When Constipation Is Not Just Constipation

This article was written by Stela Celaj, MD, PhD, Gastroenterology Fellow, Year II.

A 29-year-old female with a history of asthma presented with abdominal pain and constipation for over a week. She had tried lactulose, magnesium citrate, and bisacodyl without success. She usually takes MiralaxTM daily and has one to two bowel movements every other day. She had a colonoscopy the year prior for constipation, which showed two hyperplastic polyps but otherwise no mucosal abnormalities.

Her exam was notable for a distended and tympanitic abdomen without rebound or rigidity. Blood work was unremarkable.

Computed tomography (CT) of the abdomen and pelvis showed an extremely distended colon with fluid, suggesting colonic obstruction. In addition, an ill-defined mass was seen in the rectum, raising suspicion for a malignant lesion. The patient underwent decompressive colonoscopy the following day, where an obstructing mass was identified about 10 cm from the anal verge. The mucosa overlaying the mass appeared only mildly congested but was otherwise similar in morphology to the surrounding healthy rectal mucosa. Biopsies of the mass showed colonic mucosa with focal active colitis, which was negative for malignancy. Tumor markers (CEA and CA-19-9) were negative. Rebiopsy was recommended. Her abdominal pain and distension improved in the subsequent days, and she started to have bowel movements. She was discharged with an aggressive bowel regimen and planned to pursue a rectal EUS for tissue sampling.

However, the patient returned to the hospital 10 days later with recurrent constipation and abdominal distension despite implementation of scheduled laxatives. A rectal EUS showed congested mucosa causing narrowing and tortuosity in the rectum, and diffuse wall thickening with surrounding ill-defined inflammatory response. Increased thickness of the intramural wall was also visualized endosonographically, but the wall layers could not be fully defined due to the inability to pass the echoendoscope beyond the tortuous region. A few benign appearing lymph nodes were biopsied in the perirectal region. There was limited tissue for evaluation, but an equally mixed population of T and B cells was believed to be benign lymphoid tissue. A second decompression tube was placed at that time, which unfortunately dislodged a few days later and she developed obstipation again.

A decompressive sigmoidoscopy as well as a repeat rectal EUS were performed that again demonstrated diffuse wall thickening at the site of stricturing, but with no definitive mass discerned. The rectal wall layers were distorted and appeared tethered with heterogenous changes extrinsic to the rectal wall. Fine needle aspiration (FNA) showed gastrointestinal epithelial contaminants and fragments of bland smooth muscle. These findings were nonspecific and nondiagnostic overall, with differential including spindle cell neoplasm, endometriosis, and leiomyoma. Upon further investigation of her history, the patient noted that constipation was worsened by the onset of menses. A pelvic MRI showed a mass-like circumferential submucosal thickening of midrectum with adjacent stranding extending posteriorly to the right pelvic sidewall. Multiple prominent perirectal lymph nodes and uterus with tiny fibroids were also seen. The ovaries appeared unremarkable without evidence of endometriomas. Gynecology was consulted, and it was believed that rectal endometriosis, though possible, was atypical due to lack of evidence of disease in the other parts of the pelvis. Her symptoms improved, and she was discharged with gynecology follow-up for further evaluation.

Unfortunately, she presented again four days later with constipation and distension, and underwent repeat flexible sigmoidoscopy for decompression. Given the persistence of symptoms and recurrent hospitalizations and procedures within one month, a decision was made to pursue diagnostic laparoscopy and exam under anesthesia with Colorectal Surgery. As soon as the pelvis was visualized on laparoscopy, extensive adhesions and implants were detected in the uterus, right ovary, right fallopian tube, and right uterosacral region, extending circumferentially to involve the middle third of the rectum. These findings were concerning for stage IV endometriosis, and gynecology was consulted intraoperatively. Given the extent of disease, right salpingo-oophorectomy and uterolysis, as well as enterolysis along the perirectal spaces, were pursued in efforts to free up the area of endometrial implants. After further dissection and evaluation however, the fibrosis around the rectum could not be released. Therefore, a diverting sigmoid loop colostomy was created with plans to pursue a low anterior resection later on. The patient did well postsurgery. Biopsy of the uterosacral adhesions showed fibrous and smooth muscle tissue with endometriosis, present also in the biopsies of the right fallopian tube and right ovary.

Endometriosis affects the bowel in approximately 5% to 12% of all cases, with 90% involving the rectum or sigmoid colon.¹ Disease often presents as a mass or luminal stenosis, and mainly involves the muscularis propria and serosa. As a result, endoscopic biopsies are frequently not sufficient because mucosal involvement is sparse, leading to a high proportion of falsely negative evaluations.² The average time from onset of symptoms to achieving a diagnosis of endometriosis can be prolonged. Therefore, high clinical suspicion is warranted to ensure prompt recognition.

References/Recommended Reading

1. Habib N, Centini G, Lazzeri L, Amoruso N, El Khoury L, Zupi E, Afors K. Bowel endometriosis: Current perspectives on diagnosis and treatment. Int J Womens Health. 2020;12:35-47. Review. PMID: 32099483

2. Kaufman LC, Smyrk TC, Levy MJ, Enders FT, Oxentenko AS. Symptomatic intestinal endometriosis requiring surgical resection: Clinical presentation and preoperative diagnosis. Am J Gastroenterol. 2011;106: 1325-32. PMID: 21502995