and extrusion of blood.^{[18, 10]}

The finding of an ovarian mass may suggest a focus for torsion but may also be misleading as to this is itself the source of pain. Because implicated masses are most frequently nonneoplastic or hemorrhagic cysts, which can themselves produce pain of similar quality and location, diagnosis can be challenging even with appropriate imaging. Nevertheless, when the history is suggestive of torsion, the discovery of an ovarian cyst should greatly increase one’s suspicion of the diagnosis.

Auslender et al suggested a classification of severity of adnexal torsion and treatment strategy that was based on blood flow as depicted on Doppler ultrasonography.^[23] In their small study (n=17), they used Doppler and gray-scale ultrasonography to visualize coiling of the ovarian vessels, concluding that when coiling of the ovarian vessels is present, Doppler flow examination of the ovary can help differentiate between ischemic adnexal torsion and coiling of the ovarian blood vessels without strangulation, thus facilitating the choice of treatment.^[23]

In 9 of these 17 patients, arterial and venous blood flow was present within the ovary, and ultrasonographic and surgical findings usually demonstrated normal-sized or mildly enlarged ovaries; in 5, only arterial blood flow was detected within the ovary, and surgery usually revealed enlarged ovaries with normal color or mild discoloration; and in 3, neither arterial nor venous blood flow was seen within the ovary, vessel coiling was evident only on gray-scale and not on Doppler examination, and signs of ovarian ischemia or necrosis were found at surgery.^[23]

In a study of 39 patients by Shadinger et al, ovarian enlargement and the absence of ovarian venous Doppler flow were the most frequent sonographic indications of ovarian torsion. Frequent clinical symptoms included abdominal pain and vomiting. The authors concluded that ovarian torsion should be strongly suspected in the presence of ovarian enlargement and clinical symptoms, even if arterial and venous Doppler flow are present.^[28]

Diagnostic reliability and limitations

Combining Doppler flow imaging with morphologic assessment of the ovary may improve diagnostic accuracy. However, the interpretation of Doppler sonography is inconsistent as a consequence of the dual ovarian blood supply from the uterine artery and the ovarian artery.

A small study in a specialized ultrasound unit found 74.6% accuracy when using sonography to diagnose ovarian torsion. The most diagnostically accurate sonographic signs were abnormal ovarian blood flow and the presence of free fluid. The authors cautioned that ovarian torsion should not be ruled out when typical indicators are absent, especially when clinical history is suggestive of the condition.^[24]

The presence of an enlarged ovary with lack of intraovarian arterial or venous flow is highly indicative of torsion, particularly if the typical appearance of an enlarged ovary with small peripheral cysts is depicted. However, the presence of adnexal flow should not be construed as ruling out the diagnosis.

Early in the progression of disease, arterial perfusion may be preserved, with only venous and lymphatic flow obstructed. Additionally, if the scan is performed during a transient period of detorsion of the ovary, a normal Doppler flow may falsely suggest a normal ovary.

Although a lack of intraovarian arterial and venous flow enables confident diagnosis, adnexal torsion (ovarian torsion) may be incomplete; incomplete torsion may be associated with adnexal flow, as depicted with color Doppler sonography. Rarely, the use of improper settings can cause erroneous findings of absent flow. Check that the proper settings are used by looking for flow in the internal iliac vein.

In some cases, flow depiction may be difficult to obtain from the affected ovary, as well as the healthy contralateral ovary. In these cases, the characteristic gray-scale morphologic image of ovarian torsion alone may help in making the diagnosis.

Chronic tuboovarian abscesses and/or complexes may mimic torsion, particularly torsion with contained areas of infarction.

• References

Computed Tomography

Multiple CT findings have been described in ovarian torsion^{[25, 14, 29, 30]} :

• Enlarged adnexal structure (>5cm)
• Thick, straight blood vessels draped around the lesion
• Complete absence of enhancement
• Hemorrhage or gas in the torsed lesion
• Misplacement of the torsed structure (to the midline or contralateral side)
• Deviation of the uterus to the involved side
• Infiltration of the periadnexal fat
• Tubal thickening
• Thickened vascular pedical with engorged vessels
• Ascites

In a study by Moore et al, before undergoing surgery for ovarian torsion, 28 of 28 patients had had CT confirmation of an enlarged ovary, ovarian cyst, or adnexal mass of the involved ovary^[31] ; the authors therefore concluded that ovarian torsion can be ruled out by well-visualized normal-appearing ovaries on CT and that either abnormal findings or inability to visualize the ovaries on CT necessitates further evaluation for possible ovarian torsion.

