Year: 2024
Type: article
Abstract: Large bowel obstruction is common life-threatening condition Prompt assessment and management are critical for successful treatment, particularly in the presence of closed loop obstruction CT with intravenous contrast is the investigation of choice Surgery is the mainstay of treatment, but selected patients with large bowel obstruction of malignant origin may be suitable for colonic stenting as a bridge to surgery in those with potentially curative disease, and definitive treatment in those or are unfit or who have incurable disease Bowel obstruction is defined as complete or partial mechanical blockage of the bowel lumen, in contrast with pseudo-obstruction which relates to motility issues without mechanical obstruction1,2. Bowel obstruction is the most common presentation requiring emergency laparotomy in the UK National Emergency Laparotomy Audit (NELA)3, with large bowel obstruction (LBO) accounting for approximately 25% of these procedures4. It is associated with significant morbidity, mortality, and economic burden5,6. Only 48% of patients presenting with LBO secondary to cancer are treated with curative intent, compared with 69% from a primary-care referral and 85% through a screening programme7. LBO can be divided into malignant and non-malignant causes. Approximately 19% of colorectal malignancies in the UK present as an emergency, with 80% of these presenting with LBO7. Recently, an increase in index emergency presentation of colorectal cancer in younger patients (aged less than 50 years), who may present with aggressive and advanced disease, has been reported5. Some patients with known colonic cancer also present during the window between diagnosis and surgery, or as a result of response to neoadjuvant chemotherapy or immunotherapy. Benign causes of LBO include strictures (for example diverticular disease, Crohn’s disease, ischaemic, postradiation), volvulus, adhesions, foreign bodies, intussusception, and incarceration within a hernia. Rarely, extrinsic compression of the large bowel can be caused by gynaecological or urological malignancies or extensive peritoneal disease. LBO with closed-loop obstruction from a competent ileocaecal valve is a time-critical surgical emergency. In this situation, there is progressive dilatation of the obstructed colon followed by a sequence of venous congestion, arterial compromise, ischaemia, necrosis, and, ultimately, perforation of the colon (typically caecum). Decompression through an incompetent ileocaecal valve allows more time and ultimately means a lower risk of perforation (although much more likely to present with vomiting). Patients should be assessed in keeping with a Royal College of Surgeons of England’s Care of the Critically Ill Surgical Patient Approach. Patients typically present with abdominal distension and absolute constipation with or without vomiting. The history may give the likely cause of obstruction (for example rectal bleeding, change in bowel habit in colorectal cancer, or recurrent attacks of diverticulitis in a diverticular stricture). Examination is important in establishing the absence or presence of peritonitis or hernia. Rectal examination is important to exclude an anal or lower-third rectal malignancy, or faecal impaction (CT can miss lesions here). The physiology and severity of illness is reflected by recorded patient observations in an early warning score and will help guide the level/prioritization of care. Patients with LBO are typically dehydrated from third-space losses and should receive intravenous fluids and have a urinary catheter. Vomiting is relieved by a nasogastric drainage tube. Bowel distension is painful and multimodal analgesia should be commenced, avoiding the oral route. Patients with sepsis should be treated with sepsis bundles in keeping with local protocols before diagnosis and source control. Full blood count, measurement of levels of lactate, urea, electrolytes, and C-reactive protein, liver function tests, and group and save should be done. Blood cultures should be assessed in patients with sepsis. These results help guide resuscitation, identify sepsis, and enable risk assessment (NELA risk score, American College of Surgeons National Surgical Quality Improvement Program Surgical Risk Calculator). Once rehydration and sepsis treatment has started (where appropriate), the patient should move rapidly to imaging. Urgent CT with intravenous contrast is the imaging modality of choice for LBO8. This outlines the level of the obstruction, the likely cause, and may highlight important findings that will feed into discussions about urgency (perforation, ischaemia) or treatment strategy (local staging and metastatic disease) (Fig. 1). Plain radiographs