In what percentage of chronic diarrhea cases is ultrasound non-diagnostic?

In what percentage of chronic diarrhea cases is ultrasound non-diagnostic?

• A. ~20%
• B. ~40%
• C. ~60%
• D. ~80%

Answer: (C)

Ultrasound has limited diagnostic yield in chronic diarrhea because many causes are mucosal or functional and don’t create visible structural changes. It’s good at catching obvious issues like masses, obstruction, or significant wall thickening, but it often misses subtle inflammatory or microscopic conditions such as microscopic colitis or early small-bowel disease. Gas, body habitus, and operator dependence further reduce its sensitivity. For these reasons, about six in ten chronic diarrhea cases yield a non-diagnostic ultrasound. When ultrasound doesn’t provide answers, follow-up with colonoscopy with biopsies and targeted small-bowel imaging (like CT or MR enterography) to pursue mucosal or subtle inflammatory etiologies.

Ultrasound has limited diagnostic yield in chronic diarrhea because many causes are mucosal or functional and don’t create visible structural changes. It’s good at catching obvious issues like masses, obstruction, or significant wall thickening, but it often misses subtle inflammatory or microscopic conditions such as microscopic colitis or early small-bowel disease. Gas, body habitus, and operator dependence further reduce its sensitivity. For these reasons, about six in ten chronic diarrhea cases yield a non-diagnostic ultrasound. When ultrasound doesn’t provide answers, follow-up with colonoscopy with biopsies and targeted small-bowel imaging (like CT or MR enterography) to pursue mucosal or subtle inflammatory etiologies.