Ovarian torsion in a 20-year-old patient

Case Reports

CJEM 2006;8(2):126-129

Abstract

Résumé

Introduction

Torsion of the uterine adnexa is a gynecological emergency that requires prompt diagnosis and emergency surgical treatment. It can involve the fallopian tube, the ovary, and other adnexal structures.^1,2 Although this condition is generally viewed as uncommon, studies suggest that adnexal torsion is the 5th most common gynecological emergency, representing 2%-3% of acute surgical emergencies.³ Adnexal torsion can be a diagnostic challenge in the emergency department (ED), as most women present with non-specific symptoms. New advances in conservative surgical management have made early recognition critical for ovarian salvage, especially in the reproductive population.

Case report

A 20-year-old woman presented to the ED 3 hours after the abrupt onset of right lower quadrant abdominal pain radiating to her back. She described the pain as a constant severe ache that was intermittently sharp and stabbing, associated with nausea, vomiting and anorexia. Acetaminophen provided no relief, but curling into a fetal position eased some of her discomfort. She denied any other gastrointestinal or genitourinary symptoms. Her last normal menstrual period had ended 2 weeks before. She had not been sexually active within a year, was not using birth control and denied any history of sexually transmitted disease. She reported a similar episode one year earlier, which resolved spontaneously and was diagnosed as musculoskeletal pain.

On arrival to the ED, she was alert, oriented and in mild discomfort. Oral temperature was 36.8°C, respiratory rate was 16 breaths/min, heart rate was 84 beats/min, and blood pressure was 106/60 mm Hg. Her cardiovascular and respiratory examinations were unremarkable. Her abdomen was soft, with tenderness in the right lower quadrant. She had neither costovertebral angle tenderness nor hepatosplenomegaly. Rovsing's, psoas, and obturator signs were negative, and bowel sounds were normal. The pelvic exam revealed cervical motion tenderness as well as right adnexal fullness and tenderness, with no vaginal discharge. The patient's β-HCG was negative. A pelvic ultrasound was performed (Fig. 1), showing a 10-cm complex solid/ cystic mass lying superior to the bladder. The uterus and left ovary were normal, but the right ovary was not identified. Images were interpreted by the radiologist to represent a right ovarian mass torsion.

Fig. 1. 10 cm-complex mixed solid/cystic mass situated posterior and superior to the bladder with no flow on Doppler identified within the mass. With no normal right ovary identified, it should be regarded as an ovarian mass torsion until proven otherwise.

Emergent laparoscopy confirmed a right ovarian torsion secondary to a 10-cm dermoid cyst.

Discussion

Ovarian torsion, first described by Kuestner in 1891, results from partial or complete rotation of the ovarian pedicle on its long axis, potentially compromising venous and lymphatic drainage.⁴ If the rotation is partial or intermittent, the venous and lymphatic congestion may subside quickly, along with symptoms. If rotation is complete and prolonged, venous and arterial thrombosis occur, ultimately causing adnexal infarction.^4,5 Adnexal torsion is rarely bilateral and is more common on the right side,^3,6 perhaps because the sigmoid colon leaves limited space for left adnexal mobility.⁷ Torsion occurs more commonly in young women, with the greatest incidence in the 20- to 30-year age group.⁸

Ovarian enlargement, adnexal masses, pregnancy, ovulation induction and previous pelvic surgery are the most common predisposing factors for ovarian torsion, and the exact mechanism of torsion varies according to its cause. Ovarian enlargement of any etiology predisposes the adnexa to torsion; however, normal ovaries may undergo torsion, especially in prepubescent females.⁴ Ovarian tumours or adnexal masses can act as fulcrums, resulting in torsion. Benign ovarian neoplasms carry an 11% risk, and dermoid tumours (a.k.a. benign cystic teratomas), the most common ovarian neoplasms in young females, are a relatively common antecedent of adnexal torsion.^3,9 Malignant ovarian tumours are more likely to adhere to or invade other pelvic structures, hence carry a lower risk of torsion — only 2%.^3,10 Because of the anatomy of the broad ligament, both the ovary (or adnexal mass) and the fallopian tube are usually involved in the torsion; it is uncommon for these structures to be involved in isolation.⁶

During pregnancy, the growing uterus displaces the adnexa in the face of increasingly lax supporting tissues, increasing the likelihood of adnexal torsion. This is most common between 6 and 14 weeks' gestation, and in the immediate peurperium.¹¹ Patients undergoing ovulation induction are also at higher risk of adnexal torsion — theoretically because of ovarian enlargement from multiple maturing follicles and theca lutein cysts.¹² Another predisposing factor for torsion is a hypermobile adnexa due to hydrosalpinx or an elongated mesosalpinx. Finally, previous gynecological surgery (including tubal ligation) is a risk factor for torsion because adhesions may act as pivot points upon which the adnexa can rotate.⁸

