A. Post-operative ileus resolves within 24-48 hours
I. Types A. Simple mechanical obstruction
1. Bowel lumen is obstructed 2. No vascular compromise
B. Closed loop obstruction 1. Both ends of a bowel loop are obstructed 2. Results in strangulated obstruction if untreated 3. Rapid rise in intraluminal pressure
C. Strangulated obstruction1. Bowel lumen and vascular supply is
Mechanical ileusII. Causes A. Most Common Causes
1. Postoperative Adhesions (accounts for 50% of cases)
2. Hernia (25% of cases, especially younger patients)
3. Neoplasms (10% of cases, esp. older patients) a. Colon Cancer (most common) b. Ovarian Cancer c. Pancreatic cancer d. Gastric Cancer
A. Intrinsic bowel lesions 1. Congenital anomalies (Pediatric)
c. Bowel duplication
2. Strictures a. Inflammatory Bowel Disease (e.g. Crohn's Disease) b. Colon Cancerc. Intussusception
a. Children: Usually idiopathic b. Adults: 95% have underlying mechanical cause c. AIDS may predispose to Intussusception
d. Gallstones that have entered the bowel lumen a. More common in those over age 65 years
e. Bezoarf. Barium g. Ascaris infection h. Tuberculosis i. Actinomycosis j. Diverticulitis
C. Extrinsic bowel lesions 1. Adhesion
a. Abdominal or pelvic surgery b. Presence of peritonitis or trauma
2. Hernia (higher risk for strangulation) a. Inguinal hernia (direct ,indirect) b. Internal hernias via mesenteric defectsc. Obturator hernia
More common in emaciated elderly women
3. Small bowel volvulus a. Rare compared to colon volvulus
b. More common in Africa, Middle East and India
c. Occurs in intestinal malrotation or adhesions
D. Idiopathic Intestinal Obstruction1. See Bowel Pseudoobstruction
A. Frequent and recurrent Generalized Abdominal Pain
B. Duration: Seconds to minutes 1. Character: Spasms of crampy abdominal pain
2. Frequency a. Intermittent pain initially
b. Every few minutes in proximal obstruction
c. Constant pain suggests ischemia or perforation
Mechanical ileusB. Stool passage
1. Initially may be present despite complete obstruction
2. Later, obstipation (no stool) in complete obstruction
C. Symptoms more severe in proximal obstruction 1. Proximal obstruction
Severe, colicky abdominal pain Constant pain suggests ischemia or perforation Develops over hours and occurs every few minutes Bilious Emesis Mild abdominal distention
May occur at any point in length of small bowel
1. Distal obstruction a. Develops over days and becomes
b. Emesis may occur and is brown and feculent
c. Significant abdominal distention
IV. Signs A. Bowel sounds
1. Initial: High pitched, hyperactive bowel sounds 2. Later: hypoactive or absent bowel sounds
B. Tender abdominal mass 1. Closed loop Bowel Obstruction may be palpable
C. Abdominal distention and tympany on percussion
1. Indicates distal obstruction
Rectal examination for blood
How does it present?
Symptoms: Colicky abdominal pain, nausea, vomiting, and obstipation.
Continued passage of gas and/or stool beyond 12 hours after onset of symptoms is characteristic of partial rather than complete obstruction.
Signs: Abdominal Distention (Greater the farther distal the obstruction) and hyperactive, high pitched bowel sounds.
Laboratory Findings: Intravascular volume depletion (consist of hemoconcentration and electrolyte abnormalities) Mild leukocytosis.
Features of Strangulated Obstruction (Bowel Infarction):Acute Abdomen,Tachycardia, localized abdominal tenderness, fever, marked leukocytosis, and acidosis. Serum levels of amylase, lipase, lactate dehydrogenase, phosphate, and potassium may be elevated.
How is it diagnosed?
Evaluation Goals: • Distinguishing mechanical obstruction from ileus • Determining the etiology of the obstruction• Discriminating partial from complete obstruction• Discriminating simple from strangulating obstruction.
History:• Prior abdominal operations • Presence of abdominal disorders (cancer or IBD)• Last BM and Flatus• Pediatrics - Ingestion of foreign body
Physical Exam:• Meticulous Search for Hernias (inguinal and femoral) • Rectal Exam to look for gross or occult blood.
The diagnosis is usually confirmed by Radiology
V. Radiology: Flat and upright (or decubitus) abdominal X-Ray
A. Sensitivity: 60% (up to 90%) B. Typical findings of Bowel Obstruction
1. Bowel distention proximal to obstruction 2. Bowel collapsed distal to obstruction 3. Upright or decubitus view: Air-fluid levels 4. Supine view findings
a. Sharply angulated distended bowel loops b. Step-ladder arrangement or parallel bowel
Abdominal series 1. Radiograph of the abdomen in a supine position2. Radiograph of the abdomen in an upright position3. Radiograph of the chest in an upright position.
