PAEA Surgery End Of Rotation (EOR) Practice Exam

What does an abdominal film or barium enema reveal in a patient with toxic megacolon?

1. Air-filled bowel loops

2. Thickened bowel wall and dilated lumen

3. Normal bowel appearance

4. Fluid levels in the abdomen

The correct answer is: Thickened bowel wall and dilated lumen

In patients with toxic megacolon, imaging studies such as abdominal films or barium enemas typically reveal a thickened bowel wall and a dilated lumen. This radiological finding is a direct result of the underlying pathophysiological processes associated with toxic megacolon, which involves excessive dilation of the colon due to inflammatory conditions, such as ulcerative colitis or Crohn's disease. The thickening of the bowel wall occurs due to inflammation and edema, and the dilation of the lumen is evident as the colon becomes unable to effectively propel contents due to loss of motility. This can lead to significant distension, sometimes causing the colon to reach dangerously large diameters, which heightens the risk for perforation. Normal bowel appearance is not consistent with toxic megacolon, as the condition specifically produces notable aberrations in the structure and size of the colon. Similarly, air-filled bowel loops may be observed in various other gastrointestinal conditions, but they do not capture the characteristic findings of toxic megacolon. Fluid levels in the abdomen may be present but are not definitive indicators of toxic megacolon itself. Instead, a clear indication of bowel wall thickening and dilation is a hallmark feature that confirms the diagnosis and severity of toxic megacol