are of very limited value other than perhaps in a patient with recurrent sigmoid volvulus with its typical ‘coffee bean’ appearance (who has had recent CT and presents without clinical concern of perforation or ischaemia). CT image of patient presenting with large bowel obstruction secondary to rectosigmoid cancer a Sagittal image with intravenous contrast showing level of obstruction of a known T4b N1 M0 upper rectal cancer invading the uterine body and causing obstruction while undergoing neoadjuvant chemotherapy. The red arrow tip shows the level of the bowel obstruction. b Coronal image with intravenous contrast showing acute large bowel obstruction and grossly distended caecum (asterisk) resulting from an upper rectal adenocarcinoma causing obstruction during neoadjuvant chemotherapy. Patients with perforation, ischaemia or closed-loop colonic obstruction require urgent intervention (usually surgical) after appropriate risk assessment including frailty and senior multidisciplinary input (surgical, anaesthetic, critical care). A colonic stent is an option in selected patients in whom there are no concerns about existing perforation or bowel viability. It has the advantage of avoiding the morbidity of major surgery. Guidelines9 recommend its use as a bridge to surgery in patients with potentially curable colonic cancer, and as a recommended alternative to surgery in those with metastatic disease. Some 30 per cent of patients with malignant LBO have metastatic disease at presentation7. Trials have suggested a lower stoma rate in those treated with curative intent, and initial concerns about worse oncological outcomes have not been confirmed in more recent studies10. Stenting is also a good option for patients whose co-morbidity, risk assessment or frailty score indicate that they would have a poor outcome from emergency surgery. Colonic stenting for benign or extraluminal disease is controversial and not so well studied but can be considered in selected patients. Endoscopic decompression can be useful for colonic volvulus (typically sigmoid) either in isolation or before definitive surgery. Surgical management is the standard for patients with perforation or ischaemic bowel, or who are significantly physiologically compromised as a result of the LBO. In patients without perforation or ischaemia, the options are to defunction, as a bridge to definitive surgery or oncological therapy (neoadjuvant or palliative), or resection of the obstructing lesion with or without an anastomosis. These decisions are challenging and should be made by experienced surgeons who are more likely to be adept at dealing with unprepared bowel, bowel lumen discrepancies, and complex intraoperative decision-making (Fig. 2). Anastomotic leak rates in the emergency setting have been shown to be significantly higher than those reported in elective practice. Intraoperative image and resected specimen a Intraoperative findings in a patient with large bowel obstruction. Appearance of laparotomy incision immediately after opening with the ascending colon protruding from the abdomen, and the discrepancy between small and large bowel diameter reflecting the large bowel obstruction and the competence of the ileocaecal valve. b Photograph of resected bowel cancer that presented as an emergency with bowel obstruction following emergency laparotomy and Hartmann’s procedure with distended colon above obstructing rectal cancer taken en bloc with uterus, ovaries, and fallopian tubes. The extent of any resection will clearly be dependent on the pathology involved (colorectal cancer, diverticular, volvulus). Shared decision-making here is important; it should be crafted around the unique clinical situation and should include the patient’s priorities. Minimally invasive approaches have been shown to be safe in selected patients. LBO commonly presents to acute surgical services and may be have malignant or benign causes. Prompt clinical assessment and rapid imaging via CT is key to obtaining a diagnosis and allowing an informed multidisciplinary approach to treatment. Surgery is still usually required, either by resection or defunctioning stoma, but, in this heterogeneous group of patients, colonoscopy with decompression of volvulus or stent placement has an important role. The authors have no funding to declare. The authors declare no conflict of interest. Gita Lingam (Writing—original draft), Michael Okocha (Writing—original draft), and Ben Griffiths (Supervision, Writing—review & editing)
Source: British journal of surgery
DOI: 10.1093/bjs/znae202
Authors: Gita Lingam, Michael Okocha, Ben Griffiths
Language: English
Subfield: Oncology
Field: Medicine
Domain: Health Sciences
Open Access status: bronze
OpenAlex ID: W4401547450