Risk factors for abscess development in patients with endometrioma who present with an acute abdomen
Hanako Kaseki1, Masao Ichikawa1, Masafumi Toyoshima1, Shigeru Matsuda1, Kimihiko Nakao1, Kenichiro Watanabe2, Shuichi Ono1, Toshiyuki Takeshita3, Shigeo Akira4, Shunji Suzuki1
1 Department of Obstetrics and Gynecology, Nippon Medical School, Bunkyo-Ku, Tokyo, Japan
2 Department of Obstetrics and Gynecology, Nippon Medical School, Bunkyo-Ku, Tokyo; Sannoh Clinic, Shiraoka, Shiraoka, Japan
3 Department of Obstetrics and Gynecology, Nippon Medical School, Bunkyo-Ku; Takeshita Ladies Clinic, Shinjuku-Ku, Tokyo, Japan
4 Department of Obstetrics and Gynecology, Nippon Medical School, Bunkyo-Ku; Meirikai Tokyo Yamato Hospital, Itabashi-Ku, Tokyo, Japan
Correspondence Address:
Dr. Hanako Kaseki
Department of Obstetrics and Gynecology, Nippon Medical School, 1-1-5 Sendagi, Bunkyo-Ku, Tokyo 113-8603
Japan
Source of Support: None, Conflict of Interest: None
DOI: 10.4103/gmit.gmit_36_22
Objectives: The objective of this study was to assess the potential risk factors for abscess development in patients with endometrioma who present with an acute abdomen.
Materials and Methods: We retrospectively reviewed the records of 51 patients who underwent emergency surgery for acute abdomen involving an endometrioma at our hospital between April 2011 and August 2021. The patients were divided into an infected group (n = 22) and a control group (n = 29). We analyzed patient characteristics; imaging findings; clinical data, including bacterial cultures; and perioperative outcomes to assess for differences between groups.
Results: Patients in the infected group were significantly older than those in the control group (P = 0.03). They were more likely to have a history of endometriosis surgery (P = 0.04) and more likely to have undergone transvaginal manipulation within 3 months of presentation (P = 0.01). Body temperature on the day of admission was significantly higher in the infected group (P = 0.007), as were C-reactive protein levels on the day of admission and before surgery (P < 0.001; P = 0.018) and the white blood cell count on the day of admission (P = 0.016). Preoperative imaging showed significant thickening of the tumor wall (P < 0.001) and an enhanced contrast effect (P < 0.001) in the infected group.
Conclusion: We identified several factors that suggest abscess in patients with an acute abdomen who have a complication of pathologically confirmed endometriosis. A recent vaginal procedure is a particular risk factor for abscess development in patients with endometriomas.
Keywords: Abscess, acute abdomen, endometrioma, endometriosis, risk factor
Endometriosis refers to endometrial growth outside the uterine cavity; this can also include growth within the myometrium. The condition is estimated to affect 10%–15% of women of reproductive age.[1] The number of patients with endometriosis is on the rise due to increasing nulliparity and advancing maternal age at first delivery. The most common site of endometriosis is the ovary; when endometriosis appears as a cystic lesion within the ovary, this is called an endometrioma. When endometriomas rupture or become infected, patients often report severe abdominal pain and may develop an acute abdomen. With a simple ruptured endometrioma, symptoms may be relieved with conservative treatment such as the administration of analgesics. However, surgical treatment is often needed for infected endometriomas, otherwise, abscess development in the pelvis may result in serious, life-threatening conditions, including sepsis.[2],[3] Indeed, pelvic infections in patients with endometriosis are likely to be more severe than in those without endometriosis.[4] There are case reports of infected endometriomas forming vesico-ovarian fistulas[5] and causing perforation of the colon during the postpartum period, resulting in an acute abdomen.[6]
It is crucial to determine whether the cause of acute abdomen in patients with endometriomas is rupture or infection. Correctly and quickly identifying the likelihood of infection, and performing early surgical intervention when indicated, will improve treatment for patients with endometriomas. Herein, we study the potential risk factors for abscess development in patients with endometrioma who present with an acute abdomen.
Materials and MethodsWe performed a retrospective analysis of patients with endometrioma who were diagnosed with an acute abdomen and underwent emergent surgery at our institution between April 2011 and August 2021. Emergency surgery was indicated for patients in whom abdominal pain did not improve and muscular guarding persisted despite the use of intravenous analgesics or antibiotics; the attending physician was also required to determine that surgery was necessary. If symptoms improved with conservative treatment and the attending physician judged that emergency surgery was unnecessary, patients were excluded from the study.
Patients were divided into two groups based on the contents of the endometrioma. In the infected group, the cyst contents were either noted to be purulent on visual inspection during surgery, or bacteria were detected on culture. Patients without infection represented the control group [Figure 1]. Laparotomy was selected for patients who were expected to have severe adhesions based on previous surgery or on the findings of their preoperative examination.[7] In all other patients, laparoscopy was the procedure of choice for emergency surgery. The cyst contents were submitted for culture when cyst infection was suspected preoperatively, or the surgeon deemed this necessary. The surgeon collected 3–5 mL of the endometrioma contents using an aseptic technique and promptly injected the contents into an anaerobic container. The specimens were submitted for examination during or after surgery.