The diagnosis of ovarian torsion can be difficult because the presenting signs and symptoms, abdominal pain, nausea and vomiting, are common to many causes of acute abdomen, including appendicitis, bowel obstruction, gastrointestinal infection, ruptured ovarian cyst, ectopic pregnancy, pelvic inflammatory disease, cystitis and renal colic. Acute appendicitis is the most common incorrect diagnosis but, fortunately, this diagnosis does not delay surgical intervention. Non-surgical misdiagnoses such as gastrointestinal infection or pelvic inflammatory disease delay surgical intervention and may lead to adverse consequences.¹ Therefore, the diagnosis of adnexal torsion must be considered in any female patient presenting with lower abdominal pain.

Classically, patients with ovarian torsion will present with acute onset of severe, progressive unilateral abdominal or pelvic pain that is crampy or colicky in nature.¹³ The pain may radiate into the thigh or lower back on the affected side.⁷ Incomplete or intermittent torsion may be characterized by bouts of severe pain separated by asymptomatic periods as the ovary twists and untwists.⁶ Nausea and vomiting is common,^3,14 and low grade fever (<38.0°C) may occur.⁸ The physical exam may reveal a soft abdomen with lower quadrant tenderness; however, if the torsion is longstanding, the abdomen may be diffusely tender with peritonitis and rigidity, making localization difficult.⁷ Bimanual pelvic exam may demonstrate uterine shift toward the affected side. Adnexal tenderness is typical and up to 50% of women have a palpable adnexal mass.⁸

Few investigations are sensitive or specific for adnexal torsion, and commonly used tests are most useful to rule out other causes of lower abdominal pain. A negative β-HCG can rule out causes such as ectopic pregnancy, and a urine dipstick and microscopy should be performed to assess the possibility of urinary tract infection or stone. Studies have demonstrated elevated white blood cell counts in 16% to 38% of cases,^1,8 but this result is of little value in differentiating ovarian torsion from other causes of abdominal pain.

In cases of suspected torsion, immediate ultrasound is the investigation of choice, and >93% of patients with ovarian torsion will have abnormal ultrasound findings.⁸ Findings depend on the duration of torsion and the degree of ovarian ischemia,¹⁰ with the most common finding ovarian enlargement.⁶ In cases of incomplete ovarian torsion, ultrasonography may show massive ovarian edema due to compromise of lymphatic drainage, without ischemic necrosis.⁵ Free fluid is found in the cul-de-sac in a small number of patients from ovarian capsule transudate secondary to lymphatic and venous obstruction.¹¹ In the early stages of ovarian torsion, the ovary is enlarged with prominent peripheral follicles. Hyperechogenic and hypoechogenic areas may be seen which correspond to hemorrhage and edema respectively. With prolonged and complete torsion, infarction may appear as cystic, clotted areas.²

Colour Doppler sonograpy (CDS) has been used increasingly in recent years to evaluate ovarian viability. Abnormal flow on CDS increases the likelihood of torsion,^6,9 but torsion may occur with incomplete vascular obstruction; therefore, evidence of vascular flow does not rule out torsion with certainty.⁸ In one recent case series, 14 of 15 patients with ovarian torsion had abnormal CDS flow patterns,⁶ but in another small retrospective series of 10 surgically confirmed cases, CDS often showed normal ovarian flow, and this test was associated with significant delays to diagnosis (5.3 v. 59 hours).¹⁵

Diagnostic laparoscopy is indicated when there is a high suspicion of ovarian torsion and the need for surgical intervention remains unclear.¹³ Experienced laparoscopists may be able to manage an ovarian torsion through a laparoscope, but larger adnexal structures or relative inexperience with the laparoscope will require conversion to laparotomy. In the past, oophorectomy was considered the standard of care, because of concern that untwisting of the adnexa might precipitate pulmonary embolism from a thrombosed vein.³ Several studies have shown that in the absence of a grossly necrotic ovary, untwisting of the adnexa can be performed, and the ovary salvaged, without significant risk of thromboembolism.^16,17 Conversely, an obvious hemorrhagic infarction or gangrenous adnexal structure requires surgical removal without attempt to untwist.

Conclusion

Ovarian torsion is a surgical emergency that often presents a difficult diagnostic challenge. A detailed history and physical, including a pelvic exam is crucial, and ancillary tests such as β-HCG are useful to exclude other possibilities. Ultrasound with or without Doppler imaging may be helpful; however, direct laparoscopic visualization is the only way to confirm the diagnosis. New advances in conservative surgery have made rapid investigation imperative, since the ability to save a viable ovary is time dependent.