Pathogenesis:
• Normal luminal flow of intestinal contents is interrupted
• Bowel proximal to obstruction dilates as intestinal secretions are prevented from
passing distally
• Nausea and emesis
• Swallowed air and gas from bacterial fermentation accumulates, adding to dilatation
• Bacterial overgrowth occurs in the proximal SB
• Emesis can become feculent due to bacterial overgrowth
• Bowel wall becomes edematous and intestine's normal absorptive function is lost -
more fluid is sequestered in bowel lumen
• Secretion of fluid into lumen of proximal dilated bowel increases. - transudative loss
of fluid into peritoneal cavity
• Tachycardia, oliguria, azotemia, and hypotension can result from progressive
dehydration
• Strangulation complicates approximately 10% of bowel obstructions, and occurs
when bowel wall edema and increasing intraluminal pressure compromise perfusion
to a segment of intestine
• Necrosis with concomitant fever and leukocytosis, which will eventually lead to
perforation unless the process is interrupted
Causes:
• Postop or primary
• Extrinsic: Post-operative adhesions (75%), hernias, volvulus
• Intrinsic: Tumors, inflammatory stricture (Crohn’s), radiation enteritis
• Normal lumen: Intussusception, gallstones, feces, bezoar, traumatic intramural
hematoma
Symptoms:
• Obstipation, nausea, vomiting, abdominal pain, and bloating
• No reliable sign or symptom differentiating patients with strangulation or impending
strangulation from those in whom surgery will not be necessary
Incidence:
• >300,000 hospitalizations for adhesiolysis, resulting in >800,000 days of inpatient
care and $1.3 billion in expenditures
• Postoperative adhesions/SBO occur in 5-15% of patients
Types:
• Complete
• Partial
Physical examination:
• Fever and tachycardia - associated with strangulation
• Hypotension, oliguria, and dry mucous membranes indicate dehydration
• Inspect the abdomen for surgical scars and the degree of distention
• Auscultate - high-pitched or hypoactive bowel sounds
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