Ovarian Torsion, Acute

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Diagnosis and reasoning

Acute pelvic pain is a common complaint which may be due to either surgical or gynecological causes. In this lady, the differential diagnoses include acute appendicitis, ureteric colic, ovarian torsion, ectopic pregnancy and pelvic inflammatory disease. The location of the pain is compatible with appendicitis, as is the mild fever, nausea and vomiting. While many patients also experience initial peri-umbilical pain which subsequently migrates to the right lower abdomen, the absence of this finding does not exclude this diagnosis. Ureteric colic may also present in this manner. In this context, the fever would be due to secondary infection arising from urinary stasis. Note that such patients may not manifest urinary symptoms such as frequency, urgency or dysuria. Both rupture of an ovarian cyst and ovarian torsion may cause severe unilateral pain associated with nausea and vomiting. In case of torsion, the previous mild, intermittent pain might be due to the ovary repeatedly twisting and unwinding. In case of a cyst, this might be due to stretching of the cyst wall or ovary or twisting of the cyst around its pedicle. While ectopic pregnancy is excluded by the history of sexual abstinence for an year, this should not preclude hCG testing by the wary clinician. Pelvic inflammatory disease secondary to STDs (especially gonococcal infection) may present in this abrupt manner. However, the sexual abstinence and lack of previous STDs make this diagnosis less likely. Note that pelvic inflammatory disease due to other organisms usually presents in a more subacute manner. Examination shows both tenderness and rebound tenderness in the right iliac fossa. While this favors appendicitis, it should be kept in mind that ovarian pathologies may also manifest these signs. The vaginal examination demonstrates cervical motion tenderness, right sided adnexal tenderness and an adnexal mass. This drastically narrows down the diagnoses to either a slow leaking ectopic pregnancy, pelvic inflammatory disease with abscess formation, or ovarian pathologies. The negative beta-hCG test makes ectopic pregnancy unlikely, while the normal urinalysis removes any lingering doubt of urinary tract pathology. The marked neutrophil leukocytosis in the full blood count might be due to pelvic inflammatory disease - but might also be due to secondary infection of a necrotic ovary. As the initial investigations are inconclusive, a logical next step would be a pelvic ultrasound scan. This demonstrates a large pelvic mass with cystic and solid areas and no evidence of blood flow, while the right ovary cannot be identified. These sonographic findings favor torsion of a right ovarian mass (such as a cystadenoma or a teratoma) - this would explain why the ovary cannot be identified and why no blood flow is noted. However, these findings are also compatible with a tubo-ovarian abscess, although these are typically somewhat smaller in size. Regardless of the exact pathology, what is certain is that urgent surgical exploration is required. In addition, IV antibiotics should also be empirically commenced and continued until a definitive diagnosis is achieved. In this patient's case, at the time of operation, ovarian torsion secondary to a large dermoid cyst was noted. Note that methotrexate is a means of treating stable, uncomplicated ectopic pregnancy and is not indicated in this patient. Steroids are of no benefit.


Discussion

Acute ovarian torsion is a gynecological emergency resulting from partial or complete rotation of the ovarian pedicle on its long axis, with subsequent compromise of venous and lymphatic drainage. Prolonged torsion results in edema, venous and arterial thrombosis and ultimately, ovarian infarction. Ovarian torsion accounts for approximately 2.7% of acute gynecological presentations, and most often affects women in the 20 to 30 year age group. Important predisposing factors include pregnancy (where the ovaries enlarge in size), ovarian tumors or cysts (which may act as fulcrums for torsion), induction of ovulation (which results in ovarian cyst formation), and previous pelvic surgery (due to adhesions or damage to the ligaments attached to the ovaries). The presenting symptoms are often vague and non-specific and include acute unilateral severe and progressive pelvic pain, which is crampy or colicky in nature and which may radiate to the thigh or lower back on the affected side. If the torsion is intermittent, there may be bouts of pain separated by asymptomatic intervals, as the ovary twists and unwinds. Nausea and vomiting are common, as is mild fever. Examination typically reveals a soft abdomen, with lower quadrant tenderness. However, with longstanding torsion (resulting in ovarian necrosis), this may be replaced by diffuse tenderness and even guarding and rigidity. Pelvic examination typically shows adnexal tenderness on the affected side. In half of patients, an adnexal mass may also be palpable. Cervical motion excitation may also be present and bimanual palpation may demonstrate uterine shift towards the affected side. Where torsion is suspected, urgent pelvic ultrasound is the investigation of choice, with almost all patients showing abnormal sonographic findings. These include ovarian enlargement, hyper and hypo-echogenic areas corresponding to hemorrhage and edema respectively, and cystic, clotted areas indicating infarction. Where adnexal or ovarian masses are present, these may also be seen. Color doppler flowmetry may show reduced or absent blood flow. If the sonographic findings are inconclusive and the diagnosis of torsion is in doubt, further pelvic imaging (such as CT or MRI) may be considered. However, if the diagnosis of torsion is strongly suspected, surgical exploration may be preferred. Urgent surgery is the treatment of choice. Either laparoscopy or laparotomy may be performed, with important considerations being the condition of the patient, and where tumors are noted, their size and suspicion of malignancy. If an obvious hemorrhagic infarction is noted or if gangrenous adnexal structures are present, a salpingo-oophorectomy should be performed. However, if the ovary appears viable, untwisting of the adnexa should be considered. Where untwisting of the ovary is performed, prophylactic ovariopexy (to prevent retorsion) may also be considered. However, this is controversial, with only limited literature available on this procedure.


Take home messages

  1. The symptoms of ovarian torsion are vague and non-specific and include unilateral pelvic pain, nausea and vomiting.
  2. Important signs include lower quadrant tenderness, adnexal tenderness and a palpable adnexal mass.
  3. Pelvic ultrasound is the diagnostic modality of choice and is abnormal in almost all patients.
  4. Urgent surgery is the treatment of choice.

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  1. AFP: Evaluation of Acute Pelvic Pain in Women (2011)
  2. European Journal of Emergency Medicine : Torsion of the ovary: a known but frequently missed diagnosis (2009)
  3. European Journal of Obstetrics & Gynecology and Reproductive Biology : Adnexal torsion: a literature review (2010)
  4. Journal of Ultrasound in Medicine : Acute abdomen in pregnancy: role of sonography (2010)
  5. Obstetric and Gynecologic Clinics of North America : Benign disorders of the ovary (2008)
  6. Obstetric and Gynecologic Clinics of North America : Ultrasound evaluation of gynecologic causes of pelvic pain (2011)