What is the appropriate next step if the ultrasound shows a "target sign" indicative of intussusception?

The presence of a "target sign" on ultrasound is indicative of intussusception, a condition where a part of the intestine telescopes into an adjacent segment, leading to obstruction. The appropriate next step upon confirming intussusception via ultrasound is to perform an air or water-soluble contrast enema.

This procedure serves a dual purpose: it can both diagnose and potentially treat intussusception. The introduction of contrast material into the intestines can help to reduce the intussusception by creating pressure that can unfold the telescoped segment. This non-surgical approach is preferred initially, as it is less invasive and can avoid the risks associated with surgery, especially in cases where the condition may be resolved without it.

Using intravenous fluids alone would not address the immediate issue of the obstruction caused by the intussusception, and observation may lead to complications if the intussusception does not resolve on its own. Depending on the clinical scenario and the patient's condition, if the enema reduction is unsuccessful or if there are signs of complications, surgical intervention may then be considered.