Caecal endometriosis presenting with an acute abdomen in pregnancy

A multiparous woman (gravida 2, para 1) in her mid-30s presented to the Maternity Assessment Unit with a 24-hour history of right-sided abdominal pain at 34 +6 weeks of gestation. She was diagnosed with COVID-19 24 hours prior to her presentation. She denied a history of urinary symptoms and she was passing stool normally. There was no nausea, vomiting, vaginal loss or bleeding. Fetal movements were normal. Her gynaecological history included a diagnostic laparoscopy, which confirmed the diagnosis of endometriosis in the pouch of Douglas and ovarian fossa as well as bilateral endometriomas. She had no history of an abnormal cervical smear. Her obstetric history included an induction of labour and a non-rotational-assisted vaginal delivery at 40 +5 weeks of gestation. Her body mass index was 19 kg/m 2 . Her antenatal care was unremarkable. Sonography confirmed a cephalic presentation. The placenta was posterior and high. Maternal observations scored zero on the Maternity Early Warning Scoring System: BP 120/90 mm Hg, heart rate 90 bpm, respiratory rate 14, SpO2 100% on air and temperature 36.7°C. Physical examination confirmed guarding but no peritonism in the right iliac fossa (RIF). There was no renal angle tenderness. Speculum examination demonstrated a closed cervix. There was no evidence of preterm labour. Digital rectal examination confirmed an empty rectum with no evidence of melena.

Twenty-four hours post admission, she developed severe right-sided abdominal pain with perineal pressure. Physical examination confirmed peritonism. Vaginal examination revealed 3 cm dilation with effacement. The CTG was pathological. Her CRP increased to 158 mg/L. An emergency caesarean section under GA (General anaesthesia) was requested with surgical input. An indwelling urinary catheter was inserted. Her antibiotics were converted to intravenous Tazocin 4.5 g three times per day. The lower segment was well formed and the neonate was delivered via a low transverse incision. The uterus was atonic and a 40-unit syntocinon infusion was administered. The neonate was transferred to the Neonatal Intensive Care Unit for continuous positive airway pressure and intravenous antimicrobial therapy. A mass in the caecum was observed with mucopurulent discharge and impending perforation at the caecal pole. The terminal ileum appeared nodular and oedematous. The appendix appeared macroscopically normal. No collections were evident. The decision was made to proceed to an ileocaecal resection in the patient’s best interest. The National Emergency Laparotomy Audit risk score estimated the risk of death within 30 days of emergency abdominal surgery as 0.2%. The caecum was mobilised. The mesentery was divided close to the bowel wall with clips and ties. Approximately 20 cm of small bowel was resected. The GIA 100 (single use reloadable stapler) was used to do the anastomosis (Barcelona technique). The mesenteric defect was closed. She was placed on the Enhanced Recovery After Surgery [ERAS] protocol. She received low-molecular weight heparin (dalteparin) 6 hours following surgery. The total estimated blood loss was 1.4 L. Her postoperative Hb was 86 g/L. Macroscopically, the specimen consisted of a right hemicolectomy comprising terminal ileum measuring 130 mm × 60 mm ( figure 2 ). A limited amount of mesentery was attached measuring to a depth of 15 mm. The attached appendix measured 35 mm × 5 mm. Lying 60 mm from the DRM (Distal resection margin), the serosal surface was heavily congested and fibrinous purulent exudate was seen although no full thickness defect was identified. The bowel wall was thickened up to 30 mm. Adjacent to this exudate was a polypoidal haemorrhagic area 25 mm in diameter. A further haemorrhagic nodule was seen on the terminal ileum serosal surface measuring 10 mm in maximum diameter. On opening, the mucosa of the terminal ileum was unremarkable while the mucosa of the caecal pole appeared granular and flattened ( figure 3 ). The remaining mucosa of the large bowel was unremarkable. Both resection margins appeared viable. Sections from the haemorrhagic nodule on the terminal ileum and the thickened area of the caecal wall shared similar features—sheets of cells with abundant pale, eosinophilic, granular cytoplasm and relatively bland round nuclei. Some of the cells appeared vacuolated. No marked atypia or mitotic activity was seen. Immunostaining showed the cells to express CD10 and progesterone receptor while MNF-116 highlighted the cells lining the gland-like structures only ( figure 4 ). Overall, the appearances were in keeping with endometriosis showing features of decidualisation ( figure 5 ). Similar decidualised cells were seen within the subserosal tissue surrounding the appendix (which was otherwise fibro-obliterated), and a few scattered decidualised cells were noted within the subserosa of the proximal margin. The mucosa of the resected bowel showed sparse polymorph infiltration of the distal margin, but otherwise appeared viable. She was discharged home with oral amoxicillin three times per day for 1 week and ferrous sulphate 200 mg two times per day for 1 month. Follow-up was advised with her GP (General practitioner) in 6 weeks to check her full blood count. Ileo-caecal resection. Macroscopic specimen. (A) Low power view with colon lumen in top left and endometriosis in bottom right. (B) Low power image of endometriosis to include glands interspersed between decidualised stromal cells. (A) Immunostaining with MNF-116 demonstrates the glands. (B) Immunostaining with CD10 highlights the stromal component. High-power view of endometriosis.

