A 28-year-old female presents with severe lower right quadrant pain. Her intermittent pain started three days ago. She has had several episodes of non-bloody emesis, which usually occurs when the pain worsens, but she denies vaginal bleeding, vaginal discharge, urinary symptoms, fever, diarrhea, back pain, or other symptoms. She is significantly tender in the right lower quadrant, but a pelvic exam is unrevealing.
Explore This IssueACEP Now: Vol 39 – No 06 – June 2020
Abdominal and pelvic pain are common presentations in the emergency department, ranging from benign to serious. One important and dangerous condition not to miss is ovarian torsion.
Ovarian torsion occurs when the ovary completely or partially rotates on the ligamentous supports, resulting in necrosis and infertility if missed.1–5 Here are five myths that can mislead the emergency physician.
Myth #1: Only Women of Reproductive Age Experience Ovarian Torsion
While ovarian torsion most commonly affects women of reproductive age, typically around 30 years old, the risk factor most strongly associated with torsion is an adnexal mass >5 cm, occurring in up to 80 percent of patients with torsion; underlying risks include polycystic ovarian syndrome, undergoing fertility therapies, history of previous torsion, and history of tubal ligation.3–16
Approximately 15 percent of ovarian torsion cases occur in pediatric patients, which is thought to occur due to an elongated utero-ovarian ligament.3–5,11–13 Unlike other patient populations, more than half of pediatric patients with ovarian torsion have normal ovaries.3–5,9–16 Postmenopausal patients account for another 15 percent of cases, although almost all of these patients have an enlarged ovary or mass within the pelvis. Pregnant patients are also at risk, accounting for 10 to 25 percent of all cases.5,9,16–20 In fact, pregnancy is a significant risk factor for torsion, primarily due to progesterone increasing the risk of ovarian cyst formation.16–20 Most patients with torsion during pregnancy experience it in the first 17 weeks (81 percent), and 73 percent of these patients have undergone fertility therapy.4,18–20 Fertility treatments can result in ovarian hyperstimulation, further increasing the risk of ovarian cyst formation.5,15
Key Point: Consider ovarian torsion in female patients of all ages.
Myth #2: All Patients with Ovarian Torsion Present with Acute Severe Pain and Vomiting
Symptoms of ovarian torsion occur due to occlusion of vascular flow from torsion of the vascular pedicle. We classically associate this with abrupt, severe pain in the lower abdomen that radiates to the flank or inguinal area as well as nausea and vomiting.4–7,10,21,22 However, sudden, severe pain only occurs in 50 percent of patients.4–7,22 Some form of pain is present in up to 90 percent of patients, but the description of the pain varies.4–7,22 Symptoms can be vague, lasting for days to months, and be constant or episodic due to intermittent torsion and detorsion of the ovary.23,24 Pain may resemble that of appendicitis, urolithiasis, ectopic pregnancy, and other conditions. Nausea and vomiting occurs in up to 70 percent of patients, and fever may also occur in 2 to 20 percent of patients, further complicating the diagnosis.4,6,7,12,23,24 Diagnosing torsion in infants is extremely difficult, as these patients may present with irritability, fussiness, vomiting, or feeding intolerance.5,11–13 Pediatric females can present with diffuse pain and fever, typically resulting in delayed diagnosis.5,25,26
Importantly, the critical ischemia time for the ovaries that results in necrosis is unknown. Patients may have symptoms for hours to days, and there is no specific time cutoff that reliably predicts irreversible necrosis.4,5,27–29
Key Point: Patients with ovarian torsion may present with constant, severe, abrupt, intermittent, or mild pain.
Myth #3: A Normal Physical Exam, Including Pelvic Exam, Can Rule Out Torsion
Up to one-third of patients have no tenderness on either an abdominal or pelvic exam.4–7,10 One of the key risk factors is an ovarian mass or cyst, but unfortunately, exams are also unreliable in detecting the presence of adnexal tenderness or mass, with an inter-examiner reliability ranging from 23 to 32 percent.5,30 Results are no better with a gynecologist-performed exam, with a sensitivity of detecting a mass >5 cm of 15 to 36 percent.5,31 The exam’s reliability further decreases in the setting of increased patient weight (defined as >200 pounds) and in patients older than age 55.32
Key Point: A normal abdominal or pelvic exam does not exclude ovarian torsion.
