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
•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
• History of
– 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
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
Any questions?
This presentation can be found on www.drzaid.com