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Colonic Obstruction Last Updated: June 4, 2006 |
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| Synonyms and related keywords: large bowel obstruction, bowel obstruction, obstructed bowels, volvulus, incarcerated hernia, stricture, obstipation, complete bowel obstruction, partial bowel obstruction, constipation, colostomy, ileostomy |
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AUTHOR INFORMATION
| Section 1 of 10   |
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| Author: Marc D Basson, MD, PhD, Chief of Surgery, John D Dingell VA Medical Center; Professor, Department of Surgery, Wayne State University School of Medicine |
| Marc D Basson, MD, PhD, is a member of the following medical societies:
American College of Surgeons, and
American Gastroenterological Association |
| Editor(s): Juan B Ochoa, MD, Assistant Professor, Department of Surgery, University of Pittsburgh; Francisco Talavera, PharmD, PhD, Senior Pharmacy Editor, eMedicine;
BS Anand, MD, Professor, Department of Internal Medicine, Division of Gastroenterology, Baylor University College of Medicine;
Alex J Mechaber, MD, FACP, Assistant Dean for Medical Curriculum, Associate Professor of Medicine, Division of General Internal Medicine, University of Miami Miller School of Medicine;
and Julian Katz, MD, Clinical Professor of Medicine, Drexel University College of Medicine; Consulting Staff, Department of Medicine, Section of Gastroenterology and Hepatology, Hospital of the Medical College of Pennsylvania |
Disclosure
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INTRODUCTION
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Background: Large bowel obstruction may be caused by neoplasms or anatomic abnormalities such as volvulus, incarcerated hernia, stricture, or obstipation. The challenges in managing this condition are distinguishing colonic obstruction from ileus, ruling out nonsurgical causes, and determining the best surgical management. Pathophysiology: Large bowel obstruction from an anatomic abnormality leads to colonic distention, abdominal pain, anorexia, and, late in the course, feculent vomiting. Persistent vomiting may result in dehydration and electrolyte disturbances.
Mortality/Morbidity:
- Large bowel obstruction is a surgical entity.
- The morbidity and mortality often are related to the surgical procedure used to relieve the colonic obstruction and, in the long term, to the underlying disease that caused the obstruction.
Age:
- Colonic obstruction is most common in elderly individuals because the incidence of neoplasms and other causative diseases is higher in this population.
- In neonates, colonic obstruction may be caused by an imperforate anus or other anatomic abnormalities. Obstruction also may be secondary to meconium ileus.
- Hirschsprung disease resembles colonic obstruction in the pediatric population.
History: - History focuses initially on the failure to pass stools or gas. One should attempt to distinguish complete bowel obstruction from partial obstruction, which is associated with passage of some gas or stools, and from ileus.
- Further historical questioning may be directed at the patient's current and past history in an attempt to determine the most likely cause.
- Complete obstruction is characterized by the failure to pass either stools or flatus and the presence of an empty rectal vault upon rectal examination, unless the obstruction is in the rectum.
- Partial obstruction, in which the patient appears obstipated but continues to pass some gas or stools, is a less urgent condition.
- Distinguishing colonic ileus from organic obstruction is important.
- Ileus may be suggested by abdominal pain as a dominant feature of the clinical presentation, by peritoneal signs, or by the presence of pronounced fever and leukocytosis.
- Large bowel obstruction, or even constipation, may be accompanied by some degree of fever or leukocytosis. Similarly, based on peritoneal signs, distinguishing the tender gas-filled and stool-filled colon observed in organic obstruction from a tender abdomen due to peritonitis is difficult.
- Obtaining a thorough history of previous bowel function, abdominal pain, and general systemic issues is important.
- History of chronic weight loss and passage of melanotic bloody stools suggest neoplastic obstruction.
- Conversely, a history of recurrent left lower quadrant abdominal pain over several years is more consistent with diverticulitis, a diverticular stricture, or similar problems.
- A history of aortic surgery suggests the possibility of an ischemic stricture.
Physical: Although a complete physical examination is necessary, key elements of the physical examination should focus on thorough examination of the abdomen, groin, and rectum. - Perform the examination in standard fashion, ie, inspection, auscultation, percussion, and palpation.