Myth #4: A Normal Ultrasound Can Rule Out Torsion
Transvaginal ultrasound (TVUS) with grayscale imaging and Doppler flow is usually the go-to imaging modality to evaluate for torsion. While TVUS has high specificity, it has poor sensitivity, ranging from 35 to 85 percent.33–35 The most common finding is an enlarged ovary due to edema, often with a mass.5,16,17,33–36 Other signs include an ovary displaced to the midline. The “string-of-pearls sign,” in which an enlarged ovary is lined around the periphery by follicles, suggests torsion.5,16,17,33–36 Grayscale may demonstrate a hypoechoic appearance of the ovary due to edema. Color Doppler may reveal decreased or absent intraovarian venous flow, which may be followed by absent arterial flow later in the disease (see Figure 1).5,16,17,33–36 One major pitfall with TVUS use is reliance of normal arterial flow to exclude torsion, as the ovaries have dual blood flow from the ovarian and uterine arteries.5,34 Torsion initially occurs with lymphatic and venous outflow obstruction. Arterial inflow is not compromised until later in the disease course.35,36 Arterial flow is completely normal in more than 25 percent of patients with surgery-confirmed torsion, and more than half of patients will have detectable arterial flow.16,17,35,36 Therefore, assessing venous flow is a better indicator. However, intermittent or partial torsion may also result in normal venous flow TVUS.
Literature suggests that combining ultrasound findings can improve sensitivity and specificity compared to only focusing on vascular flow.5 Evaluating for free fluid within the pelvis, ovarian enlargement and edema, and vascular flow can improve sensitivity.5 The whirlpool sign is strongly suggestive of torsion; it consists of a circular collection of blood vessels within an enlarged ovary or mass.5,37,38
Key Point: Do not rely on normal vascular flow to rule out ovarian torsion. A combination of TVUS findings such as ovarian enlargement and mass, free fluid in the pelvis, and vascular flow may improve your ability to diagnose ovarian torsion.
Myth #5: CT of the Abdomen and Pelvis Has No Role in Evaluating Ovarian Torsion
Patients with undifferentiated abdominal pain often undergo CT, but can CT assist in ruling in or out ovarian torsion? CT with IV contrast will often display findings suggestive of torsion.5,16,33,39–42 Findings on CT with high specificity for ovarian torsion include a twisted vascular pedicle (see Figure 2), a thickened fallopian tube with target/beak-like appearance, absent or reduced ovarian enhancement with contrast, and an enlarged ovary with a follicular ovarian stroma and peripherally displaced follicles.16,33,39–42 Features that are commonly found but not specific include an enlarged ovary, an adnexal mass, adnexal mass mural thickening, free pelvic fluid, fat stranding surrounding the ovary, uterine deviation toward the torsed ovary, and ovarian displacement toward the uterus.16,33,39–42 CT with contrast demonstrates a high sensitivity for these secondary findings, approaching 100 percent.16,33,39–42 If one of these secondary findings is present, TVUS and OB/GYN consultation should be expedited. If these findings are not present and the ovary is normal in size, TVUS may not be needed, depending on the any changes in the clinical course. If the ovary is abnormal on CT, then obtain TVUS.
Finally, if suspicious of torsion based on your history and exam, an ob-gyn consultation should be initiated prior to imaging. If an ob-gyn is unavailable, a general surgery consultation is warranted. Torsion is a time-sensitive condition; early involvement of specialists is paramount.
Key Point: A normal CT of the abdomen and pelvis with contrast that has no secondary findings displays high sensitivity for excluding ovarian torsion. If secondary findings such as an enlarged ovary are present, then obtain TVUS.
The CT of the abdomen and pelvis reveals a normal appendix but an enlarged right ovary. A small amount of pelvic free fluid and fat stranding around the right ovary are observed. You consult the ob-gyn on call, who requests a TVUS. The TVUS reveals an enlarged ovary with decreased venous flow on Doppler. The ob-gyn evaluates the patient and takes her to the operating room, where detorsion is successful.
Dr. Long is an emergency physician in the San Antonio Uniformed Services Health Education Consortium at Fort Sam Houston, Texas. Dr. Koyfman (@EMHighAK) is assistant professor of emergency medicine at UT Southwestern Medical Center and an attending physician at Parkland Memorial Hospital in Dallas. Dr. Gottlieb is associate professor, ultrasound division director, and ultrasound fellowship director in the department of emergency medicine at Rush University Medical Center in Chicago.
- Ovarian torsion can affect women of all ages.
- Pain in the setting of ovarian torsion can vary significantly; it may be abrupt, intermittent, or not present at all.
- The exam is unreliable. Do not use it to exclude ovarian torsion.
- Use a combination of factors on TVUS when evaluating torsion: Doppler flow, ovarian size, and free fluid within the pelvis.
- A completely normal CT of the abdomen/pelvis with contrast is sensitive for ovarian torsion. If there are secondary findings (eg, enlarged ovary), obtain a TVUS.
- Consult an ob-gyn early in the care of these patients.
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