Intestinal Obstruction

last authored: Aug 2009, David LaPierre

 

Introduction

 

 

The Case of...

A 36 year-old presents with 10 hour history of crampy abdominal pain, nausea, anorexia, and chills.

 

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Differential Diagnosis

mechanical

extrinsic

  • adhesions
  • hernias
  • metastatic cancer
  • volvulus
  • intra-abdominal abscess or hematoma
  • pancreatic pseudocyst
  • intra-abdominal drains
  • tight fascial opening at stoma

 

intralumenal

  • tumours (most common in colon)
  • gallstones
  • foreign body
  • worms
  • bezoars

 

 

intramural abdomanlities

  • tumours
  • strictures (IBD, diverticulitis)
  • hematoma
  • intussusception
  • regional enteritis
  • radiation enteritis

 

Paralytic ileus

intra-abdominal

  • peritonitis
  • inflammatory
  • pancreatitis

 

extra-abdominal

  • MI
  • pneumonia
  • infection, trauma, narcotics, lack of ambulation, electrolyte abnormality

 

 

 

 

To distinguish from gastroenteritis:

 

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History and Physical Exam

  • history
  • physical exam

History

With new obstructions, peristalsis increases: borborygmy (sp)

pain

  • visceral:
  • colicky or crampy

nausea and vomiting

diarrhea can occur early on but tends to dissipate

abdominal distention

failure to pass flatus or feces (though bowel needs to empty out)

if ischemia follows, constant pain will occur. Immediate operation is required

 

past medical hx

  • previous intra-abdominal surgery
  • prior SBO
  • inflammatory bowel disease
  • radiation
  • tumours

Physical Exam

ABCs: tachycardia/hypotension from hypovolemic shock

Inspection

  • previous scars
  • lumps or bumps
  • hernia

Auscultate

  • high-pitched bowel sounds

Palpation

  • peritonitis
  • localized tenderness (RED FLAG: ischemia)

DRE

  • obstructing rectal tumour

 

Red Flags

  • fever
  • peritoneal signs
  • hernia

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Investigations

  • lab investigations
  • diagnostic imaging

Lab Investigations

Following hypovolemia

  • electrolytes
  • WBC (RED FLAG)
  • acidosis (RED FLAG)

Diagnostic Imaging

 

Upright X-ray (diagnostic in 60% of cases)

  • distended small bowel (3 cm max for normal)
  • fluid-filled not seen; can see air
  • air-fluid levels
  • string of pearls sign

CT (useful with diagnostic uncertainty)

 

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Management

90% of cases do not require surgery; place an NG tube to decompress stomach

Fluid resuscitation

NG tube

Situations necessating emergent operation

Surgery

adequate fluid resuscitation and peri-operative antibiotics

be very caution due to fragile tissue

lysis of adhesions

running the bowel: travel all the way along to assess for obstruction

determination of viability

 

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Pathophysiology

Waves of peristalsis and fluid leakage following inflammation can cause diarrhea early on.

Aerophagia can cause air bubbles

Bowel wall swelling can cause worsening obstruction

Further obstruction can compromise intestinal blood flow, leading to ischemia. This causes pain to be constant

Bowel necrosis can be followed by perforation, peritonitis, and sepsis

Fluid and electrolyte shifts

 

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The Case of...

 

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Additional Resources

 

 

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Topic Development

created: DLP, Aug 09

authors: DLP, Aug 09

editors:

reviewers:

 

 

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