Large Bowel Obstruction Robert R. Zaid November 30th, 2005 Genesys Regional Medical Center

Large Bowel Obstruction Introduction Background: An emergent condition Requires early identification and prompt surgical intervention Colonic obstruction may result from Infectious/inflammatory Neoplastic Mechanical pathology Volvulus Incarcerated hernia Stricture Obstipation Etiology Age dependent Serosa can expand to only a variable but limited diameter Rupture and fecal soilage of the peritoneal cavity can occur

Large Bowel Obstruction Introduction Pathophysiology: Caused by anatomic abnormality Leads to Colonic distention Abdominal pain Anorexia Late in the course Feculent vomiting Persistent vomiting May result in Dehydration and electrolyte disturbances.

Large Bowel Obstruction Introduction Pathophysiology: Rotating or twisting of the cecum or sigmoid Causes abrupt onset of symptoms Sigmoid volvulus Usually occurs in older individuals History of straining at stool Cecal volvulus Features a congenital defect in the peritoneum Inadequate fixation of the cecum It generally occurs in much younger individuals Venous drainage and arterial inflow are compromised by a closed loop obstruction As the colon twists on its mesentery

Large Bowel Obstruction Age Most common in elderly individuals 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 May be secondary to meconium ileus In pediatrics Hirschsprung disease resembles colonic obstruction

Large Bowel Obstruction Clinical Manifestations History Initially focus on Failure to pass stools or gas Distinguish complete bowel obstruction from partial obstruction and from ileus Associated with passage of some gas or stools Further historical questioning May be directed at the patient's current and past history Attempt to determine the most likely cause. Obtain history of bowel movements, flatus, obstipation and symptoms Major complaints Abdominal distention Nausea Vomiting Crampy abdominal pain.

Large Bowel Obstruction Clinical Manifestations Complete obstruction Characterized by Failure to pass either stools or flatus Presence of an empty rectal vault upon rectal examination Partial obstruction Patient appears obstipated but continues to pass some gas or stools Less urgent condition. Ileus Distinguishing colonic ileus from organic obstruction is important Ileus may be suggested by Abdominal pain as a dominant feature of the clinical presentation Peritoneal signs Fever and leukocytosis. Constipation also may be accompanied by some degree of fever or leukocytosis

Large Bowel Obstruction Clinical Manifestations Obtaining a thorough history of previous bowel function, abdominal pain, and general systemic issues is important. Neoplastic obstruction History of Chronic weight loss Passage of melanotic bloody stools Diverticulitis, diverticular stricture Recurrent left lower quadrant abdominal pain over several years A history of aortic surgery suggests the possibility of an ischemic stricture.

Large Bowel Obstruction Clinical Manifestations Development history Right-sided Can grow quite large before obstruction Large capacity of the right colon Soft stool consistency. Sigmoid colon and rectal tumors Cause colonic obstruction more rapidly Colon is narrower and the stool is harder in that area. Large-bowel obstruction prior to perforation Obstruction that dilates the colon Visceral abdominal cramps Vague Pain receptors sense Distention or vigorous contraction. Peritonitis may ensue. Obstipation Patients may state that pants or belts are not fitting properly. Intervention is necessary to prevent perforation

Large Bowel Obstruction Clinical Manifestations Obstruction secondary to intussusception Crampy abdominal pain Colicky Relieved by assuming fetal position. Weight loss and fatigue are common. Fistulization Sigmoid colon to the bladder Pneumaturia Mucinuria Fecaluria

Large Bowel Obstruction Clinical Manifestations: Physical Complete physical examination is necessary Key elements should focus on Abdomen Groin Rectum Abdominal examination Standard Inspection Auscultation Percussion Palpation Bowel sounds Diminished or Absent bowel sounds. Late stages Quality of abdomen Distended May be tender. Involuntary guarding or peritoneal signs Must think about intraabdominal process such as an abcess

Large Bowel Obstruction Clinical Manifestations: Physical Examination of inguinal and femoral regions Should be an integral part of the examination. Incarcerated hernias Frequently missed cause of bowel obstruction. Left-sided inguinal hernia Colonic obstruction often is caused by Sigmoid colon incarcerated in the hernia.

Large Bowel Obstruction Clinical Manifestations: Physical Digital rectal examination Verify the patency of the anus in a neonate. Focus on identifying Rectal pathology May be causing the obstruction Determining the contents of the rectal vault. Hard stools Suggests impaction. Soft stools Suggest obstipation. Empty vault Suggests obstruction Proximal to the level that the examining finger can reach Fecal occult blood testing Positive result may suggest the possibility of a more proximal neoplasm

Large Bowel Obstruction Clinical Manifestations: Causes Obstructions caused by: Tumors Gradual onset Normally result from tumor ingrowth into the colonic lumen Diverticulitis Muscular hypertrophy of the colonic wall Repetitive episodes of inflammation Lumen becomes narrow as the colonic wall becomes fibrotic and thickened Intussusception Commonly involves a tumor Volvulus Incarcerated hernia Ogilvie syndrome Symptoms and definition May occur in elderly individuals who abuse cathartics or have diabetes Loss of peristalsis. No obstruction is evident Colon becomes significantly and dangerously dilated. Once a contrast evaluation demonstrates nonobstructive colonic dilation Management should be pharmacologic Stimulation of colonic contractions Intravenous neostigmine has been therapeutic in these situations

