Wednesday, 20 May 2009

Abdominal X-ray

Abdomnal x-ray (AXR)

AXR should be taken if after examination the following conditions are suspected:
  • Bowel obstruction - in order to confirm this diagnosis and locate the site of the blockage
  • Perforation of hollow viscous - although a vertical chest x-ray would be more senstitive
  • Complications of Crohn's disease or ulcerative colitis - obstruction, mucosal thickening, toxic megacolon and perforation
  • Pancreatitis - exclude peptic ulcer, look for appearance of a "sentinel loop" which is a dilated segment of the small bowel seen in the upper abdomen

Sentinel Loop is indicated below:

AXR should not be taken if the following conditions are suspected:

  • Acute gastrointestinal bleed - an AXR cannot reveal its location
  • Palpable mass - CT scan would be preferential as accurating sizing and organ of origin can be confirmed
  • Constipation - history and examination more sensitive to quantify extent of condition
  • Cholecystitis - ultrasound more sensitive, only 10% gallstones seen on AXR
  • Appendicitis - requires a clinical diagnosis; if uncertain, ultrasound more sensitive

An example of a normal AXR is below:

There are a number of questions that are important to ask yourself when looking at an AXR:
  • Bowel gas pattern - normal, too little, too much - which parts affected? which parts normal?
  • Is there free gas? - evidence of perforation
  • Bowel wall thickening? - which part is affected? colon most common site
  • Abnormal opacities? - usually due to calculi

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