Diagnosis and management of small bowel obstruction in the ileum caused by endometriosis: A case report

A 37-year-old woman presented to the emergency room with a one-day history of upper abdominal pain, nausea, and vomiting. Her pain was described as moderate, dull, and achy with no aggravating or alleviating factors. She denied any changes in diet but noted she was menstruating currently. She had a remote history of endometriosis including two laparoscopic ablation interventions. In the past her endometriosis presented as lower abdominal pain and pelvic pain with severe cramps during her cycles. Her prior medical history was significant for endometriosis requiring two laparoscopic ablation interventions and her surgical history included a laparoscopic cholecystectomy. Physical exam showed a nondistended abdomen positive for upper abdominal tenderness in the epigastric region and in the right upper and lower quadrants. Abdominal series showed a single prominent loop of small bowel in the right lower quadrant showing air-fluid levels. Computerized tomography (CT) showed findings consistent with a partial SBO with a transition point at the terminal ileum. The terminal ileum was found on CT to be decompressed and irregular with a 1 cm adjacent soft-tissue nodule. The patient was given pain medication and antiemetics and was admitted for observation. A second CT with oral contrast the next day showed that contrast passed the obstruction but there was some proximal dilation ( Fig. 1 ). On CT the terminal ileum was notable for wall thickening. Fig. 1 CT with contrast of small bowel obstruction as indicated by the arrow. Fig. 1 CT with contrast of small bowel obstruction as indicated by the arrow. The patient had no improvement in bowel function and had progressively worsening symptoms. She subsequently underwent a diagnostic laparoscopy for SBO, 3 days after her initial admission. A 2 cm lesion was present in the ileum, located 4.8 cm from the ileocecal valve and 1.0 cm from the appendix. There were scattered adhesions involving the terminal ileum and right colon. A right hemicolectomy was performed. Her post-operative diagnosis was reported as small bowel obstruction and endometriosis of the right round ligament. Pathology was negative for malignancy and described endometriosis involving the muscularis propria and serosa of the terminal ileum, ascending colon, and appendix. SBO was found to be caused by a 1.8 × 1.5 × 1.1 endometrial mass ( Fig. 2 ). The patient's post-operative course was uncomplicated, and she was discharged home 4 days after her procedure. Fig. 2 Pathology images of slides collected intraoperatively showing endometrial glands and stroma. Image B endometrial tissue (200 × 200). Fig. 2 Pathology images of slides collected intraoperatively showing endometrial glands and stroma. Image B endometrial tissue (200 × 200).

The treatment for SBO caused by endometriosis has not changed over the years, and the gold standard remains surgery. The importance of history taking is highlighted in this situation because it is required to inform clinical decision making and will help personalize treatment to the individual patient. The variable presentation of ileal SBO caused by endometriosis and the difficulty finding the pathology on multiple imaging modalities only amplify the importance of asking questions that may lead to the diagnosis. In this case, the patient was menstruating at the time of presentation and had a history of endometriosis requiring several surgeries. Although adhesions from those prior surgeries is an explanation for her obstruction, endometriosis was also present on the differential. The accuracy of pre-operative diagnosis has not improved because of the nonspecific symptoms and findings on imaging that mimic other diseases and pathology. However, newer imaging developments and awareness show promise for the future. If a patient presents with vague abdominal complaints, it is crucial to take a thorough history, and ask about previous endometriosis diagnosis because serial imaging might provide clues of endometrial proliferation in the bowel, and lead to earlier treatment of proliferating lesions preventing future progression. Furthermore, educating endometriosis patients about the potential complications of their disease, including SBO, may lead to an earlier detection in the disease course. In the case of SBO, the etiology of obstruction is not going to change the course of treatment, but if a patient with known endometriosis is presenting it may help influence treatment. For example, when attempting conservative treatment, if it is known that endometriosis is present in the intestine, augmenting therapy by using hormone therapy such as a GnRH analog may be helpful and prevent progression of endometriosis. More research on improving diagnostic imaging as it relates to endometriosis is needed. In the case of SBO, this might reduce the need for surgery, reducing the economic burden of the disease and increasing patient quality of life.

