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

3. 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

4. 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.

5. 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

6. 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

7. 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.

8. 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

9. 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.

10. 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

11. 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

12. 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

13. 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.

14. 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

15. 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

16. 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

17. 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

18. 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.

19. 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

20. 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.

21. Large Bowel Obstruction

22. Large Bowel Obstruction

23. 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.

24. 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

25. 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

26. 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.

27. 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?

28. 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

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

30. Any questions?
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