- Large bowel obstruction may be characterized by diminished or, in later stages, absent bowel sounds.
- The abdomen is distended and may be tender.
- The presence of true involuntary guarding or peritoneal signs should raise the specter of another intra-abdominal process, such as an abscess.
- The practice of seeking rebound tenderness is misleading and potentially cruel. Many patients without peritoneal signs complain vigorously after an aggressive rebound maneuver. Seeking tenderness and pain by having the patient cough or by shaking the bed probably is more useful.
- Examination of inguinal and femoral regions
- This should be an integral part of the examination.
- Incarcerated hernias represent a frequently missed cause of bowel obstruction.
- In particular, colonic obstruction often is caused by a left-sided inguinal hernia with the sigmoid colon incarcerated in the hernia.
- Digital rectal examination
- Perform this to verify the patency of the anus in a neonate.
- The examination focuses on identifying rectal pathology that may be causing the obstruction and determining the contents of the rectal vault.
- Hard stools suggest impaction.
- Soft stools suggest obstipation.
- An empty vault suggests obstruction proximal to the level that the examining finger can reach.
- Fecal occult blood testing should be performed, and a positive result may suggest the possibility of a more proximal neoplasm.
Causes: - Causes of adult large bowel obstruction include the following:
- Neoplasm (benign or malignant)
- Stricture (diverticular or ischemic)
- Intussusception, usually with an identifiable anatomic abnormality in adults but not in children
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DIFFERENTIALS
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Abdominal Hernias
Acute Mesenteric Ischemia
Appendicitis
Colon Cancer, Adenocarcinoma
Colonic Polyps
Constipation
Diverticulitis
Intestinal Perforation
Intestinal Pseudo-obstruction: Surgical Perspective
Megacolon, Chronic
Megacolon, Toxic
Mesenteric Artery Ischemia
Pseudomembranous Colitis
Pseudomembranous Colitis
Rectal Cancer
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Lab Studies:
- Studies are directed at evaluating the dehydration and electrolyte imbalance that may occur as a consequence of large bowel obstruction and at ruling out ileus as a diagnosis.
- Routine serum chemistries and urine specific gravity should be evaluated.
- Suggestion of an abnormal anion gap also should prompt an arterial blood gas measurement and/or a serum lactate level measurement.
- A decreased hematocrit level, particularly with evidence of chronic iron-deficiency anemia, may suggest chronic lower gastrointestinal bleeding, particularly due to colon cancer.
- A stool guaiac test also should be performed, for similar reasons.
- Although bowel obstruction, or even constipation, may mildly elevate the WBC count, substantial leukocytosis should prompt reconsideration of the diagnosis. Ileus, secondary to an intra-abdominal or extra-abdominal infection or another process, is a possibility.
Imaging Studies:
- Flat and upright abdominal roentgenography demonstrates dilation of the small and/or large bowel and air fluid levels.
- An upright chest x-ray generally is ordered simultaneously to determine whether free air is present, which would suggest perforation of a hollow viscus and ileus rather than organic obstruction.
- Tracing colonic air around the colon, into the left gutter, and down into the rectum or demonstrating an abrupt cut-off in colonic air suggests the anatomic location of the obstruction.
- A dilated colon without air in the rectum is more consistent with obstruction. The presence of air in the rectum is consistent with obstipation, ileus, or partial obstruction.
- This finding can be misleading, particularly if the patient has undergone rectal examinations or enemas.
- The characteristic bird's beak of volvulus may be seen.
- Radiopaque contrast material may be administered and imaging of the colon may be performed under the following circumstances.
- Perform it if the diagnosis of large bowel obstruction is suspected but not proven.
- If differentiation between obstipation and obstruction is required, imaging with contrast is indicated.
- If localization is required for surgical intervention, imaging with contrast is indicated.
- Water-soluble Gastrografin has important advantages over barium as a contrast agent and generally should be employed first.
- It usually does not cause chemical peritonitis if the patient has colonic perforation.