The patient characteristics assessed
age, body mass index, history of gynecologic consultation, history of medication for endometriosis, history of endometriosis-related surgery, and history of a transvaginal procedure within 3 months of presentation were assessed. Transvaginal procedures included endometrial cytology collection, oocyte retrieval or embryo transfer for assisted reproductive technology (ART), and insertion or removal of an intrauterine device (IUD). We also assessed the phase of the menstrual cycle at the onset of abdominal pain; preoperative body temperature; preoperative laboratory data, including white blood cell count and the serum C-reactive protein (CRP) level; and the number of days of hospitalization.
Preoperative imaging findings included the characteristics of the endometrioma, the diameter of the cyst, and the presence of ascites; these were evaluated using ultrasonography in all patients. Computed tomography (CT) or magnetic resonance imaging (MRI) was performed to further assess the acute abdomen, except in six patients who had severe pain and were taken for immediate surgery after ultrasonography. Nine patients had taken CT or MRI without contrast media due to medical reasons. We collected data on the operative time, amount of bleeding, and the number of postoperative hospital days.
Univariate logistic regression analysis was performed for both categorical and continuous variables using JMP software, version 10 (SAS Institute Inc., Cary, NC). P < 0.05 was considered statistically significant. We obtained written informed consent as a comprehensive agreement to participate in research from all patients before surgery. This study was reviewed and approved by the Ethics Committee of Nippon Medical School (B-2020-107).
ResultsBetween April 2011 and August 2021, a total of 58 patients with endometriomas underwent emergency surgery for acute abdomen at our hospital. Seven patients were excluded from this study: three who did not have a pathologic diagnosis of endometrioma, two in whom appendicitis could not be ruled out, one with severe diabetes, and one with complications of uncontrolled malignancy. Records from the remaining 51 patients were reviewed for analysis. Based on the content of the endometrioma, the patients were divided into an infected group (n = 22) and a control group (n = 29), as illustrated in the study flow chart [Figure 1].
[Table 1] shows the characteristics of the patients in both groups. The mean patient age was higher in the infected group than in the control group (40.9 ± 9.6 years vs. 35.2 ± 9.0 years; P = 0.03). There were significantly more patients who had a history of previous endometriosis surgery in the infected group (27% [6/22] vs. 6% [2/29]; P = 0.04). The number of patients who underwent a transvaginal procedure within 3 months of the presentation was significantly higher in the infected group (40% [9/22] vs. 10% [3/29]; P = 0.01). The median time to onset of symptoms after a transvaginal procedure was 10 days (minimum 4 days and maximum 60 days). The specific transvaginal procedures performed were endometrial cytology collection, embryo transfer, and IUD insertion. There was no statistically significant difference between the two groups regarding the menstrual cycle when abdominal pain occurred.
Table 1: Patient- and menstrual cycle characteristics at the onset of abdominal painOf the patients in the infected group who did not know their menstrual status at the time of presentation, one was pregnant, three had taken dienogest, and two had taken a gonadotropin-releasing hormone analog. In the control group, two patients were pregnant, but no one had taken dienogest or a gonadotropin-releasing hormone analog. No other significant differences were observed between the two groups [Table 1].
Physical findings and laboratory data are shown in [Table 2]. Body temperature after admission was significantly higher in the infected group (38.3°C ± 0.7°C vs. 37.0°C ± 0.5°C; P = 0.007). The CRP level was higher in the infected group, both at the time of presentation and before surgery (16.9 ± 11.3 mg/dL vs. 2.9 ± 3.9 mg/dL; P < 0.0001 and 15.5 ± 12.7 mg/dL vs. 6.1 ± 9.8 mg/dL; P = 0.018). There was no significant difference between the groups in terms of the cyst diameter or the duration before surgery. Laparoscopic surgery was selected for 54% of patients in the infected group and 62% of patients in the control group. On imaging, tumor wall thickening and a contrast effect were significantly more frequent in the infected group (73% [16/22] vs. 4.3% [1/23]; P < 0.001; 89% [17/19] vs. 35% [6/17]; P < 0.001). However, irregularly shaped cyst margins were significantly more frequent in the control group (45% [10/22] vs. 83% [19/23]; P < 0.001).
[Table 3] shows the surgical details and procedures for both groups. The operative time was significantly longer for laparotomy in the infected group compared to the control groups (195 min vs. 127 min; P = 0.0085). The number of hospital days after surgery was significantly longer in the patients in the infected group who underwent laparoscopy compared to the control group (8.0 ± 4.0 days vs. 4.6 ± 1.6 days; P = 0.006). Bacterial cultures of the endometrioma contents were more likely to be positive in the infected group (65% [13/20]) than in the control group (0% [0/10]). The types and proportions of the detected bacteria are shown in [Figure 2]. More than 80% of the bacteria were of intestinal origin.