Most Specific Finding: The Triad 1. Dilated small-bowel loops (>3 cm in diameter)2. Air-Fluid levels on upright films3. Paucity of air in the colon.
Sensitivity is 70 to 80%.
Specificity is low, because ileus and colonic obstruction have similar appearing findings.
Despite some limitations, Plain films remain an important study
because of their widespread availability and low cost.
Small Bowel Gas Pattern •Centrally located•Soft tissue across entire lumen
Colon Gas Pattern •Peripheral Located•Mostly not overlapping•Haustra markings
c .String of pearls sign (specific for obstruction) 1. Series of small pockets of gas in a row
d. Pseudotumor Sign 1. Bowel loop filled with fluid (resembles mass)
Mechanical ileusVI. Radiology A. MRI Abdomen (93% Test Sensitivity for SBO
cause) B. CT Abdomen (88% Test Sensitivity for SBO
cause) 1. Adjunct to plain XRay to identify obstruction site 2. Findings
a. Intussusceptionb. Volvulus c. Extraluminal mass (e.g. abscess, neoplasm)d. Closed loop obstruction e. Strangulated bowel
Flat Abdominal Film
Dilated Loops of Small Bowel
No Air in Colon or Rectum
Air - Fluid Levels
Dilated Small Bowel
Upright Abdominal Film
Computed Tomographic (CT) scanning
Study preformed with oral and IV contrast.
Findings:1. Discrete transition zone with dilation of bowel proximally and
decompressed distally2. Intraluminal contrast that does not pass beyond the transition zone3. Colon containing little gas or fluid.
Strangulation: Suggested by thickening of the bowel wall, pneumatosis intestinalis (air in the bowel wall), portal venous gas, mesenteric haziness, and poor uptake of intravenous contrast into the wall of the affected bowel.
Offers a global evaluation of the abdomen.
Important when intestinal obstruction represents only one possible diagnosis in all acute abdominal conditions.
Sensitivity 80 to 90% (More sensitive the higher grade obstruction)
Specificity 70 to 90%
• Dilated Loops of Small Bowel with Air-Fluid levels• Area of non-dilated small bowel.• Absence of Air in the Colon.
•Dilated Loops of SB
•Air in Wall of SB
•No Air in Colon
Mechanical ileusVII. Differential Diagnosis
A. Adynamic Ileus B. Bowel PseudoobstructionC. Ischemic bowel (superior mesenteric syndrome) D. GastroenteritisE. CholelithiasisF. Cholecystitis G. PancreatitisH. Peptic Ulcer Disease I. Appendicitis J. Myocardial Infarction K. Pregnancy
Mechanical ileusVIII. Management: Conservative Therapy A. Fluid replacement B. Bowel decompression
1. Nasogastric Tube2. Long intestinal tube (eg. Cantor) offers no advantage
C. Antibiotic 1. Indications (Not for routine use)
A. Surgery planned B. Bowel ischemia or infarction C. Bowel perforation
A. Cover Gram Negatives and Anaerobesa. Second-generation Cephalosporin
IX. Management: surgical intervention
A. Spontaneous resolution often occurs without surgery
1. Partial small bowel obstruction: 75%
2. Complete small bowel obstruction: up to 50%
A. Predictors of resolution without surgery 1. Early postoperative bowel obstruction
2. Adhesive obstruction (prior laparotomy)
3. Crohn's disease
B. Indications for surgery 1. Inadequate relief with Nasogastric tube
Patients with acute SBO treated laparoscopically (LAP; n = 52) and
conventionally (CONV; n = 52) were compared in a retrospective matched-pair
analysis. Conversions were included in the laparoscopic
1.IntraOP major complication: (Perforation ,Hemorrhage ,Injury to mesentery) LAP 15/52 (28.8%) CONV 8/52 (15.4%) p=0.1562.PostOP complication (Pulmonary, Cardiac, Deep vain thrombosis, Death…) LAP 10/52 (19.2%) CONV 8/52 (40.4%)
p=0.0323.Bowel movement, days after OP LAP 3.5 CONV 4.4 (p=0.001)4.Days of hospital stay LAP 11.3 CONV 18.1 (p=0.001)
1. Laparoscopic treatment of acute SBO was feasible in about half of these patients.
2. Postoperative recovery was improved after laparoscopic procedures but the risk of intraoperative complications increased .
3. Laparoscopic management of acute SBO seems justified in patients with fewer than two previous laparotomies but should not be offered to other patients because of the unacceptably high risk of intraoperative bowel perforation.