Large Bowel Obstruction Differential Colorectal carcinoma Cecal volvulus Intussusception Ogilvie syndrome Sigmoid volvulus 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 Rectal Cancer

Large Bowel Obstruction Workup Lab Studies: Obtain blood for a CBC Electrolyte levels PT Type and crossmatch. Imaging Studies: Upright chest radiograph Will demonstrate free air of perforated Flat and upright abdominal radiographs May be diagnostic of sigmoid or cecal volvulus Kidney bean appearance on the radiograph CT Gastrografin An enema with water-soluble contrast CT with intravenous and rectal contrast. Procedures: Nasogastric tube If the patient has been vomiting Intravenous fluid resuscitation (intravascular depletion) Isotonic saline or Ringer lactate solution

Large Bowel Obstruction Workup Lab Studies: Chemistry Evaluating the dehydration Electrolyte imbalance May occur as a consequence of large bowel obstruction Ruling out ileus as a diagnosis. Abnormail anion gap Should prompt an arterial blood gas and/or a serum lactate level Routine urine specific gravity should be evaluated. A decreased hematocrit With evidence of chronic iron-deficiency anemia Suggests chronic lower gastrointestinal bleeding Colon cancer? Stool guaiac test Colon cancer Leukocytosis Mild leukocytosis may be seen with obstruction or constipation Severe leukocytosis should prompt reconsideration of the diagnosis Ileus, secondary to an intra-abdominal or extra-abdominal infection or another process, is a possibility.

Large Bowel Obstruction Workup Imaging Studies: Upright chest radiograph Will demonstrate free air of perforated Flat and upright abdominal radiographs May be diagnostic of sigmoid or cecal volvulus Kidney bean appearance on the radiograph Demonstrates dilation of the small and/or large bowel and air fluid levels Sigmoid volvulus

Large Bowel Obstruction Workup X-ray findings 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 Air in the rectum is consistent with Obstipation Iileus Partial obstruction. Rectal examinations may cause misleading results The characteristic bird's beak of volvulus may be seen. Radiopaque contrast 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. Gastrografin (water soluble) Advantages over barium (first line) 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. Barium enema If large bowel perforation is ruled out using a Gastrografin study and More detailed anatomic definition is required (particularly of the right colon) CT scanning 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.

Large Bowel Obstruction

Large Bowel Obstruction

Large Bowel Obstruction Workup Procedures: Endoscopic reduction of volvulus Indicated for sigmoid volvulus when Peritoneal signs are absent Dead bowel or perforation Evidence of mucosal ischemia is not present upon endoscopy Rigid sigmoidoscope May be used if a flexible instrument is not available Reduction of a volvulus does not imply cure Sigmoid usually revolvulizes Patients admitted, subjected to mechanical bowel preparation, and managed surgically by sigmoid resection Barium enema for reduction of intussusception Children Often successful Adults Success is far less likely, and patients still require surgery to deal with their pathology. Cleansing enemas Used if obstipation is suspected rather than true large bowel obstruction Also perform them to prepare the distal colon for endoscopic evaluation.

Large Bowel Obstruction Treatment Emergency Department Care Initial therapy Directed at patient comfort Volume resuscitation Ultimate goal to decompress the large intestine. Medical Care: Resuscitation Correction of fluid and electrolyte imbalance Nasogastric decompression Treat temporarily Obstruction and prevent vomiting and aspiration Directed primarily at supporting the patient and treating any comorbid illnesses

Large Bowel Obstruction Treatment Surgical Care: Surgical care is directed at relieving the obstruction Obstructed lesion is resected.(most cases) 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. Diverting proximal colostomy or ileostomy Substantial comorbidity and surgical risk or in the presence of an unresectable tumor Diverting transverse loop colostomy Least invasive procedure for a very ill patient with a left colonic obstruction Permits relief of the obstruction and further resuscitation without compromising chances for a subsequent resection Sigmoid colostomy without resection 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. Youth 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 nonsurgical therapy employed i.e. decompressing a volvulus Deferring surgery temporarily and supporting the patient while the large bowel is cleansed so that primary anastomosis may be performed more safely is preferable

Large Bowel Obstruction Treatment Consultations Obtain early consultation from a general surgeon Surgical intervention frequently is indicated Diet Complete obstruction – NPO Partial obstruction – Clear liquids Specific cases Sigmoid volvulus First choice is sigmoidoscopy with volvulus reduction. Second choice is sigmoid colectomy. Cecal volvulus First choice is hemicolectomy. Second choice is colonoscopy. Sigmoid obstruction secondary to diverticulitis or carcinoma Procedure of choice is a sigmoid resection and Hartman procedure or a sigmoid resection. Alternative is primary anastomosis. Obstruction of splenic flexure First choice is extended hemicolectomy. Second choice is proximal colostomy with delayed resection.

Large Bowel Obstruction Treatment 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. Chemotherapy? Temporary or permanent colostomy?

Large Bowel Obstruction Follow up Complications: Perforation Sepsis Intra-abdominal abscess Death Prognosis: If treated early, outcome is generally good. If secondary to carcinoma Outcome is dependent on the carcinoma prognosis

References www.emedicine.com Large bowel obstruction, 2004 Colonic Obstruction, 2004 Baker, R., Fischer, J., LBO, Mastery of Surgery, fourth edition, pp 1405-1407 Haubrich, W., Schaffner, F., 1995, Gastroenterology, LBO, pp 1189

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