Clinical case: Ovarian torsion
In this article, we describe a case of a pregnant woman who presented with acute abdominal pain, vomiting, guarding, and rigidity. Her diagnosis was ovarian torsion, a complication of a previously identified ovarian dermoid cyst, resulting in an emergency cesarean section. We will follow her journey from admission and history all the way to prognosis and evolution. We will also look at the risk factors and mechanism of ovarian torsion, together with possible management options and relevant anatomical considerations.
Abdominal guarding and rigidity | Guarding is stiffness of the abdominal wall muscles upon palpation, while rigidity involves spasms of the same muscles upon palpation. |
Ovarian and testicular torsion |
They involve rotation of the organs, swelling, pain, and degeneration if not promptly corrected. Specifically for testicular torsion, the failure of the gubernaculum to fix the testicle to the scrotal floor contributes to this pathology. |
Dermoid cyst/teratomas | Encapsulated tumors with mature tissue or organ components derived from multiple germ cell layers. |
Pregnancy associated hypercoagulability | Physiologically adaptive mechanism to minimize blood loss during delivery, increasing the plasma levels of many blood clotting factors. |
After reviewing this case you should be able to describe the following:
- The underlying basis of abdominal guarding and rigidity.
- The anatomical layers that are usually incised in order to perform a midline cesarean section.
- How ovarian torsion is similar/different from testicular torsion.
- The derivation of a dermoid cyst.
- Why a hypercoagulable state is found in advanced pregnancy.
- Why radiological imaging is problematic during pregnancy especially during the first trimester.
This article is based on a case report published in the Journal "Case Reports in Surgery" in 2015, by Caroline C. Jadlowiec, Beata E. Lobel, Namita Akolkar, Michael D. Bourque, Thomas J. Devers, and David W. McFadden.
It has been modified and reviewed by Joel A. Vilensky PhD, Carlos A. Suárez-Quian PhD, Aykut Üren, MD.
Case description
History and physical exam
A 33-year-old woman had a planned hospital admittance for cesarean delivery. However, at presentation, 35 weeks + 2 days of gestation, she had a four-hour history of sudden onset, and severe and constant abdominal pain in the right lower quadrant. Changing positions was very painful for her and examination displayed involuntary guarding and rigidity of her right abdominal wall. She also had uncontrollable vomiting. The patient did not have a history of vaginal bleeding, and normal fetal movements had been noticed. On further examination, the patient was normotensive and tachycardic; pulse rate was 110 bpm; respiratory rate was 16/min, and oxygen saturations were 100% in air. She was afebrile.
Imaging
Ultrasound assessment of the fetus demonstrated heart activity, cephalic presentation, and an anterior high lying placenta. The initial diagnosis based on physical exam and symptoms was acute appendicitis. The patient was managed conservatively overnight but required high doses of oral morphine and antiemetics.
A subsequent vagina ultrasound scan showed a right-sided 6 × 3 cm cystic lesion, which was believed to either be a degenerating fibroid or a torsed ovary. When an ultrasound exam from three years earlier was checked, it was found that the radiologist had noted a 3 cm right ovarian dermoid cyst. Thus the patient now had an MRI, but this examination did not provide any additional information on the source of her pain.
Management and evolution
The decision to perform a midline laparotomy was made with emergency cesarean section. Upon opening the abdominal cavity through the midline laparotomy incision, a large purple non-necrotic right-sided mass was identified (Figure 1).
The cesarean section was then performed delivering a healthy female infant. The uterus was closed in two layers. The purple mass was identified as a twice torsed right ovary, with an enlarged size of 7 × 4 cm (Figure 1). The dermoid cyst was also identified and a cystectomy was done (Figure 1B). The right uterine tube and ovary were maintained. The surgeon also identified, but did not resect a 2 cm ovarian cyst, dermoid in the appearance on the left ovary. The patient recovered uneventfully and histological examination of the ovarian cyst confirmed a dermoid cyst (Figure 2). Follow up was recommended for surveillance of the left ovarian cyst.
Surgical and anatomical considerations
Ovarian torsion involves rotation of the ovarian tissue on its pedicle leading to decreased venous return, stromal edema, internal hemorrhage, and blockage of arterial inflow (Figure 3; note the swollen ovary).