Although CT may demonstrate an enlarged ovary and adnexal masses, it is unable to evaluate the presence or absence of blood flow to the involved ovary. In cases of diagnostic uncertainty, however, CT may be useful in ruling out other possible causes of lower abdominal pain.^[32] Additionally, CT can exclude the presence of a pelvic mass, thereby greatly enhancing the clinician’s ability to rule out torsion.

In a study of women who presented to the ED and were evaluated for ovarian torsion, the negative predictive value of a negative CT examination was 100%. It was also found that color Doppler ultrasound offered no utility in evaluating for ovarian torsion after a negative contrast-enhanced CT scan of the abdomen and pelvis.^[33]

• References

Magnetic Resonance Imaging

MRI may demonstrate ovarian enlargement and intraperitoneal fluid. In a case report, MRI demonstrated a twisted pedicle. If hemorrhagic infarction is present, MRI can demonstrate an enlarged ovary with displaced follicles. T2-weighted images show low signal intensity caused by interstitial hemorrhage, and T1-weighted images show a thin rim of high signal intensity without contrast enhancement.^{[25, 27, 34, 35]}

• References

Approach Considerations

In a patient with a history and physical examination findings suggestive of ovarian torsion, gynecologic consultation and subsequent laparoscopy are critical, regardless of whether laboratory and radiologic studies yield normal results.

Approximately 1 in 1800 pregnancies is complicated by adnexal torsion, typically between the sixth and fourteenth weeks of gestation. This increased frequency in pregnant women is likely due to greater laxity of the tissues adjoining the ovaries and oviducts during pregnancy, as well as to enlargement of the ovary in early pregnancy secondary to the corpus luteum cyst.

Detorsion of the adnexa during pregnancy has not been found to compromise fetal well-being. However, if the corpus luteum cyst is removed during salpingo-oophorectomy, supplemental progesterone is indicated.

Outpatient care has no role in the treatment of ovarian torsion. Patients with either a suspected or confirmed diagnosis of ovarian torsion should be admitted and either operated on or observed by a gynecologist. Laparoscopy can be used for both confirmation of the diagnosis and treatment.

• References

Medication Summary

Pain medication may be given to a patient who presents with abdominal pain that is suspected of deriving from ovarian torsion. The use of nonsteroidal anti-inflammatory drugs (NSAIDs) and opioids is acceptable.

• References

Ketorolac (ReadySharp Ketorolac)

• Dosing, Interactions, etc.

Clinical Context:  Ketorolac inhibits prostaglandin synthesis by decreasing the activity of the enzyme cyclooxygenase, which results in decreased formation of prostaglandin precursors.

• References

Morphine (Astramorph, Duramorph, MS Contin, Avinza, Kadian, Depodur, Infumorph, MorphaBond, Arymo ER)

• Dosing, Interactions, etc.

Clinical Context:  Morphine is the drug of choice for narcotic analgesia because of its reliable and predictable effects, its safety profile, and the ease with which its effects can be reversed with naloxone.

Morphine sulfate administered intravenously (IV) may be dosed in a number of ways and is commonly titrated until the desired effect is obtained.

For chronic severe pain unremitting to alternative therapy, oral immediate–release and extended-release morphine sulfate may be warranted. Arymo ER is a morphine sulfate abuse-deterrent derivative.

• References

Class Summary

Pain control is essential to quality patient care and should not be delayed while the patient is awaiting surgical or gynecologic evaluation.

A review of opioid equivalents and conversions may be found in the following reference article:

 http://emedicine.medscape.com/article/2138678-overview

• References

Prochlorperazine (Compazine, Compro)

• Dosing, Interactions, etc.

Clinical Context:  Prochlorperazine may relieve nausea and vomiting by blocking postsynaptic mesolimbic dopamine receptors through its anticholinergic effects and depressing the reticular activating system. In addition to its antiemetic effects, it has the advantage of augmenting hypoxic ventilatory response, acting as a respiratory stimulant at high altitude.

• References

Metoclopramide (Reglan, Metozolv)

• Dosing, Interactions, etc.

Clinical Context:  Metoclopramide blocks dopamine receptors in the chemoreceptor trigger zone of the central nervous system.

• References

Ondansetron (Zofran, Zuplenz)

• Dosing, Interactions, etc.

Clinical Context:  Ondansetron is a selective 5-HT3-receptor antagonist that blocks serotonin both peripherally and centrally. It prevents the nausea and vomiting associated with emetogenic cancer chemotherapy (eg, high-dose cisplatin) and complete-body radiotherapy.

• References

Class Summary

Antiemetics are useful in the treatment of nausea associated with the clinical symptoms of ovarian torsion. Some antiemetics also have sedative effects.

• References