Due to the risk of developing necrotising enterocolitis, she commenced treatment with oral amoxicillin 1 g three times daily and omeprazole 40 mg/day. Fetal monitoring was performed with the CTG.

Endometriosis is defined as the presence of extrauterine benign endometrial tissue and it affects up to 12% of women of childbearing age. 1 Endometrial deposits are commonly found on the ovaries (endometriomas), uterosacral ligaments, pouch of Douglas, rectosigmoid colon, bladder and distal ureter. Intestinal involvement occurs in 3–37% of patients. 1 Endometriosis is common yet complex, as it is associated with a broad spectrum of clinical presentations and may present with a plethora of symptoms, hence resulting in a diagnostic delay. Symptoms include dysmenorrhoea, dyspareunia, cyclical pelvic pain and subfertility. Non-specific urinary symptoms, an altered bowel habit and back pain, may also occur. Caecal endometriosis can present as acute appendicitis, intussusception, volvulus, chronic abdominal/pelvic pain, tubo-ovarian abscess or malignancy. Acute abdominal pain may occur in 8% of cases. 2 For ileocecal endometriosis, distinguishing it from entities such as Crohn’s disease or malignancy is often difficult and surgical resection is frequently required. The assessment of acute surgical pathologies is often challenging during pregnancy owing to the deviation of organs caused by the gravid uterus and relaxation of the abdominal wall musculature. At late gestations, as in this case, the laxity of the abdominal muscles makes it difficult to elicit the physical findings of abdominal rigidity, guarding, rebound tenderness and peritonism. As pregnancy slows the intestinal transit, an effect mediated by progesterone, pseudo-obstruction may occur.

