A one-week-old 25-week EGA infant on breast milk feeds develops abdominal distention and hypotension. Abdominal plain films reveal distended bowel loops, but no pneumoperitoneum, pneumatosis intestinalis or portal venous gas. The NICU team is interested in decreasing radiation exposure and would like to utilize bowel ultrasound for serial examinations. What findings on ultrasound[size=20px] have been associated with the need for surgery?

 

A Absent peristalsis

 

B Increased bowel wall perfusion

 

C Pneumatosis intestinalis

 

D Portal venous gas

 

E Simple ascites​[/size]

D

A

A

A

A

D

A

D

D

E

A

A

Correct answer

A Absent peristalsis

 

Necrotizing enterocolitis (NEC) is a devastating inflammatory gastrointestinal disease that is a significant source of morbidity and mortality in preterm infants. Early diagnosis and treatment decisions often rely upon abdominal imaging. Recently, there have been numerous studies investigating the use of bowel ultrasound (BU) for imaging and evaluating infants with suspected NEC. There are US findings with high specificity for NEC, including:

• focal fluid collections
  
• complex fluid collections
  
• pneumoperitoneum
  
• thinning of bowel wall
  
• absent peristalsis
  
• absent perfusion of bowel wall
  
• increased echogenicity of bowel wall
  
• pneumatosis intestinalis
  
• portal venous gas
  

The issues surrounding these findings rest with determining their predictive value in determining which infants may benefit from more aggressive interventions such as surgery. A 2018 meta-analysis by Cuna et al. showed that BUS findings of complex ascites, absent peristalsis, pneumoperitoneum, bowel wall echogenicity, bowel wall thinning/thickening, absent perfusion, or dilated bowel were associated with surgery or death. However, portal venous gas, increased bowel perfusion and simple ascites were not associated with surgery or death. Other researchers have suggested that BUS might be used as an adjunct to abdominal x-rays because they found that the overall sensitivity and negative predictive value of BUS was very low. Alexander and colleagues found there may be as many as 25-40% false negatives, resulting in the potential to miss NEC if relying upon BUS alone.