Figure 2: Percentage of each type of detected bacteria in the infected group (n = 13) DiscussionThe purpose of this study is to assess the potential risk factors for abscess development in patients with endometrioma who present with an acute abdomen. Certain procedures can reportedly cause serious infections in existing endometriomas. There are reports of systemic sepsis following diagnostic hysteroscopy,[3] infection occurring after oocyte retrieval,[8],[9],[10] and ovarian abscesses occurring after repeated intrauterine insemination attempts.[11] We found a significantly higher rate of abscess formation in patients who had undergone a transvaginal procedure within 3 months before surgery; endometrial cytology collection was the most common reason for transvaginal procedure-related abscess formation in this study (n = 7). Because of the rapid increase in endometrial cancer over the past decade,[12] patients with endometriosis may have more opportunities to undergo transvaginal procedures such as endometrial cytology or biopsy.
Infertility is on the rise, and the proportion of women with endometriomas who wish to have children has increased over the past few decades. In addition, women with endometriosis and “chocolate cysts” often have associated infertility and are more likely to undergo ART than women with endometriosis but no chocolate cysts. In fact, the prevalence of endometriosis has increased dramatically these days, to as high as 25%–50%, in women with infertility.[13] If an infertile woman has endometrioma, the decision to proceed with ovarian cystectomy versus ART remains controversial;[14] there are many reports of endometrioma infection following oocyte retrieval.[15],[16] It has also been reported that, when a serious infection occurs during a pregnancy that was established following oocyte retrieval and embryo transfer, the prognosis for both mother and child is poor, despite intensive treatment.[17],[18]
In our study, the median number of days from a transvaginal procedure to the onset of abdominal pain was 10, with a minimum of 4 days and a maximum of 60 days. It has been noted that endometrioma infection after ART might not manifest until a relatively long time after the oocyte retrieval or embryo transfer. In fact, some patients do not experience an obvious infection until 20 weeks after embryo transfer; surgical intervention is required in such cases.[19],[20],[21],[22] It is not yet known precisely how long it takes for the infection to occur and for symptoms to appear.[9]
Pelvic infections in the setting of endometriosis are reportedly more serious than those that occur in patients without endometriosis,[4] because old blood in the endometrioma could be a potential culture medium for pathogenic microorganisms, and more severe endometriosis reportedly increases the likelihood of endometrioma infection.[23],[24] Many of the bacteria detected on endometrioma cultures are intestinal in nature and are also the causative agents for bacterial vaginosis.[25] We noted that women were more likely to be menstruating at the onset of abdominal pain than to be at another point in their cycle. This could be explained by menstrual blood refluxing from the Fallopian tube More Detailss into the abdominal cavity.
We also noted that the operative time for laparotomy was significantly longer in the infected group than in the control group. This is to be expected, given the deteriorated environment in the abdominal cavity and the vulnerable condition of the intestinal wall due to inflammation; these conditions make it difficult to perform intraoperative adhesion detachment and peri-intestinal surgery.[26] In addition, it takes time to perform washings to eliminate inflammation caused by the abscess.
Our data also show that the length of admission after surgery is significantly longer in patients with infection who undergo laparoscopy compared to the control group. Six patients in the infected group who underwent laparoscopy had an extended postoperative hospital stay of 12 days or more due to paralytic ileus. There was no evidence of ileus on the preoperative images in these patients, suggesting that the condition was caused by severe inflammation which was present before surgery (hence the acute abdomen).
The limitation of this study is that this study is a retrospective study and is based on a relatively small number of cases. It is ethically difficult to set up a prospective study on the treatment of patients with acute abdomen. Preoperative randomization is also difficult because the patients are those diagnosed with endometriosis on postoperative pathology. We have an outpatient clinic specializing in endometriosis and perform many emergency surgeries for endometriosis. However, this study was conducted at a single institution and involved a relatively small number of patients. Therefore, it cannot be denied that there is some degree of bias in the results of the analysis in this study. We hope to draw more accurate conclusions by increasing the number of cases in a multicenter study. Based on the results of this study, future research is planned for ART cases complicated by endometriosis, since ART requires procedures such as egg retrieval, which carries a high risk of pelvic infection, and because pelvic abscesses in the early stages of pregnancy are difficult to treat. We would examine in detail what kind of ART procedures result in endometriosis infection by studying a large number of cases.
ConclusionWe found that patients with endometrioma abscesses who present with an acute abdomen often have a history of a transvaginal procedure within the last 3 months. These procedures can include IUD insertion, endometrial cytology collection, or ART procedures. We also noted that infected endometriomas were characterized by thickening of the cyst wall and an enhanced contrast effect on imaging.[27] Repeated surgery on an endometrioma often results in diminished ovarian reserve and requires advanced surgical skills. However, if a bacterial infection is suspected in a patient with an acute abdomen, surgical intervention is necessary. If surgery is not performed, the environment in the abdominal cavity will worsen, possibly leading to severe consequences such as sepsis.
Acknowledgments
The authors wish to thank their colleagues at Nippon Medical School for their useful advice regarding patient management.
Financial support and sponsorship
Nil.
Conflicts of interest
Prof. Toshiyuki Takeshita, an editorial board member at Gynecology and Minimally Invasive Therapy, had no role in the peer review process of or decision to publish this article. The other authors declared no conflicts of interest in writing this paper.
References
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