Small Intestine, Obstruction

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

Epidemiology

• • 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

    -Hematoma

    -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 ...