- It has an osmotic laxative effect that may actually wash out an obstipated colon.
- If large bowel perforation is ruled out using a Gastrografin study but a more detailed anatomic definition is required (particularly of the right colon), a barium enema may be performed.
- Although CT scanning is useful to help rule out intra-abdominal abscess or other causes of ileus, it generally is not used initially in patients with large bowel obstruction unless a diagnosis has been made.
- CT scan, particularly with rectal contrast, may demonstrate a mass or evidence of metastatic disease.
- Generally, the findings do not alter management because these patients will be explored and operatively decompressed, regardless of the CT scan findings.
Other Tests:
- Flexible endoscopy preceded by rectal enema may be useful in evaluating left-sided colonic obstruction, including the anatomic location and pathology of the lesion.
- Because the cecum is not reached in such cases, the endoscopist must be alert to the possibility of incorrectly identifying anatomic landmarks and the location of the obstruction.
- An abdominal roentgenogram with the tip of the endoscope at the site of the obstruction may be extraordinarily helpful in identifying and documenting the location of the large bowel obstruction.
- Although flexible endoscopy is relatively comfortable for the patient and provides a better view than rigid sigmoidoscopy, the latter also may be used, depending on the availability of resources and training of personnel.
- Right-sided colonic obstruction is more difficult to evaluate without first administering an oral bowel preparation, which is contraindicated in the setting of bowel obstruction.
Procedures:
- Endoscopic reduction of volvulus
- This procedure is indicated for sigmoid volvulus when peritoneal signs are absent, which would imply dead bowel or perforation. It also is indicated when evidence of mucosal ischemia is not present upon endoscopy.
- An experienced person should perform the procedure.
- A rigid sigmoidoscope may be used if a flexible instrument is not available. The endoscopist must have sufficient experience with this technique.
- Reduction of a volvulus does not imply cure. The sigmoid usually revolvulizes if definitive treatment is not carried out.
- These patients generally are admitted, subjected to mechanical bowel preparation, and managed surgically by sigmoid resection, unless contraindications are present.
- Barium enema for reduction of intussusception
- This is useful and often successful in children in whom a pathological leading point for the intussusception is unlikely.
- It should be performed by an experienced radiologist because the risk of perforation is significant.
- In adults, typically a pathologic leading point for the intussusception is present. Success is far less likely, and patients still require surgery to deal with their pathology.
- Perform these if obstipation is suspected rather than true large bowel obstruction.
- Also perform them to prepare the distal colon for endoscopic evaluation.
- Endoscopic dilation and stenting of colonic obstruction
- This procedure is indicated for colonic near total obstruction through which some small amount of lumen remains.
- The procedure may be palliative in a high-risk patient with an unresectable malignancy, accepting a risk of reobstruction of the stent, or preparatory to surgical resection.
- In cases in which the stent is deployed prior to surgery, it permits relief of the acute obstruction, resuscitation of the patient, and mechanical bowel preparation prior to a one-stage colonic resection and reanastomosis, thus avoiding temporary or permanent colostomy.
- The procedure 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.
Histologic Findings: Histology is of minimal relevance to the acute management of a large bowel obstruction because the obstruction must be relieved regardless of the pathology. However, the histological distinction between malignant and benign causes of obstruction obviously is important for subsequent patient management.
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TREATMENT
| Section 6 of 10 |
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Medical Care: - It involves resuscitation, correction of fluid and electrolyte imbalance, and nasogastric decompression to temporarily treat the obstruction and prevent vomiting and aspiration.
- Medical care is directed primarily at supporting the patient and treating any comorbid illnesses.
Surgical Care: - Surgical care is directed at relieving the obstruction.
- In most patients, the obstructing lesion is resected.
- Because the colon has not been cleansed, anastomosis often is risky.
- After resection, most surgeons perform a proximal colostomy if the obstruction is on the left side or ileostomy if it is on the right side.
- In patients with substantial comorbidity and surgical risk or in the presence of an unresectable tumor, a diverting proximal colostomy or ileostomy may be performed without resection.