Endometriosis is defined as the presence of ectopic endometrial gland or stroma outside the endometrial cavity. 3 4 Endometriosis involving organs outside of the pelvis is characterised as extragenital endometriosis. It affects up to 12% of fertile women and has a peak predilection between the ages of 29–39 years. Several theories have been hypothesised including Sampson’s theory of retrograde menstruation involving peritoneal implantation of endometrium proposed in 1927. 5 Minh’s theory states that endometriosis is a metaplastic transformation of peritoneal mesothelium. Cell migration through the haematogenous, lymphatic or nervous system is the third theory of extrapelvic endometriosis. 5 Genetic and immunological factors have also been implicated, with recent research suggesting that differences in genetic and immunologic factors exist between affected and unaffected individuals. 6 It is often classified into the following three groups: peritoneal, ovarian (endometrioma) and deep infiltrating endometriosis (DIE), often described as an ingrowth >5 mm into the peritoneum and underlying structures. 6 DIE often presents late due to extensive fibrosis caused by chronic inflammation. Intestinal involvement occurs in 3–37% of affected cases and it is typically associated with the disease at other sites. 1 The caecum, as in our case, is involved in <5% of all intestinal cases. 1 Chapron’s study showed that in individuals diagnosed with intestinal DIE, the most frequent sites affected were the rectum and the rectosigmoid junction. 7 Asymptomatic endometriosis has an estimated prevalence of 3%–45% and is an incidental finding at laparoscopy. 8 Several studies have reported a long delay in establishing the diagnosis of endometriosis, for example, 8 years in the UK and 4–5 years in Ireland. 9 The risk factors for developing endometriosis included early menarche, nulliparity, haematocolpos, retrograde menstruation or a positive family history. Intestinal endometriosis is most commonly found in the subserosa as superficial serosal implants. The implants of the endometrial stroma are usually found in the antimesenteric edge of the bowel. Transmural involvement into the bowel mucosa is rare. The small intestine shows less frequency of involvement. Gastric and transverse colonic endometriotic involvement has also been described. Under cyclical hormonal influences, these implants may proliferate and infiltrate the intestinal wall and cause a fibrotic reaction with formation of strictures and adhesions, which may lead to bowel obstruction. The incidence of complete large bowel obstruction due to endometriosis is rare because of its large intraluminal diameter. Symptoms may include heavy or irregular periods, cyclic pelvic pain, dyspareunia and dysmenorrhoea ( box 1 ). The symptoms associated with intestinal endometriosis often mimic irritable bowel syndrome, inflammatory bowel disease, Crohn’s disease and ulcerative colitis. Diarrhoea and intestinal cramping occur due to increased smooth muscle contractility caused by the release of prostaglandins from the endometriosis implants. Large endometriotic nodules may infiltrate and disrupt the intestinal nervous plexus and damage the interstitial cajal cells, resulting in an alteration in bowel physiology. Patients may experience rectal pain, which worsens with defecation, tenesmus, constipation, diarrhoea, rectal bleeding and non-specific abdominal pain. Endometriosis may also present as a severe rectosigmoid stricture, leading to obstructive symptoms. Although the most commonly affected gastrointestinal site is the rectosigmoid, there remains a relative dearth of reported cases of individuals presenting with an acute abdomen. 10 Disease limited to the bowel serosa may be asymptomatic. The phenomenon of malignant transformation of endometriosis was first described by Sampson in 1925. Endometrioid adenocarcinoma can occur on a background of benign endometriosis. Dysmenorrhoea. Chronic pelvic pain. Deep dyspareunia. Infertility. Premenstrual bleeding/heavy menstrual bleeding. Dyschezia (pain on defecation). Tenesmus and cyclical rectal bleeding during menstruation. Haematuria. Abdominal bloating. Altered bowel habit: diarrhoea/constipation/hyperperistalsis/flatulence. Physical examination may reveal painful induration and/or nodules of the rectovaginal wall. Vaginal nodules may be evident in the posterior vaginal fornix. An adnexal mass may be present on examination. The diagnosis of endometriosis is suspected based on the history, symptoms and signs, corelated with physical examination findings. According to the European Society of Human Reproduction and Embryology Guideline, the ureter, the bladder and the bowels should be assessed if DIE is suspected, in order to establish the extent of the disease. 11 The combination of laparoscopy and the histological verification of endometrial glands and/or stroma is considered to be the gold standard for the diagnosis of the disease. It is not recommended to use biomarkers in endometrial tissue, menstrual or uterine fluid. MRI is commonly used to evaluate bowel endometriosis and is currently one of the most accurate methods to assess the lateral extension of the lesions. Transvaginal ultrasonography may also detect the depth of infiltration of the endometrioma in the intestinal wall. Rectal endoscopic ultrasonography has also been widely used. Multidetector CT enteroclysis can identify the presence of endometriosis foci and also evaluate the characteristics, depth and infiltration of the nodule. Mucosal involvement is rare, so colonoscopy has a limited diagnostic role. Indeed, Campagnacci reported seven cases of colorectal endometriosis with a normal mucosa at colonoscopy in all cases. 