As in this case, ovarian cysts are more common in ovarian torsion cohorts than in the general population. Pregnancy is also a risk factor for torsion. Ovarian torsion classically occurs unilaterally in a pathologically enlarged ovary (e.g., due to the presence of cyst) because the irregularity of the ovary is thought to create a fulcrum around which the ovary and adnexa can rotate. The process can involve only the ovary but more commonly affects both the ovary and the uterine tube (adnexal torsion). During early pregnancy, the presence of an enlarged corpus luteum cyst likely explains the relationship between torsion and pregnancy. Benign dermoid cysts/teratomas are the most common ovarian tumors and were found in this case. They are derived from germ cells and composed of multiple types of tissue (Figure 2).
Torsion of the ovary during the third trimester of pregnancy, however, is unusual because the compressive effect of the gravid uterus limits the mobility of the ovarian pedicle. However, as demonstrated in this patient, it still may occur. Thus, ovarian torsion needs to be considered as a differential diagnosis. Surgery during advanced pregnancy has increased risks because the patient is in a hypercoagulable state. Furthermore, laparoscopic surgery has increased risks during late pregnancy because of the risk of injury to the gravid uterus and poor visualization of the surgical fields. Additionally, this case was complicated because of the difficulty in obtaining MRI confirmation of the patient’s condition.
Explanations to objectives
Objectives
- The underlying basis of abdominal guarding and rigidity.
- The anatomical layers that are usually incised in order to perform a midline cesarean section.
- How ovarian torsion is similar/different from testicular torsion.
- The derivation of a dermoid cyst.
- Why a hypercoagulable state is found in advanced pregnancy.
- Why radiological imaging is problematic during pregnancy especially during the first trimester.
Abdominal rigidity and guarding
Abdominal rigidity is stiffness of the muscles in the abdominal wall, which can be felt when touched or pressed. The cause of rigidity includes an abdominal abscess, appendicitis, cholecystitis, gastrointestinal perforation, peritonitis, or, as in this case, swollen ovary. The direct cause of the rigidity is irritation of the parietal peritoneum. Guarding is a spasm of the abdominal wall muscles that is triggered by palpation or pressure. The etiology is identical to that of rigidity.
Midline cesarean section
Majority of cesarean sections (C-section) are done through a Pfannenstiel incision in the suprapubic area. The patient, in this case, had two prior C-sections. However, in her most recent C-section, due to the uncertainty of her diagnosis leading to abdominal pain, the surgeon has chosen a midline laparotomy incision, which provides a much better exposure of the entire abdomen compared to Pfannenstiel incision. This approach to doing a C-section requires incisions through the skin, subcutaneous tissue (both Camper’s and Scarpa’s layers), linea alba, transversalis fascia, peritoneum, and anterior muscular wall of the uterus.
Comparison between ovarian and testicular torsion
Testicular torsion involves testicular rotation in the same way that ovarian torsion involves rotation of the ovary. Also similar, the testicle swells, is very painful and will result in degeneration of the testicle if not corrected. However, testicular torsion results from failure of the gubernaculum testes to adequately fix the testicle to the scrotal floor. And in contrast to ovarian torsion, testicular torsion is typically found in children rather than in adults.
Dermoid cysts
Mature cystic teratomas are encapsulated tumors with mature tissue or organ components. They contain well-differentiated derivations from at least two of the three germ cell layers (i.e. ectoderm, mesoderm, and endoderm). Thus within these cysts are typically mature skin complete with hair follicles and sweat glands, sometimes bundles of long hair, and often pockets of sebum, blood, fat, bone, nails, teeth, eyes, cartilage, and thyroid tissue (Figure 2). They are almost always benign.
Pregnancy associated hypercoagulability
Pregnancy-induced hypercoagulability is believed to be a physiologically adaptive mechanism to minimize blood loss during delivery. During pregnancy, the plasma levels of many of the blood clotting factors, e.g., fibrinogen, changes to facilitate clotting. Prolonged bed rest in high-risk pregnancies also increases the likelihood of blood clots.
Radiological imaging during pregnancy
During pregnancy, radiographic procedures such as plain radiograph and CT are not advised especially during the first trimester, because of the risk to the developing fetus posed by the radiation that is used to produce these images. In specific circumstances, plain radiographs and CT images can be obtained during the third trimester. MRI poses no such risk to the mother and fetus but in advanced pregnancies, the patients have difficulty maintaining the still postures that are required to obtained good MRI images.
Furthermore, the abdominal and pelvic anatomy of women in advanced pregnancy is distorted so that it is difficult for radiologists to make firm diagnoses based on this distorted anatomy, especially when radiologists do not have much experience evaluating images from patients in advanced pregnancy. Ultrasound is typically the imaging modality of choice in pregnancy, but ultrasound has limited value in interpreting complex pathology, especially again when the anatomy is distorted.
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