- A diverting transverse loop colostomy may be the least invasive procedure for a very ill patient with a left colonic obstruction. It permits relief of the obstruction and further resuscitation without compromising chances for a subsequent resection.
- A sigmoid colostomy without resection may be employed in patients with a rectal obstruction that cannot be managed without a combined abdominoperineal approach.
- Cecostomy should not be performed because the diversion is inadequate.
- In younger patients without substantial comorbidity, some surgeons would consider primary anastomosis, rather than ileostomy, in the right colon, assuming no intraoperative hypotension, blood loss, or other complications are present.
- If resection and proximal colostomy or ileostomy are performed, a mucous fistula generally is extracted from the distal end, unless the obstruction is rectosigmoid, in which case the distal end may be oversewn or stapled and left to drain transanally.
- If the cause of the obstruction can be relieved nonsurgically, through procedures such as decompressing a volvulus, or if the obstruction is only partial, deferring surgery temporarily and supporting the patient while the large bowel is cleansed so that primary anastomosis may be performed more safely is preferable.
Consultations: - Gastroenterologist or surgeon for assessment and probable endoscopy
Diet: - Patients with complete large bowel obstruction should receive nothing by mouth.
- Patients with a partial obstruction may tolerate minimal clear liquids, oral medications, and a gradual bowel preparation.
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MEDICATION
| Section 7 of 10 |
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Oral laxatives are contraindicated if large bowel obstruction is suspected. If any evidence suggests simple constipation, patients should be managed with transrectal enemas. Tap water, isotonic sodium chloride solution, and a variety of other fluids may be used. In patients with renal insufficiency, the physician should be sensitive to the electrolyte content of the fluid.
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FOLLOW-UP
| Section 8 of 10 |
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Further Inpatient Care:
- Anatomic and, if possible, pathological characterization of the cause of the obstruction
- Bowel cleansing if the obstruction is incomplete
- Surgical relief of the obstruction
- Dictated by the demands of postoperative convalescence
Further Outpatient Care:
- Care after discharge focuses on surgical convalescence and, if relevant, the need to care for the disease that caused the obstruction.
- An obstructing colon cancer may require postoperative chemotherapy, depending on the stage of the disease.
- The patient who is chronically obstipated may need stool softeners.
- 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.
- Most patients who retain a rectum are, at least in principle, candidates for reanastomosis at a subsequent stage.
- Generally, it is performed 2-3 months after the initial operation.
- Careful counseling and assessment are required before proceeding with the second procedure.
- Counseling is directed at the risks of the second procedure because the patient must understand that this surgery is elective and that a colostomy or ileostomy is compatible with a reasonable lifestyle. Often, local ostomy support groups and meeting with other patients with ostomies are helpful at this time.
- Patients who had stool incontinence before their first operation, those with substantial surgical risks, and patients with decreased mental status who are cared for in nursing homes may potentially be better off without a reanastomosis.
- In addition, the remaining colon, both proximally and distally, must be evaluated radiographically or endoscopically to rule out synchronous colonic lesions such as neoplasms because the presence of the large bowel obstruction prevented this from being performed before the first procedure.
In/Out Patient Meds:
- Pain medicines generally should be avoided preoperatively. If the pain is sufficiently severe to merit use of significant analgesics, peritonitis, rather than large bowel obstruction, should be considered as the first diagnosis.
- Oral laxatives are contraindicated in patients with complete large bowel obstruction.
- A slow preoperative mechanical bowel preparation is indicated for patients who have incomplete obstruction, provided the patient can tolerate it.
- The author's preference is for polyethylene glycol solutions, such as GO-LYTELY, because they avoid issues of fluid and electrolyte imbalance. The fluid should be administered slowly (rather than given in the standard manner of 1 gal over 4 h), and the patient should be observed for abdominal cramping and intolerance.
Transfer:
- Transfer to another facility is indicated if adequate surgical management or backup is not available.
- Prior to transfer, the patient should be adequately hydrated and resuscitated.
