Initial therapy in patients with suspected large-bowel obstruction (LBO) includes volume resuscitation, appropriate preoperative broad-spectrum antibiotics, and timely surgical consultation.
A nasogastric tube should be considered for patients with severe colonic distention and vomiting. The patient's intravascular volume is usually depleted, and early intravenous fluid (IVF) resuscitation with isotonic saline or lactated Ringer solution is necessary.
Surgical intervention is frequently indicated, depending on the cause of the obstruction. Closed loop obstructions, bowel ischemia, and volvulus are surgical emergencies.
Transfer to another facility is indicated if adequate surgical management or backup is not available.
Adynamic ileus is treated with conservative measures. This involves correction of fluid and electrolyte imbalances, and treatment of the underlying disorder. Nasogastric decompression may be helpful if the patient is vomiting. Medications that slow colonic motility should be stopped, if possible.
Acute Colonic Pseudo-Obstruction
If no perforation is present, acute colonic pseudo-obstruction (ACPO; Ogilvie syndrome) is treated with conservative management for the first 24 hours. This includes bowel rest, hydration, and management of underlying disorders.
Pharmacologic treatment of ACPO with neostigmine or colonoscopic decompression may be effective in cases that do not resolve with conservative management.  Colonoscopic decompression may be successful in as many as 80% of patients with ACPO. 
Surgical intervention for ACPO is associated with a high mortality and morbidity. This treatment is reserved for refractory cases or cases complicated by perforation. 
Endoscopic reduction and decompression of a sigmoid volvulus can be performed in the absence of peritoneal signs. This procedure is also contraindicated when evidence of mucosal ischemia is present on endoscopy. An experienced person should perform the procedure.
Recurrence after decompression is as high as 50%; thus, surgical resection is indicated. In healthy patients who have undergone successful decompression, an elective resection should follow. Emergency surgery is indicated in patients with evidence of perforated or ischemic bowel, or if attempts at endoscopic reduction and decompression are not successful.
The preferred treatment for cecal or transverse colon volvulus is surgical resection and anastomosis. Endoscopic detorsion and decompression is an option when the patient is a poor surgical candidate.
A contrast enema (barium or air) can successfully reduce 60-80% of intussusceptions. It is often successful in children in whom a pathologic leading point for the intussusception is unlikely. This procedure should be performed by an experienced radiologist, because the risk of perforation is significant.
In adults, a pathologic leading point for the intussusception is usually present. Reduction with a contrast enema is far less likely, and patients are more likely to require surgery.
Surgery is indicated if there are signs of peritonitis or bowel perforation, or if attempts at reduction by contrast enema are unsuccessful.
Intussusception may recur in approximately 3% of patients after contrast enema reduction and 1% of patients after operative repair.
Colonic Masses and Strictures
Endoscopic dilation and stenting of colonic obstruction is helpful in selected cases and may be an alternative to multistage surgery.  The procedure may be palliative in a high-risk patient with an unresectable malignancy, or it may be preparatory to surgical resection. [14, 15]
In cases where the stent is deployed before surgery, this procedure permits relief of the acute obstruction and resuscitation of the patient, and it allows for mechanical bowel preparation before colonic resection and reanastomosis, thus avoiding temporary or permanent colostomy.
In a study aimed at determining long-term outcomes of colonic stent insertion followed by surgery for malignant LBO (MLBO), Matsuda et al found that in analyses of all patients and patients who underwent curative resection, disease-free survival and recurrence did not differ significantly between bridge to surgery (BTS) and emergency surgery groups.  . After a comprehensive literature search to identify studies comparing long-term outcomes between BTS and emergency surgery for MLBO, their meta-analysis included 11 studies with a total of 1136 patients.
Use of a decompression tube may be a feasible, safe, and effective BTS for acute malignant left-side colonic obstruction.  Surgical treatment of left colon carcinoma includes resection without primary anastomosis or resection with primary anastomosis and intraoperative lavage. [18, 19] Endoscopically placed self-expandable metal stents (SEMS) can be used to relieve the large-bowel obstruction, thus allowing a primary colorectal anastomosis. 
In a randomized controlled trial designed to assess whether stent insertion improved quality of life and survival in comparison with surgical decompression in patients with malignant incurable LBO (N=52), Young et al found that stent use in patients with incurable LBO conferred a number of advantages, including faster return to diet, decreased stoma rates, reduced postprocedure stay, and some quality-of-life benefits. 
Right-side colonic obstructions are treated with a right colectomy and a primary anastomosis between the ileum and the transverse colon. Patients with high-risk features for surgery (advanced age, complete obstruction, or severe comorbidities) may benefit from stent placement until the patient can be optimized for a surgical procedure. [22, 23] Palliative colorectal stents are an option in patients who are poor surgical candidates or have advanced cancer. [24, 25]
Endoscopic dilation and stenting of colonic obstruction should be performed only by an endoscopist experienced in such procedures. Surgical consultation and backup should be available, as the risk of perforation is increased during attempts at such procedures, with a potentially catastrophic result. Studies in recent years have identified the following as predictive factors for outcomes after SEMS for LBO:
In addition, SEMS appears to significantly improve histopathologic edema as compared with transanal drainage tube and emergency surgery after failure of decompression for malignant colorectal obstruction. 
Patients with persistent obstruction secondary to diverticular disease despite appropriate medical management are treated surgically. Surgical resection follows the same principles as the treatment of carcinomas. Elective colonic resection is offered to patients with recurrent disease.
Obstructed Defecation Syndrome
For obstructed defecation syndrome (ODS) with rectocele, surgery is a last resort.
In a study of 90 rectocele patients with functional constipation, 64 responded to treatment with fiber supplements and biofeedback training with significant improvements in ODS symptoms, including 15 of the 17 patients with rectocele and concomitant intussusception  ; the remaining 26 required surgical intervention. Median cumulative ODS scores improved significantly, from 15.0 before treatment to 10.5 after treatment in the medical management group and from 13.5 before surgery to 10.5 after surgery in the surgical intervention group.
The morbidity and mortality of LBO are often related to the surgical procedure used to relieve the colonic obstruction and, in the long term, to the underlying disease that caused the obstruction. Thus, complications may include the following:
Peritonitis from bowel perforation secondary to overstrenuous attempts at reduction of a volvulus or intussusception, or injudicious attempts to dilate or stent an unsuitable colonic obstruction
Sepsis – Seen more frequently in cases in which a delay in diagnosis or treatment occurred
Intra-abdominal abscess from anastomotic leakage
Pneumonia from aspiration during emesis
Aggressive screening for colorectal cancer in individuals who are older than 50 years or who have a strong family history of colorectal cancer, as indicated by current guidelines, should reduce the future incidence of malignant colonic obstruction.
Care after discharge following surgical management of LBO focuses on surgical convalescence and, if relevant, the need to care for the disease that caused the obstruction.
If the patient has received a colostomy or ileostomy, a decision regarding whether it is temporary or permanent may have been made at the time of discharge, depending on the patient's diagnosis, comorbidity, and postoperative convalescence.
In addition, the remaining colon, both proximally and distally, must be evaluated radiographically or endoscopically to rule out synchronous colonic lesions, such as neoplasms.
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