12 Nezhat described the first laparoscopic bowel resection for endometriosis in 2001. 13 Daraï’s prospective trial has demonstrated that laparoscopy is a safe option in the treatment of bowel endometriosis and offers a high pregnancy rate and a good quality of life. 14 Surgery is the treatment of choice in complicated bowel endometriosis (obstruction, bleeding and perforation). It is also considered the treatment of choice for symptomatic DIE as the complete removal of lesions results in significant pain relief and an improvement in the quality of life scores. 15 Hormonal contraceptives are effective in treating pain in women with endometriosis. A combined hormonal contraceptive reduces endometriosis-associated dyspareunia, dysmenorrhoea and non-menstrual pain. Chronic symptoms generally subside with gonadotropin-releasing hormone analogues. Ablation and excision of peritoneal endometriosis should be considered to reduce endometriosis-associated pain. Hormonal changes in pregnancy, in particular those effects mediated by progesterone, may result in gastrointestinal motility disorders. Pregnancy also slows the intestinal transit and pseudo-obstruction may occur. 16 Large endometriotic nodules may contain extensive fibrosis and cause thickening of the bowel wall, resulting in stenosis of the intestinal lumen. Although endometriosis improves during pregnancy under the effect of progesterone, the ectopic endometrium becomes decidualised with a progressive reduction in size. 17 The intestinal wall becomes weak by the reduction of the transmural endometriotic lesion under the influence of progesterone during pregnancy, particularly in the third trimester. Decidualisation causes a severe inflammatory response with an increased number of natural killer cells and decidual changes, which are responsible for a higher risk of perforation. 18 Partial or complete intestinal obstruction can be produced by endometriosis causing pressure over the bowel lumen interrupting the flow or by causing intussusception. Stenosis of the bowel lumen may occur caused by smooth muscle hyperplasia and fibrosis by benign ectopic glandular tissue and localised repeated inflammation of the bowel wall due to cyclical haemorrhage. 19 Intestinal perforation from endometriosis is a rare occurrence and up to 42.8% of cases occur in pregnancy, due to progressive traction of the enlarged uterus on the strictly adherent loops of intestine. 17 20 Rectosigmoid stenosis can occur due to extrinsic compression. This case suggests that the endocrine changes in pregnancy do not prevent the progression or development of complications associated with endometriosis in some women. These complications although rare are probably under reported. It also demonstrates the challenges when assessing abdominal pain in pregnancy. Clinicians should consider the diagnosis of endometriosis in women presenting with gynaecological symptoms such as dysmenorrhea, non-cyclical pelvic pain, deep dyspareunia and infertility. It should also be considered in individuals of reproductive age with non-gynaecological symptoms such as dyschezia, dysuria, haematuria and rectal bleeding. Bowel involvement is frequently multifocal and the most commonly affected areas are the rectosigmoid colon, the appendix, the caecum and the distal ileum. Intestinal endometriosis may present as an acute abdomen and obstruction may occur due to intussusception or compression. This case demonstrates the challenges when assessing patients with a gravid uterus.

A surgical review was requested and the clinical impression was of an acute appendicitis. Further investigation with an MRI abdomen showed the gravid uterus displacing the large and small bowel, limiting radiological assessment of the RIF. Generalised inflammation was observed within the RIF surrounding the caecal pole ( figure 1 ). Crescentic diffusion restriction was seen lying in a dependent position lying in the RIF alongside a trace of free fluid. There was no significant adenopathy or evidence of proximal obstruction. While the appendix was not confidently identified within the limits of the study, acute appendicitis remained within the differential. She was counselled on conservative and surgical management options. The maternal and fetal risks of an appendectomy during pregnancy in a COVID+ patient were explained. The woman opted for conservative management. Generalised inflammation was observed within the right iliac fossa surrounding the caecal pole.

The fetal heartbeat was auscultated. Cardiotocography (CTG) was normal and the Dawes-Redman criteria was met. Urinalysis was negative. Laboratory investigations confirmed a microcytic anaemia (haemoglobin; Hb 105 g/L, mean cell volume; MCV 78.5 fl) and an elevated C reactive protein (61 mg/L). Her electrolyte and coagulation profile was normal ( table 1 ). Laboratory investigations showed a microcytic anaemia