Complications:
- Peritonitis from bowel perforation secondary to overstrenuous attempts at reduction of volvulus or intussusception or injudicious attempts to dilate or stent an unsuitable colonic obstruction
- Misdiagnosis of an ileus secondary to intra-abdominal infection as large bowel obstruction, with consequent delay in treatment
- Intra-abdominal abscess from anastomotic leakage
- Pneumonia from aspiration during emesis
Prognosis:
- Prior to surgical decompression, the patient's overall medical condition and presence of any comorbidities that define surgical risk determine the prognosis.
- After surgical decompression, prognosis is determined by the underlying disease.
Patient Education:
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MISCELLANEOUS
| Section 9 of 10 |
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Medical/Legal Pitfalls:
- Failure to recognize an incarcerated hernia as the cause of obstruction
- Confusing large bowel obstruction with obstipation and managing it nonoperatively for a prolonged period
- Confusing peritonitis and ileus with large bowel obstruction, resulting in delayed surgery
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BIBLIOGRAPHY
| Section 10 of 10 |
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De Giorgio R, Stanghellini V, Barbara G, et al: Prokinetics in the treatment of acute intestinal pseudo-obstruction. IDrugs 2004 Feb; 7(2): 160-5[Medline].
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de Gregorio MA, Mainar A, Tejero E: Acute colorectal obstruction: stent placement for palliative treatment-- results of a multicenter study. Radiology 1998 Oct; 209(1): 117-20[Medline].
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Deen KI, Madoff RD, Goldberg SM: Surgical management of left colon obstruction: the University of Minnesota experience. J Am Coll Surg 1998 Dec; 187(6): 573-6[Medline].
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Fan YB, Cheng YS, Chen NW, et al: Clinical application of self-expanding metallic stent in the management of acute left-sided colorectal malignant obstruction. World J Gastroenterol 2006 Feb 7; 12(5): 755-9[Medline].
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Forloni B, Reduzzi R, Paludetti A: Intraoperative colonic lavage in emergency surgical treatment of left- sided colonic obstruction. Dis Colon Rectum 1998 Jan; 41(1): 23-7[Medline].
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Isbister WH, Prasad J: Emergency large bowel surgery: a 15-year audit. Int J Colorectal Dis 1997; 12(5): 285-90[Medline].
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Lopez-Kostner F, Hool GR, Lavery IC: Management and causes of acute large-bowel obstruction. Surg Clin North Am 1997 Dec; 77(6): 1265-90[Medline].
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Reemst PH, Kuijpers HC, Wobbes T: Management of left-sided colonic obstruction by subtotal colectomy and ileocolic anastomosis. Eur J Surg 1998 Jul; 164(7): 537-40; discussion 541-2[Medline].
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Schermer CR, Hanosh JJ, Davis M: Ogilvie's syndrome in the surgical patient: a new therapeutic modality. J Gastrointest Surg 1999 Mar-Apr; 3(2): 173-7[Medline].
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Sgouros SN, Vlachogiannakos J, Vassiliadis K, et al: Effect of polyethylene glycol electrolyte balanced solution on patients with acute colonic pseudo obstruction after resolution of colonic dilation: a prospective, randomised, placebo controlled trial. Gut 2006 May; 55(5): 638-42[Medline].
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Stefanidis D, Brown K, Nazario H, et al: Safety and efficacy of metallic stents in the management of colorectal obstruction. JSLS 2005 Oct-Dec; 9(4): 454-9[Medline].
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Suri S, Gupta S, Sudhakar PJ: Comparative evaluation of plain films, ultrasound and CT in the diagnosis of intestinal obstruction. Acta Radiol 1999 Jul; 40(4): 422-8[Medline].
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Turegano-Fuentes F, Echenagusia-Belda A, Simo-Muerza G: Transanal self-expanding metal stents as an alternative to palliative colostomy in selected patients with malignant obstruction of the left colon. Br J Surg 1998 Feb; 85(2): 232-5[Medline].
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Turegano-Fuentes F, Munoz-Jimenez F, Del Valle-Hernandez E: Early resolution of Ogilvie's syndrome with intravenous neostigmine: a simple, effective treatment. Dis Colon Rectum 1997 Nov; 40(11): 1353-7[Medline].
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