Introduction

Primary blast injury affecting the GI tract is rare and usually accompanies primary blast injury to other organs.

• Shock waves cause compression then rapid re-expansion of the gas-filled gut, putting the gut wall under tension and causing acute, often multifocal perforation and mural haemorrhage (Fig 1)
• Mesenteries are threatened by shear waves
• The colon, containing more gas than the small bowel, is at the greatest risk, particularly at the ileocaecal junction (Fig 2)
• Solid organs vibrate as entire entities on exposure to blast forces and are more likely to be affected by secondary or tertiary blast injury (Fig 3)
• A negative FAST examination in stable patients with increased pain or vomiting, should be followed up with CT examination of the abdomen and pelvis.

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