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Proximal Obstruction

  • • Vomiting

    • Abdominal discomfort

    • Abnormal PO contrast x-rays

Mid or Distal Obstruction

  • • Colicky abdominal pain

    • Vomiting

    • Abdominal distention

    • Constipation-obstipation

    • Peristaltic rushes

    • Dilated small bowel on x-ray


  • • The most common surgical disorder of the small intestine

    • Common causes of obstruction:

    • -Adhesions: The most common cause of mechanical small bowel obstruction

      -Neoplasms: Intrinsic or extrinsic

      -Hernia: Due to incarceration of bowel

      -Intussusception: Common in children

      -Volvulus: Often results from congenital anomalies or acquired adhesions

      -Foreign bodies: Luminal blockage

      -Gallstone ileus: Passage of a large gallstone through a cholecystenteric fistula

      -Inflammatory bowel disease: Lumen is

      narrowed by inflammation or fibrosis

      -Stricture-luminal narrowing

      -Cystic fibrosis: Partial obstruction of the distal ileum and right colon


      -Paralytic ileus: Neurogenic

Symptoms and Signs

  • • Vomiting

    • Cramping abdominal pain

    • Obstipation

    • Distention

    • -Minimal in proximal obstruction

      -Pronounced in distal obstruction

    • Mild abdominal tenderness

    • Audible rushes and high-pitched tinkles

Strangulation Obstruction

  • • Shock

    • High fever

    • Abdominal pain: Severe and continuous

    • Vomitus may contain blood

    • Abdominal tenderness and rigidity

Laboratory Findings

  • • Hemoconcentration

    • Leukocytosis

    • Electrolyte abnormalities that depend on the level of obstruction and the severity of dehydration

    • Serum amylase is often elevated

Strangulation Obstruction

  • • Marked leukocytosis not accounted for by hemoconcentration

    • Metabolic acidosis

Imaging Findings

  • Abdominal x-ray

    • -Dilated bowel

      -Air-fluid levels (minimal in early, proximal, or closed loop obstruction)

    • The colon is often devoid of gas

    • Intraperitoneal air indicates perforation

    Contrast upper GI series: Assesses completeness of obstruction

    CT scan

    • -Intraperitoneal free fluid

      -Dilated bowel proximal and decompressed distal to the obstruction

      -Point of obstruction may be visualized

    • Gas within the bowel wall or portal vein may be seen in strangulation

    • Intraperitoneal free air or air-fluid levels indicate perforation

  • • Classification of small bowel obstruction

    • Functional (failure of peristalsis to propel intestinal contents) or mechanical (a physical barrier impedes aboral progress of intestinal contents)

    • Complete or partial

    • Simple (occludes the lumen only) or strangulated (impaired the blood supply leading to necrosis of the intestine)

    • Open loop (the lumen is occluded in 1 place) or closed loop (the lumen is occluded in at least 2 places)

    • 33% of strangulation obstructions are unsuspected before operation

Rule Out

  • • Acute appendicitis

    • Obstruction of the large intestine

    • Acute gastroenteritis

    • Acute pancreatitis

    • Mesenteric vascular occlusion

    • Pseudo-obstruction associated with scleroderma, systemic lupus erythematosus, amyloidosis, drug abuse, or radiation

    • Intrinsic dysmotility

  • • Abdominal x-ray

    • CBC

    • Serum electrolytes

    • ABG measurements (if ...

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