Acute SBO secondary to ileal endometriosis is a rare pathology that requires emergency surgery. While bowel involvement is relatively common in endometriosis, it rarely causes bowel obstruction, especially at the ileum. While the etiology of endometriosis is unknown, the leading theory behind endometriosis reaching the gastrointestinal tract is the Sampson's retrograde menstruation theory of endometrial tissue reflux through the fallopian tubes and intra-abdominal visceral implantation and growth [ 5 ]. This is supported by the relative pelvic distribution of endometriosis, including rectosigmoid colon, small bowel, appendix and cecum affected in 50–90%, 2–16%, 3–18%, and 2–5% of cases respectively [ 6 ]. Symptoms of endometriosis are often nonspecific, such as dysmenorrhea and dyspareunia. More specific symptoms of bowel involvement can include constipation, diarrhea, dyschezia, and bowel obstruction but these can lead to misdiagnosis because they can be mistaken for Crohn's disease, irritable bowel syndrome, and malignancy [ 7 ]. While symptoms can be an indication, many women remain asymptomatic, presenting only as endometriosis progresses and involves more bowel. It is thought that progression occurs through growth and invasion of bowel serosa and muscularis propria by neovascularization mediated by pro-angiogenic factors such as VEGF [ 8 ]. This infiltration of the muscularis propria may lead to fibrosis of the bowel wall leading to strictures and even obstruction [ 9 ]. A diagnostic sign which should raise the suspicion for endometriosis is cyclic symptoms corresponding to a woman's menstrual cycle. Because of the nonspecific presentation of ileal endometriosis, most cases in which endometriosis causes SBO are diagnosed as well as treated with laparoscopic surgery. However, 66% of women who went under surgical treatment for SBO caused by endometriosis had a previous diagnosis [ 2 ]. Therefore, detailed patient history can be crucial when making clinical decisions for patients. Accurate and efficient diagnosis of pelvic endometriosis can ensure patients are given the best treatment options, including medical therapies such as oral contraceptives and gonadotropin-releasing hormone (GNRH) analogs which can slow the ectopic proliferation of endometrial tissue [ 10 ]. Furthermore, bowel endometriosis, if detected earlier in the disease course, can be mitigated with treatment, minimizing disease complications and reducing the need for surgery. Previously, imaging modalities did not have great success, but new developments in imaging show promise at detecting bowel lesions. In one report, multislice CT combined with enteroclysis (MSCTe) was shown to locate 94.8% of bowel endometriotic nodules [ 11 ]. Magnetic resonance imaging (MRI) has a high sensitivity for detecting endometriosis, but has difficulty distinguishing it from other disease as well as being costly. Ultrasound, on the other hand, is an economical and efficient means of examining and diagnosing bowel endometriosis. In the case of ultrasound, the accuracy of discovery depends significantly on the expertise of the sonographer [ 12 ]. In an effort to improve this technique, a systematic approach, standardizing the evaluation of pelvic endometriosis was developed. Even with this development, detection of small bowel involvement was usually not possible but was sporadically achieved [ 13 ]. Research investigating biomarkers is also a potentially promising field in the detection of endometriosis, but the literature indicates that biomarkers are, as of yet, nonspecific and nonsensitive. This method relies on the accumulation of information, including serum and urine inflammatory markers, to detect endometriosis proliferation. New technology in proteomics, metabolomics, and genomics, which accumulate and analyze a panel of biomarkers and gene profiles, may eventually develop to the point of becoming a diagnostic tool for endometriosis, effectively reducing the need for surgeries [ 14 ].

Endometriosis is a condition defined by the presence endometrial tissue outside of the uterus and affects 8–15% of females [ 1 ]. Endometriosis is a chronic, inflammatory, and estrogen-dependent disease that most frequently affects the surrounding organs [ 2 ]. Endometriosis involving the bowel occurs in approximately 3–33% of cases, most commonly affecting the rectosigmoid tract. Endometriosis affecting the ileum occurs in only 4% of cases, and progresses to intestinal obstruction in 7–23% of these [ 3 ]. The diagnosis of ileal endometriosis is difficult as its symptomatology can be non-specific. Diagnosis is often made incidentally during surgery or following complications such as bowel obstruction, perforation, or ileocecal intussusception [ 4 ]. The definitive treatment of small bowel obstruction (SBO) caused by endometriosis is resection of the affected bowel with end-to-end anastomosis; this procedure serves as both a diagnostic and a therapeutic measure. The first reported case of SBO of the ileum caused by endometriosis was in 1913; since then the number of cases reported in the literature has increased but the diagnosis and treatment have remained unchanged [ 5 ]. In the current case, a patient with a known history of endometriosis presented with SBO caused by endometriosis. This report highlights an area in which advanced imaging techniques may help to improve treatment and personalize management for patients with SBO caused by endometriosis.