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Bowel Disorders

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Abdominal Pain in Older Adults

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Bile Acid Oral Dissolution Therapy

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Colicky Abdominal Pain

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Mechanical IleusAka: Mechanical Bowel Obstruction, Small Bowel Obstruction

See Also
1. Bowel Obstruction in Terminally Ill Patient
Types
1. Simple mechanical obstruction
  1. Bowel lumen is obstructed
  2. No vascular compromise
2. 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
3. Strangulated obstruction
  1. Bowel lumen and vascular supply is compromised
Causes
1. 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)
    1. Colon Cancer (most common)
    2. Ovarian Cancer
    3. Pancreatic Cancer
    4. Gastric Cancer
2. Obturation
  1. Colonic Polyp
  2. Intussusception
    1. Children: Usually idiopathic
    2. Adults: 95% have underlying mechanical cause
    3. AIDS may predispose to Intussusception
  3. Gallstones that have entered the bowel lumen
    1. More common in those over age 65 years
  4. Bezoar
  5. Barium
  6. Ascaris infection
  7. Tuberculosis
  8. Actinomycosis
  9. Diverticulitis
3. Intrinsic bowel lesions
  1. Congenital anomalies (Pediatric)
    1. Atresia
    2. Stenosis
    3. Bowel duplication
  2. Strictures
    1. Inflammatory Bowel Disease (e.g. Crohn's Disease)
    2. Colon Cancer
4. Extrinsic bowel lesions
  1. Adhesion
    1. Abdominal or pelvic surgery
    2. Surgery in presence of peritonitis or trauma
  2. Hernia (higher risk for strangulation)
    1. Internal hernias via mesenteric defects
    2. External hernias abdominal wall
    3. Obturator hernia
      1. More common in emaciated elderly women
  3. Small bowel volvulus
    1. Rare compared to colon volvulus
    2. More common in Africa, Middle East and India
    3. Occurs in intestinal malrotation or adhesions
5. Idiopathic Intestinal Obstruction
  1. See Bowel Pseudoobstruction)
Symptoms
1. Frequent and recurrent Generalized Abdominal Pain
  1. Duration: Seconds to minutes
  2. Character: Spasms of crampy Abdominal Pain
  3. Frequency
    1. Intermittent pain initially
    2. Every few minutes in proximal obstruction
    3. Constant pain suggests ischemia or perforation
2. Stool passage
  1. Initially may be present despite complete obstruction
  2. Later, obstipation (no stool) in complete obstruction
3. Symptoms more severe in proximal obstruction
  1. Proximal obstruction
    1. Severe, Colicky Abdominal Pain
    2. Develops over hours and occurs every few minutes
    3. Bilious Emesis
    4. Mild abdominal distention
  2. Distal obstruction
    1. Develops over days and becomes progressively worse
    2. Emesis may occur and is brown and feculent
    3. Significant abdominal distention
Signs
1. Bowel sounds
  1. Initial: High pitched, hyperactive bowel sounds
  2. Later: hypoactive or absent bowel sounds
2. Tender abdominal mass
  1. Closed loop Bowel Obstruction may be palpable
3. Abdominal distention and tympany on percussion
  1. Indicates distal obstruction
4. Rectal examination for blood
Diagnosis: Factors predicting Bowel Obstruction
1. History of prior surgery
2. Constipation history
3. Age over 50 years
4. Vomiting
5. Abdominal distention
6. Hyperactive bowel sounds
Radiology: Flat and upright (or decubitus) abdominal XRay
1. Sensitivity: 60% (up to 90%)
2. 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
    1. Sharply angulated distended bowel loops
    2. Step-ladder arrangement or parallel bowel loops
3. String of pearls sign (specific for obstruction)
  1. Series of small pockets of gas in a row
4. Coffee-bean sign
  1. Bowel loops are distended and air filled
  2. U-Shaped bowel loop divided by edematous bowel wall
5. Pseudotumor Sign
  1. Bowel loop filled with fluid (resembles mass)
Radiology
1. MRI Abdomen (93% Test Sensitivity for SBO cause)
2. CT Abdomen (88% Test Sensitivity for SBO cause)
  1. Adjunct to plain XRay to identify obstruction site
  2. Findings
    1. Intussusception
    2. Volvulus
    3. Extraluminal mass (e.g. abscess, neoplasm)
    4. Closed loop obstruction
    5. Strangulated bowel
3. References
  1. Matsuoka (2002) Am J Surg 183:614
Differential Diagnosis
1. Adynamic Ileus
2. Bowel Pseudoobstruction
3. Ischemic bowel (superior mesenteric syndrome)
4. Gastroenteritis
5. Cholelithiasis
6. Cholecystitis
7. Pancreatitis
8. Peptic Ulcer Disease
9. Appendicitis
10. Myocardial Infarction
11. Pregnancy
Management: Conservative Therapy
1. Fluid replacement
2. Bowel decompression
  1. Nasogastric Tube
  2. Long intestinal tube (eg. Cantor) offers no advantage
3. Surgical Consultation
4. Antibiotic
  1. Indications (Not for routine use)
    1. Surgery planned
    2. Bowel ischemia or infarction
    3. Bowel perforation
  2. Cover Gram Negatives and Anaerobes
    1. Second-generation Cephalosporin
5. Possible benefit: Magnesium, Acidophilus, Simethicone
  1. Give orally, then clamp NG tube x1 hour; Repeat tid
    1. Magnesium oxide 500 mg
    2. L. acidophilus 0.3 grams
    3. Simethicone 40 mg
  2. Studied in partial small Bowel Obstruction
    1. Unblinded trial
    2. Reduced length of stay and number needing surgery
    3. Chen (2005) CMAJ 173:1165
Management: Surgical Intervention
1. Spontaneous resolution often occurs without surgery
  1. Partial small Bowel Obstruction: 75%
  2. Complete small Bowel Obstruction: Up to 50%
2. Predictors of resolution without surgery
  1. Early postoperative Bowel Obstruction
  2. Adhesive obstruction (prior laparotomy)
  3. Crohn's Disease
3. Indications for Surgery
  1. Inadequate relief with Nasogastric Tube placement
  2. Persistant symptoms >48 hours despite treatment
Complications
1. Intestinal Ischemia or infarction
2. Bowel necrosis, perforation and bacterial peritonitis
3. Hypovolemia
4. Complications of surgical intervention if needed
Prognosis: Recurrence of obstruction due to adhesions
1. Risk after first episode: 53%
2. Risk after more than one episode: 83%
References
1. Torrey in Marx (2002) Rosen's Emergency Med, p. 1283-7
2. Townsend (2001) Sabiston Surgery, p. 883-8
3. Turnage in Feldman (1998) Sleisenger GI, p. 1799-804

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